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kc3-lang/angle/src/libANGLE/Context.cpp

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  • Author : Jiajia Qin
    Date : 2016-11-29 16:30:31
    Hash : 9d7d0b14
    Message : Add support for GL_DRAW_INDIRECT_BUFFER_BINDING binding point BUG=angleproject:1595 TEST=dEQP-GLES31.functional.state_query.integer.draw_indirect_buffer_binding* Change-Id: Ib8f712fdf10411ef0b7b63742d17c3caca99137b Reviewed-on: https://chromium-review.googlesource.com/416193 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>

  • src/libANGLE/Context.cpp
  • //
    // Copyright (c) 2002-2014 The ANGLE Project Authors. All rights reserved.
    // Use of this source code is governed by a BSD-style license that can be
    // found in the LICENSE file.
    //
    
    // Context.cpp: Implements the gl::Context class, managing all GL state and performing
    // rendering operations. It is the GLES2 specific implementation of EGLContext.
    
    #include "libANGLE/Context.h"
    
    #include <iterator>
    #include <sstream>
    #include <string.h>
    #include <vector>
    
    #include "common/matrix_utils.h"
    #include "common/platform.h"
    #include "common/utilities.h"
    #include "common/version.h"
    #include "libANGLE/Buffer.h"
    #include "libANGLE/Compiler.h"
    #include "libANGLE/Display.h"
    #include "libANGLE/Fence.h"
    #include "libANGLE/Framebuffer.h"
    #include "libANGLE/FramebufferAttachment.h"
    #include "libANGLE/Path.h"
    #include "libANGLE/Program.h"
    #include "libANGLE/Query.h"
    #include "libANGLE/Renderbuffer.h"
    #include "libANGLE/ResourceManager.h"
    #include "libANGLE/Sampler.h"
    #include "libANGLE/Surface.h"
    #include "libANGLE/Texture.h"
    #include "libANGLE/TransformFeedback.h"
    #include "libANGLE/VertexArray.h"
    #include "libANGLE/formatutils.h"
    #include "libANGLE/validationES.h"
    #include "libANGLE/Workarounds.h"
    #include "libANGLE/renderer/ContextImpl.h"
    #include "libANGLE/renderer/EGLImplFactory.h"
    #include "libANGLE/queryconversions.h"
    #include "libANGLE/queryutils.h"
    
    namespace
    {
    
    template <typename T>
    std::vector<gl::Path *> GatherPaths(gl::ResourceManager &resourceManager,
                                        GLsizei numPaths,
                                        const void *paths,
                                        GLuint pathBase)
    {
        std::vector<gl::Path *> ret;
        ret.reserve(numPaths);
    
        const auto *nameArray = static_cast<const T *>(paths);
    
        for (GLsizei i = 0; i < numPaths; ++i)
        {
            const GLuint pathName = nameArray[i] + pathBase;
    
            ret.push_back(resourceManager.getPath(pathName));
        }
    
        return ret;
    }
    
    std::vector<gl::Path *> GatherPaths(gl::ResourceManager &resourceManager,
                                        GLsizei numPaths,
                                        GLenum pathNameType,
                                        const void *paths,
                                        GLuint pathBase)
    {
        switch (pathNameType)
        {
            case GL_UNSIGNED_BYTE:
                return GatherPaths<GLubyte>(resourceManager, numPaths, paths, pathBase);
    
            case GL_BYTE:
                return GatherPaths<GLbyte>(resourceManager, numPaths, paths, pathBase);
    
            case GL_UNSIGNED_SHORT:
                return GatherPaths<GLushort>(resourceManager, numPaths, paths, pathBase);
    
            case GL_SHORT:
                return GatherPaths<GLshort>(resourceManager, numPaths, paths, pathBase);
    
            case GL_UNSIGNED_INT:
                return GatherPaths<GLuint>(resourceManager, numPaths, paths, pathBase);
    
            case GL_INT:
                return GatherPaths<GLint>(resourceManager, numPaths, paths, pathBase);
        }
    
        UNREACHABLE();
        return std::vector<gl::Path *>();
    }
    
    template <typename T>
    gl::Error GetQueryObjectParameter(gl::Query *query, GLenum pname, T *params)
    {
        ASSERT(query != nullptr);
    
        switch (pname)
        {
            case GL_QUERY_RESULT_EXT:
                return query->getResult(params);
            case GL_QUERY_RESULT_AVAILABLE_EXT:
            {
                bool available;
                gl::Error error = query->isResultAvailable(&available);
                if (!error.isError())
                {
                    *params = gl::ConvertFromGLboolean<T>(available);
                }
                return error;
            }
            default:
                UNREACHABLE();
                return gl::Error(GL_INVALID_OPERATION, "Unreachable Error");
        }
    }
    
    void MarkTransformFeedbackBufferUsage(gl::TransformFeedback *transformFeedback)
    {
        if (transformFeedback && transformFeedback->isActive() && !transformFeedback->isPaused())
        {
            for (size_t tfBufferIndex = 0; tfBufferIndex < transformFeedback->getIndexedBufferCount();
                 tfBufferIndex++)
            {
                const OffsetBindingPointer<gl::Buffer> &buffer =
                    transformFeedback->getIndexedBuffer(tfBufferIndex);
                if (buffer.get() != nullptr)
                {
                    buffer->onTransformFeedback();
                }
            }
        }
    }
    
    // Attribute map queries.
    EGLint GetClientMajorVersion(const egl::AttributeMap &attribs)
    {
        return static_cast<EGLint>(attribs.get(EGL_CONTEXT_CLIENT_VERSION, 1));
    }
    
    EGLint GetClientMinorVersion(const egl::AttributeMap &attribs)
    {
        return static_cast<EGLint>(attribs.get(EGL_CONTEXT_MINOR_VERSION, 0));
    }
    
    gl::Version GetClientVersion(const egl::AttributeMap &attribs)
    {
        return gl::Version(GetClientMajorVersion(attribs), GetClientMinorVersion(attribs));
    }
    
    GLenum GetResetStrategy(const egl::AttributeMap &attribs)
    {
        EGLAttrib attrib = attribs.get(EGL_CONTEXT_OPENGL_RESET_NOTIFICATION_STRATEGY_EXT,
                                       EGL_NO_RESET_NOTIFICATION_EXT);
        switch (attrib)
        {
            case EGL_NO_RESET_NOTIFICATION:
                return GL_NO_RESET_NOTIFICATION_EXT;
            case EGL_LOSE_CONTEXT_ON_RESET:
                return GL_LOSE_CONTEXT_ON_RESET_EXT;
            default:
                UNREACHABLE();
                return GL_NONE;
        }
    }
    
    bool GetRobustAccess(const egl::AttributeMap &attribs)
    {
        return (attribs.get(EGL_CONTEXT_OPENGL_ROBUST_ACCESS_EXT, EGL_FALSE) == EGL_TRUE) ||
               ((attribs.get(EGL_CONTEXT_FLAGS_KHR, 0) & EGL_CONTEXT_OPENGL_ROBUST_ACCESS_BIT_KHR) !=
                0);
    }
    
    bool GetDebug(const egl::AttributeMap &attribs)
    {
        return (attribs.get(EGL_CONTEXT_OPENGL_DEBUG, EGL_FALSE) == EGL_TRUE) ||
               ((attribs.get(EGL_CONTEXT_FLAGS_KHR, 0) & EGL_CONTEXT_OPENGL_DEBUG_BIT_KHR) != 0);
    }
    
    bool GetNoError(const egl::AttributeMap &attribs)
    {
        return (attribs.get(EGL_CONTEXT_OPENGL_NO_ERROR_KHR, EGL_FALSE) == EGL_TRUE);
    }
    
    bool GetWebGLContext(const egl::AttributeMap &attribs)
    {
        return (attribs.get(EGL_CONTEXT_WEBGL_COMPATIBILITY_ANGLE, EGL_FALSE) == EGL_TRUE);
    }
    
    bool GetBindGeneratesResource(const egl::AttributeMap &attribs)
    {
        return (attribs.get(EGL_CONTEXT_BIND_GENERATES_RESOURCE_CHROMIUM, EGL_TRUE) == EGL_TRUE);
    }
    
    std::string GetObjectLabelFromPointer(GLsizei length, const GLchar *label)
    {
        std::string labelName;
        if (label != nullptr)
        {
            size_t labelLength = length < 0 ? strlen(label) : length;
            labelName          = std::string(label, labelLength);
        }
        return labelName;
    }
    
    void GetObjectLabelBase(const std::string &objectLabel,
                            GLsizei bufSize,
                            GLsizei *length,
                            GLchar *label)
    {
        size_t writeLength = objectLabel.length();
        if (label != nullptr && bufSize > 0)
        {
            writeLength = std::min(static_cast<size_t>(bufSize) - 1, objectLabel.length());
            std::copy(objectLabel.begin(), objectLabel.begin() + writeLength, label);
            label[writeLength] = '\0';
        }
    
        if (length != nullptr)
        {
            *length = static_cast<GLsizei>(writeLength);
        }
    }
    
    }  // anonymous namespace
    
    namespace gl
    {
    
    Context::Context(rx::EGLImplFactory *implFactory,
                     const egl::Config *config,
                     const Context *shareContext,
                     const egl::AttributeMap &attribs)
    
        : ValidationContext(GetClientVersion(attribs),
                            &mGLState,
                            mCaps,
                            mTextureCaps,
                            mExtensions,
                            nullptr,
                            mLimitations,
                            mFramebufferMap,
                            GetNoError(attribs)),
          mImplementation(implFactory->createContext(mState)),
          mCompiler(nullptr),
          mConfig(config),
          mClientType(EGL_OPENGL_ES_API),
          mHasBeenCurrent(false),
          mContextLost(false),
          mResetStatus(GL_NO_ERROR),
          mContextLostForced(false),
          mResetStrategy(GetResetStrategy(attribs)),
          mRobustAccess(GetRobustAccess(attribs)),
          mCurrentSurface(nullptr),
          mResourceManager(nullptr)
    {
        if (mRobustAccess)
        {
            UNIMPLEMENTED();
        }
    
        initCaps(GetWebGLContext(attribs));
        initWorkarounds();
    
        mGLState.initialize(mCaps, mExtensions, getClientVersion(), GetDebug(attribs),
                            GetBindGeneratesResource(attribs));
    
        mFenceNVHandleAllocator.setBaseHandle(0);
    
        if (shareContext != nullptr)
        {
            mResourceManager = shareContext->mResourceManager;
            mResourceManager->addRef();
        }
        else
        {
            mResourceManager = new ResourceManager();
        }
    
        mState.mResourceManager = mResourceManager;
    
        // [OpenGL ES 2.0.24] section 3.7 page 83:
        // In the initial state, TEXTURE_2D and TEXTURE_CUBE_MAP have twodimensional
        // and cube map texture state vectors respectively associated with them.
        // In order that access to these initial textures not be lost, they are treated as texture
        // objects all of whose names are 0.
    
        Texture *zeroTexture2D = new Texture(mImplementation.get(), 0, GL_TEXTURE_2D);
        mZeroTextures[GL_TEXTURE_2D].set(zeroTexture2D);
    
        Texture *zeroTextureCube = new Texture(mImplementation.get(), 0, GL_TEXTURE_CUBE_MAP);
        mZeroTextures[GL_TEXTURE_CUBE_MAP].set(zeroTextureCube);
    
        if (getClientVersion() >= Version(3, 0))
        {
            // TODO: These could also be enabled via extension
            Texture *zeroTexture3D = new Texture(mImplementation.get(), 0, GL_TEXTURE_3D);
            mZeroTextures[GL_TEXTURE_3D].set(zeroTexture3D);
    
            Texture *zeroTexture2DArray = new Texture(mImplementation.get(), 0, GL_TEXTURE_2D_ARRAY);
            mZeroTextures[GL_TEXTURE_2D_ARRAY].set(zeroTexture2DArray);
        }
        if (getClientVersion() >= Version(3, 1))
        {
            Texture *zeroTexture2DMultisample =
                new Texture(mImplementation.get(), 0, GL_TEXTURE_2D_MULTISAMPLE);
            mZeroTextures[GL_TEXTURE_2D_MULTISAMPLE].set(zeroTexture2DMultisample);
        }
    
        if (mExtensions.eglImageExternal || mExtensions.eglStreamConsumerExternal)
        {
            Texture *zeroTextureExternal =
                new Texture(mImplementation.get(), 0, GL_TEXTURE_EXTERNAL_OES);
            mZeroTextures[GL_TEXTURE_EXTERNAL_OES].set(zeroTextureExternal);
        }
    
        mGLState.initializeZeroTextures(mZeroTextures);
    
        bindVertexArray(0);
        bindArrayBuffer(0);
        bindDrawIndirectBuffer(0);
        bindElementArrayBuffer(0);
    
        bindRenderbuffer(GL_RENDERBUFFER, 0);
    
        bindGenericUniformBuffer(0);
        for (unsigned int i = 0; i < mCaps.maxUniformBufferBindings; i++)
        {
            bindIndexedUniformBuffer(0, i, 0, -1);
        }
    
        bindCopyReadBuffer(0);
        bindCopyWriteBuffer(0);
        bindPixelPackBuffer(0);
        bindPixelUnpackBuffer(0);
    
        if (getClientVersion() >= Version(3, 0))
        {
            // [OpenGL ES 3.0.2] section 2.14.1 pg 85:
            // In the initial state, a default transform feedback object is bound and treated as
            // a transform feedback object with a name of zero. That object is bound any time
            // BindTransformFeedback is called with id of zero
            bindTransformFeedback(0);
        }
    
        mCompiler = new Compiler(mImplementation.get(), mState);
    
        // Initialize dirty bit masks
        // TODO(jmadill): additional ES3 state
        mTexImageDirtyBits.set(State::DIRTY_BIT_UNPACK_ALIGNMENT);
        mTexImageDirtyBits.set(State::DIRTY_BIT_UNPACK_ROW_LENGTH);
        mTexImageDirtyBits.set(State::DIRTY_BIT_UNPACK_IMAGE_HEIGHT);
        mTexImageDirtyBits.set(State::DIRTY_BIT_UNPACK_SKIP_IMAGES);
        mTexImageDirtyBits.set(State::DIRTY_BIT_UNPACK_SKIP_ROWS);
        mTexImageDirtyBits.set(State::DIRTY_BIT_UNPACK_SKIP_PIXELS);
        mTexImageDirtyBits.set(State::DIRTY_BIT_UNPACK_BUFFER_BINDING);
        // No dirty objects.
    
        // Readpixels uses the pack state and read FBO
        mReadPixelsDirtyBits.set(State::DIRTY_BIT_PACK_ALIGNMENT);
        mReadPixelsDirtyBits.set(State::DIRTY_BIT_PACK_REVERSE_ROW_ORDER);
        mReadPixelsDirtyBits.set(State::DIRTY_BIT_PACK_ROW_LENGTH);
        mReadPixelsDirtyBits.set(State::DIRTY_BIT_PACK_SKIP_ROWS);
        mReadPixelsDirtyBits.set(State::DIRTY_BIT_PACK_SKIP_PIXELS);
        mReadPixelsDirtyBits.set(State::DIRTY_BIT_PACK_BUFFER_BINDING);
        mReadPixelsDirtyObjects.set(State::DIRTY_OBJECT_READ_FRAMEBUFFER);
    
        mClearDirtyBits.set(State::DIRTY_BIT_RASTERIZER_DISCARD_ENABLED);
        mClearDirtyBits.set(State::DIRTY_BIT_SCISSOR_TEST_ENABLED);
        mClearDirtyBits.set(State::DIRTY_BIT_SCISSOR);
        mClearDirtyBits.set(State::DIRTY_BIT_VIEWPORT);
        mClearDirtyBits.set(State::DIRTY_BIT_CLEAR_COLOR);
        mClearDirtyBits.set(State::DIRTY_BIT_CLEAR_DEPTH);
        mClearDirtyBits.set(State::DIRTY_BIT_CLEAR_STENCIL);
        mClearDirtyBits.set(State::DIRTY_BIT_COLOR_MASK);
        mClearDirtyBits.set(State::DIRTY_BIT_DEPTH_MASK);
        mClearDirtyBits.set(State::DIRTY_BIT_STENCIL_WRITEMASK_FRONT);
        mClearDirtyBits.set(State::DIRTY_BIT_STENCIL_WRITEMASK_BACK);
        mClearDirtyObjects.set(State::DIRTY_OBJECT_DRAW_FRAMEBUFFER);
    
        mBlitDirtyBits.set(State::DIRTY_BIT_SCISSOR_TEST_ENABLED);
        mBlitDirtyBits.set(State::DIRTY_BIT_SCISSOR);
        mBlitDirtyBits.set(State::DIRTY_BIT_FRAMEBUFFER_SRGB);
        mBlitDirtyObjects.set(State::DIRTY_OBJECT_READ_FRAMEBUFFER);
        mBlitDirtyObjects.set(State::DIRTY_OBJECT_DRAW_FRAMEBUFFER);
    
        handleError(mImplementation->initialize());
    }
    
    Context::~Context()
    {
        mGLState.reset();
    
        for (auto framebuffer : mFramebufferMap)
        {
            // Default framebuffer are owned by their respective Surface
            if (framebuffer.second != nullptr && framebuffer.second->id() != 0)
            {
                SafeDelete(framebuffer.second);
            }
        }
    
        for (auto fence : mFenceNVMap)
        {
            SafeDelete(fence.second);
        }
    
        for (auto query : mQueryMap)
        {
            if (query.second != nullptr)
            {
                query.second->release();
            }
        }
    
        for (auto vertexArray : mVertexArrayMap)
        {
            SafeDelete(vertexArray.second);
        }
    
        for (auto transformFeedback : mTransformFeedbackMap)
        {
            if (transformFeedback.second != nullptr)
            {
                transformFeedback.second->release();
            }
        }
    
        for (auto &zeroTexture : mZeroTextures)
        {
            zeroTexture.second.set(NULL);
        }
        mZeroTextures.clear();
    
        if (mCurrentSurface != nullptr)
        {
            releaseSurface();
        }
    
        if (mResourceManager)
        {
            mResourceManager->release();
        }
    
        SafeDelete(mCompiler);
    }
    
    void Context::makeCurrent(egl::Surface *surface)
    {
        ASSERT(surface != nullptr);
    
        if (!mHasBeenCurrent)
        {
            initRendererString();
            initVersionStrings();
            initExtensionStrings();
    
            mGLState.setViewportParams(0, 0, surface->getWidth(), surface->getHeight());
            mGLState.setScissorParams(0, 0, surface->getWidth(), surface->getHeight());
    
            mHasBeenCurrent = true;
        }
    
        // TODO(jmadill): Rework this when we support ContextImpl
        mGLState.setAllDirtyBits();
    
        if (mCurrentSurface)
        {
            releaseSurface();
        }
        surface->setIsCurrent(true);
        mCurrentSurface = surface;
    
        // Update default framebuffer, the binding of the previous default
        // framebuffer (or lack of) will have a nullptr.
        {
            Framebuffer *newDefault = surface->getDefaultFramebuffer();
            if (mGLState.getReadFramebuffer() == nullptr)
            {
                mGLState.setReadFramebufferBinding(newDefault);
            }
            if (mGLState.getDrawFramebuffer() == nullptr)
            {
                mGLState.setDrawFramebufferBinding(newDefault);
            }
            mFramebufferMap[0] = newDefault;
        }
    
        // Notify the renderer of a context switch
        mImplementation->onMakeCurrent(mState);
    }
    
    void Context::releaseSurface()
    {
        ASSERT(mCurrentSurface != nullptr);
    
        // Remove the default framebuffer
        {
            Framebuffer *currentDefault = mCurrentSurface->getDefaultFramebuffer();
            if (mGLState.getReadFramebuffer() == currentDefault)
            {
                mGLState.setReadFramebufferBinding(nullptr);
            }
            if (mGLState.getDrawFramebuffer() == currentDefault)
            {
                mGLState.setDrawFramebufferBinding(nullptr);
            }
            mFramebufferMap.erase(0);
        }
    
        mCurrentSurface->setIsCurrent(false);
        mCurrentSurface = nullptr;
    }
    
    GLuint Context::createBuffer()
    {
        return mResourceManager->createBuffer();
    }
    
    GLuint Context::createProgram()
    {
        return mResourceManager->createProgram(mImplementation.get());
    }
    
    GLuint Context::createShader(GLenum type)
    {
        return mResourceManager->createShader(mImplementation.get(),
                                              mImplementation->getNativeLimitations(), type);
    }
    
    GLuint Context::createTexture()
    {
        return mResourceManager->createTexture();
    }
    
    GLuint Context::createRenderbuffer()
    {
        return mResourceManager->createRenderbuffer();
    }
    
    GLsync Context::createFenceSync()
    {
        GLuint handle = mResourceManager->createFenceSync(mImplementation.get());
    
        return reinterpret_cast<GLsync>(static_cast<uintptr_t>(handle));
    }
    
    GLuint Context::createPaths(GLsizei range)
    {
        auto resultOrError = mResourceManager->createPaths(mImplementation.get(), range);
        if (resultOrError.isError())
        {
            handleError(resultOrError.getError());
            return 0;
        }
        return resultOrError.getResult();
    }
    
    GLuint Context::createVertexArray()
    {
        GLuint vertexArray           = mVertexArrayHandleAllocator.allocate();
        mVertexArrayMap[vertexArray] = nullptr;
        return vertexArray;
    }
    
    GLuint Context::createSampler()
    {
        return mResourceManager->createSampler();
    }
    
    GLuint Context::createTransformFeedback()
    {
        GLuint transformFeedback                 = mTransformFeedbackAllocator.allocate();
        mTransformFeedbackMap[transformFeedback] = nullptr;
        return transformFeedback;
    }
    
    // Returns an unused framebuffer name
    GLuint Context::createFramebuffer()
    {
        GLuint handle = mFramebufferHandleAllocator.allocate();
    
        mFramebufferMap[handle] = NULL;
    
        return handle;
    }
    
    GLuint Context::createFenceNV()
    {
        GLuint handle = mFenceNVHandleAllocator.allocate();
    
        mFenceNVMap[handle] = new FenceNV(mImplementation->createFenceNV());
    
        return handle;
    }
    
    // Returns an unused query name
    GLuint Context::createQuery()
    {
        GLuint handle = mQueryHandleAllocator.allocate();
    
        mQueryMap[handle] = NULL;
    
        return handle;
    }
    
    void Context::deleteBuffer(GLuint buffer)
    {
        if (mResourceManager->getBuffer(buffer))
        {
            detachBuffer(buffer);
        }
    
        mResourceManager->deleteBuffer(buffer);
    }
    
    void Context::deleteShader(GLuint shader)
    {
        mResourceManager->deleteShader(shader);
    }
    
    void Context::deleteProgram(GLuint program)
    {
        mResourceManager->deleteProgram(program);
    }
    
    void Context::deleteTexture(GLuint texture)
    {
        if (mResourceManager->getTexture(texture))
        {
            detachTexture(texture);
        }
    
        mResourceManager->deleteTexture(texture);
    }
    
    void Context::deleteRenderbuffer(GLuint renderbuffer)
    {
        if (mResourceManager->getRenderbuffer(renderbuffer))
        {
            detachRenderbuffer(renderbuffer);
        }
    
        mResourceManager->deleteRenderbuffer(renderbuffer);
    }
    
    void Context::deleteFenceSync(GLsync fenceSync)
    {
        // The spec specifies the underlying Fence object is not deleted until all current
        // wait commands finish. However, since the name becomes invalid, we cannot query the fence,
        // and since our API is currently designed for being called from a single thread, we can delete
        // the fence immediately.
        mResourceManager->deleteFenceSync(static_cast<GLuint>(reinterpret_cast<uintptr_t>(fenceSync)));
    }
    
    void Context::deletePaths(GLuint first, GLsizei range)
    {
        mResourceManager->deletePaths(first, range);
    }
    
    bool Context::hasPathData(GLuint path) const
    {
        const auto *pathObj = mResourceManager->getPath(path);
        if (pathObj == nullptr)
            return false;
    
        return pathObj->hasPathData();
    }
    
    bool Context::hasPath(GLuint path) const
    {
        return mResourceManager->hasPath(path);
    }
    
    void Context::setPathCommands(GLuint path,
                                  GLsizei numCommands,
                                  const GLubyte *commands,
                                  GLsizei numCoords,
                                  GLenum coordType,
                                  const void *coords)
    {
        auto *pathObject = mResourceManager->getPath(path);
    
        handleError(pathObject->setCommands(numCommands, commands, numCoords, coordType, coords));
    }
    
    void Context::setPathParameterf(GLuint path, GLenum pname, GLfloat value)
    {
        auto *pathObj = mResourceManager->getPath(path);
    
        switch (pname)
        {
            case GL_PATH_STROKE_WIDTH_CHROMIUM:
                pathObj->setStrokeWidth(value);
                break;
            case GL_PATH_END_CAPS_CHROMIUM:
                pathObj->setEndCaps(static_cast<GLenum>(value));
                break;
            case GL_PATH_JOIN_STYLE_CHROMIUM:
                pathObj->setJoinStyle(static_cast<GLenum>(value));
                break;
            case GL_PATH_MITER_LIMIT_CHROMIUM:
                pathObj->setMiterLimit(value);
                break;
            case GL_PATH_STROKE_BOUND_CHROMIUM:
                pathObj->setStrokeBound(value);
                break;
            default:
                UNREACHABLE();
                break;
        }
    }
    
    void Context::getPathParameterfv(GLuint path, GLenum pname, GLfloat *value) const
    {
        const auto *pathObj = mResourceManager->getPath(path);
    
        switch (pname)
        {
            case GL_PATH_STROKE_WIDTH_CHROMIUM:
                *value = pathObj->getStrokeWidth();
                break;
            case GL_PATH_END_CAPS_CHROMIUM:
                *value = static_cast<GLfloat>(pathObj->getEndCaps());
                break;
            case GL_PATH_JOIN_STYLE_CHROMIUM:
                *value = static_cast<GLfloat>(pathObj->getJoinStyle());
                break;
            case GL_PATH_MITER_LIMIT_CHROMIUM:
                *value = pathObj->getMiterLimit();
                break;
            case GL_PATH_STROKE_BOUND_CHROMIUM:
                *value = pathObj->getStrokeBound();
                break;
            default:
                UNREACHABLE();
                break;
        }
    }
    
    void Context::setPathStencilFunc(GLenum func, GLint ref, GLuint mask)
    {
        mGLState.setPathStencilFunc(func, ref, mask);
    }
    
    void Context::deleteVertexArray(GLuint vertexArray)
    {
        auto iter = mVertexArrayMap.find(vertexArray);
        if (iter != mVertexArrayMap.end())
        {
            VertexArray *vertexArrayObject = iter->second;
            if (vertexArrayObject != nullptr)
            {
                detachVertexArray(vertexArray);
                delete vertexArrayObject;
            }
    
            mVertexArrayMap.erase(iter);
            mVertexArrayHandleAllocator.release(vertexArray);
        }
    }
    
    void Context::deleteSampler(GLuint sampler)
    {
        if (mResourceManager->getSampler(sampler))
        {
            detachSampler(sampler);
        }
    
        mResourceManager->deleteSampler(sampler);
    }
    
    void Context::deleteTransformFeedback(GLuint transformFeedback)
    {
        auto iter = mTransformFeedbackMap.find(transformFeedback);
        if (iter != mTransformFeedbackMap.end())
        {
            TransformFeedback *transformFeedbackObject = iter->second;
            if (transformFeedbackObject != nullptr)
            {
                detachTransformFeedback(transformFeedback);
                transformFeedbackObject->release();
            }
    
            mTransformFeedbackMap.erase(iter);
            mTransformFeedbackAllocator.release(transformFeedback);
        }
    }
    
    void Context::deleteFramebuffer(GLuint framebuffer)
    {
        auto framebufferObject = mFramebufferMap.find(framebuffer);
    
        if (framebufferObject != mFramebufferMap.end())
        {
            detachFramebuffer(framebuffer);
    
            mFramebufferHandleAllocator.release(framebufferObject->first);
            delete framebufferObject->second;
            mFramebufferMap.erase(framebufferObject);
        }
    }
    
    void Context::deleteFenceNV(GLuint fence)
    {
        auto fenceObject = mFenceNVMap.find(fence);
    
        if (fenceObject != mFenceNVMap.end())
        {
            mFenceNVHandleAllocator.release(fenceObject->first);
            delete fenceObject->second;
            mFenceNVMap.erase(fenceObject);
        }
    }
    
    void Context::deleteQuery(GLuint query)
    {
        auto queryObject = mQueryMap.find(query);
        if (queryObject != mQueryMap.end())
        {
            mQueryHandleAllocator.release(queryObject->first);
            if (queryObject->second)
            {
                queryObject->second->release();
            }
            mQueryMap.erase(queryObject);
        }
    }
    
    Buffer *Context::getBuffer(GLuint handle) const
    {
        return mResourceManager->getBuffer(handle);
    }
    
    Texture *Context::getTexture(GLuint handle) const
    {
        return mResourceManager->getTexture(handle);
    }
    
    Renderbuffer *Context::getRenderbuffer(GLuint handle) const
    {
        return mResourceManager->getRenderbuffer(handle);
    }
    
    FenceSync *Context::getFenceSync(GLsync handle) const
    {
        return mResourceManager->getFenceSync(static_cast<GLuint>(reinterpret_cast<uintptr_t>(handle)));
    }
    
    VertexArray *Context::getVertexArray(GLuint handle) const
    {
        auto vertexArray = mVertexArrayMap.find(handle);
        return (vertexArray != mVertexArrayMap.end()) ? vertexArray->second : nullptr;
    }
    
    Sampler *Context::getSampler(GLuint handle) const
    {
        return mResourceManager->getSampler(handle);
    }
    
    TransformFeedback *Context::getTransformFeedback(GLuint handle) const
    {
        auto iter = mTransformFeedbackMap.find(handle);
        return (iter != mTransformFeedbackMap.end()) ? iter->second : nullptr;
    }
    
    LabeledObject *Context::getLabeledObject(GLenum identifier, GLuint name) const
    {
        switch (identifier)
        {
            case GL_BUFFER:
                return getBuffer(name);
            case GL_SHADER:
                return getShader(name);
            case GL_PROGRAM:
                return getProgram(name);
            case GL_VERTEX_ARRAY:
                return getVertexArray(name);
            case GL_QUERY:
                return getQuery(name);
            case GL_TRANSFORM_FEEDBACK:
                return getTransformFeedback(name);
            case GL_SAMPLER:
                return getSampler(name);
            case GL_TEXTURE:
                return getTexture(name);
            case GL_RENDERBUFFER:
                return getRenderbuffer(name);
            case GL_FRAMEBUFFER:
                return getFramebuffer(name);
            default:
                UNREACHABLE();
                return nullptr;
        }
    }
    
    LabeledObject *Context::getLabeledObjectFromPtr(const void *ptr) const
    {
        return getFenceSync(reinterpret_cast<GLsync>(const_cast<void *>(ptr)));
    }
    
    void Context::objectLabel(GLenum identifier, GLuint name, GLsizei length, const GLchar *label)
    {
        LabeledObject *object = getLabeledObject(identifier, name);
        ASSERT(object != nullptr);
    
        std::string labelName = GetObjectLabelFromPointer(length, label);
        object->setLabel(labelName);
    }
    
    void Context::objectPtrLabel(const void *ptr, GLsizei length, const GLchar *label)
    {
        LabeledObject *object = getLabeledObjectFromPtr(ptr);
        ASSERT(object != nullptr);
    
        std::string labelName = GetObjectLabelFromPointer(length, label);
        object->setLabel(labelName);
    }
    
    void Context::getObjectLabel(GLenum identifier,
                                 GLuint name,
                                 GLsizei bufSize,
                                 GLsizei *length,
                                 GLchar *label) const
    {
        LabeledObject *object = getLabeledObject(identifier, name);
        ASSERT(object != nullptr);
    
        const std::string &objectLabel = object->getLabel();
        GetObjectLabelBase(objectLabel, bufSize, length, label);
    }
    
    void Context::getObjectPtrLabel(const void *ptr,
                                    GLsizei bufSize,
                                    GLsizei *length,
                                    GLchar *label) const
    {
        LabeledObject *object = getLabeledObjectFromPtr(ptr);
        ASSERT(object != nullptr);
    
        const std::string &objectLabel = object->getLabel();
        GetObjectLabelBase(objectLabel, bufSize, length, label);
    }
    
    bool Context::isSampler(GLuint samplerName) const
    {
        return mResourceManager->isSampler(samplerName);
    }
    
    void Context::bindArrayBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(mImplementation.get(), bufferHandle);
        mGLState.setArrayBufferBinding(buffer);
    }
    
    void Context::bindDrawIndirectBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(mImplementation.get(), bufferHandle);
        mGLState.setDrawIndirectBufferBinding(buffer);
    }
    
    void Context::bindElementArrayBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(mImplementation.get(), bufferHandle);
        mGLState.getVertexArray()->setElementArrayBuffer(buffer);
    }
    
    void Context::bindTexture(GLenum target, GLuint handle)
    {
        Texture *texture = nullptr;
    
        if (handle == 0)
        {
            texture = mZeroTextures[target].get();
        }
        else
        {
            texture = mResourceManager->checkTextureAllocation(mImplementation.get(), handle, target);
        }
    
        ASSERT(texture);
        mGLState.setSamplerTexture(target, texture);
    }
    
    void Context::bindReadFramebuffer(GLuint framebufferHandle)
    {
        Framebuffer *framebuffer = checkFramebufferAllocation(framebufferHandle);
        mGLState.setReadFramebufferBinding(framebuffer);
    }
    
    void Context::bindDrawFramebuffer(GLuint framebufferHandle)
    {
        Framebuffer *framebuffer = checkFramebufferAllocation(framebufferHandle);
        mGLState.setDrawFramebufferBinding(framebuffer);
    }
    
    void Context::bindVertexArray(GLuint vertexArrayHandle)
    {
        VertexArray *vertexArray = checkVertexArrayAllocation(vertexArrayHandle);
        mGLState.setVertexArrayBinding(vertexArray);
    }
    
    void Context::bindSampler(GLuint textureUnit, GLuint samplerHandle)
    {
        ASSERT(textureUnit < mCaps.maxCombinedTextureImageUnits);
        Sampler *sampler =
            mResourceManager->checkSamplerAllocation(mImplementation.get(), samplerHandle);
        mGLState.setSamplerBinding(textureUnit, sampler);
    }
    
    void Context::bindGenericUniformBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(mImplementation.get(), bufferHandle);
        mGLState.setGenericUniformBufferBinding(buffer);
    }
    
    void Context::bindIndexedUniformBuffer(GLuint bufferHandle,
                                           GLuint index,
                                           GLintptr offset,
                                           GLsizeiptr size)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(mImplementation.get(), bufferHandle);
        mGLState.setIndexedUniformBufferBinding(index, buffer, offset, size);
    }
    
    void Context::bindGenericTransformFeedbackBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(mImplementation.get(), bufferHandle);
        mGLState.getCurrentTransformFeedback()->bindGenericBuffer(buffer);
    }
    
    void Context::bindIndexedTransformFeedbackBuffer(GLuint bufferHandle,
                                                     GLuint index,
                                                     GLintptr offset,
                                                     GLsizeiptr size)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(mImplementation.get(), bufferHandle);
        mGLState.getCurrentTransformFeedback()->bindIndexedBuffer(index, buffer, offset, size);
    }
    
    void Context::bindCopyReadBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(mImplementation.get(), bufferHandle);
        mGLState.setCopyReadBufferBinding(buffer);
    }
    
    void Context::bindCopyWriteBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(mImplementation.get(), bufferHandle);
        mGLState.setCopyWriteBufferBinding(buffer);
    }
    
    void Context::bindPixelPackBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(mImplementation.get(), bufferHandle);
        mGLState.setPixelPackBufferBinding(buffer);
    }
    
    void Context::bindPixelUnpackBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(mImplementation.get(), bufferHandle);
        mGLState.setPixelUnpackBufferBinding(buffer);
    }
    
    void Context::useProgram(GLuint program)
    {
        mGLState.setProgram(getProgram(program));
    }
    
    void Context::bindTransformFeedback(GLuint transformFeedbackHandle)
    {
        TransformFeedback *transformFeedback =
            checkTransformFeedbackAllocation(transformFeedbackHandle);
        mGLState.setTransformFeedbackBinding(transformFeedback);
    }
    
    Error Context::beginQuery(GLenum target, GLuint query)
    {
        Query *queryObject = getQuery(query, true, target);
        ASSERT(queryObject);
    
        // begin query
        Error error = queryObject->begin();
        if (error.isError())
        {
            return error;
        }
    
        // set query as active for specified target only if begin succeeded
        mGLState.setActiveQuery(target, queryObject);
    
        return Error(GL_NO_ERROR);
    }
    
    Error Context::endQuery(GLenum target)
    {
        Query *queryObject = mGLState.getActiveQuery(target);
        ASSERT(queryObject);
    
        gl::Error error = queryObject->end();
    
        // Always unbind the query, even if there was an error. This may delete the query object.
        mGLState.setActiveQuery(target, NULL);
    
        return error;
    }
    
    Error Context::queryCounter(GLuint id, GLenum target)
    {
        ASSERT(target == GL_TIMESTAMP_EXT);
    
        Query *queryObject = getQuery(id, true, target);
        ASSERT(queryObject);
    
        return queryObject->queryCounter();
    }
    
    void Context::getQueryiv(GLenum target, GLenum pname, GLint *params)
    {
        switch (pname)
        {
            case GL_CURRENT_QUERY_EXT:
                params[0] = mGLState.getActiveQueryId(target);
                break;
            case GL_QUERY_COUNTER_BITS_EXT:
                switch (target)
                {
                    case GL_TIME_ELAPSED_EXT:
                        params[0] = getExtensions().queryCounterBitsTimeElapsed;
                        break;
                    case GL_TIMESTAMP_EXT:
                        params[0] = getExtensions().queryCounterBitsTimestamp;
                        break;
                    default:
                        UNREACHABLE();
                        params[0] = 0;
                        break;
                }
                break;
            default:
                UNREACHABLE();
                return;
        }
    }
    
    void Context::getQueryObjectiv(GLuint id, GLenum pname, GLint *params)
    {
        handleError(GetQueryObjectParameter(getQuery(id), pname, params));
    }
    
    void Context::getQueryObjectuiv(GLuint id, GLenum pname, GLuint *params)
    {
        handleError(GetQueryObjectParameter(getQuery(id), pname, params));
    }
    
    void Context::getQueryObjecti64v(GLuint id, GLenum pname, GLint64 *params)
    {
        handleError(GetQueryObjectParameter(getQuery(id), pname, params));
    }
    
    void Context::getQueryObjectui64v(GLuint id, GLenum pname, GLuint64 *params)
    {
        handleError(GetQueryObjectParameter(getQuery(id), pname, params));
    }
    
    Framebuffer *Context::getFramebuffer(unsigned int handle) const
    {
        auto framebufferIt = mFramebufferMap.find(handle);
        return ((framebufferIt == mFramebufferMap.end()) ? nullptr : framebufferIt->second);
    }
    
    FenceNV *Context::getFenceNV(unsigned int handle)
    {
        auto fence = mFenceNVMap.find(handle);
    
        if (fence == mFenceNVMap.end())
        {
            return NULL;
        }
        else
        {
            return fence->second;
        }
    }
    
    Query *Context::getQuery(unsigned int handle, bool create, GLenum type)
    {
        auto query = mQueryMap.find(handle);
    
        if (query == mQueryMap.end())
        {
            return NULL;
        }
        else
        {
            if (!query->second && create)
            {
                query->second = new Query(mImplementation->createQuery(type), handle);
                query->second->addRef();
            }
            return query->second;
        }
    }
    
    Query *Context::getQuery(GLuint handle) const
    {
        auto iter = mQueryMap.find(handle);
        return (iter != mQueryMap.end()) ? iter->second : nullptr;
    }
    
    Texture *Context::getTargetTexture(GLenum target) const
    {
        ASSERT(ValidTextureTarget(this, target) || ValidTextureExternalTarget(this, target));
        return mGLState.getTargetTexture(target);
    }
    
    Texture *Context::getSamplerTexture(unsigned int sampler, GLenum type) const
    {
        return mGLState.getSamplerTexture(sampler, type);
    }
    
    Compiler *Context::getCompiler() const
    {
        return mCompiler;
    }
    
    void Context::getBooleanv(GLenum pname, GLboolean *params)
    {
        switch (pname)
        {
          case GL_SHADER_COMPILER:           *params = GL_TRUE;                             break;
          case GL_CONTEXT_ROBUST_ACCESS_EXT: *params = mRobustAccess ? GL_TRUE : GL_FALSE;  break;
          default:
              mGLState.getBooleanv(pname, params);
              break;
        }
    }
    
    void Context::getFloatv(GLenum pname, GLfloat *params)
    {
        // Queries about context capabilities and maximums are answered by Context.
        // Queries about current GL state values are answered by State.
        switch (pname)
        {
          case GL_ALIASED_LINE_WIDTH_RANGE:
            params[0] = mCaps.minAliasedLineWidth;
            params[1] = mCaps.maxAliasedLineWidth;
            break;
          case GL_ALIASED_POINT_SIZE_RANGE:
            params[0] = mCaps.minAliasedPointSize;
            params[1] = mCaps.maxAliasedPointSize;
            break;
          case GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT:
            ASSERT(mExtensions.textureFilterAnisotropic);
            *params = mExtensions.maxTextureAnisotropy;
            break;
          case GL_MAX_TEXTURE_LOD_BIAS:
            *params = mCaps.maxLODBias;
            break;
    
          case GL_PATH_MODELVIEW_MATRIX_CHROMIUM:
          case GL_PATH_PROJECTION_MATRIX_CHROMIUM:
          {
              ASSERT(mExtensions.pathRendering);
              const GLfloat *m = mGLState.getPathRenderingMatrix(pname);
              memcpy(params, m, 16 * sizeof(GLfloat));
          }
          break;
    
          default:
              mGLState.getFloatv(pname, params);
              break;
        }
    }
    
    void Context::getIntegerv(GLenum pname, GLint *params)
    {
        // Queries about context capabilities and maximums are answered by Context.
        // Queries about current GL state values are answered by State.
    
        switch (pname)
        {
          case GL_MAX_VERTEX_ATTRIBS:                       *params = mCaps.maxVertexAttributes;                            break;
          case GL_MAX_VERTEX_UNIFORM_VECTORS:               *params = mCaps.maxVertexUniformVectors;                        break;
          case GL_MAX_VERTEX_UNIFORM_COMPONENTS:            *params = mCaps.maxVertexUniformComponents;                     break;
          case GL_MAX_VARYING_VECTORS:                      *params = mCaps.maxVaryingVectors;                              break;
          case GL_MAX_VARYING_COMPONENTS:                   *params = mCaps.maxVertexOutputComponents;                      break;
          case GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS:         *params = mCaps.maxCombinedTextureImageUnits;                   break;
          case GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS:           *params = mCaps.maxVertexTextureImageUnits;                     break;
          case GL_MAX_TEXTURE_IMAGE_UNITS:                  *params = mCaps.maxTextureImageUnits;                           break;
          case GL_MAX_FRAGMENT_UNIFORM_VECTORS:             *params = mCaps.maxFragmentUniformVectors;                      break;
          case GL_MAX_FRAGMENT_UNIFORM_COMPONENTS:          *params = mCaps.maxFragmentUniformComponents;                   break;
          case GL_MAX_RENDERBUFFER_SIZE:                    *params = mCaps.maxRenderbufferSize;                            break;
          case GL_MAX_COLOR_ATTACHMENTS_EXT:                *params = mCaps.maxColorAttachments;                            break;
          case GL_MAX_DRAW_BUFFERS_EXT:                     *params = mCaps.maxDrawBuffers;                                 break;
          //case GL_FRAMEBUFFER_BINDING:                    // now equivalent to GL_DRAW_FRAMEBUFFER_BINDING_ANGLE
          case GL_SUBPIXEL_BITS:                            *params = 4;                                                    break;
          case GL_MAX_TEXTURE_SIZE:                         *params = mCaps.max2DTextureSize;                               break;
          case GL_MAX_CUBE_MAP_TEXTURE_SIZE:                *params = mCaps.maxCubeMapTextureSize;                          break;
          case GL_MAX_3D_TEXTURE_SIZE:                      *params = mCaps.max3DTextureSize;                               break;
          case GL_MAX_ARRAY_TEXTURE_LAYERS:                 *params = mCaps.maxArrayTextureLayers;                          break;
          case GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT:          *params = mCaps.uniformBufferOffsetAlignment;                   break;
          case GL_MAX_UNIFORM_BUFFER_BINDINGS:              *params = mCaps.maxUniformBufferBindings;                       break;
          case GL_MAX_VERTEX_UNIFORM_BLOCKS:                *params = mCaps.maxVertexUniformBlocks;                         break;
          case GL_MAX_FRAGMENT_UNIFORM_BLOCKS:              *params = mCaps.maxFragmentUniformBlocks;                       break;
          case GL_MAX_COMBINED_UNIFORM_BLOCKS:              *params = mCaps.maxCombinedTextureImageUnits;                   break;
          case GL_MAX_VERTEX_OUTPUT_COMPONENTS:             *params = mCaps.maxVertexOutputComponents;                      break;
          case GL_MAX_FRAGMENT_INPUT_COMPONENTS:            *params = mCaps.maxFragmentInputComponents;                     break;
          case GL_MIN_PROGRAM_TEXEL_OFFSET:                 *params = mCaps.minProgramTexelOffset;                          break;
          case GL_MAX_PROGRAM_TEXEL_OFFSET:                 *params = mCaps.maxProgramTexelOffset;                          break;
          case GL_MAJOR_VERSION:
              *params = getClientVersion().major;
              break;
          case GL_MINOR_VERSION:
              *params = getClientVersion().minor;
              break;
          case GL_MAX_ELEMENTS_INDICES:                     *params = mCaps.maxElementsIndices;                             break;
          case GL_MAX_ELEMENTS_VERTICES:                    *params = mCaps.maxElementsVertices;                            break;
          case GL_MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS: *params = mCaps.maxTransformFeedbackInterleavedComponents; break;
          case GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS:       *params = mCaps.maxTransformFeedbackSeparateAttributes;    break;
          case GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS:    *params = mCaps.maxTransformFeedbackSeparateComponents;    break;
          case GL_NUM_COMPRESSED_TEXTURE_FORMATS:
              *params = static_cast<GLint>(mCaps.compressedTextureFormats.size());
              break;
          case GL_MAX_SAMPLES_ANGLE:                        *params = mCaps.maxSamples;                                     break;
          case GL_MAX_VIEWPORT_DIMS:
            {
                params[0] = mCaps.maxViewportWidth;
                params[1] = mCaps.maxViewportHeight;
            }
            break;
          case GL_COMPRESSED_TEXTURE_FORMATS:
            std::copy(mCaps.compressedTextureFormats.begin(), mCaps.compressedTextureFormats.end(), params);
            break;
          case GL_RESET_NOTIFICATION_STRATEGY_EXT:
            *params = mResetStrategy;
            break;
          case GL_NUM_SHADER_BINARY_FORMATS:
              *params = static_cast<GLint>(mCaps.shaderBinaryFormats.size());
            break;
          case GL_SHADER_BINARY_FORMATS:
            std::copy(mCaps.shaderBinaryFormats.begin(), mCaps.shaderBinaryFormats.end(), params);
            break;
          case GL_NUM_PROGRAM_BINARY_FORMATS:
              *params = static_cast<GLint>(mCaps.programBinaryFormats.size());
            break;
          case GL_PROGRAM_BINARY_FORMATS:
            std::copy(mCaps.programBinaryFormats.begin(), mCaps.programBinaryFormats.end(), params);
            break;
          case GL_NUM_EXTENSIONS:
            *params = static_cast<GLint>(mExtensionStrings.size());
            break;
    
          // GL_KHR_debug
          case GL_MAX_DEBUG_MESSAGE_LENGTH:
              *params = mExtensions.maxDebugMessageLength;
              break;
          case GL_MAX_DEBUG_LOGGED_MESSAGES:
              *params = mExtensions.maxDebugLoggedMessages;
              break;
          case GL_MAX_DEBUG_GROUP_STACK_DEPTH:
              *params = mExtensions.maxDebugGroupStackDepth;
              break;
          case GL_MAX_LABEL_LENGTH:
              *params = mExtensions.maxLabelLength;
              break;
    
          // GL_EXT_disjoint_timer_query
          case GL_GPU_DISJOINT_EXT:
              *params = mImplementation->getGPUDisjoint();
              break;
          case GL_MAX_FRAMEBUFFER_WIDTH:
              *params = mCaps.maxFramebufferWidth;
              break;
          case GL_MAX_FRAMEBUFFER_HEIGHT:
              *params = mCaps.maxFramebufferHeight;
              break;
          case GL_MAX_FRAMEBUFFER_SAMPLES:
              *params = mCaps.maxFramebufferSamples;
              break;
          case GL_MAX_SAMPLE_MASK_WORDS:
              *params = mCaps.maxSampleMaskWords;
              break;
          case GL_MAX_COLOR_TEXTURE_SAMPLES:
              *params = mCaps.maxColorTextureSamples;
              break;
          case GL_MAX_DEPTH_TEXTURE_SAMPLES:
              *params = mCaps.maxDepthTextureSamples;
              break;
          case GL_MAX_INTEGER_SAMPLES:
              *params = mCaps.maxIntegerSamples;
              break;
          case GL_MAX_VERTEX_ATTRIB_RELATIVE_OFFSET:
              *params = mCaps.maxVertexAttribRelativeOffset;
              break;
          case GL_MAX_VERTEX_ATTRIB_BINDINGS:
              *params = mCaps.maxVertexAttribBindings;
              break;
          case GL_MAX_VERTEX_ATTRIB_STRIDE:
              *params = mCaps.maxVertexAttribStride;
              break;
          case GL_MAX_VERTEX_ATOMIC_COUNTER_BUFFERS:
              *params = mCaps.maxVertexAtomicCounterBuffers;
              break;
          case GL_MAX_VERTEX_ATOMIC_COUNTERS:
              *params = mCaps.maxVertexAtomicCounters;
              break;
          case GL_MAX_VERTEX_IMAGE_UNIFORMS:
              *params = mCaps.maxVertexImageUniforms;
              break;
          case GL_MAX_VERTEX_SHADER_STORAGE_BLOCKS:
              *params = mCaps.maxVertexShaderStorageBlocks;
              break;
          case GL_MAX_FRAGMENT_ATOMIC_COUNTER_BUFFERS:
              *params = mCaps.maxFragmentAtomicCounterBuffers;
              break;
          case GL_MAX_FRAGMENT_ATOMIC_COUNTERS:
              *params = mCaps.maxFragmentAtomicCounters;
              break;
          case GL_MAX_FRAGMENT_IMAGE_UNIFORMS:
              *params = mCaps.maxFragmentImageUniforms;
              break;
          case GL_MAX_FRAGMENT_SHADER_STORAGE_BLOCKS:
              *params = mCaps.maxFragmentShaderStorageBlocks;
              break;
          case GL_MIN_PROGRAM_TEXTURE_GATHER_OFFSET:
              *params = mCaps.minProgramTextureGatherOffset;
              break;
          case GL_MAX_PROGRAM_TEXTURE_GATHER_OFFSET:
              *params = mCaps.maxProgramTextureGatherOffset;
              break;
          case GL_MAX_COMPUTE_WORK_GROUP_INVOCATIONS:
              *params = mCaps.maxComputeWorkGroupInvocations;
              break;
          case GL_MAX_COMPUTE_UNIFORM_BLOCKS:
              *params = mCaps.maxComputeUniformBlocks;
              break;
          case GL_MAX_COMPUTE_TEXTURE_IMAGE_UNITS:
              *params = mCaps.maxComputeTextureImageUnits;
              break;
          case GL_MAX_COMPUTE_SHARED_MEMORY_SIZE:
              *params = mCaps.maxComputeSharedMemorySize;
              break;
          case GL_MAX_COMPUTE_UNIFORM_COMPONENTS:
              *params = mCaps.maxComputeUniformComponents;
              break;
          case GL_MAX_COMPUTE_ATOMIC_COUNTER_BUFFERS:
              *params = mCaps.maxComputeAtomicCounterBuffers;
              break;
          case GL_MAX_COMPUTE_ATOMIC_COUNTERS:
              *params = mCaps.maxComputeAtomicCounters;
              break;
          case GL_MAX_COMPUTE_IMAGE_UNIFORMS:
              *params = mCaps.maxComputeImageUniforms;
              break;
          case GL_MAX_COMBINED_COMPUTE_UNIFORM_COMPONENTS:
              *params = mCaps.maxCombinedComputeUniformComponents;
              break;
          case GL_MAX_COMPUTE_SHADER_STORAGE_BLOCKS:
              *params = mCaps.maxComputeShaderStorageBlocks;
              break;
          case GL_MAX_COMBINED_SHADER_OUTPUT_RESOURCES:
              *params = mCaps.maxCombinedShaderOutputResources;
              break;
          case GL_MAX_UNIFORM_LOCATIONS:
              *params = mCaps.maxUniformLocations;
              break;
          case GL_MAX_ATOMIC_COUNTER_BUFFER_BINDINGS:
              *params = mCaps.maxAtomicCounterBufferBindings;
              break;
          case GL_MAX_ATOMIC_COUNTER_BUFFER_SIZE:
              *params = mCaps.maxAtomicCounterBufferSize;
              break;
          case GL_MAX_COMBINED_ATOMIC_COUNTER_BUFFERS:
              *params = mCaps.maxCombinedAtomicCounterBuffers;
              break;
          case GL_MAX_COMBINED_ATOMIC_COUNTERS:
              *params = mCaps.maxCombinedAtomicCounters;
              break;
          case GL_MAX_IMAGE_UNITS:
              *params = mCaps.maxImageUnits;
              break;
          case GL_MAX_COMBINED_IMAGE_UNIFORMS:
              *params = mCaps.maxCombinedImageUniforms;
              break;
          case GL_MAX_SHADER_STORAGE_BUFFER_BINDINGS:
              *params = mCaps.maxShaderStorageBufferBindings;
              break;
          case GL_MAX_COMBINED_SHADER_STORAGE_BLOCKS:
              *params = mCaps.maxCombinedShaderStorageBlocks;
              break;
          case GL_SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT:
              *params = mCaps.shaderStorageBufferOffsetAlignment;
              break;
          default:
              mGLState.getIntegerv(mState, pname, params);
              break;
        }
    }
    
    void Context::getInteger64v(GLenum pname, GLint64 *params)
    {
        // Queries about context capabilities and maximums are answered by Context.
        // Queries about current GL state values are answered by State.
        switch (pname)
        {
          case GL_MAX_ELEMENT_INDEX:
            *params = mCaps.maxElementIndex;
            break;
          case GL_MAX_UNIFORM_BLOCK_SIZE:
            *params = mCaps.maxUniformBlockSize;
            break;
          case GL_MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS:
            *params = mCaps.maxCombinedVertexUniformComponents;
            break;
          case GL_MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS:
            *params = mCaps.maxCombinedFragmentUniformComponents;
            break;
          case GL_MAX_SERVER_WAIT_TIMEOUT:
            *params = mCaps.maxServerWaitTimeout;
            break;
    
          // GL_EXT_disjoint_timer_query
          case GL_TIMESTAMP_EXT:
              *params = mImplementation->getTimestamp();
              break;
    
          case GL_MAX_SHADER_STORAGE_BLOCK_SIZE:
              *params = mCaps.maxShaderStorageBlockSize;
              break;
          default:
            UNREACHABLE();
            break;
        }
    }
    
    void Context::getPointerv(GLenum pname, void **params) const
    {
        mGLState.getPointerv(pname, params);
    }
    
    void Context::getIntegeri_v(GLenum target, GLuint index, GLint *data)
    {
        // Queries about context capabilities and maximums are answered by Context.
        // Queries about current GL state values are answered by State.
    
        GLenum nativeType;
        unsigned int numParams;
        bool queryStatus = getIndexedQueryParameterInfo(target, &nativeType, &numParams);
        ASSERT(queryStatus);
    
        if (nativeType == GL_INT)
        {
            switch (target)
            {
                case GL_MAX_COMPUTE_WORK_GROUP_COUNT:
                    ASSERT(index < 3u);
                    *data = mCaps.maxComputeWorkGroupCount[index];
                    break;
                case GL_MAX_COMPUTE_WORK_GROUP_SIZE:
                    ASSERT(index < 3u);
                    *data = mCaps.maxComputeWorkGroupSize[index];
                    break;
                default:
                    mGLState.getIntegeri_v(target, index, data);
            }
        }
        else
        {
            CastIndexedStateValues(this, nativeType, target, index, numParams, data);
        }
    }
    
    void Context::getInteger64i_v(GLenum target, GLuint index, GLint64 *data)
    {
        // Queries about context capabilities and maximums are answered by Context.
        // Queries about current GL state values are answered by State.
    
        GLenum nativeType;
        unsigned int numParams;
        bool queryStatus = getIndexedQueryParameterInfo(target, &nativeType, &numParams);
        ASSERT(queryStatus);
    
        if (nativeType == GL_INT_64_ANGLEX)
        {
            mGLState.getInteger64i_v(target, index, data);
        }
        else
        {
            CastIndexedStateValues(this, nativeType, target, index, numParams, data);
        }
    }
    
    void Context::getBooleani_v(GLenum target, GLuint index, GLboolean *data)
    {
        // Queries about context capabilities and maximums are answered by Context.
        // Queries about current GL state values are answered by State.
    
        GLenum nativeType;
        unsigned int numParams;
        bool queryStatus = getIndexedQueryParameterInfo(target, &nativeType, &numParams);
        ASSERT(queryStatus);
    
        if (nativeType == GL_BOOL)
        {
            mGLState.getBooleani_v(target, index, data);
        }
        else
        {
            CastIndexedStateValues(this, nativeType, target, index, numParams, data);
        }
    }
    
    Error Context::drawArrays(GLenum mode, GLint first, GLsizei count)
    {
        syncRendererState();
        ANGLE_TRY(mImplementation->drawArrays(mode, first, count));
        MarkTransformFeedbackBufferUsage(mGLState.getCurrentTransformFeedback());
    
        return NoError();
    }
    
    Error Context::drawArraysInstanced(GLenum mode, GLint first, GLsizei count, GLsizei instanceCount)
    {
        syncRendererState();
        ANGLE_TRY(mImplementation->drawArraysInstanced(mode, first, count, instanceCount));
        MarkTransformFeedbackBufferUsage(mGLState.getCurrentTransformFeedback());
    
        return NoError();
    }
    
    Error Context::drawElements(GLenum mode,
                                GLsizei count,
                                GLenum type,
                                const GLvoid *indices,
                                const IndexRange &indexRange)
    {
        syncRendererState();
        return mImplementation->drawElements(mode, count, type, indices, indexRange);
    }
    
    Error Context::drawElementsInstanced(GLenum mode,
                                         GLsizei count,
                                         GLenum type,
                                         const GLvoid *indices,
                                         GLsizei instances,
                                         const IndexRange &indexRange)
    {
        syncRendererState();
        return mImplementation->drawElementsInstanced(mode, count, type, indices, instances,
                                                      indexRange);
    }
    
    Error Context::drawRangeElements(GLenum mode,
                                     GLuint start,
                                     GLuint end,
                                     GLsizei count,
                                     GLenum type,
                                     const GLvoid *indices,
                                     const IndexRange &indexRange)
    {
        syncRendererState();
        return mImplementation->drawRangeElements(mode, start, end, count, type, indices, indexRange);
    }
    
    Error Context::flush()
    {
        return mImplementation->flush();
    }
    
    Error Context::finish()
    {
        return mImplementation->finish();
    }
    
    void Context::insertEventMarker(GLsizei length, const char *marker)
    {
        ASSERT(mImplementation);
        mImplementation->insertEventMarker(length, marker);
    }
    
    void Context::pushGroupMarker(GLsizei length, const char *marker)
    {
        ASSERT(mImplementation);
        mImplementation->pushGroupMarker(length, marker);
    }
    
    void Context::popGroupMarker()
    {
        ASSERT(mImplementation);
        mImplementation->popGroupMarker();
    }
    
    void Context::bindUniformLocation(GLuint program, GLint location, const GLchar *name)
    {
        Program *programObject = getProgram(program);
        ASSERT(programObject);
    
        programObject->bindUniformLocation(location, name);
    }
    
    void Context::setCoverageModulation(GLenum components)
    {
        mGLState.setCoverageModulation(components);
    }
    
    void Context::loadPathRenderingMatrix(GLenum matrixMode, const GLfloat *matrix)
    {
        mGLState.loadPathRenderingMatrix(matrixMode, matrix);
    }
    
    void Context::loadPathRenderingIdentityMatrix(GLenum matrixMode)
    {
        GLfloat I[16];
        angle::Matrix<GLfloat>::setToIdentity(I);
    
        mGLState.loadPathRenderingMatrix(matrixMode, I);
    }
    
    void Context::stencilFillPath(GLuint path, GLenum fillMode, GLuint mask)
    {
        const auto *pathObj = mResourceManager->getPath(path);
        if (!pathObj)
            return;
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->stencilFillPath(pathObj, fillMode, mask);
    }
    
    void Context::stencilStrokePath(GLuint path, GLint reference, GLuint mask)
    {
        const auto *pathObj = mResourceManager->getPath(path);
        if (!pathObj)
            return;
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->stencilStrokePath(pathObj, reference, mask);
    }
    
    void Context::coverFillPath(GLuint path, GLenum coverMode)
    {
        const auto *pathObj = mResourceManager->getPath(path);
        if (!pathObj)
            return;
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->coverFillPath(pathObj, coverMode);
    }
    
    void Context::coverStrokePath(GLuint path, GLenum coverMode)
    {
        const auto *pathObj = mResourceManager->getPath(path);
        if (!pathObj)
            return;
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->coverStrokePath(pathObj, coverMode);
    }
    
    void Context::stencilThenCoverFillPath(GLuint path, GLenum fillMode, GLuint mask, GLenum coverMode)
    {
        const auto *pathObj = mResourceManager->getPath(path);
        if (!pathObj)
            return;
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->stencilThenCoverFillPath(pathObj, fillMode, mask, coverMode);
    }
    
    void Context::stencilThenCoverStrokePath(GLuint path,
                                             GLint reference,
                                             GLuint mask,
                                             GLenum coverMode)
    {
        const auto *pathObj = mResourceManager->getPath(path);
        if (!pathObj)
            return;
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->stencilThenCoverStrokePath(pathObj, reference, mask, coverMode);
    }
    
    void Context::coverFillPathInstanced(GLsizei numPaths,
                                         GLenum pathNameType,
                                         const void *paths,
                                         GLuint pathBase,
                                         GLenum coverMode,
                                         GLenum transformType,
                                         const GLfloat *transformValues)
    {
        const auto &pathObjects =
            GatherPaths(*mResourceManager, numPaths, pathNameType, paths, pathBase);
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->coverFillPathInstanced(pathObjects, coverMode, transformType, transformValues);
    }
    
    void Context::coverStrokePathInstanced(GLsizei numPaths,
                                           GLenum pathNameType,
                                           const void *paths,
                                           GLuint pathBase,
                                           GLenum coverMode,
                                           GLenum transformType,
                                           const GLfloat *transformValues)
    {
        const auto &pathObjects =
            GatherPaths(*mResourceManager, numPaths, pathNameType, paths, pathBase);
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->coverStrokePathInstanced(pathObjects, coverMode, transformType,
                                                  transformValues);
    }
    
    void Context::stencilFillPathInstanced(GLsizei numPaths,
                                           GLenum pathNameType,
                                           const void *paths,
                                           GLuint pathBase,
                                           GLenum fillMode,
                                           GLuint mask,
                                           GLenum transformType,
                                           const GLfloat *transformValues)
    {
        const auto &pathObjects =
            GatherPaths(*mResourceManager, numPaths, pathNameType, paths, pathBase);
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->stencilFillPathInstanced(pathObjects, fillMode, mask, transformType,
                                                  transformValues);
    }
    
    void Context::stencilStrokePathInstanced(GLsizei numPaths,
                                             GLenum pathNameType,
                                             const void *paths,
                                             GLuint pathBase,
                                             GLint reference,
                                             GLuint mask,
                                             GLenum transformType,
                                             const GLfloat *transformValues)
    {
        const auto &pathObjects =
            GatherPaths(*mResourceManager, numPaths, pathNameType, paths, pathBase);
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->stencilStrokePathInstanced(pathObjects, reference, mask, transformType,
                                                    transformValues);
    }
    
    void Context::stencilThenCoverFillPathInstanced(GLsizei numPaths,
                                                    GLenum pathNameType,
                                                    const void *paths,
                                                    GLuint pathBase,
                                                    GLenum fillMode,
                                                    GLuint mask,
                                                    GLenum coverMode,
                                                    GLenum transformType,
                                                    const GLfloat *transformValues)
    {
        const auto &pathObjects =
            GatherPaths(*mResourceManager, numPaths, pathNameType, paths, pathBase);
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->stencilThenCoverFillPathInstanced(pathObjects, coverMode, fillMode, mask,
                                                           transformType, transformValues);
    }
    
    void Context::stencilThenCoverStrokePathInstanced(GLsizei numPaths,
                                                      GLenum pathNameType,
                                                      const void *paths,
                                                      GLuint pathBase,
                                                      GLint reference,
                                                      GLuint mask,
                                                      GLenum coverMode,
                                                      GLenum transformType,
                                                      const GLfloat *transformValues)
    {
        const auto &pathObjects =
            GatherPaths(*mResourceManager, numPaths, pathNameType, paths, pathBase);
    
        // TODO(svaisanen@nvidia.com): maybe sync only state required for path rendering?
        syncRendererState();
    
        mImplementation->stencilThenCoverStrokePathInstanced(pathObjects, coverMode, reference, mask,
                                                             transformType, transformValues);
    }
    
    void Context::bindFragmentInputLocation(GLuint program, GLint location, const GLchar *name)
    {
        auto *programObject = getProgram(program);
    
        programObject->bindFragmentInputLocation(location, name);
    }
    
    void Context::programPathFragmentInputGen(GLuint program,
                                              GLint location,
                                              GLenum genMode,
                                              GLint components,
                                              const GLfloat *coeffs)
    {
        auto *programObject = getProgram(program);
    
        programObject->pathFragmentInputGen(location, genMode, components, coeffs);
    }
    
    void Context::handleError(const Error &error)
    {
        if (error.isError())
        {
            GLenum code = error.getCode();
            mErrors.insert(code);
            if (code == GL_OUT_OF_MEMORY && getWorkarounds().loseContextOnOutOfMemory)
            {
                markContextLost();
            }
    
            if (!error.getMessage().empty())
            {
                auto *debug = &mGLState.getDebug();
                debug->insertMessage(GL_DEBUG_SOURCE_API, GL_DEBUG_TYPE_ERROR, error.getID(),
                                     GL_DEBUG_SEVERITY_HIGH, error.getMessage());
            }
        }
    }
    
    // Get one of the recorded errors and clear its flag, if any.
    // [OpenGL ES 2.0.24] section 2.5 page 13.
    GLenum Context::getError()
    {
        if (mErrors.empty())
        {
            return GL_NO_ERROR;
        }
        else
        {
            GLenum error = *mErrors.begin();
            mErrors.erase(mErrors.begin());
            return error;
        }
    }
    
    // NOTE: this function should not assume that this context is current!
    void Context::markContextLost()
    {
        if (mResetStrategy == GL_LOSE_CONTEXT_ON_RESET_EXT)
        {
            mResetStatus = GL_UNKNOWN_CONTEXT_RESET_EXT;
            mContextLostForced = true;
        }
        mContextLost     = true;
    }
    
    bool Context::isContextLost()
    {
        return mContextLost;
    }
    
    GLenum Context::getResetStatus()
    {
        // Even if the application doesn't want to know about resets, we want to know
        // as it will allow us to skip all the calls.
        if (mResetStrategy == GL_NO_RESET_NOTIFICATION_EXT)
        {
            if (!mContextLost && mImplementation->getResetStatus() != GL_NO_ERROR)
            {
                mContextLost = true;
            }
    
            // EXT_robustness, section 2.6: If the reset notification behavior is
            // NO_RESET_NOTIFICATION_EXT, then the implementation will never deliver notification of
            // reset events, and GetGraphicsResetStatusEXT will always return NO_ERROR.
            return GL_NO_ERROR;
        }
    
        // The GL_EXT_robustness spec says that if a reset is encountered, a reset
        // status should be returned at least once, and GL_NO_ERROR should be returned
        // once the device has finished resetting.
        if (!mContextLost)
        {
            ASSERT(mResetStatus == GL_NO_ERROR);
            mResetStatus = mImplementation->getResetStatus();
    
            if (mResetStatus != GL_NO_ERROR)
            {
                mContextLost = true;
            }
        }
        else if (!mContextLostForced && mResetStatus != GL_NO_ERROR)
        {
            // If markContextLost was used to mark the context lost then
            // assume that is not recoverable, and continue to report the
            // lost reset status for the lifetime of this context.
            mResetStatus = mImplementation->getResetStatus();
        }
    
        return mResetStatus;
    }
    
    bool Context::isResetNotificationEnabled()
    {
        return (mResetStrategy == GL_LOSE_CONTEXT_ON_RESET_EXT);
    }
    
    const egl::Config *Context::getConfig() const
    {
        return mConfig;
    }
    
    EGLenum Context::getClientType() const
    {
        return mClientType;
    }
    
    EGLenum Context::getRenderBuffer() const
    {
        auto framebufferIt = mFramebufferMap.find(0);
        if (framebufferIt != mFramebufferMap.end())
        {
            const Framebuffer *framebuffer              = framebufferIt->second;
            const FramebufferAttachment *backAttachment = framebuffer->getAttachment(GL_BACK);
    
            ASSERT(backAttachment != nullptr);
            return backAttachment->getSurface()->getRenderBuffer();
        }
        else
        {
            return EGL_NONE;
        }
    }
    
    VertexArray *Context::checkVertexArrayAllocation(GLuint vertexArrayHandle)
    {
        // Only called after a prior call to Gen.
        VertexArray *vertexArray = getVertexArray(vertexArrayHandle);
        if (!vertexArray)
        {
            vertexArray = new VertexArray(mImplementation.get(), vertexArrayHandle, MAX_VERTEX_ATTRIBS);
    
            mVertexArrayMap[vertexArrayHandle] = vertexArray;
        }
    
        return vertexArray;
    }
    
    TransformFeedback *Context::checkTransformFeedbackAllocation(GLuint transformFeedbackHandle)
    {
        // Only called after a prior call to Gen.
        TransformFeedback *transformFeedback = getTransformFeedback(transformFeedbackHandle);
        if (!transformFeedback)
        {
            transformFeedback =
                new TransformFeedback(mImplementation.get(), transformFeedbackHandle, mCaps);
            transformFeedback->addRef();
            mTransformFeedbackMap[transformFeedbackHandle] = transformFeedback;
        }
    
        return transformFeedback;
    }
    
    Framebuffer *Context::checkFramebufferAllocation(GLuint framebuffer)
    {
        // Can be called from Bind without a prior call to Gen.
        auto framebufferIt = mFramebufferMap.find(framebuffer);
        bool neverCreated = framebufferIt == mFramebufferMap.end();
        if (neverCreated || framebufferIt->second == nullptr)
        {
            Framebuffer *newFBO = new Framebuffer(mCaps, mImplementation.get(), framebuffer);
            if (neverCreated)
            {
                mFramebufferHandleAllocator.reserve(framebuffer);
                mFramebufferMap[framebuffer] = newFBO;
                return newFBO;
            }
    
            framebufferIt->second = newFBO;
        }
    
        return framebufferIt->second;
    }
    
    bool Context::isVertexArrayGenerated(GLuint vertexArray)
    {
        ASSERT(mVertexArrayMap.find(0) != mVertexArrayMap.end());
        return mVertexArrayMap.find(vertexArray) != mVertexArrayMap.end();
    }
    
    bool Context::isTransformFeedbackGenerated(GLuint transformFeedback)
    {
        ASSERT(mTransformFeedbackMap.find(0) != mTransformFeedbackMap.end());
        return mTransformFeedbackMap.find(transformFeedback) != mTransformFeedbackMap.end();
    }
    
    void Context::detachTexture(GLuint texture)
    {
        // Simple pass-through to State's detachTexture method, as textures do not require
        // allocation map management either here or in the resource manager at detach time.
        // Zero textures are held by the Context, and we don't attempt to request them from
        // the State.
        mGLState.detachTexture(mZeroTextures, texture);
    }
    
    void Context::detachBuffer(GLuint buffer)
    {
        // Simple pass-through to State's detachBuffer method, since
        // only buffer attachments to container objects that are bound to the current context
        // should be detached. And all those are available in State.
    
        // [OpenGL ES 3.2] section 5.1.2 page 45:
        // Attachments to unbound container objects, such as
        // deletion of a buffer attached to a vertex array object which is not bound to the context,
        // are not affected and continue to act as references on the deleted object
        mGLState.detachBuffer(buffer);
    }
    
    void Context::detachFramebuffer(GLuint framebuffer)
    {
        // Framebuffer detachment is handled by Context, because 0 is a valid
        // Framebuffer object, and a pointer to it must be passed from Context
        // to State at binding time.
    
        // [OpenGL ES 2.0.24] section 4.4 page 107:
        // If a framebuffer that is currently bound to the target FRAMEBUFFER is deleted, it is as though
        // BindFramebuffer had been executed with the target of FRAMEBUFFER and framebuffer of zero.
    
        if (mGLState.removeReadFramebufferBinding(framebuffer) && framebuffer != 0)
        {
            bindReadFramebuffer(0);
        }
    
        if (mGLState.removeDrawFramebufferBinding(framebuffer) && framebuffer != 0)
        {
            bindDrawFramebuffer(0);
        }
    }
    
    void Context::detachRenderbuffer(GLuint renderbuffer)
    {
        mGLState.detachRenderbuffer(renderbuffer);
    }
    
    void Context::detachVertexArray(GLuint vertexArray)
    {
        // Vertex array detachment is handled by Context, because 0 is a valid
        // VAO, and a pointer to it must be passed from Context to State at
        // binding time.
    
        // [OpenGL ES 3.0.2] section 2.10 page 43:
        // If a vertex array object that is currently bound is deleted, the binding
        // for that object reverts to zero and the default vertex array becomes current.
        if (mGLState.removeVertexArrayBinding(vertexArray))
        {
            bindVertexArray(0);
        }
    }
    
    void Context::detachTransformFeedback(GLuint transformFeedback)
    {
        // Transform feedback detachment is handled by Context, because 0 is a valid
        // transform feedback, and a pointer to it must be passed from Context to State at
        // binding time.
    
        // The OpenGL specification doesn't mention what should happen when the currently bound
        // transform feedback object is deleted. Since it is a container object, we treat it like
        // VAOs and FBOs and set the current bound transform feedback back to 0.
        if (mGLState.removeTransformFeedbackBinding(transformFeedback))
        {
            bindTransformFeedback(0);
        }
    }
    
    void Context::detachSampler(GLuint sampler)
    {
        mGLState.detachSampler(sampler);
    }
    
    void Context::setVertexAttribDivisor(GLuint index, GLuint divisor)
    {
        mGLState.setVertexAttribDivisor(index, divisor);
    }
    
    void Context::samplerParameteri(GLuint sampler, GLenum pname, GLint param)
    {
        Sampler *samplerObject =
            mResourceManager->checkSamplerAllocation(mImplementation.get(), sampler);
        SetSamplerParameteri(samplerObject, pname, param);
    }
    
    void Context::samplerParameteriv(GLuint sampler, GLenum pname, const GLint *param)
    {
        Sampler *samplerObject =
            mResourceManager->checkSamplerAllocation(mImplementation.get(), sampler);
        SetSamplerParameteriv(samplerObject, pname, param);
    }
    
    void Context::samplerParameterf(GLuint sampler, GLenum pname, GLfloat param)
    {
        Sampler *samplerObject =
            mResourceManager->checkSamplerAllocation(mImplementation.get(), sampler);
        SetSamplerParameterf(samplerObject, pname, param);
    }
    
    void Context::samplerParameterfv(GLuint sampler, GLenum pname, const GLfloat *param)
    {
        Sampler *samplerObject =
            mResourceManager->checkSamplerAllocation(mImplementation.get(), sampler);
        SetSamplerParameterfv(samplerObject, pname, param);
    }
    
    void Context::getSamplerParameteriv(GLuint sampler, GLenum pname, GLint *params)
    {
        const Sampler *samplerObject =
            mResourceManager->checkSamplerAllocation(mImplementation.get(), sampler);
        QuerySamplerParameteriv(samplerObject, pname, params);
    }
    
    void Context::getSamplerParameterfv(GLuint sampler, GLenum pname, GLfloat *params)
    {
        const Sampler *samplerObject =
            mResourceManager->checkSamplerAllocation(mImplementation.get(), sampler);
        QuerySamplerParameterfv(samplerObject, pname, params);
    }
    
    void Context::programParameteri(GLuint program, GLenum pname, GLint value)
    {
        gl::Program *programObject = getProgram(program);
        ASSERT(programObject != nullptr);
    
        ASSERT(pname == GL_PROGRAM_BINARY_RETRIEVABLE_HINT);
        programObject->setBinaryRetrievableHint(value != GL_FALSE);
    }
    
    void Context::initRendererString()
    {
        std::ostringstream rendererString;
        rendererString << "ANGLE (";
        rendererString << mImplementation->getRendererDescription();
        rendererString << ")";
    
        mRendererString = MakeStaticString(rendererString.str());
    }
    
    void Context::initVersionStrings()
    {
        const Version &clientVersion = getClientVersion();
    
        std::ostringstream versionString;
        versionString << "OpenGL ES " << clientVersion.major << "." << clientVersion.minor << " (ANGLE "
                      << ANGLE_VERSION_STRING << ")";
        mVersionString = MakeStaticString(versionString.str());
    
        std::ostringstream shadingLanguageVersionString;
        shadingLanguageVersionString << "OpenGL ES GLSL ES "
                                     << (clientVersion.major == 2 ? 1 : clientVersion.major) << "."
                                     << clientVersion.minor << "0 (ANGLE " << ANGLE_VERSION_STRING
                                     << ")";
        mShadingLanguageString = MakeStaticString(shadingLanguageVersionString.str());
    }
    
    void Context::initExtensionStrings()
    {
        auto mergeExtensionStrings = [](const std::vector<const char *> &strings) {
            std::ostringstream combinedStringStream;
            std::copy(strings.begin(), strings.end(),
                      std::ostream_iterator<const char *>(combinedStringStream, " "));
            return MakeStaticString(combinedStringStream.str());
        };
    
        mExtensionStrings.clear();
        for (const auto &extensionString : mExtensions.getStrings())
        {
            mExtensionStrings.push_back(MakeStaticString(extensionString));
        }
        mExtensionString = mergeExtensionStrings(mExtensionStrings);
    
        mRequestableExtensionStrings.clear();
        for (const auto &extensionInfo : GetExtensionInfoMap())
        {
            if (extensionInfo.second.Requestable &&
                !(mExtensions.*(extensionInfo.second.ExtensionsMember)))
            {
                mRequestableExtensionStrings.push_back(MakeStaticString(extensionInfo.first));
            }
        }
        mRequestableExtensionString = mergeExtensionStrings(mRequestableExtensionStrings);
    }
    
    const GLubyte *Context::getString(GLenum name) const
    {
        switch (name)
        {
            case GL_VENDOR:
                return reinterpret_cast<const GLubyte *>("Google Inc.");
    
            case GL_RENDERER:
                return reinterpret_cast<const GLubyte *>(mRendererString);
    
            case GL_VERSION:
                return reinterpret_cast<const GLubyte *>(mVersionString);
    
            case GL_SHADING_LANGUAGE_VERSION:
                return reinterpret_cast<const GLubyte *>(mShadingLanguageString);
    
            case GL_EXTENSIONS:
                return reinterpret_cast<const GLubyte *>(mExtensionString);
    
            case GL_REQUESTABLE_EXTENSIONS_ANGLE:
                return reinterpret_cast<const GLubyte *>(mRequestableExtensionString);
    
            default:
                UNREACHABLE();
                return nullptr;
        }
    }
    
    const GLubyte *Context::getStringi(GLenum name, GLuint index) const
    {
        switch (name)
        {
            case GL_EXTENSIONS:
                return reinterpret_cast<const GLubyte *>(mExtensionStrings[index]);
    
            case GL_REQUESTABLE_EXTENSIONS_ANGLE:
                return reinterpret_cast<const GLubyte *>(mRequestableExtensionStrings[index]);
    
            default:
                UNREACHABLE();
                return nullptr;
        }
    }
    
    size_t Context::getExtensionStringCount() const
    {
        return mExtensionStrings.size();
    }
    
    void Context::requestExtension(const char *name)
    {
        const ExtensionInfoMap &extensionInfos = GetExtensionInfoMap();
        ASSERT(extensionInfos.find(name) != extensionInfos.end());
        const auto &extension = extensionInfos.at(name);
        ASSERT(extension.Requestable);
    
        if (mExtensions.*(extension.ExtensionsMember))
        {
            // Extension already enabled
            return;
        }
    
        mExtensions.*(extension.ExtensionsMember) = true;
        updateCaps();
        initExtensionStrings();
    }
    
    size_t Context::getRequestableExtensionStringCount() const
    {
        return mRequestableExtensionStrings.size();
    }
    
    void Context::beginTransformFeedback(GLenum primitiveMode)
    {
        TransformFeedback *transformFeedback = mGLState.getCurrentTransformFeedback();
        ASSERT(transformFeedback != nullptr);
        ASSERT(!transformFeedback->isPaused());
    
        transformFeedback->begin(primitiveMode, mGLState.getProgram());
    }
    
    bool Context::hasActiveTransformFeedback(GLuint program) const
    {
        for (auto pair : mTransformFeedbackMap)
        {
            if (pair.second != nullptr && pair.second->hasBoundProgram(program))
            {
                return true;
            }
        }
        return false;
    }
    
    void Context::initCaps(bool webGLContext)
    {
        mCaps = mImplementation->getNativeCaps();
    
        mExtensions = mImplementation->getNativeExtensions();
    
        mLimitations = mImplementation->getNativeLimitations();
    
        if (getClientVersion() < Version(3, 0))
        {
            // Disable ES3+ extensions
            mExtensions.colorBufferFloat = false;
            mExtensions.eglImageExternalEssl3 = false;
            mExtensions.textureNorm16         = false;
        }
    
        if (getClientVersion() > Version(2, 0))
        {
            // FIXME(geofflang): Don't support EXT_sRGB in non-ES2 contexts
            //mExtensions.sRGB = false;
        }
    
        // Some extensions are always available because they are implemented in the GL layer.
        mExtensions.bindUniformLocation = true;
        mExtensions.vertexArrayObject   = true;
        mExtensions.bindGeneratesResource = true;
        mExtensions.requestExtension      = true;
    
        // Enable the no error extension if the context was created with the flag.
        mExtensions.noError = mSkipValidation;
    
        // Explicitly enable GL_KHR_debug
        mExtensions.debug                   = true;
        mExtensions.maxDebugMessageLength   = 1024;
        mExtensions.maxDebugLoggedMessages  = 1024;
        mExtensions.maxDebugGroupStackDepth = 1024;
        mExtensions.maxLabelLength          = 1024;
    
        // Explicitly enable GL_ANGLE_robust_client_memory
        mExtensions.robustClientMemory = true;
    
        // Apply implementation limits
        mCaps.maxVertexAttributes = std::min<GLuint>(mCaps.maxVertexAttributes, MAX_VERTEX_ATTRIBS);
        mCaps.maxVertexUniformBlocks = std::min<GLuint>(mCaps.maxVertexUniformBlocks, IMPLEMENTATION_MAX_VERTEX_SHADER_UNIFORM_BUFFERS);
        mCaps.maxVertexOutputComponents = std::min<GLuint>(mCaps.maxVertexOutputComponents, IMPLEMENTATION_MAX_VARYING_VECTORS * 4);
    
        mCaps.maxFragmentInputComponents = std::min<GLuint>(mCaps.maxFragmentInputComponents, IMPLEMENTATION_MAX_VARYING_VECTORS * 4);
    
        // WebGL compatibility
        mExtensions.webglCompatibility = webGLContext;
        for (const auto &extensionInfo : GetExtensionInfoMap())
        {
            // If this context is for WebGL, disable all enableable extensions
            if (webGLContext && extensionInfo.second.Requestable)
            {
                mExtensions.*(extensionInfo.second.ExtensionsMember) = false;
            }
        }
    
        // Generate texture caps
        updateCaps();
    }
    
    void Context::updateCaps()
    {
        mCaps.compressedTextureFormats.clear();
        mTextureCaps.clear();
    
        const TextureCapsMap &rendererFormats = mImplementation->getNativeTextureCaps();
        for (TextureCapsMap::const_iterator i = rendererFormats.begin(); i != rendererFormats.end(); i++)
        {
            GLenum format = i->first;
            TextureCaps formatCaps = i->second;
    
            const InternalFormat &formatInfo = GetInternalFormatInfo(format);
    
            // Update the format caps based on the client version and extensions.
            // Caps are AND'd with the renderer caps because some core formats are still unsupported in
            // ES3.
            formatCaps.texturable =
                formatCaps.texturable && formatInfo.textureSupport(getClientVersion(), mExtensions);
            formatCaps.renderable =
                formatCaps.renderable && formatInfo.renderSupport(getClientVersion(), mExtensions);
            formatCaps.filterable =
                formatCaps.filterable && formatInfo.filterSupport(getClientVersion(), mExtensions);
    
            // OpenGL ES does not support multisampling with integer formats
            if (!formatInfo.renderSupport || formatInfo.componentType == GL_INT || formatInfo.componentType == GL_UNSIGNED_INT)
            {
                formatCaps.sampleCounts.clear();
            }
    
            if (formatCaps.texturable && formatInfo.compressed)
            {
                mCaps.compressedTextureFormats.push_back(format);
            }
    
            mTextureCaps.insert(format, formatCaps);
        }
    }
    
    void Context::initWorkarounds()
    {
        // Lose the context upon out of memory error if the application is
        // expecting to watch for those events.
        mWorkarounds.loseContextOnOutOfMemory = (mResetStrategy == GL_LOSE_CONTEXT_ON_RESET_EXT);
    }
    
    void Context::syncRendererState()
    {
        const State::DirtyBits &dirtyBits = mGLState.getDirtyBits();
        mImplementation->syncState(mGLState, dirtyBits);
        mGLState.clearDirtyBits();
        mGLState.syncDirtyObjects();
    }
    
    void Context::syncRendererState(const State::DirtyBits &bitMask,
                                    const State::DirtyObjects &objectMask)
    {
        const State::DirtyBits &dirtyBits = (mGLState.getDirtyBits() & bitMask);
        mImplementation->syncState(mGLState, dirtyBits);
        mGLState.clearDirtyBits(dirtyBits);
    
        mGLState.syncDirtyObjects(objectMask);
    }
    
    void Context::blitFramebuffer(GLint srcX0,
                                  GLint srcY0,
                                  GLint srcX1,
                                  GLint srcY1,
                                  GLint dstX0,
                                  GLint dstY0,
                                  GLint dstX1,
                                  GLint dstY1,
                                  GLbitfield mask,
                                  GLenum filter)
    {
        Framebuffer *drawFramebuffer = mGLState.getDrawFramebuffer();
        ASSERT(drawFramebuffer);
    
        Rectangle srcArea(srcX0, srcY0, srcX1 - srcX0, srcY1 - srcY0);
        Rectangle dstArea(dstX0, dstY0, dstX1 - dstX0, dstY1 - dstY0);
    
        syncStateForBlit();
    
        handleError(drawFramebuffer->blit(mImplementation.get(), srcArea, dstArea, mask, filter));
    }
    
    void Context::clear(GLbitfield mask)
    {
        syncStateForClear();
        handleError(mGLState.getDrawFramebuffer()->clear(mImplementation.get(), mask));
    }
    
    void Context::clearBufferfv(GLenum buffer, GLint drawbuffer, const GLfloat *values)
    {
        syncStateForClear();
        handleError(mGLState.getDrawFramebuffer()->clearBufferfv(mImplementation.get(), buffer,
                                                                 drawbuffer, values));
    }
    
    void Context::clearBufferuiv(GLenum buffer, GLint drawbuffer, const GLuint *values)
    {
        syncStateForClear();
        handleError(mGLState.getDrawFramebuffer()->clearBufferuiv(mImplementation.get(), buffer,
                                                                  drawbuffer, values));
    }
    
    void Context::clearBufferiv(GLenum buffer, GLint drawbuffer, const GLint *values)
    {
        syncStateForClear();
        handleError(mGLState.getDrawFramebuffer()->clearBufferiv(mImplementation.get(), buffer,
                                                                 drawbuffer, values));
    }
    
    void Context::clearBufferfi(GLenum buffer, GLint drawbuffer, GLfloat depth, GLint stencil)
    {
        Framebuffer *framebufferObject = mGLState.getDrawFramebuffer();
        ASSERT(framebufferObject);
    
        // If a buffer is not present, the clear has no effect
        if (framebufferObject->getDepthbuffer() == nullptr &&
            framebufferObject->getStencilbuffer() == nullptr)
        {
            return;
        }
    
        syncStateForClear();
        handleError(framebufferObject->clearBufferfi(mImplementation.get(), buffer, drawbuffer, depth,
                                                     stencil));
    }
    
    void Context::readPixels(GLint x,
                             GLint y,
                             GLsizei width,
                             GLsizei height,
                             GLenum format,
                             GLenum type,
                             GLvoid *pixels)
    {
        if (width == 0 || height == 0)
        {
            return;
        }
    
        syncStateForReadPixels();
    
        Framebuffer *framebufferObject = mGLState.getReadFramebuffer();
        ASSERT(framebufferObject);
    
        Rectangle area(x, y, width, height);
        handleError(framebufferObject->readPixels(mImplementation.get(), area, format, type, pixels));
    }
    
    void Context::copyTexImage2D(GLenum target,
                                 GLint level,
                                 GLenum internalformat,
                                 GLint x,
                                 GLint y,
                                 GLsizei width,
                                 GLsizei height,
                                 GLint border)
    {
        // Only sync the read FBO
        mGLState.syncDirtyObject(GL_READ_FRAMEBUFFER);
    
        Rectangle sourceArea(x, y, width, height);
    
        const Framebuffer *framebuffer = mGLState.getReadFramebuffer();
        Texture *texture =
            getTargetTexture(IsCubeMapTextureTarget(target) ? GL_TEXTURE_CUBE_MAP : target);
        handleError(texture->copyImage(target, level, sourceArea, internalformat, framebuffer));
    }
    
    void Context::copyTexSubImage2D(GLenum target,
                                    GLint level,
                                    GLint xoffset,
                                    GLint yoffset,
                                    GLint x,
                                    GLint y,
                                    GLsizei width,
                                    GLsizei height)
    {
        if (width == 0 || height == 0)
        {
            return;
        }
    
        // Only sync the read FBO
        mGLState.syncDirtyObject(GL_READ_FRAMEBUFFER);
    
        Offset destOffset(xoffset, yoffset, 0);
        Rectangle sourceArea(x, y, width, height);
    
        const Framebuffer *framebuffer = mGLState.getReadFramebuffer();
        Texture *texture =
            getTargetTexture(IsCubeMapTextureTarget(target) ? GL_TEXTURE_CUBE_MAP : target);
        handleError(texture->copySubImage(target, level, destOffset, sourceArea, framebuffer));
    }
    
    void Context::copyTexSubImage3D(GLenum target,
                                    GLint level,
                                    GLint xoffset,
                                    GLint yoffset,
                                    GLint zoffset,
                                    GLint x,
                                    GLint y,
                                    GLsizei width,
                                    GLsizei height)
    {
        if (width == 0 || height == 0)
        {
            return;
        }
    
        // Only sync the read FBO
        mGLState.syncDirtyObject(GL_READ_FRAMEBUFFER);
    
        Offset destOffset(xoffset, yoffset, zoffset);
        Rectangle sourceArea(x, y, width, height);
    
        const Framebuffer *framebuffer = mGLState.getReadFramebuffer();
        Texture *texture               = getTargetTexture(target);
        handleError(texture->copySubImage(target, level, destOffset, sourceArea, framebuffer));
    }
    
    void Context::framebufferTexture2D(GLenum target,
                                       GLenum attachment,
                                       GLenum textarget,
                                       GLuint texture,
                                       GLint level)
    {
        Framebuffer *framebuffer = mGLState.getTargetFramebuffer(target);
        ASSERT(framebuffer);
    
        if (texture != 0)
        {
            Texture *textureObj = getTexture(texture);
    
            ImageIndex index = ImageIndex::MakeInvalid();
    
            if (textarget == GL_TEXTURE_2D)
            {
                index = ImageIndex::Make2D(level);
            }
            else
            {
                ASSERT(IsCubeMapTextureTarget(textarget));
                index = ImageIndex::MakeCube(textarget, level);
            }
    
            framebuffer->setAttachment(GL_TEXTURE, attachment, index, textureObj);
        }
        else
        {
            framebuffer->resetAttachment(attachment);
        }
    
        mGLState.setObjectDirty(target);
    }
    
    void Context::framebufferRenderbuffer(GLenum target,
                                          GLenum attachment,
                                          GLenum renderbuffertarget,
                                          GLuint renderbuffer)
    {
        Framebuffer *framebuffer = mGLState.getTargetFramebuffer(target);
        ASSERT(framebuffer);
    
        if (renderbuffer != 0)
        {
            Renderbuffer *renderbufferObject = getRenderbuffer(renderbuffer);
            framebuffer->setAttachment(GL_RENDERBUFFER, attachment, gl::ImageIndex::MakeInvalid(),
                                       renderbufferObject);
        }
        else
        {
            framebuffer->resetAttachment(attachment);
        }
    
        mGLState.setObjectDirty(target);
    }
    
    void Context::framebufferTextureLayer(GLenum target,
                                          GLenum attachment,
                                          GLuint texture,
                                          GLint level,
                                          GLint layer)
    {
        Framebuffer *framebuffer = mGLState.getTargetFramebuffer(target);
        ASSERT(framebuffer);
    
        if (texture != 0)
        {
            Texture *textureObject = getTexture(texture);
    
            ImageIndex index = ImageIndex::MakeInvalid();
    
            if (textureObject->getTarget() == GL_TEXTURE_3D)
            {
                index = ImageIndex::Make3D(level, layer);
            }
            else
            {
                ASSERT(textureObject->getTarget() == GL_TEXTURE_2D_ARRAY);
                index = ImageIndex::Make2DArray(level, layer);
            }
    
            framebuffer->setAttachment(GL_TEXTURE, attachment, index, textureObject);
        }
        else
        {
            framebuffer->resetAttachment(attachment);
        }
    
        mGLState.setObjectDirty(target);
    }
    
    void Context::drawBuffers(GLsizei n, const GLenum *bufs)
    {
        Framebuffer *framebuffer = mGLState.getDrawFramebuffer();
        ASSERT(framebuffer);
        framebuffer->setDrawBuffers(n, bufs);
        mGLState.setObjectDirty(GL_DRAW_FRAMEBUFFER);
    }
    
    void Context::readBuffer(GLenum mode)
    {
        Framebuffer *readFBO = mGLState.getReadFramebuffer();
        readFBO->setReadBuffer(mode);
        mGLState.setObjectDirty(GL_READ_FRAMEBUFFER);
    }
    
    void Context::discardFramebuffer(GLenum target, GLsizei numAttachments, const GLenum *attachments)
    {
        // Only sync the FBO
        mGLState.syncDirtyObject(target);
    
        Framebuffer *framebuffer = mGLState.getTargetFramebuffer(target);
        ASSERT(framebuffer);
    
        // The specification isn't clear what should be done when the framebuffer isn't complete.
        // We leave it up to the framebuffer implementation to decide what to do.
        handleError(framebuffer->discard(numAttachments, attachments));
    }
    
    void Context::invalidateFramebuffer(GLenum target,
                                        GLsizei numAttachments,
                                        const GLenum *attachments)
    {
        // Only sync the FBO
        mGLState.syncDirtyObject(target);
    
        Framebuffer *framebuffer = mGLState.getTargetFramebuffer(target);
        ASSERT(framebuffer);
    
        if (framebuffer->checkStatus(mState) != GL_FRAMEBUFFER_COMPLETE)
        {
            return;
        }
    
        handleError(framebuffer->invalidate(numAttachments, attachments));
    }
    
    void Context::invalidateSubFramebuffer(GLenum target,
                                           GLsizei numAttachments,
                                           const GLenum *attachments,
                                           GLint x,
                                           GLint y,
                                           GLsizei width,
                                           GLsizei height)
    {
        // Only sync the FBO
        mGLState.syncDirtyObject(target);
    
        Framebuffer *framebuffer = mGLState.getTargetFramebuffer(target);
        ASSERT(framebuffer);
    
        if (framebuffer->checkStatus(mState) != GL_FRAMEBUFFER_COMPLETE)
        {
            return;
        }
    
        Rectangle area(x, y, width, height);
        handleError(framebuffer->invalidateSub(numAttachments, attachments, area));
    }
    
    void Context::texImage2D(GLenum target,
                             GLint level,
                             GLint internalformat,
                             GLsizei width,
                             GLsizei height,
                             GLint border,
                             GLenum format,
                             GLenum type,
                             const GLvoid *pixels)
    {
        syncStateForTexImage();
    
        Extents size(width, height, 1);
        Texture *texture =
            getTargetTexture(IsCubeMapTextureTarget(target) ? GL_TEXTURE_CUBE_MAP : target);
        handleError(texture->setImage(mGLState.getUnpackState(), target, level, internalformat, size,
                                      format, type, reinterpret_cast<const uint8_t *>(pixels)));
    }
    
    void Context::texImage3D(GLenum target,
                             GLint level,
                             GLint internalformat,
                             GLsizei width,
                             GLsizei height,
                             GLsizei depth,
                             GLint border,
                             GLenum format,
                             GLenum type,
                             const GLvoid *pixels)
    {
        syncStateForTexImage();
    
        Extents size(width, height, depth);
        Texture *texture = getTargetTexture(target);
        handleError(texture->setImage(mGLState.getUnpackState(), target, level, internalformat, size,
                                      format, type, reinterpret_cast<const uint8_t *>(pixels)));
    }
    
    void Context::texSubImage2D(GLenum target,
                                GLint level,
                                GLint xoffset,
                                GLint yoffset,
                                GLsizei width,
                                GLsizei height,
                                GLenum format,
                                GLenum type,
                                const GLvoid *pixels)
    {
        // Zero sized uploads are valid but no-ops
        if (width == 0 || height == 0)
        {
            return;
        }
    
        syncStateForTexImage();
    
        Box area(xoffset, yoffset, 0, width, height, 1);
        Texture *texture =
            getTargetTexture(IsCubeMapTextureTarget(target) ? GL_TEXTURE_CUBE_MAP : target);
        handleError(texture->setSubImage(mGLState.getUnpackState(), target, level, area, format, type,
                                         reinterpret_cast<const uint8_t *>(pixels)));
    }
    
    void Context::texSubImage3D(GLenum target,
                                GLint level,
                                GLint xoffset,
                                GLint yoffset,
                                GLint zoffset,
                                GLsizei width,
                                GLsizei height,
                                GLsizei depth,
                                GLenum format,
                                GLenum type,
                                const GLvoid *pixels)
    {
        // Zero sized uploads are valid but no-ops
        if (width == 0 || height == 0 || depth == 0)
        {
            return;
        }
    
        syncStateForTexImage();
    
        Box area(xoffset, yoffset, zoffset, width, height, depth);
        Texture *texture = getTargetTexture(target);
        handleError(texture->setSubImage(mGLState.getUnpackState(), target, level, area, format, type,
                                         reinterpret_cast<const uint8_t *>(pixels)));
    }
    
    void Context::compressedTexImage2D(GLenum target,
                                       GLint level,
                                       GLenum internalformat,
                                       GLsizei width,
                                       GLsizei height,
                                       GLint border,
                                       GLsizei imageSize,
                                       const GLvoid *data)
    {
        syncStateForTexImage();
    
        Extents size(width, height, 1);
        Texture *texture =
            getTargetTexture(IsCubeMapTextureTarget(target) ? GL_TEXTURE_CUBE_MAP : target);
        handleError(texture->setCompressedImage(mGLState.getUnpackState(), target, level,
                                                internalformat, size, imageSize,
                                                reinterpret_cast<const uint8_t *>(data)));
    }
    
    void Context::compressedTexImage3D(GLenum target,
                                       GLint level,
                                       GLenum internalformat,
                                       GLsizei width,
                                       GLsizei height,
                                       GLsizei depth,
                                       GLint border,
                                       GLsizei imageSize,
                                       const GLvoid *data)
    {
        syncStateForTexImage();
    
        Extents size(width, height, depth);
        Texture *texture = getTargetTexture(target);
        handleError(texture->setCompressedImage(mGLState.getUnpackState(), target, level,
                                                internalformat, size, imageSize,
                                                reinterpret_cast<const uint8_t *>(data)));
    }
    
    void Context::compressedTexSubImage2D(GLenum target,
                                          GLint level,
                                          GLint xoffset,
                                          GLint yoffset,
                                          GLsizei width,
                                          GLsizei height,
                                          GLenum format,
                                          GLsizei imageSize,
                                          const GLvoid *data)
    {
        syncStateForTexImage();
    
        Box area(xoffset, yoffset, 0, width, height, 1);
        Texture *texture =
            getTargetTexture(IsCubeMapTextureTarget(target) ? GL_TEXTURE_CUBE_MAP : target);
        handleError(texture->setCompressedSubImage(mGLState.getUnpackState(), target, level, area,
                                                   format, imageSize,
                                                   reinterpret_cast<const uint8_t *>(data)));
    }
    
    void Context::compressedTexSubImage3D(GLenum target,
                                          GLint level,
                                          GLint xoffset,
                                          GLint yoffset,
                                          GLint zoffset,
                                          GLsizei width,
                                          GLsizei height,
                                          GLsizei depth,
                                          GLenum format,
                                          GLsizei imageSize,
                                          const GLvoid *data)
    {
        // Zero sized uploads are valid but no-ops
        if (width == 0 || height == 0)
        {
            return;
        }
    
        syncStateForTexImage();
    
        Box area(xoffset, yoffset, zoffset, width, height, depth);
        Texture *texture = getTargetTexture(target);
        handleError(texture->setCompressedSubImage(mGLState.getUnpackState(), target, level, area,
                                                   format, imageSize,
                                                   reinterpret_cast<const uint8_t *>(data)));
    }
    
    void Context::generateMipmap(GLenum target)
    {
        Texture *texture = getTargetTexture(target);
        handleError(texture->generateMipmap());
    }
    
    void Context::copyTextureCHROMIUM(GLuint sourceId,
                                      GLuint destId,
                                      GLint internalFormat,
                                      GLenum destType,
                                      GLboolean unpackFlipY,
                                      GLboolean unpackPremultiplyAlpha,
                                      GLboolean unpackUnmultiplyAlpha)
    {
        syncStateForTexImage();
    
        gl::Texture *sourceTexture = getTexture(sourceId);
        gl::Texture *destTexture   = getTexture(destId);
        handleError(destTexture->copyTexture(internalFormat, destType, unpackFlipY == GL_TRUE,
                                             unpackPremultiplyAlpha == GL_TRUE,
                                             unpackUnmultiplyAlpha == GL_TRUE, sourceTexture));
    }
    
    void Context::copySubTextureCHROMIUM(GLuint sourceId,
                                         GLuint destId,
                                         GLint xoffset,
                                         GLint yoffset,
                                         GLint x,
                                         GLint y,
                                         GLsizei width,
                                         GLsizei height,
                                         GLboolean unpackFlipY,
                                         GLboolean unpackPremultiplyAlpha,
                                         GLboolean unpackUnmultiplyAlpha)
    {
        // Zero sized copies are valid but no-ops
        if (width == 0 || height == 0)
        {
            return;
        }
    
        syncStateForTexImage();
    
        gl::Texture *sourceTexture = getTexture(sourceId);
        gl::Texture *destTexture   = getTexture(destId);
        Offset offset(xoffset, yoffset, 0);
        Rectangle area(x, y, width, height);
        handleError(destTexture->copySubTexture(offset, area, unpackFlipY == GL_TRUE,
                                                unpackPremultiplyAlpha == GL_TRUE,
                                                unpackUnmultiplyAlpha == GL_TRUE, sourceTexture));
    }
    
    void Context::compressedCopyTextureCHROMIUM(GLuint sourceId, GLuint destId)
    {
        syncStateForTexImage();
    
        gl::Texture *sourceTexture = getTexture(sourceId);
        gl::Texture *destTexture   = getTexture(destId);
        handleError(destTexture->copyCompressedTexture(sourceTexture));
    }
    
    void Context::getBufferPointerv(GLenum target, GLenum pname, void **params)
    {
        Buffer *buffer = mGLState.getTargetBuffer(target);
        ASSERT(buffer);
    
        QueryBufferPointerv(buffer, pname, params);
    }
    
    GLvoid *Context::mapBuffer(GLenum target, GLenum access)
    {
        Buffer *buffer = mGLState.getTargetBuffer(target);
        ASSERT(buffer);
    
        Error error = buffer->map(access);
        if (error.isError())
        {
            handleError(error);
            return nullptr;
        }
    
        return buffer->getMapPointer();
    }
    
    GLboolean Context::unmapBuffer(GLenum target)
    {
        Buffer *buffer = mGLState.getTargetBuffer(target);
        ASSERT(buffer);
    
        GLboolean result;
        Error error = buffer->unmap(&result);
        if (error.isError())
        {
            handleError(error);
            return GL_FALSE;
        }
    
        return result;
    }
    
    GLvoid *Context::mapBufferRange(GLenum target,
                                    GLintptr offset,
                                    GLsizeiptr length,
                                    GLbitfield access)
    {
        Buffer *buffer = mGLState.getTargetBuffer(target);
        ASSERT(buffer);
    
        Error error = buffer->mapRange(offset, length, access);
        if (error.isError())
        {
            handleError(error);
            return nullptr;
        }
    
        return buffer->getMapPointer();
    }
    
    void Context::flushMappedBufferRange(GLenum /*target*/, GLintptr /*offset*/, GLsizeiptr /*length*/)
    {
        // We do not currently support a non-trivial implementation of FlushMappedBufferRange
    }
    
    void Context::syncStateForReadPixels()
    {
        syncRendererState(mReadPixelsDirtyBits, mReadPixelsDirtyObjects);
    }
    
    void Context::syncStateForTexImage()
    {
        syncRendererState(mTexImageDirtyBits, mTexImageDirtyObjects);
    }
    
    void Context::syncStateForClear()
    {
        syncRendererState(mClearDirtyBits, mClearDirtyObjects);
    }
    
    void Context::syncStateForBlit()
    {
        syncRendererState(mBlitDirtyBits, mBlitDirtyObjects);
    }
    
    void Context::activeTexture(GLenum texture)
    {
        mGLState.setActiveSampler(texture - GL_TEXTURE0);
    }
    
    void Context::blendColor(GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha)
    {
        mGLState.setBlendColor(clamp01(red), clamp01(green), clamp01(blue), clamp01(alpha));
    }
    
    void Context::blendEquation(GLenum mode)
    {
        mGLState.setBlendEquation(mode, mode);
    }
    
    void Context::blendEquationSeparate(GLenum modeRGB, GLenum modeAlpha)
    {
        mGLState.setBlendEquation(modeRGB, modeAlpha);
    }
    
    void Context::blendFunc(GLenum sfactor, GLenum dfactor)
    {
        mGLState.setBlendFactors(sfactor, dfactor, sfactor, dfactor);
    }
    
    void Context::blendFuncSeparate(GLenum srcRGB, GLenum dstRGB, GLenum srcAlpha, GLenum dstAlpha)
    {
        mGLState.setBlendFactors(srcRGB, dstRGB, srcAlpha, dstAlpha);
    }
    
    void Context::clearColor(GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha)
    {
        mGLState.setColorClearValue(red, green, blue, alpha);
    }
    
    void Context::clearDepthf(GLclampf depth)
    {
        mGLState.setDepthClearValue(depth);
    }
    
    void Context::clearStencil(GLint s)
    {
        mGLState.setStencilClearValue(s);
    }
    
    void Context::colorMask(GLboolean red, GLboolean green, GLboolean blue, GLboolean alpha)
    {
        mGLState.setColorMask(red == GL_TRUE, green == GL_TRUE, blue == GL_TRUE, alpha == GL_TRUE);
    }
    
    void Context::cullFace(GLenum mode)
    {
        mGLState.setCullMode(mode);
    }
    
    void Context::depthFunc(GLenum func)
    {
        mGLState.setDepthFunc(func);
    }
    
    void Context::depthMask(GLboolean flag)
    {
        mGLState.setDepthMask(flag != GL_FALSE);
    }
    
    void Context::depthRangef(GLclampf zNear, GLclampf zFar)
    {
        mGLState.setDepthRange(zNear, zFar);
    }
    
    void Context::disable(GLenum cap)
    {
        mGLState.setEnableFeature(cap, false);
    }
    
    void Context::disableVertexAttribArray(GLuint index)
    {
        mGLState.setEnableVertexAttribArray(index, false);
    }
    
    void Context::enable(GLenum cap)
    {
        mGLState.setEnableFeature(cap, true);
    }
    
    void Context::enableVertexAttribArray(GLuint index)
    {
        mGLState.setEnableVertexAttribArray(index, true);
    }
    
    void Context::frontFace(GLenum mode)
    {
        mGLState.setFrontFace(mode);
    }
    
    void Context::hint(GLenum target, GLenum mode)
    {
        switch (target)
        {
            case GL_GENERATE_MIPMAP_HINT:
                mGLState.setGenerateMipmapHint(mode);
                break;
    
            case GL_FRAGMENT_SHADER_DERIVATIVE_HINT_OES:
                mGLState.setFragmentShaderDerivativeHint(mode);
                break;
    
            default:
                UNREACHABLE();
                return;
        }
    }
    
    void Context::lineWidth(GLfloat width)
    {
        mGLState.setLineWidth(width);
    }
    
    void Context::pixelStorei(GLenum pname, GLint param)
    {
        switch (pname)
        {
            case GL_UNPACK_ALIGNMENT:
                mGLState.setUnpackAlignment(param);
                break;
    
            case GL_PACK_ALIGNMENT:
                mGLState.setPackAlignment(param);
                break;
    
            case GL_PACK_REVERSE_ROW_ORDER_ANGLE:
                mGLState.setPackReverseRowOrder(param != 0);
                break;
    
            case GL_UNPACK_ROW_LENGTH:
                ASSERT((getClientMajorVersion() >= 3) || getExtensions().unpackSubimage);
                mGLState.setUnpackRowLength(param);
                break;
    
            case GL_UNPACK_IMAGE_HEIGHT:
                ASSERT(getClientMajorVersion() >= 3);
                mGLState.setUnpackImageHeight(param);
                break;
    
            case GL_UNPACK_SKIP_IMAGES:
                ASSERT(getClientMajorVersion() >= 3);
                mGLState.setUnpackSkipImages(param);
                break;
    
            case GL_UNPACK_SKIP_ROWS:
                ASSERT((getClientMajorVersion() >= 3) || getExtensions().unpackSubimage);
                mGLState.setUnpackSkipRows(param);
                break;
    
            case GL_UNPACK_SKIP_PIXELS:
                ASSERT((getClientMajorVersion() >= 3) || getExtensions().unpackSubimage);
                mGLState.setUnpackSkipPixels(param);
                break;
    
            case GL_PACK_ROW_LENGTH:
                ASSERT((getClientMajorVersion() >= 3) || getExtensions().packSubimage);
                mGLState.setPackRowLength(param);
                break;
    
            case GL_PACK_SKIP_ROWS:
                ASSERT((getClientMajorVersion() >= 3) || getExtensions().packSubimage);
                mGLState.setPackSkipRows(param);
                break;
    
            case GL_PACK_SKIP_PIXELS:
                ASSERT((getClientMajorVersion() >= 3) || getExtensions().packSubimage);
                mGLState.setPackSkipPixels(param);
                break;
    
            default:
                UNREACHABLE();
                return;
        }
    }
    
    void Context::polygonOffset(GLfloat factor, GLfloat units)
    {
        mGLState.setPolygonOffsetParams(factor, units);
    }
    
    void Context::sampleCoverage(GLclampf value, GLboolean invert)
    {
        mGLState.setSampleCoverageParams(clamp01(value), invert == GL_TRUE);
    }
    
    void Context::scissor(GLint x, GLint y, GLsizei width, GLsizei height)
    {
        mGLState.setScissorParams(x, y, width, height);
    }
    
    void Context::stencilFuncSeparate(GLenum face, GLenum func, GLint ref, GLuint mask)
    {
        if (face == GL_FRONT || face == GL_FRONT_AND_BACK)
        {
            mGLState.setStencilParams(func, ref, mask);
        }
    
        if (face == GL_BACK || face == GL_FRONT_AND_BACK)
        {
            mGLState.setStencilBackParams(func, ref, mask);
        }
    }
    
    void Context::stencilMaskSeparate(GLenum face, GLuint mask)
    {
        if (face == GL_FRONT || face == GL_FRONT_AND_BACK)
        {
            mGLState.setStencilWritemask(mask);
        }
    
        if (face == GL_BACK || face == GL_FRONT_AND_BACK)
        {
            mGLState.setStencilBackWritemask(mask);
        }
    }
    
    void Context::stencilOpSeparate(GLenum face, GLenum fail, GLenum zfail, GLenum zpass)
    {
        if (face == GL_FRONT || face == GL_FRONT_AND_BACK)
        {
            mGLState.setStencilOperations(fail, zfail, zpass);
        }
    
        if (face == GL_BACK || face == GL_FRONT_AND_BACK)
        {
            mGLState.setStencilBackOperations(fail, zfail, zpass);
        }
    }
    
    void Context::vertexAttrib1f(GLuint index, GLfloat x)
    {
        GLfloat vals[4] = {x, 0, 0, 1};
        mGLState.setVertexAttribf(index, vals);
    }
    
    void Context::vertexAttrib1fv(GLuint index, const GLfloat *values)
    {
        GLfloat vals[4] = {values[0], 0, 0, 1};
        mGLState.setVertexAttribf(index, vals);
    }
    
    void Context::vertexAttrib2f(GLuint index, GLfloat x, GLfloat y)
    {
        GLfloat vals[4] = {x, y, 0, 1};
        mGLState.setVertexAttribf(index, vals);
    }
    
    void Context::vertexAttrib2fv(GLuint index, const GLfloat *values)
    {
        GLfloat vals[4] = {values[0], values[1], 0, 1};
        mGLState.setVertexAttribf(index, vals);
    }
    
    void Context::vertexAttrib3f(GLuint index, GLfloat x, GLfloat y, GLfloat z)
    {
        GLfloat vals[4] = {x, y, z, 1};
        mGLState.setVertexAttribf(index, vals);
    }
    
    void Context::vertexAttrib3fv(GLuint index, const GLfloat *values)
    {
        GLfloat vals[4] = {values[0], values[1], values[2], 1};
        mGLState.setVertexAttribf(index, vals);
    }
    
    void Context::vertexAttrib4f(GLuint index, GLfloat x, GLfloat y, GLfloat z, GLfloat w)
    {
        GLfloat vals[4] = {x, y, z, w};
        mGLState.setVertexAttribf(index, vals);
    }
    
    void Context::vertexAttrib4fv(GLuint index, const GLfloat *values)
    {
        mGLState.setVertexAttribf(index, values);
    }
    
    void Context::vertexAttribPointer(GLuint index,
                                      GLint size,
                                      GLenum type,
                                      GLboolean normalized,
                                      GLsizei stride,
                                      const GLvoid *ptr)
    {
        mGLState.setVertexAttribState(index, mGLState.getTargetBuffer(GL_ARRAY_BUFFER), size, type,
                                      normalized == GL_TRUE, false, stride, ptr);
    }
    
    void Context::viewport(GLint x, GLint y, GLsizei width, GLsizei height)
    {
        mGLState.setViewportParams(x, y, width, height);
    }
    
    void Context::vertexAttribIPointer(GLuint index,
                                       GLint size,
                                       GLenum type,
                                       GLsizei stride,
                                       const GLvoid *pointer)
    {
        mGLState.setVertexAttribState(index, mGLState.getTargetBuffer(GL_ARRAY_BUFFER), size, type,
                                      false, true, stride, pointer);
    }
    
    void Context::vertexAttribI4i(GLuint index, GLint x, GLint y, GLint z, GLint w)
    {
        GLint vals[4] = {x, y, z, w};
        mGLState.setVertexAttribi(index, vals);
    }
    
    void Context::vertexAttribI4ui(GLuint index, GLuint x, GLuint y, GLuint z, GLuint w)
    {
        GLuint vals[4] = {x, y, z, w};
        mGLState.setVertexAttribu(index, vals);
    }
    
    void Context::vertexAttribI4iv(GLuint index, const GLint *v)
    {
        mGLState.setVertexAttribi(index, v);
    }
    
    void Context::vertexAttribI4uiv(GLuint index, const GLuint *v)
    {
        mGLState.setVertexAttribu(index, v);
    }
    
    void Context::debugMessageControl(GLenum source,
                                      GLenum type,
                                      GLenum severity,
                                      GLsizei count,
                                      const GLuint *ids,
                                      GLboolean enabled)
    {
        std::vector<GLuint> idVector(ids, ids + count);
        mGLState.getDebug().setMessageControl(source, type, severity, std::move(idVector),
                                              (enabled != GL_FALSE));
    }
    
    void Context::debugMessageInsert(GLenum source,
                                     GLenum type,
                                     GLuint id,
                                     GLenum severity,
                                     GLsizei length,
                                     const GLchar *buf)
    {
        std::string msg(buf, (length > 0) ? static_cast<size_t>(length) : strlen(buf));
        mGLState.getDebug().insertMessage(source, type, id, severity, std::move(msg));
    }
    
    void Context::debugMessageCallback(GLDEBUGPROCKHR callback, const void *userParam)
    {
        mGLState.getDebug().setCallback(callback, userParam);
    }
    
    GLuint Context::getDebugMessageLog(GLuint count,
                                       GLsizei bufSize,
                                       GLenum *sources,
                                       GLenum *types,
                                       GLuint *ids,
                                       GLenum *severities,
                                       GLsizei *lengths,
                                       GLchar *messageLog)
    {
        return static_cast<GLuint>(mGLState.getDebug().getMessages(count, bufSize, sources, types, ids,
                                                                   severities, lengths, messageLog));
    }
    
    void Context::pushDebugGroup(GLenum source, GLuint id, GLsizei length, const GLchar *message)
    {
        std::string msg(message, (length > 0) ? static_cast<size_t>(length) : strlen(message));
        mGLState.getDebug().pushGroup(source, id, std::move(msg));
    }
    
    void Context::popDebugGroup()
    {
        mGLState.getDebug().popGroup();
    }
    
    void Context::bufferData(GLenum target, GLsizeiptr size, const GLvoid *data, GLenum usage)
    {
        Buffer *buffer = mGLState.getTargetBuffer(target);
        ASSERT(buffer);
        handleError(buffer->bufferData(target, data, size, usage));
    }
    
    void Context::bufferSubData(GLenum target, GLintptr offset, GLsizeiptr size, const GLvoid *data)
    {
        if (data == nullptr)
        {
            return;
        }
    
        Buffer *buffer = mGLState.getTargetBuffer(target);
        ASSERT(buffer);
        handleError(buffer->bufferSubData(target, data, size, offset));
    }
    
    void Context::attachShader(GLuint program, GLuint shader)
    {
        auto programObject = mResourceManager->getProgram(program);
        auto shaderObject  = mResourceManager->getShader(shader);
        ASSERT(programObject && shaderObject);
        programObject->attachShader(shaderObject);
    }
    
    const Workarounds &Context::getWorkarounds() const
    {
        return mWorkarounds;
    }
    
    void Context::copyBufferSubData(GLenum readTarget,
                                    GLenum writeTarget,
                                    GLintptr readOffset,
                                    GLintptr writeOffset,
                                    GLsizeiptr size)
    {
        // if size is zero, the copy is a successful no-op
        if (size == 0)
        {
            return;
        }
    
        // TODO(jmadill): cache these.
        Buffer *readBuffer  = mGLState.getTargetBuffer(readTarget);
        Buffer *writeBuffer = mGLState.getTargetBuffer(writeTarget);
    
        handleError(writeBuffer->copyBufferSubData(readBuffer, readOffset, writeOffset, size));
    }
    
    void Context::bindAttribLocation(GLuint program, GLuint index, const GLchar *name)
    {
        Program *programObject = getProgram(program);
        // TODO(jmadill): Re-use this from the validation if possible.
        ASSERT(programObject);
        programObject->bindAttributeLocation(index, name);
    }
    
    void Context::bindBuffer(GLenum target, GLuint buffer)
    {
        switch (target)
        {
            case GL_ARRAY_BUFFER:
                bindArrayBuffer(buffer);
                break;
            case GL_ELEMENT_ARRAY_BUFFER:
                bindElementArrayBuffer(buffer);
                break;
            case GL_COPY_READ_BUFFER:
                bindCopyReadBuffer(buffer);
                break;
            case GL_COPY_WRITE_BUFFER:
                bindCopyWriteBuffer(buffer);
                break;
            case GL_PIXEL_PACK_BUFFER:
                bindPixelPackBuffer(buffer);
                break;
            case GL_PIXEL_UNPACK_BUFFER:
                bindPixelUnpackBuffer(buffer);
                break;
            case GL_UNIFORM_BUFFER:
                bindGenericUniformBuffer(buffer);
                break;
            case GL_TRANSFORM_FEEDBACK_BUFFER:
                bindGenericTransformFeedbackBuffer(buffer);
                break;
            case GL_ATOMIC_COUNTER_BUFFER:
                if (buffer != 0)
                {
                    // Binding buffers to this binding point is not implemented yet.
                    UNIMPLEMENTED();
                }
                break;
            case GL_SHADER_STORAGE_BUFFER:
                if (buffer != 0)
                {
                    // Binding buffers to this binding point is not implemented yet.
                    UNIMPLEMENTED();
                }
                break;
            case GL_DRAW_INDIRECT_BUFFER:
                bindDrawIndirectBuffer(buffer);
                break;
            case GL_DISPATCH_INDIRECT_BUFFER:
                if (buffer != 0)
                {
                    // Binding buffers to this binding point is not implemented yet.
                    UNIMPLEMENTED();
                }
                break;
    
            default:
                UNREACHABLE();
                break;
        }
    }
    
    void Context::bindFramebuffer(GLenum target, GLuint framebuffer)
    {
        if (target == GL_READ_FRAMEBUFFER || target == GL_FRAMEBUFFER)
        {
            bindReadFramebuffer(framebuffer);
        }
    
        if (target == GL_DRAW_FRAMEBUFFER || target == GL_FRAMEBUFFER)
        {
            bindDrawFramebuffer(framebuffer);
        }
    }
    
    void Context::bindRenderbuffer(GLenum target, GLuint renderbuffer)
    {
        ASSERT(target == GL_RENDERBUFFER);
        Renderbuffer *object =
            mResourceManager->checkRenderbufferAllocation(mImplementation.get(), renderbuffer);
        mGLState.setRenderbufferBinding(object);
    }
    
    }  // namespace gl