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

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  • Author : Ian Ewell
    Date : 2016-04-05 13:46:26
    Hash : ec2c0c5e
    Message : Update internal AttributeMap type to EGLAttrib. Newer EGL functions use EGLAttrib to pass in attributes, which can be either 32-bit or 64-bit depending on the system while the old attributes are passed in as EGLints, which are usually 32-bits. To support these newer functions, AttributeMap now uses EGLAttrib internally instead of EGLint, and all the code using AttributeMap has been updated to cast properly. BUG=angleproject:1348 Change-Id: I7c4dd9ef23ea1b1741f3a565502fb5e26bf962d7 Reviewed-on: https://chromium-review.googlesource.com/337162 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Ian Ewell <ewell@google.com>

  • 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 "common/platform.h"
    #include "common/utilities.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/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/renderer/Renderer.h"
    
    namespace
    {
    
    template <typename T>
    gl::Error GetQueryObjectParameter(gl::Context *context, GLuint id, GLenum pname, T *params)
    {
        gl::Query *queryObject = context->getQuery(id, false, GL_NONE);
        ASSERT(queryObject != nullptr);
    
        switch (pname)
        {
            case GL_QUERY_RESULT_EXT:
                return queryObject->getResult(params);
            case GL_QUERY_RESULT_AVAILABLE_EXT:
            {
                bool available;
                gl::Error error = queryObject->isResultAvailable(&available);
                if (!error.isError())
                {
                    *params = static_cast<T>(available ? GL_TRUE : GL_FALSE);
                }
                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 GetClientVersion(const egl::AttributeMap &attribs)
    {
        return static_cast<EGLint>(attribs.get(EGL_CONTEXT_CLIENT_VERSION, 1));
    }
    
    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);
    }
    
    bool GetDebug(const egl::AttributeMap &attribs)
    {
        return (attribs.get(EGL_CONTEXT_OPENGL_DEBUG, EGL_FALSE) == EGL_TRUE);
    }
    
    bool GetNoError(const egl::AttributeMap &attribs)
    {
        return (attribs.get(EGL_CONTEXT_OPENGL_NO_ERROR_KHR, EGL_FALSE) == EGL_TRUE);
    }
    
    }  // anonymous namespace
    
    namespace gl
    {
    
    Context::Context(const egl::Config *config,
                     const Context *shareContext,
                     rx::Renderer *renderer,
                     const egl::AttributeMap &attribs)
        : ValidationContext(GetClientVersion(attribs),
                            mState,
                            mCaps,
                            mTextureCaps,
                            mExtensions,
                            nullptr,
                            mLimitations,
                            GetNoError(attribs)),
          mCompiler(nullptr),
          mRenderer(renderer),
          mClientVersion(GetClientVersion(attribs)),
          mConfig(config),
          mClientType(EGL_OPENGL_ES_API),
          mHasBeenCurrent(false),
          mContextLost(false),
          mResetStatus(GL_NO_ERROR),
          mResetStrategy(GetResetStrategy(attribs)),
          mRobustAccess(GetRobustAccess(attribs)),
          mCurrentSurface(nullptr),
          mResourceManager(nullptr)
    {
        ASSERT(!mRobustAccess);  // Unimplemented
    
        initCaps(mClientVersion);
    
        mState.initialize(mCaps, mExtensions, mClientVersion, GetDebug(attribs));
    
        mFenceNVHandleAllocator.setBaseHandle(0);
    
        if (shareContext != NULL)
        {
            mResourceManager = shareContext->mResourceManager;
            mResourceManager->addRef();
        }
        else
        {
            mResourceManager = new ResourceManager(mRenderer);
        }
    
        mData.resourceManager = 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(mRenderer->createTexture(GL_TEXTURE_2D), 0, GL_TEXTURE_2D);
        mZeroTextures[GL_TEXTURE_2D].set(zeroTexture2D);
    
        Texture *zeroTextureCube = new Texture(mRenderer->createTexture(GL_TEXTURE_CUBE_MAP), 0, GL_TEXTURE_CUBE_MAP);
        mZeroTextures[GL_TEXTURE_CUBE_MAP].set(zeroTextureCube);
    
        if (mClientVersion >= 3)
        {
            // TODO: These could also be enabled via extension
            Texture *zeroTexture3D = new Texture(mRenderer->createTexture(GL_TEXTURE_3D), 0, GL_TEXTURE_3D);
            mZeroTextures[GL_TEXTURE_3D].set(zeroTexture3D);
    
            Texture *zeroTexture2DArray = new Texture(mRenderer->createTexture(GL_TEXTURE_2D_ARRAY), 0, GL_TEXTURE_2D_ARRAY);
            mZeroTextures[GL_TEXTURE_2D_ARRAY].set(zeroTexture2DArray);
        }
    
        mState.initializeZeroTextures(mZeroTextures);
    
        bindVertexArray(0);
        bindArrayBuffer(0);
        bindElementArrayBuffer(0);
    
        bindRenderbuffer(0);
    
        bindGenericUniformBuffer(0);
        for (unsigned int i = 0; i < mCaps.maxCombinedUniformBlocks; i++)
        {
            bindIndexedUniformBuffer(0, i, 0, -1);
        }
    
        bindCopyReadBuffer(0);
        bindCopyWriteBuffer(0);
        bindPixelPackBuffer(0);
        bindPixelUnpackBuffer(0);
    
        if (mClientVersion >= 3)
        {
            // [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(mRenderer, getData());
    
        // 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);
        // 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);
        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);
        mBlitDirtyObjects.set(State::DIRTY_OBJECT_READ_FRAMEBUFFER);
        mBlitDirtyObjects.set(State::DIRTY_OBJECT_DRAW_FRAMEBUFFER);
    }
    
    Context::~Context()
    {
        mState.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();
            initExtensionStrings();
    
            mState.setViewportParams(0, 0, surface->getWidth(), surface->getHeight());
            mState.setScissorParams(0, 0, surface->getWidth(), surface->getHeight());
    
            mHasBeenCurrent = true;
        }
    
        // TODO(jmadill): Rework this when we support ContextImpl
        mState.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 (mState.getReadFramebuffer() == nullptr)
            {
                mState.setReadFramebufferBinding(newDefault);
            }
            if (mState.getDrawFramebuffer() == nullptr)
            {
                mState.setDrawFramebufferBinding(newDefault);
            }
            mFramebufferMap[0] = newDefault;
        }
    
        // Notify the renderer of a context switch
        mRenderer->onMakeCurrent(getData());
    }
    
    void Context::releaseSurface()
    {
        ASSERT(mCurrentSurface != nullptr);
    
        // Remove the default framebuffer
        {
            Framebuffer *currentDefault = mCurrentSurface->getDefaultFramebuffer();
            if (mState.getReadFramebuffer() == currentDefault)
            {
                mState.setReadFramebufferBinding(nullptr);
            }
            if (mState.getDrawFramebuffer() == currentDefault)
            {
                mState.setDrawFramebufferBinding(nullptr);
            }
            mFramebufferMap.erase(0);
        }
    
        mCurrentSurface->setIsCurrent(false);
        mCurrentSurface = nullptr;
    }
    
    // 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;
        mContextLost = true;
    }
    
    bool Context::isContextLost()
    {
        return mContextLost;
    }
    
    GLuint Context::createBuffer()
    {
        return mResourceManager->createBuffer();
    }
    
    GLuint Context::createProgram()
    {
        return mResourceManager->createProgram();
    }
    
    GLuint Context::createShader(GLenum type)
    {
        return mResourceManager->createShader(mRenderer->getRendererLimitations(), type);
    }
    
    GLuint Context::createTexture()
    {
        return mResourceManager->createTexture();
    }
    
    GLuint Context::createRenderbuffer()
    {
        return mResourceManager->createRenderbuffer();
    }
    
    GLsync Context::createFenceSync()
    {
        GLuint handle = mResourceManager->createFenceSync();
    
        return reinterpret_cast<GLsync>(static_cast<uintptr_t>(handle));
    }
    
    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(mRenderer->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::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);
    }
    
    Shader *Context::getShader(GLuint handle) const
    {
        return mResourceManager->getShader(handle);
    }
    
    Program *Context::getProgram(GLuint handle) const
    {
        return mResourceManager->getProgram(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)));
    }
    
    bool Context::isSampler(GLuint samplerName) const
    {
        return mResourceManager->isSampler(samplerName);
    }
    
    void Context::bindArrayBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(bufferHandle);
        mState.setArrayBufferBinding(buffer);
    }
    
    void Context::bindElementArrayBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(bufferHandle);
        mState.getVertexArray()->setElementArrayBuffer(buffer);
    }
    
    void Context::bindTexture(GLenum target, GLuint handle)
    {
        Texture *texture = nullptr;
    
        if (handle == 0)
        {
            texture = mZeroTextures[target].get();
        }
        else
        {
            texture = mResourceManager->checkTextureAllocation(handle, target);
        }
    
        ASSERT(texture);
        mState.setSamplerTexture(target, texture);
    }
    
    void Context::bindReadFramebuffer(GLuint framebufferHandle)
    {
        Framebuffer *framebuffer = checkFramebufferAllocation(framebufferHandle);
        mState.setReadFramebufferBinding(framebuffer);
    }
    
    void Context::bindDrawFramebuffer(GLuint framebufferHandle)
    {
        Framebuffer *framebuffer = checkFramebufferAllocation(framebufferHandle);
        mState.setDrawFramebufferBinding(framebuffer);
    }
    
    void Context::bindRenderbuffer(GLuint renderbufferHandle)
    {
        Renderbuffer *renderbuffer = mResourceManager->checkRenderbufferAllocation(renderbufferHandle);
        mState.setRenderbufferBinding(renderbuffer);
    }
    
    void Context::bindVertexArray(GLuint vertexArrayHandle)
    {
        VertexArray *vertexArray = checkVertexArrayAllocation(vertexArrayHandle);
        mState.setVertexArrayBinding(vertexArray);
    }
    
    void Context::bindSampler(GLuint textureUnit, GLuint samplerHandle)
    {
        ASSERT(textureUnit < mCaps.maxCombinedTextureImageUnits);
        Sampler *sampler = mResourceManager->checkSamplerAllocation(samplerHandle);
        mState.setSamplerBinding(textureUnit, sampler);
    }
    
    void Context::bindGenericUniformBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(bufferHandle);
        mState.setGenericUniformBufferBinding(buffer);
    }
    
    void Context::bindIndexedUniformBuffer(GLuint bufferHandle,
                                           GLuint index,
                                           GLintptr offset,
                                           GLsizeiptr size)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(bufferHandle);
        mState.setIndexedUniformBufferBinding(index, buffer, offset, size);
    }
    
    void Context::bindGenericTransformFeedbackBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(bufferHandle);
        mState.getCurrentTransformFeedback()->bindGenericBuffer(buffer);
    }
    
    void Context::bindIndexedTransformFeedbackBuffer(GLuint bufferHandle,
                                                     GLuint index,
                                                     GLintptr offset,
                                                     GLsizeiptr size)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(bufferHandle);
        mState.getCurrentTransformFeedback()->bindIndexedBuffer(index, buffer, offset, size);
    }
    
    void Context::bindCopyReadBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(bufferHandle);
        mState.setCopyReadBufferBinding(buffer);
    }
    
    void Context::bindCopyWriteBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(bufferHandle);
        mState.setCopyWriteBufferBinding(buffer);
    }
    
    void Context::bindPixelPackBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(bufferHandle);
        mState.setPixelPackBufferBinding(buffer);
    }
    
    void Context::bindPixelUnpackBuffer(GLuint bufferHandle)
    {
        Buffer *buffer = mResourceManager->checkBufferAllocation(bufferHandle);
        mState.setPixelUnpackBufferBinding(buffer);
    }
    
    void Context::useProgram(GLuint program)
    {
        mState.setProgram(getProgram(program));
    }
    
    void Context::bindTransformFeedback(GLuint transformFeedbackHandle)
    {
        TransformFeedback *transformFeedback =
            checkTransformFeedbackAllocation(transformFeedbackHandle);
        mState.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
        mState.setActiveQuery(target, queryObject);
    
        return Error(GL_NO_ERROR);
    }
    
    Error Context::endQuery(GLenum target)
    {
        Query *queryObject = mState.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.
        mState.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] = getState().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;
        }
    }
    
    Error Context::getQueryObjectiv(GLuint id, GLenum pname, GLint *params)
    {
        return GetQueryObjectParameter(this, id, pname, params);
    }
    
    Error Context::getQueryObjectuiv(GLuint id, GLenum pname, GLuint *params)
    {
        return GetQueryObjectParameter(this, id, pname, params);
    }
    
    Error Context::getQueryObjecti64v(GLuint id, GLenum pname, GLint64 *params)
    {
        return GetQueryObjectParameter(this, id, pname, params);
    }
    
    Error Context::getQueryObjectui64v(GLuint id, GLenum pname, GLuint64 *params)
    {
        return GetQueryObjectParameter(this, 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(mRenderer->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));
        return mState.getTargetTexture(target);
    }
    
    Texture *Context::getSamplerTexture(unsigned int sampler, GLenum type) const
    {
        return mState.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:
            mState.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;
          default:
            mState.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 = mClientVersion;                                       break;
          case GL_MINOR_VERSION:                            *params = 0;                                                    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 = mRenderer->getGPUDisjoint();
              break;
    
          default:
            mState.getIntegerv(getData(), 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 = mRenderer->getTimestamp();
              break;
          default:
            UNREACHABLE();
            break;
        }
    }
    
    void Context::getPointerv(GLenum pname, void **params) const
    {
        mState.getPointerv(pname, params);
    }
    
    bool Context::getIndexedIntegerv(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.
        // Indexed integer queries all refer to current state, so this function is a
        // mere passthrough.
        return mState.getIndexedIntegerv(target, index, data);
    }
    
    bool Context::getIndexedInteger64v(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.
        // Indexed integer queries all refer to current state, so this function is a
        // mere passthrough.
        return mState.getIndexedInteger64v(target, index, data);
    }
    
    bool Context::getQueryParameterInfo(GLenum pname, GLenum *type, unsigned int *numParams)
    {
        if (pname >= GL_DRAW_BUFFER0_EXT && pname <= GL_DRAW_BUFFER15_EXT)
        {
            *type = GL_INT;
            *numParams = 1;
            return true;
        }
    
        // Please note: the query type returned for DEPTH_CLEAR_VALUE in this implementation
        // is FLOAT rather than INT, as would be suggested by the GL ES 2.0 spec. This is due
        // to the fact that it is stored internally as a float, and so would require conversion
        // if returned from Context::getIntegerv. Since this conversion is already implemented
        // in the case that one calls glGetIntegerv to retrieve a float-typed state variable, we
        // place DEPTH_CLEAR_VALUE with the floats. This should make no difference to the calling
        // application.
        switch (pname)
        {
          case GL_COMPRESSED_TEXTURE_FORMATS:
            {
                *type = GL_INT;
                *numParams = static_cast<unsigned int>(mCaps.compressedTextureFormats.size());
            }
            return true;
          case GL_PROGRAM_BINARY_FORMATS_OES:
            {
                *type = GL_INT;
                *numParams = static_cast<unsigned int>(mCaps.programBinaryFormats.size());
            }
            return true;
          case GL_SHADER_BINARY_FORMATS:
            {
                *type = GL_INT;
                *numParams = static_cast<unsigned int>(mCaps.shaderBinaryFormats.size());
            }
            return true;
    
          case GL_MAX_VERTEX_ATTRIBS:
          case GL_MAX_VERTEX_UNIFORM_VECTORS:
          case GL_MAX_VARYING_VECTORS:
          case GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS:
          case GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS:
          case GL_MAX_TEXTURE_IMAGE_UNITS:
          case GL_MAX_FRAGMENT_UNIFORM_VECTORS:
          case GL_MAX_RENDERBUFFER_SIZE:
          case GL_MAX_COLOR_ATTACHMENTS_EXT:
          case GL_MAX_DRAW_BUFFERS_EXT:
          case GL_NUM_SHADER_BINARY_FORMATS:
          case GL_NUM_COMPRESSED_TEXTURE_FORMATS:
          case GL_ARRAY_BUFFER_BINDING:
          //case GL_FRAMEBUFFER_BINDING: // equivalent to DRAW_FRAMEBUFFER_BINDING_ANGLE
          case GL_DRAW_FRAMEBUFFER_BINDING_ANGLE:
          case GL_READ_FRAMEBUFFER_BINDING_ANGLE:
          case GL_RENDERBUFFER_BINDING:
          case GL_CURRENT_PROGRAM:
          case GL_PACK_ALIGNMENT:
          case GL_PACK_REVERSE_ROW_ORDER_ANGLE:
          case GL_UNPACK_ALIGNMENT:
          case GL_GENERATE_MIPMAP_HINT:
          case GL_FRAGMENT_SHADER_DERIVATIVE_HINT_OES:
          case GL_RED_BITS:
          case GL_GREEN_BITS:
          case GL_BLUE_BITS:
          case GL_ALPHA_BITS:
          case GL_DEPTH_BITS:
          case GL_STENCIL_BITS:
          case GL_ELEMENT_ARRAY_BUFFER_BINDING:
          case GL_CULL_FACE_MODE:
          case GL_FRONT_FACE:
          case GL_ACTIVE_TEXTURE:
          case GL_STENCIL_FUNC:
          case GL_STENCIL_VALUE_MASK:
          case GL_STENCIL_REF:
          case GL_STENCIL_FAIL:
          case GL_STENCIL_PASS_DEPTH_FAIL:
          case GL_STENCIL_PASS_DEPTH_PASS:
          case GL_STENCIL_BACK_FUNC:
          case GL_STENCIL_BACK_VALUE_MASK:
          case GL_STENCIL_BACK_REF:
          case GL_STENCIL_BACK_FAIL:
          case GL_STENCIL_BACK_PASS_DEPTH_FAIL:
          case GL_STENCIL_BACK_PASS_DEPTH_PASS:
          case GL_DEPTH_FUNC:
          case GL_BLEND_SRC_RGB:
          case GL_BLEND_SRC_ALPHA:
          case GL_BLEND_DST_RGB:
          case GL_BLEND_DST_ALPHA:
          case GL_BLEND_EQUATION_RGB:
          case GL_BLEND_EQUATION_ALPHA:
          case GL_STENCIL_WRITEMASK:
          case GL_STENCIL_BACK_WRITEMASK:
          case GL_STENCIL_CLEAR_VALUE:
          case GL_SUBPIXEL_BITS:
          case GL_MAX_TEXTURE_SIZE:
          case GL_MAX_CUBE_MAP_TEXTURE_SIZE:
          case GL_SAMPLE_BUFFERS:
          case GL_SAMPLES:
          case GL_IMPLEMENTATION_COLOR_READ_TYPE:
          case GL_IMPLEMENTATION_COLOR_READ_FORMAT:
          case GL_TEXTURE_BINDING_2D:
          case GL_TEXTURE_BINDING_CUBE_MAP:
          case GL_RESET_NOTIFICATION_STRATEGY_EXT:
          case GL_NUM_PROGRAM_BINARY_FORMATS_OES:
            {
                *type = GL_INT;
                *numParams = 1;
            }
            return true;
          case GL_MAX_SAMPLES_ANGLE:
            {
                if (mExtensions.framebufferMultisample)
                {
                    *type = GL_INT;
                    *numParams = 1;
                }
                else
                {
                    return false;
                }
            }
            return true;
          case GL_MAX_VIEWPORT_DIMS:
            {
                *type = GL_INT;
                *numParams = 2;
            }
            return true;
          case GL_VIEWPORT:
          case GL_SCISSOR_BOX:
            {
                *type = GL_INT;
                *numParams = 4;
            }
            return true;
          case GL_SHADER_COMPILER:
          case GL_SAMPLE_COVERAGE_INVERT:
          case GL_DEPTH_WRITEMASK:
          case GL_CULL_FACE:                // CULL_FACE through DITHER are natural to IsEnabled,
          case GL_POLYGON_OFFSET_FILL:      // but can be retrieved through the Get{Type}v queries.
          case GL_SAMPLE_ALPHA_TO_COVERAGE: // For this purpose, they are treated here as bool-natural
          case GL_SAMPLE_COVERAGE:
          case GL_SCISSOR_TEST:
          case GL_STENCIL_TEST:
          case GL_DEPTH_TEST:
          case GL_BLEND:
          case GL_DITHER:
          case GL_CONTEXT_ROBUST_ACCESS_EXT:
            {
                *type = GL_BOOL;
                *numParams = 1;
            }
            return true;
          case GL_COLOR_WRITEMASK:
            {
                *type = GL_BOOL;
                *numParams = 4;
            }
            return true;
          case GL_POLYGON_OFFSET_FACTOR:
          case GL_POLYGON_OFFSET_UNITS:
          case GL_SAMPLE_COVERAGE_VALUE:
          case GL_DEPTH_CLEAR_VALUE:
          case GL_LINE_WIDTH:
            {
                *type = GL_FLOAT;
                *numParams = 1;
            }
            return true;
          case GL_ALIASED_LINE_WIDTH_RANGE:
          case GL_ALIASED_POINT_SIZE_RANGE:
          case GL_DEPTH_RANGE:
            {
                *type = GL_FLOAT;
                *numParams = 2;
            }
            return true;
          case GL_COLOR_CLEAR_VALUE:
          case GL_BLEND_COLOR:
            {
                *type = GL_FLOAT;
                *numParams = 4;
            }
            return true;
          case GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT:
            if (!mExtensions.maxTextureAnisotropy)
            {
                return false;
            }
            *type = GL_FLOAT;
            *numParams = 1;
            return true;
          case GL_TIMESTAMP_EXT:
              if (!mExtensions.disjointTimerQuery)
              {
                  return false;
              }
              *type      = GL_INT_64_ANGLEX;
              *numParams = 1;
              return true;
          case GL_GPU_DISJOINT_EXT:
              if (!mExtensions.disjointTimerQuery)
              {
                  return false;
              }
              *type      = GL_INT;
              *numParams = 1;
              return true;
        }
    
        if (mExtensions.debug)
        {
            switch (pname)
            {
                case GL_DEBUG_LOGGED_MESSAGES:
                case GL_DEBUG_NEXT_LOGGED_MESSAGE_LENGTH:
                case GL_DEBUG_GROUP_STACK_DEPTH:
                case GL_MAX_DEBUG_MESSAGE_LENGTH:
                case GL_MAX_DEBUG_LOGGED_MESSAGES:
                case GL_MAX_DEBUG_GROUP_STACK_DEPTH:
                case GL_MAX_LABEL_LENGTH:
                    *type      = GL_INT;
                    *numParams = 1;
                    return true;
    
                case GL_DEBUG_OUTPUT_SYNCHRONOUS:
                case GL_DEBUG_OUTPUT:
                    *type      = GL_BOOL;
                    *numParams = 1;
                    return true;
            }
        }
    
        // Check for ES3.0+ parameter names which are also exposed as ES2 extensions
        switch (pname)
        {
            case GL_PACK_ROW_LENGTH:
            case GL_PACK_SKIP_ROWS:
            case GL_PACK_SKIP_PIXELS:
                if ((mClientVersion < 3) && !mExtensions.packSubimage)
                {
                    return false;
                }
                *type      = GL_INT;
                *numParams = 1;
                return true;
            case GL_UNPACK_ROW_LENGTH:
            case GL_UNPACK_SKIP_ROWS:
            case GL_UNPACK_SKIP_PIXELS:
                if ((mClientVersion < 3) && !mExtensions.unpackSubimage)
                {
                    return false;
                }
                *type      = GL_INT;
                *numParams = 1;
                return true;
            case GL_VERTEX_ARRAY_BINDING:
                if ((mClientVersion < 3) && !mExtensions.vertexArrayObject)
                {
                    return false;
                }
                *type      = GL_INT;
                *numParams = 1;
                return true;
            case GL_PIXEL_PACK_BUFFER_BINDING:
            case GL_PIXEL_UNPACK_BUFFER_BINDING:
                if ((mClientVersion < 3) && !mExtensions.pixelBufferObject)
                {
                    return false;
                }
                *type      = GL_INT;
                *numParams = 1;
                return true;
        }
    
        if (mClientVersion < 3)
        {
            return false;
        }
    
        // Check for ES3.0+ parameter names
        switch (pname)
        {
          case GL_MAX_UNIFORM_BUFFER_BINDINGS:
          case GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT:
          case GL_UNIFORM_BUFFER_BINDING:
          case GL_TRANSFORM_FEEDBACK_BINDING:
          case GL_TRANSFORM_FEEDBACK_BUFFER_BINDING:
          case GL_COPY_READ_BUFFER_BINDING:
          case GL_COPY_WRITE_BUFFER_BINDING:
          case GL_SAMPLER_BINDING:
          case GL_READ_BUFFER:
          case GL_TEXTURE_BINDING_3D:
          case GL_TEXTURE_BINDING_2D_ARRAY:
          case GL_MAX_3D_TEXTURE_SIZE:
          case GL_MAX_ARRAY_TEXTURE_LAYERS:
          case GL_MAX_VERTEX_UNIFORM_BLOCKS:
          case GL_MAX_FRAGMENT_UNIFORM_BLOCKS:
          case GL_MAX_COMBINED_UNIFORM_BLOCKS:
          case GL_MAX_VERTEX_OUTPUT_COMPONENTS:
          case GL_MAX_FRAGMENT_INPUT_COMPONENTS:
          case GL_MAX_VARYING_COMPONENTS:
          case GL_MAX_VERTEX_UNIFORM_COMPONENTS:
          case GL_MAX_FRAGMENT_UNIFORM_COMPONENTS:
          case GL_MIN_PROGRAM_TEXEL_OFFSET:
          case GL_MAX_PROGRAM_TEXEL_OFFSET:
          case GL_NUM_EXTENSIONS:
          case GL_MAJOR_VERSION:
          case GL_MINOR_VERSION:
          case GL_MAX_ELEMENTS_INDICES:
          case GL_MAX_ELEMENTS_VERTICES:
          case GL_MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS:
          case GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS:
          case GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS:
          case GL_UNPACK_IMAGE_HEIGHT:
          case GL_UNPACK_SKIP_IMAGES:
            {
                *type = GL_INT;
                *numParams = 1;
            }
            return true;
    
          case GL_MAX_ELEMENT_INDEX:
          case GL_MAX_UNIFORM_BLOCK_SIZE:
          case GL_MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS:
          case GL_MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS:
          case GL_MAX_SERVER_WAIT_TIMEOUT:
            {
                *type = GL_INT_64_ANGLEX;
                *numParams = 1;
            }
            return true;
    
          case GL_TRANSFORM_FEEDBACK_ACTIVE:
          case GL_TRANSFORM_FEEDBACK_PAUSED:
          case GL_PRIMITIVE_RESTART_FIXED_INDEX:
          case GL_RASTERIZER_DISCARD:
            {
                *type = GL_BOOL;
                *numParams = 1;
            }
            return true;
    
          case GL_MAX_TEXTURE_LOD_BIAS:
            {
                *type = GL_FLOAT;
                *numParams = 1;
            }
            return true;
        }
    
        return false;
    }
    
    bool Context::getIndexedQueryParameterInfo(GLenum target, GLenum *type, unsigned int *numParams)
    {
        if (mClientVersion < 3)
        {
            return false;
        }
    
        switch (target)
        {
          case GL_TRANSFORM_FEEDBACK_BUFFER_BINDING:
          case GL_UNIFORM_BUFFER_BINDING:
            {
                *type = GL_INT;
                *numParams = 1;
            }
            return true;
          case GL_TRANSFORM_FEEDBACK_BUFFER_START:
          case GL_TRANSFORM_FEEDBACK_BUFFER_SIZE:
          case GL_UNIFORM_BUFFER_START:
          case GL_UNIFORM_BUFFER_SIZE:
            {
                *type = GL_INT_64_ANGLEX;
                *numParams = 1;
            }
        }
    
        return false;
    }
    
    Error Context::drawArrays(GLenum mode, GLint first, GLsizei count)
    {
        syncRendererState();
        Error error = mRenderer->drawArrays(getData(), mode, first, count);
        if (error.isError())
        {
            return error;
        }
    
        MarkTransformFeedbackBufferUsage(mState.getCurrentTransformFeedback());
    
        return Error(GL_NO_ERROR);
    }
    
    Error Context::drawArraysInstanced(GLenum mode, GLint first, GLsizei count, GLsizei instanceCount)
    {
        syncRendererState();
        Error error = mRenderer->drawArraysInstanced(getData(), mode, first, count, instanceCount);
        if (error.isError())
        {
            return error;
        }
    
        MarkTransformFeedbackBufferUsage(mState.getCurrentTransformFeedback());
    
        return Error(GL_NO_ERROR);
    }
    
    Error Context::drawElements(GLenum mode,
                                GLsizei count,
                                GLenum type,
                                const GLvoid *indices,
                                const IndexRange &indexRange)
    {
        syncRendererState();
        return mRenderer->drawElements(getData(), mode, count, type, indices, indexRange);
    }
    
    Error Context::drawElementsInstanced(GLenum mode,
                                         GLsizei count,
                                         GLenum type,
                                         const GLvoid *indices,
                                         GLsizei instances,
                                         const IndexRange &indexRange)
    {
        syncRendererState();
        return mRenderer->drawElementsInstanced(getData(), 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 mRenderer->drawRangeElements(getData(), mode, start, end, count, type, indices,
                                            indexRange);
    }
    
    Error Context::flush()
    {
        return mRenderer->flush();
    }
    
    Error Context::finish()
    {
        return mRenderer->finish();
    }
    
    void Context::insertEventMarker(GLsizei length, const char *marker)
    {
        ASSERT(mRenderer);
        mRenderer->insertEventMarker(length, marker);
    }
    
    void Context::pushGroupMarker(GLsizei length, const char *marker)
    {
        ASSERT(mRenderer);
        mRenderer->pushGroupMarker(length, marker);
    }
    
    void Context::popGroupMarker()
    {
        ASSERT(mRenderer);
        mRenderer->popGroupMarker();
    }
    
    void Context::recordError(const Error &error)
    {
        if (error.isError())
        {
            mErrors.insert(error.getCode());
    
            if (!error.getMessage().empty())
            {
                auto &debug = mState.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;
        }
    }
    
    GLenum Context::getResetStatus()
    {
        //TODO(jmadill): needs MANGLE reworking
        if (mResetStatus == GL_NO_ERROR && !mContextLost)
        {
            // mResetStatus will be set by the markContextLost callback
            // in the case a notification is sent
            if (mRenderer->testDeviceLost())
            {
                mRenderer->notifyDeviceLost();
            }
        }
    
        GLenum status = mResetStatus;
    
        if (mResetStatus != GL_NO_ERROR)
        {
            ASSERT(mContextLost);
    
            if (mRenderer->testDeviceResettable())
            {
                mResetStatus = GL_NO_ERROR;
            }
        }
    
        return status;
    }
    
    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(mRenderer, 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(mRenderer, 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, mRenderer, framebuffer);
            if (neverCreated)
            {
                mFramebufferHandleAllocator.reserve(framebuffer);
                mFramebufferMap[framebuffer] = newFBO;
                return newFBO;
            }
    
            framebufferIt->second = newFBO;
        }
    
        return framebufferIt->second;
    }
    
    bool Context::isVertexArrayGenerated(GLuint vertexArray)
    {
        return mVertexArrayMap.find(vertexArray) != mVertexArrayMap.end();
    }
    
    bool Context::isTransformFeedbackGenerated(GLuint transformFeedback)
    {
        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.
        mState.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
        mState.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 (mState.removeReadFramebufferBinding(framebuffer) && framebuffer != 0)
        {
            bindReadFramebuffer(0);
        }
    
        if (mState.removeDrawFramebufferBinding(framebuffer) && framebuffer != 0)
        {
            bindDrawFramebuffer(0);
        }
    }
    
    void Context::detachRenderbuffer(GLuint renderbuffer)
    {
        mState.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 (mState.removeVertexArrayBinding(vertexArray))
        {
            bindVertexArray(0);
        }
    }
    
    void Context::detachTransformFeedback(GLuint transformFeedback)
    {
        mState.detachTransformFeedback(transformFeedback);
    }
    
    void Context::detachSampler(GLuint sampler)
    {
        mState.detachSampler(sampler);
    }
    
    void Context::setVertexAttribDivisor(GLuint index, GLuint divisor)
    {
        mState.setVertexAttribDivisor(index, divisor);
    }
    
    void Context::samplerParameteri(GLuint sampler, GLenum pname, GLint param)
    {
        mResourceManager->checkSamplerAllocation(sampler);
    
        Sampler *samplerObject = getSampler(sampler);
        ASSERT(samplerObject);
    
        // clang-format off
        switch (pname)
        {
          case GL_TEXTURE_MIN_FILTER:         samplerObject->setMinFilter(static_cast<GLenum>(param));    break;
          case GL_TEXTURE_MAG_FILTER:         samplerObject->setMagFilter(static_cast<GLenum>(param));    break;
          case GL_TEXTURE_WRAP_S:             samplerObject->setWrapS(static_cast<GLenum>(param));        break;
          case GL_TEXTURE_WRAP_T:             samplerObject->setWrapT(static_cast<GLenum>(param));        break;
          case GL_TEXTURE_WRAP_R:             samplerObject->setWrapR(static_cast<GLenum>(param));        break;
          case GL_TEXTURE_MAX_ANISOTROPY_EXT: samplerObject->setMaxAnisotropy(std::min(static_cast<GLfloat>(param), getExtensions().maxTextureAnisotropy)); break;
          case GL_TEXTURE_MIN_LOD:            samplerObject->setMinLod(static_cast<GLfloat>(param));      break;
          case GL_TEXTURE_MAX_LOD:            samplerObject->setMaxLod(static_cast<GLfloat>(param));      break;
          case GL_TEXTURE_COMPARE_MODE:       samplerObject->setCompareMode(static_cast<GLenum>(param));  break;
          case GL_TEXTURE_COMPARE_FUNC:       samplerObject->setCompareFunc(static_cast<GLenum>(param));  break;
          default:                            UNREACHABLE(); break;
        }
        // clang-format on
    }
    
    void Context::samplerParameterf(GLuint sampler, GLenum pname, GLfloat param)
    {
        mResourceManager->checkSamplerAllocation(sampler);
    
        Sampler *samplerObject = getSampler(sampler);
        ASSERT(samplerObject);
    
        // clang-format off
        switch (pname)
        {
          case GL_TEXTURE_MIN_FILTER:         samplerObject->setMinFilter(uiround<GLenum>(param));   break;
          case GL_TEXTURE_MAG_FILTER:         samplerObject->setMagFilter(uiround<GLenum>(param));   break;
          case GL_TEXTURE_WRAP_S:             samplerObject->setWrapS(uiround<GLenum>(param));       break;
          case GL_TEXTURE_WRAP_T:             samplerObject->setWrapT(uiround<GLenum>(param));       break;
          case GL_TEXTURE_WRAP_R:             samplerObject->setWrapR(uiround<GLenum>(param));       break;
          case GL_TEXTURE_MAX_ANISOTROPY_EXT: samplerObject->setMaxAnisotropy(std::min(param, getExtensions().maxTextureAnisotropy)); break;
          case GL_TEXTURE_MIN_LOD:            samplerObject->setMinLod(param);                       break;
          case GL_TEXTURE_MAX_LOD:            samplerObject->setMaxLod(param);                       break;
          case GL_TEXTURE_COMPARE_MODE:       samplerObject->setCompareMode(uiround<GLenum>(param)); break;
          case GL_TEXTURE_COMPARE_FUNC:       samplerObject->setCompareFunc(uiround<GLenum>(param)); break;
          default:                            UNREACHABLE(); break;
        }
        // clang-format on
    }
    
    GLint Context::getSamplerParameteri(GLuint sampler, GLenum pname)
    {
        mResourceManager->checkSamplerAllocation(sampler);
    
        Sampler *samplerObject = getSampler(sampler);
        ASSERT(samplerObject);
    
        // clang-format off
        switch (pname)
        {
          case GL_TEXTURE_MIN_FILTER:         return static_cast<GLint>(samplerObject->getMinFilter());
          case GL_TEXTURE_MAG_FILTER:         return static_cast<GLint>(samplerObject->getMagFilter());
          case GL_TEXTURE_WRAP_S:             return static_cast<GLint>(samplerObject->getWrapS());
          case GL_TEXTURE_WRAP_T:             return static_cast<GLint>(samplerObject->getWrapT());
          case GL_TEXTURE_WRAP_R:             return static_cast<GLint>(samplerObject->getWrapR());
          case GL_TEXTURE_MAX_ANISOTROPY_EXT: return static_cast<GLint>(samplerObject->getMaxAnisotropy());
          case GL_TEXTURE_MIN_LOD:            return iround<GLint>(samplerObject->getMinLod());
          case GL_TEXTURE_MAX_LOD:            return iround<GLint>(samplerObject->getMaxLod());
          case GL_TEXTURE_COMPARE_MODE:       return static_cast<GLint>(samplerObject->getCompareMode());
          case GL_TEXTURE_COMPARE_FUNC:       return static_cast<GLint>(samplerObject->getCompareFunc());
          default:                            UNREACHABLE(); return 0;
        }
        // clang-format on
    }
    
    GLfloat Context::getSamplerParameterf(GLuint sampler, GLenum pname)
    {
        mResourceManager->checkSamplerAllocation(sampler);
    
        Sampler *samplerObject = getSampler(sampler);
        ASSERT(samplerObject);
    
        // clang-format off
        switch (pname)
        {
          case GL_TEXTURE_MIN_FILTER:         return static_cast<GLfloat>(samplerObject->getMinFilter());
          case GL_TEXTURE_MAG_FILTER:         return static_cast<GLfloat>(samplerObject->getMagFilter());
          case GL_TEXTURE_WRAP_S:             return static_cast<GLfloat>(samplerObject->getWrapS());
          case GL_TEXTURE_WRAP_T:             return static_cast<GLfloat>(samplerObject->getWrapT());
          case GL_TEXTURE_WRAP_R:             return static_cast<GLfloat>(samplerObject->getWrapR());
          case GL_TEXTURE_MAX_ANISOTROPY_EXT: return samplerObject->getMaxAnisotropy();
          case GL_TEXTURE_MIN_LOD:            return samplerObject->getMinLod();
          case GL_TEXTURE_MAX_LOD:            return samplerObject->getMaxLod();
          case GL_TEXTURE_COMPARE_MODE:       return static_cast<GLfloat>(samplerObject->getCompareMode());
          case GL_TEXTURE_COMPARE_FUNC:       return static_cast<GLfloat>(samplerObject->getCompareFunc());
          default:                            UNREACHABLE(); return 0;
        }
        // clang-format on
    }
    
    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 << mRenderer->getRendererDescription();
        rendererString << ")";
    
        mRendererString = MakeStaticString(rendererString.str());
    }
    
    const std::string &Context::getRendererString() const
    {
        return mRendererString;
    }
    
    void Context::initExtensionStrings()
    {
        mExtensionStrings = mExtensions.getStrings();
    
        std::ostringstream combinedStringStream;
        std::copy(mExtensionStrings.begin(), mExtensionStrings.end(), std::ostream_iterator<std::string>(combinedStringStream, " "));
        mExtensionString = combinedStringStream.str();
    }
    
    const std::string &Context::getExtensionString() const
    {
        return mExtensionString;
    }
    
    const std::string &Context::getExtensionString(size_t idx) const
    {
        return mExtensionStrings[idx];
    }
    
    size_t Context::getExtensionStringCount() const
    {
        return mExtensionStrings.size();
    }
    
    void Context::beginTransformFeedback(GLenum primitiveMode)
    {
        TransformFeedback *transformFeedback = getState().getCurrentTransformFeedback();
        ASSERT(transformFeedback != nullptr);
        ASSERT(!transformFeedback->isPaused());
    
        transformFeedback->begin(primitiveMode, getState().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(GLuint clientVersion)
    {
        mCaps = mRenderer->getRendererCaps();
    
        mExtensions = mRenderer->getRendererExtensions();
    
        mLimitations = mRenderer->getRendererLimitations();
    
        if (clientVersion < 3)
        {
            // Disable ES3+ extensions
            mExtensions.colorBufferFloat = false;
        }
    
        if (clientVersion > 2)
        {
            // FIXME(geofflang): Don't support EXT_sRGB in non-ES2 contexts
            //mExtensions.sRGB = false;
        }
    
        // Explicitly enable GL_KHR_debug
        mExtensions.debug                   = true;
        mExtensions.maxDebugMessageLength   = 1024;
        mExtensions.maxDebugLoggedMessages  = 1024;
        mExtensions.maxDebugGroupStackDepth = 1024;
        mExtensions.maxLabelLength          = 1024;
    
        // 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);
    
        mCaps.compressedTextureFormats.clear();
    
        const TextureCapsMap &rendererFormats = mRenderer->getRendererTextureCaps();
        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(clientVersion, mExtensions);
            formatCaps.renderable =
                formatCaps.renderable && formatInfo.renderSupport(clientVersion, mExtensions);
            formatCaps.filterable =
                formatCaps.filterable && formatInfo.filterSupport(clientVersion, 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::syncRendererState()
    {
        const State::DirtyBits &dirtyBits = mState.getDirtyBits();
        mRenderer->syncState(mState, dirtyBits);
        mState.clearDirtyBits();
        mState.syncDirtyObjects();
    }
    
    void Context::syncRendererState(const State::DirtyBits &bitMask,
                                    const State::DirtyObjects &objectMask)
    {
        const State::DirtyBits &dirtyBits = (mState.getDirtyBits() & bitMask);
        mRenderer->syncState(mState, dirtyBits);
        mState.clearDirtyBits(dirtyBits);
    
        mState.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 *readFramebuffer = mState.getReadFramebuffer();
        ASSERT(readFramebuffer);
    
        Framebuffer *drawFramebuffer = mState.getDrawFramebuffer();
        ASSERT(drawFramebuffer);
    
        Rectangle srcArea(srcX0, srcY0, srcX1 - srcX0, srcY1 - srcY0);
        Rectangle dstArea(dstX0, dstY0, dstX1 - dstX0, dstY1 - dstY0);
    
        syncStateForBlit();
    
        Error error = drawFramebuffer->blit(mState, srcArea, dstArea, mask, filter, readFramebuffer);
        if (error.isError())
        {
            recordError(error);
            return;
        }
    }
    
    void Context::clear(GLbitfield mask)
    {
        syncStateForClear();
    
        Error error = mState.getDrawFramebuffer()->clear(mData, mask);
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    void Context::clearBufferfv(GLenum buffer, GLint drawbuffer, const GLfloat *values)
    {
        syncStateForClear();
    
        Error error = mState.getDrawFramebuffer()->clearBufferfv(mData, buffer, drawbuffer, values);
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    void Context::clearBufferuiv(GLenum buffer, GLint drawbuffer, const GLuint *values)
    {
        syncStateForClear();
    
        Error error = mState.getDrawFramebuffer()->clearBufferuiv(mData, buffer, drawbuffer, values);
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    void Context::clearBufferiv(GLenum buffer, GLint drawbuffer, const GLint *values)
    {
        syncStateForClear();
    
        Error error = mState.getDrawFramebuffer()->clearBufferiv(mData, buffer, drawbuffer, values);
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    void Context::clearBufferfi(GLenum buffer, GLint drawbuffer, GLfloat depth, GLint stencil)
    {
        Framebuffer *framebufferObject = mState.getDrawFramebuffer();
        ASSERT(framebufferObject);
    
        // If a buffer is not present, the clear has no effect
        if (framebufferObject->getDepthbuffer() == nullptr &&
            framebufferObject->getStencilbuffer() == nullptr)
        {
            return;
        }
    
        syncStateForClear();
    
        Error error = framebufferObject->clearBufferfi(mData, buffer, drawbuffer, depth, stencil);
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    void Context::readPixels(GLint x,
                             GLint y,
                             GLsizei width,
                             GLsizei height,
                             GLenum format,
                             GLenum type,
                             GLvoid *pixels)
    {
        syncStateForReadPixels();
    
        Framebuffer *framebufferObject = mState.getReadFramebuffer();
        ASSERT(framebufferObject);
    
        Rectangle area(x, y, width, height);
        Error error = framebufferObject->readPixels(mState, area, format, type, pixels);
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    void Context::copyTexImage2D(GLenum target,
                                 GLint level,
                                 GLenum internalformat,
                                 GLint x,
                                 GLint y,
                                 GLsizei width,
                                 GLsizei height,
                                 GLint border)
    {
        // Only sync the read FBO
        mState.syncDirtyObject(GL_READ_FRAMEBUFFER);
    
        Rectangle sourceArea(x, y, width, height);
    
        const Framebuffer *framebuffer = mState.getReadFramebuffer();
        Texture *texture =
            getTargetTexture(IsCubeMapTextureTarget(target) ? GL_TEXTURE_CUBE_MAP : target);
        Error error = texture->copyImage(target, level, sourceArea, internalformat, framebuffer);
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    void Context::copyTexSubImage2D(GLenum target,
                                    GLint level,
                                    GLint xoffset,
                                    GLint yoffset,
                                    GLint x,
                                    GLint y,
                                    GLsizei width,
                                    GLsizei height)
    {
        // Only sync the read FBO
        mState.syncDirtyObject(GL_READ_FRAMEBUFFER);
    
        Offset destOffset(xoffset, yoffset, 0);
        Rectangle sourceArea(x, y, width, height);
    
        const Framebuffer *framebuffer = mState.getReadFramebuffer();
        Texture *texture =
            getTargetTexture(IsCubeMapTextureTarget(target) ? GL_TEXTURE_CUBE_MAP : target);
        Error error = texture->copySubImage(target, level, destOffset, sourceArea, framebuffer);
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    void Context::copyTexSubImage3D(GLenum target,
                                    GLint level,
                                    GLint xoffset,
                                    GLint yoffset,
                                    GLint zoffset,
                                    GLint x,
                                    GLint y,
                                    GLsizei width,
                                    GLsizei height)
    {
        // Only sync the read FBO
        mState.syncDirtyObject(GL_READ_FRAMEBUFFER);
    
        Offset destOffset(xoffset, yoffset, zoffset);
        Rectangle sourceArea(x, y, width, height);
    
        const Framebuffer *framebuffer = mState.getReadFramebuffer();
        Texture *texture               = getTargetTexture(target);
        Error error = texture->copySubImage(target, level, destOffset, sourceArea, framebuffer);
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    void Context::framebufferTexture2D(GLenum target,
                                       GLenum attachment,
                                       GLenum textarget,
                                       GLuint texture,
                                       GLint level)
    {
        Framebuffer *framebuffer = mState.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);
        }
    
        mState.setObjectDirty(target);
    }
    
    void Context::framebufferRenderbuffer(GLenum target,
                                          GLenum attachment,
                                          GLenum renderbuffertarget,
                                          GLuint renderbuffer)
    {
        Framebuffer *framebuffer = mState.getTargetFramebuffer(target);
        ASSERT(framebuffer);
    
        if (renderbuffer != 0)
        {
            Renderbuffer *renderbufferObject = getRenderbuffer(renderbuffer);
            framebuffer->setAttachment(GL_RENDERBUFFER, attachment, gl::ImageIndex::MakeInvalid(),
                                       renderbufferObject);
        }
        else
        {
            framebuffer->resetAttachment(attachment);
        }
    
        mState.setObjectDirty(target);
    }
    
    void Context::framebufferTextureLayer(GLenum target,
                                          GLenum attachment,
                                          GLuint texture,
                                          GLint level,
                                          GLint layer)
    {
        Framebuffer *framebuffer = mState.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);
        }
    
        mState.setObjectDirty(target);
    }
    
    void Context::drawBuffers(GLsizei n, const GLenum *bufs)
    {
        Framebuffer *framebuffer = mState.getDrawFramebuffer();
        ASSERT(framebuffer);
        framebuffer->setDrawBuffers(n, bufs);
        mState.setObjectDirty(GL_DRAW_FRAMEBUFFER);
    }
    
    void Context::readBuffer(GLenum mode)
    {
        Framebuffer *readFBO = mState.getReadFramebuffer();
        readFBO->setReadBuffer(mode);
        mState.setObjectDirty(GL_READ_FRAMEBUFFER);
    }
    
    void Context::discardFramebuffer(GLenum target, GLsizei numAttachments, const GLenum *attachments)
    {
        // Only sync the FBO
        mState.syncDirtyObject(target);
    
        Framebuffer *framebuffer = mState.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.
        Error error = framebuffer->discard(numAttachments, attachments);
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    void Context::invalidateFramebuffer(GLenum target,
                                        GLsizei numAttachments,
                                        const GLenum *attachments)
    {
        // Only sync the FBO
        mState.syncDirtyObject(target);
    
        Framebuffer *framebuffer = mState.getTargetFramebuffer(target);
        ASSERT(framebuffer);
    
        if (framebuffer->checkStatus(mData) == GL_FRAMEBUFFER_COMPLETE)
        {
            Error error = framebuffer->invalidate(numAttachments, attachments);
            if (error.isError())
            {
                recordError(error);
                return;
            }
        }
    }
    
    void Context::invalidateSubFramebuffer(GLenum target,
                                           GLsizei numAttachments,
                                           const GLenum *attachments,
                                           GLint x,
                                           GLint y,
                                           GLsizei width,
                                           GLsizei height)
    {
        // Only sync the FBO
        mState.syncDirtyObject(target);
    
        Framebuffer *framebuffer = mState.getTargetFramebuffer(target);
        ASSERT(framebuffer);
    
        if (framebuffer->checkStatus(mData) == GL_FRAMEBUFFER_COMPLETE)
        {
            Rectangle area(x, y, width, height);
            Error error = framebuffer->invalidateSub(numAttachments, attachments, area);
            if (error.isError())
            {
                recordError(error);
                return;
            }
        }
    }
    
    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);
        Error error = texture->setImage(mState.getUnpackState(), target, level, internalformat, size,
                                        format, type, reinterpret_cast<const uint8_t *>(pixels));
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    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);
        Error error = texture->setImage(mState.getUnpackState(), target, level, internalformat, size,
                                        format, type, reinterpret_cast<const uint8_t *>(pixels));
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    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);
        Error error = texture->setSubImage(mState.getUnpackState(), target, level, area, format, type,
                                           reinterpret_cast<const uint8_t *>(pixels));
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    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);
        Error error = texture->setSubImage(mState.getUnpackState(), target, level, area, format, type,
                                           reinterpret_cast<const uint8_t *>(pixels));
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    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);
        Error error =
            texture->setCompressedImage(mState.getUnpackState(), target, level, internalformat, size,
                                        imageSize, reinterpret_cast<const uint8_t *>(data));
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    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);
        Error error =
            texture->setCompressedImage(mState.getUnpackState(), target, level, internalformat, size,
                                        imageSize, reinterpret_cast<const uint8_t *>(data));
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    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);
        Error error =
            texture->setCompressedSubImage(mState.getUnpackState(), target, level, area, format,
                                           imageSize, reinterpret_cast<const uint8_t *>(data));
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    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);
        Error error =
            texture->setCompressedSubImage(mState.getUnpackState(), target, level, area, format,
                                           imageSize, reinterpret_cast<const uint8_t *>(data));
        if (error.isError())
        {
            recordError(error);
        }
    }
    
    void Context::getBufferPointerv(GLenum target, GLenum /*pname*/, void **params)
    {
        Buffer *buffer = getState().getTargetBuffer(target);
        ASSERT(buffer);
    
        if (!buffer->isMapped())
        {
            *params = nullptr;
        }
        else
        {
            *params = buffer->getMapPointer();
        }
    }
    
    GLvoid *Context::mapBuffer(GLenum target, GLenum access)
    {
        Buffer *buffer = getState().getTargetBuffer(target);
        ASSERT(buffer);
    
        Error error = buffer->map(access);
        if (error.isError())
        {
            recordError(error);
            return nullptr;
        }
    
        return buffer->getMapPointer();
    }
    
    GLboolean Context::unmapBuffer(GLenum target)
    {
        Buffer *buffer = getState().getTargetBuffer(target);
        ASSERT(buffer);
    
        GLboolean result;
        Error error = buffer->unmap(&result);
        if (error.isError())
        {
            recordError(error);
            return GL_FALSE;
        }
    
        return result;
    }
    
    GLvoid *Context::mapBufferRange(GLenum target,
                                    GLintptr offset,
                                    GLsizeiptr length,
                                    GLbitfield access)
    {
        Buffer *buffer = getState().getTargetBuffer(target);
        ASSERT(buffer);
    
        Error error = buffer->mapRange(offset, length, access);
        if (error.isError())
        {
            recordError(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);
    }
    
    }  // namespace gl