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

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  • Author : Geoff Lang
    Date : 2017-04-05 12:40:40
    Hash : 677bb6ff
    Message : Update checks for floating point renderability. * Expose GL_CHROMIUM_color_buffer_float_rgb and GL_CHROMIUM_color_buffer_float_rgba * Fix many texture formats that were incorrectly checking the wrong extension for support or renderability. * Make all floating point texture extensions dynamically enableable. BUG=angleproject:1958 BUG=angleproject:1715 Change-Id: Iefccc8b5ae5edd97623affa9de05b1d9af5c9598 Reviewed-on: https://chromium-review.googlesource.com/468450 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>

  • src/libANGLE/Framebuffer.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.
    //
    
    // Framebuffer.cpp: Implements the gl::Framebuffer class. Implements GL framebuffer
    // objects and related functionality. [OpenGL ES 2.0.24] section 4.4 page 105.
    
    #include "libANGLE/Framebuffer.h"
    
    #include "common/bitset_utils.h"
    #include "common/Optional.h"
    #include "common/utilities.h"
    #include "libANGLE/Config.h"
    #include "libANGLE/Context.h"
    #include "libANGLE/Display.h"
    #include "libANGLE/FramebufferAttachment.h"
    #include "libANGLE/Renderbuffer.h"
    #include "libANGLE/Surface.h"
    #include "libANGLE/Texture.h"
    #include "libANGLE/formatutils.h"
    #include "libANGLE/renderer/ContextImpl.h"
    #include "libANGLE/renderer/FramebufferImpl.h"
    #include "libANGLE/renderer/GLImplFactory.h"
    #include "libANGLE/renderer/RenderbufferImpl.h"
    #include "libANGLE/renderer/SurfaceImpl.h"
    
    using namespace angle;
    
    namespace gl
    {
    
    namespace
    {
    
    void BindResourceChannel(OnAttachmentDirtyBinding *binding, FramebufferAttachmentObject *resource)
    {
        binding->bind(resource ? resource->getDirtyChannel() : nullptr);
    }
    
    }  // anonymous namespace
    
    // This constructor is only used for default framebuffers.
    FramebufferState::FramebufferState()
        : mLabel(),
          mColorAttachments(1),
          mDrawBufferStates(IMPLEMENTATION_MAX_DRAW_BUFFERS, GL_NONE),
          mReadBufferState(GL_BACK),
          mDefaultWidth(0),
          mDefaultHeight(0),
          mDefaultSamples(0),
          mDefaultFixedSampleLocations(GL_FALSE),
          mWebGLDepthStencilConsistent(true)
    {
        ASSERT(mDrawBufferStates.size() > 0);
        mDrawBufferStates[0] = GL_BACK;
        mEnabledDrawBuffers.set(0);
    }
    
    FramebufferState::FramebufferState(const Caps &caps)
        : mLabel(),
          mColorAttachments(caps.maxColorAttachments),
          mDrawBufferStates(caps.maxDrawBuffers, GL_NONE),
          mReadBufferState(GL_COLOR_ATTACHMENT0_EXT),
          mDefaultWidth(0),
          mDefaultHeight(0),
          mDefaultSamples(0),
          mDefaultFixedSampleLocations(GL_FALSE),
          mWebGLDepthStencilConsistent(true)
    {
        ASSERT(mDrawBufferStates.size() > 0);
        mDrawBufferStates[0] = GL_COLOR_ATTACHMENT0_EXT;
    }
    
    FramebufferState::~FramebufferState()
    {
    }
    
    const std::string &FramebufferState::getLabel()
    {
        return mLabel;
    }
    
    const FramebufferAttachment *FramebufferState::getAttachment(GLenum attachment) const
    {
        if (attachment >= GL_COLOR_ATTACHMENT0 && attachment <= GL_COLOR_ATTACHMENT15)
        {
            return getColorAttachment(attachment - GL_COLOR_ATTACHMENT0);
        }
    
        switch (attachment)
        {
            case GL_COLOR:
            case GL_BACK:
                return getColorAttachment(0);
            case GL_DEPTH:
            case GL_DEPTH_ATTACHMENT:
                return getDepthAttachment();
            case GL_STENCIL:
            case GL_STENCIL_ATTACHMENT:
                return getStencilAttachment();
            case GL_DEPTH_STENCIL:
            case GL_DEPTH_STENCIL_ATTACHMENT:
                return getDepthStencilAttachment();
            default:
                UNREACHABLE();
                return nullptr;
        }
    }
    
    const FramebufferAttachment *FramebufferState::getReadAttachment() const
    {
        if (mReadBufferState == GL_NONE)
        {
            return nullptr;
        }
        ASSERT(mReadBufferState == GL_BACK || (mReadBufferState >= GL_COLOR_ATTACHMENT0 && mReadBufferState <= GL_COLOR_ATTACHMENT15));
        size_t readIndex = (mReadBufferState == GL_BACK ? 0 : static_cast<size_t>(mReadBufferState - GL_COLOR_ATTACHMENT0));
        ASSERT(readIndex < mColorAttachments.size());
        return mColorAttachments[readIndex].isAttached() ? &mColorAttachments[readIndex] : nullptr;
    }
    
    const FramebufferAttachment *FramebufferState::getFirstNonNullAttachment() const
    {
        auto *colorAttachment = getFirstColorAttachment();
        if (colorAttachment)
        {
            return colorAttachment;
        }
        return getDepthOrStencilAttachment();
    }
    
    const FramebufferAttachment *FramebufferState::getFirstColorAttachment() const
    {
        for (const FramebufferAttachment &colorAttachment : mColorAttachments)
        {
            if (colorAttachment.isAttached())
            {
                return &colorAttachment;
            }
        }
    
        return nullptr;
    }
    
    const FramebufferAttachment *FramebufferState::getDepthOrStencilAttachment() const
    {
        if (mDepthAttachment.isAttached())
        {
            return &mDepthAttachment;
        }
        if (mStencilAttachment.isAttached())
        {
            return &mStencilAttachment;
        }
        return nullptr;
    }
    
    const FramebufferAttachment *FramebufferState::getStencilOrDepthStencilAttachment() const
    {
        if (mStencilAttachment.isAttached())
        {
            return &mStencilAttachment;
        }
        return getDepthStencilAttachment();
    }
    
    const FramebufferAttachment *FramebufferState::getColorAttachment(size_t colorAttachment) const
    {
        ASSERT(colorAttachment < mColorAttachments.size());
        return mColorAttachments[colorAttachment].isAttached() ?
               &mColorAttachments[colorAttachment] :
               nullptr;
    }
    
    const FramebufferAttachment *FramebufferState::getDepthAttachment() const
    {
        return mDepthAttachment.isAttached() ? &mDepthAttachment : nullptr;
    }
    
    const FramebufferAttachment *FramebufferState::getStencilAttachment() const
    {
        return mStencilAttachment.isAttached() ? &mStencilAttachment : nullptr;
    }
    
    const FramebufferAttachment *FramebufferState::getDepthStencilAttachment() const
    {
        // A valid depth-stencil attachment has the same resource bound to both the
        // depth and stencil attachment points.
        if (mDepthAttachment.isAttached() && mStencilAttachment.isAttached() &&
            mDepthAttachment == mStencilAttachment)
        {
            return &mDepthAttachment;
        }
    
        return nullptr;
    }
    
    bool FramebufferState::attachmentsHaveSameDimensions() const
    {
        Optional<Extents> attachmentSize;
    
        auto hasMismatchedSize = [&attachmentSize](const FramebufferAttachment &attachment)
        {
            if (!attachment.isAttached())
            {
                return false;
            }
    
            if (!attachmentSize.valid())
            {
                attachmentSize = attachment.getSize();
                return false;
            }
    
            return (attachment.getSize() != attachmentSize.value());
        };
    
        for (const auto &attachment : mColorAttachments)
        {
            if (hasMismatchedSize(attachment))
            {
                return false;
            }
        }
    
        if (hasMismatchedSize(mDepthAttachment))
        {
            return false;
        }
    
        return !hasMismatchedSize(mStencilAttachment);
    }
    
    const gl::FramebufferAttachment *FramebufferState::getDrawBuffer(size_t drawBufferIdx) const
    {
        ASSERT(drawBufferIdx < mDrawBufferStates.size());
        if (mDrawBufferStates[drawBufferIdx] != GL_NONE)
        {
            // ES3 spec: "If the GL is bound to a draw framebuffer object, the ith buffer listed in bufs
            // must be COLOR_ATTACHMENTi or NONE"
            ASSERT(mDrawBufferStates[drawBufferIdx] == GL_COLOR_ATTACHMENT0 + drawBufferIdx ||
                   (drawBufferIdx == 0 && mDrawBufferStates[drawBufferIdx] == GL_BACK));
            return getAttachment(mDrawBufferStates[drawBufferIdx]);
        }
        else
        {
            return nullptr;
        }
    }
    
    size_t FramebufferState::getDrawBufferCount() const
    {
        return mDrawBufferStates.size();
    }
    
    bool FramebufferState::colorAttachmentsAreUniqueImages() const
    {
        for (size_t firstAttachmentIdx = 0; firstAttachmentIdx < mColorAttachments.size();
             firstAttachmentIdx++)
        {
            const gl::FramebufferAttachment &firstAttachment = mColorAttachments[firstAttachmentIdx];
            if (!firstAttachment.isAttached())
            {
                continue;
            }
    
            for (size_t secondAttachmentIdx = firstAttachmentIdx + 1;
                 secondAttachmentIdx < mColorAttachments.size(); secondAttachmentIdx++)
            {
                const gl::FramebufferAttachment &secondAttachment =
                    mColorAttachments[secondAttachmentIdx];
                if (!secondAttachment.isAttached())
                {
                    continue;
                }
    
                if (firstAttachment == secondAttachment)
                {
                    return false;
                }
            }
        }
    
        return true;
    }
    
    Framebuffer::Framebuffer(const Caps &caps, rx::GLImplFactory *factory, GLuint id)
        : mState(caps),
          mImpl(factory->createFramebuffer(mState)),
          mId(id),
          mCachedStatus(),
          mDirtyDepthAttachmentBinding(this, DIRTY_BIT_DEPTH_ATTACHMENT),
          mDirtyStencilAttachmentBinding(this, DIRTY_BIT_STENCIL_ATTACHMENT)
    {
        ASSERT(mId != 0);
        ASSERT(mImpl != nullptr);
        ASSERT(mState.mColorAttachments.size() == static_cast<size_t>(caps.maxColorAttachments));
    
        for (uint32_t colorIndex = 0;
             colorIndex < static_cast<uint32_t>(mState.mColorAttachments.size()); ++colorIndex)
        {
            mDirtyColorAttachmentBindings.emplace_back(this, DIRTY_BIT_COLOR_ATTACHMENT_0 + colorIndex);
        }
    }
    
    Framebuffer::Framebuffer(egl::Surface *surface)
        : mState(),
          mImpl(surface->getImplementation()->createDefaultFramebuffer(mState)),
          mId(0),
          mCachedStatus(GL_FRAMEBUFFER_COMPLETE),
          mDirtyDepthAttachmentBinding(this, DIRTY_BIT_DEPTH_ATTACHMENT),
          mDirtyStencilAttachmentBinding(this, DIRTY_BIT_STENCIL_ATTACHMENT)
    {
        ASSERT(mImpl != nullptr);
        mDirtyColorAttachmentBindings.emplace_back(this, DIRTY_BIT_COLOR_ATTACHMENT_0);
    
        setAttachmentImpl(GL_FRAMEBUFFER_DEFAULT, GL_BACK, gl::ImageIndex::MakeInvalid(), surface);
    
        if (surface->getConfig()->depthSize > 0)
        {
            setAttachmentImpl(GL_FRAMEBUFFER_DEFAULT, GL_DEPTH, gl::ImageIndex::MakeInvalid(), surface);
        }
    
        if (surface->getConfig()->stencilSize > 0)
        {
            setAttachmentImpl(GL_FRAMEBUFFER_DEFAULT, GL_STENCIL, gl::ImageIndex::MakeInvalid(),
                              surface);
        }
    }
    
    Framebuffer::Framebuffer(rx::GLImplFactory *factory)
        : mState(),
          mImpl(factory->createFramebuffer(mState)),
          mId(0),
          mCachedStatus(GL_FRAMEBUFFER_UNDEFINED_OES),
          mDirtyDepthAttachmentBinding(this, DIRTY_BIT_DEPTH_ATTACHMENT),
          mDirtyStencilAttachmentBinding(this, DIRTY_BIT_STENCIL_ATTACHMENT)
    {
        mDirtyColorAttachmentBindings.emplace_back(this, DIRTY_BIT_COLOR_ATTACHMENT_0);
    }
    
    Framebuffer::~Framebuffer()
    {
        SafeDelete(mImpl);
    }
    
    void Framebuffer::destroy(const Context *context)
    {
        mImpl->destroy(rx::SafeGetImpl(context));
    }
    
    void Framebuffer::destroyDefault(const egl::Display *display)
    {
        mImpl->destroyDefault(rx::SafeGetImpl(display));
    }
    
    void Framebuffer::setLabel(const std::string &label)
    {
        mState.mLabel = label;
    }
    
    const std::string &Framebuffer::getLabel() const
    {
        return mState.mLabel;
    }
    
    void Framebuffer::detachTexture(const Context *context, GLuint textureId)
    {
        detachResourceById(context, GL_TEXTURE, textureId);
    }
    
    void Framebuffer::detachRenderbuffer(const Context *context, GLuint renderbufferId)
    {
        detachResourceById(context, GL_RENDERBUFFER, renderbufferId);
    }
    
    void Framebuffer::detachResourceById(const Context *context, GLenum resourceType, GLuint resourceId)
    {
        for (size_t colorIndex = 0; colorIndex < mState.mColorAttachments.size(); ++colorIndex)
        {
            detachMatchingAttachment(&mState.mColorAttachments[colorIndex], resourceType, resourceId,
                                     DIRTY_BIT_COLOR_ATTACHMENT_0 + colorIndex);
        }
    
        if (context->isWebGL1())
        {
            const std::array<FramebufferAttachment *, 3> attachments = {
                {&mState.mWebGLDepthStencilAttachment, &mState.mWebGLDepthAttachment,
                 &mState.mWebGLStencilAttachment}};
            for (FramebufferAttachment *attachment : attachments)
            {
                if (attachment->isAttached() && attachment->type() == resourceType &&
                    attachment->id() == resourceId)
                {
                    resetAttachment(context, attachment->getBinding());
                }
            }
        }
        else
        {
            detachMatchingAttachment(&mState.mDepthAttachment, resourceType, resourceId,
                                     DIRTY_BIT_DEPTH_ATTACHMENT);
            detachMatchingAttachment(&mState.mStencilAttachment, resourceType, resourceId,
                                     DIRTY_BIT_STENCIL_ATTACHMENT);
        }
    }
    
    void Framebuffer::detachMatchingAttachment(FramebufferAttachment *attachment,
                                               GLenum matchType,
                                               GLuint matchId,
                                               size_t dirtyBit)
    {
        if (attachment->isAttached() && attachment->type() == matchType && attachment->id() == matchId)
        {
            attachment->detach();
            mDirtyBits.set(dirtyBit);
        }
    }
    
    const FramebufferAttachment *Framebuffer::getColorbuffer(size_t colorAttachment) const
    {
        return mState.getColorAttachment(colorAttachment);
    }
    
    const FramebufferAttachment *Framebuffer::getDepthbuffer() const
    {
        return mState.getDepthAttachment();
    }
    
    const FramebufferAttachment *Framebuffer::getStencilbuffer() const
    {
        return mState.getStencilAttachment();
    }
    
    const FramebufferAttachment *Framebuffer::getDepthStencilBuffer() const
    {
        return mState.getDepthStencilAttachment();
    }
    
    const FramebufferAttachment *Framebuffer::getDepthOrStencilbuffer() const
    {
        return mState.getDepthOrStencilAttachment();
    }
    
    const FramebufferAttachment *Framebuffer::getStencilOrDepthStencilAttachment() const
    {
        return mState.getStencilOrDepthStencilAttachment();
    }
    
    const FramebufferAttachment *Framebuffer::getReadColorbuffer() const
    {
        return mState.getReadAttachment();
    }
    
    GLenum Framebuffer::getReadColorbufferType() const
    {
        const FramebufferAttachment *readAttachment = mState.getReadAttachment();
        return (readAttachment != nullptr ? readAttachment->type() : GL_NONE);
    }
    
    const FramebufferAttachment *Framebuffer::getFirstColorbuffer() const
    {
        return mState.getFirstColorAttachment();
    }
    
    const FramebufferAttachment *Framebuffer::getAttachment(GLenum attachment) const
    {
        return mState.getAttachment(attachment);
    }
    
    size_t Framebuffer::getDrawbufferStateCount() const
    {
        return mState.mDrawBufferStates.size();
    }
    
    GLenum Framebuffer::getDrawBufferState(size_t drawBuffer) const
    {
        ASSERT(drawBuffer < mState.mDrawBufferStates.size());
        return mState.mDrawBufferStates[drawBuffer];
    }
    
    const std::vector<GLenum> &Framebuffer::getDrawBufferStates() const
    {
        return mState.getDrawBufferStates();
    }
    
    void Framebuffer::setDrawBuffers(size_t count, const GLenum *buffers)
    {
        auto &drawStates = mState.mDrawBufferStates;
    
        ASSERT(count <= drawStates.size());
        std::copy(buffers, buffers + count, drawStates.begin());
        std::fill(drawStates.begin() + count, drawStates.end(), GL_NONE);
        mDirtyBits.set(DIRTY_BIT_DRAW_BUFFERS);
    
        mState.mEnabledDrawBuffers.reset();
        for (size_t index = 0; index < count; ++index)
        {
            if (drawStates[index] != GL_NONE && mState.mColorAttachments[index].isAttached())
            {
                mState.mEnabledDrawBuffers.set(index);
            }
        }
    }
    
    const FramebufferAttachment *Framebuffer::getDrawBuffer(size_t drawBuffer) const
    {
        return mState.getDrawBuffer(drawBuffer);
    }
    
    bool Framebuffer::hasEnabledDrawBuffer() const
    {
        for (size_t drawbufferIdx = 0; drawbufferIdx < mState.mDrawBufferStates.size(); ++drawbufferIdx)
        {
            if (getDrawBuffer(drawbufferIdx) != nullptr)
            {
                return true;
            }
        }
    
        return false;
    }
    
    GLenum Framebuffer::getReadBufferState() const
    {
        return mState.mReadBufferState;
    }
    
    void Framebuffer::setReadBuffer(GLenum buffer)
    {
        ASSERT(buffer == GL_BACK || buffer == GL_NONE ||
               (buffer >= GL_COLOR_ATTACHMENT0 &&
                (buffer - GL_COLOR_ATTACHMENT0) < mState.mColorAttachments.size()));
        mState.mReadBufferState = buffer;
        mDirtyBits.set(DIRTY_BIT_READ_BUFFER);
    }
    
    size_t Framebuffer::getNumColorBuffers() const
    {
        return mState.mColorAttachments.size();
    }
    
    bool Framebuffer::hasDepth() const
    {
        return (mState.mDepthAttachment.isAttached() && mState.mDepthAttachment.getDepthSize() > 0);
    }
    
    bool Framebuffer::hasStencil() const
    {
        return (mState.mStencilAttachment.isAttached() &&
                mState.mStencilAttachment.getStencilSize() > 0);
    }
    
    bool Framebuffer::usingExtendedDrawBuffers() const
    {
        for (size_t drawbufferIdx = 1; drawbufferIdx < mState.mDrawBufferStates.size(); ++drawbufferIdx)
        {
            if (getDrawBuffer(drawbufferIdx) != nullptr)
            {
                return true;
            }
        }
    
        return false;
    }
    
    void Framebuffer::invalidateCompletenessCache()
    {
        if (mId != 0)
        {
            mCachedStatus.reset();
        }
    }
    
    GLenum Framebuffer::checkStatus(const Context *context)
    {
        // The default framebuffer is always complete except when it is surfaceless in which
        // case it is always unsupported. We return early because the default framebuffer may
        // not be subject to the same rules as application FBOs. ie, it could have 0x0 size.
        if (mId == 0)
        {
            ASSERT(mCachedStatus.valid());
            ASSERT(mCachedStatus.value() == GL_FRAMEBUFFER_COMPLETE ||
                   mCachedStatus.value() == GL_FRAMEBUFFER_UNDEFINED_OES);
            return mCachedStatus.value();
        }
    
        if (hasAnyDirtyBit() || !mCachedStatus.valid())
        {
            mCachedStatus = checkStatusImpl(context);
        }
    
        return mCachedStatus.value();
    }
    
    GLenum Framebuffer::checkStatusImpl(const Context *context)
    {
        const ContextState &state = context->getContextState();
    
        ASSERT(mId != 0);
    
        unsigned int colorbufferSize = 0;
        int samples = -1;
        bool missingAttachment = true;
        Optional<GLboolean> fixedSampleLocations;
        bool hasRenderbuffer = false;
    
        for (const FramebufferAttachment &colorAttachment : mState.mColorAttachments)
        {
            if (colorAttachment.isAttached())
            {
                const Extents &size = colorAttachment.getSize();
                if (size.width == 0 || size.height == 0)
                {
                    return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                }
    
                const InternalFormat &format = *colorAttachment.getFormat().info;
                if (!format.renderSupport(context->getClientVersion(), context->getExtensions()))
                {
                    return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                }
    
                if (format.depthBits > 0 || format.stencilBits > 0)
                {
                    return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                }
    
                if (colorAttachment.type() == GL_TEXTURE)
                {
                    if (colorAttachment.layer() >= size.depth)
                    {
                        return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                    }
    
                    // ES3 specifies that cube map texture attachments must be cube complete.
                    // This language is missing from the ES2 spec, but we enforce it here because some
                    // desktop OpenGL drivers also enforce this validation.
                    // TODO(jmadill): Check if OpenGL ES2 drivers enforce cube completeness.
                    const Texture *texture = colorAttachment.getTexture();
                    ASSERT(texture);
                    if (texture->getTarget() == GL_TEXTURE_CUBE_MAP &&
                        !texture->getTextureState().isCubeComplete())
                    {
                        return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                    }
    
                    // ES3.1 (section 9.4) requires that the value of TEXTURE_FIXED_SAMPLE_LOCATIONS
                    // should be the same for all attached textures.
                    GLboolean fixedSampleloc = colorAttachment.getTexture()->getFixedSampleLocations(
                        colorAttachment.getTextureImageIndex().type, 0);
                    if (fixedSampleLocations.valid() && fixedSampleloc != fixedSampleLocations.value())
                    {
                        return GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE;
                    }
                    else
                    {
                        fixedSampleLocations = fixedSampleloc;
                    }
                }
                else if (colorAttachment.type() == GL_RENDERBUFFER)
                {
                    hasRenderbuffer = true;
                }
    
                if (!missingAttachment)
                {
                    // APPLE_framebuffer_multisample, which EXT_draw_buffers refers to, requires that
                    // all color attachments have the same number of samples for the FBO to be complete.
                    if (colorAttachment.getSamples() != samples)
                    {
                        return GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT;
                    }
    
                    // in GLES 2.0, all color attachments attachments must have the same number of bitplanes
                    // in GLES 3.0, there is no such restriction
                    if (state.getClientMajorVersion() < 3)
                    {
                        if (format.pixelBytes != colorbufferSize)
                        {
                            return GL_FRAMEBUFFER_UNSUPPORTED;
                        }
                    }
                }
                else
                {
                    samples           = colorAttachment.getSamples();
                    colorbufferSize   = format.pixelBytes;
                    missingAttachment = false;
                }
            }
        }
    
        const FramebufferAttachment &depthAttachment = mState.mDepthAttachment;
        if (depthAttachment.isAttached())
        {
            const Extents &size = depthAttachment.getSize();
            if (size.width == 0 || size.height == 0)
            {
                return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
            }
    
            const InternalFormat &format = *depthAttachment.getFormat().info;
    
            if (!format.renderSupport(context->getClientVersion(), context->getExtensions()))
            {
                return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
            }
    
            if (format.depthBits == 0)
            {
                return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
            }
    
            if (missingAttachment)
            {
                samples = depthAttachment.getSamples();
                missingAttachment = false;
            }
            else if (samples != depthAttachment.getSamples())
            {
                // CHROMIUM_framebuffer_mixed_samples allows a framebuffer to be
                // considered complete when its depth or stencil samples are a
                // multiple of the number of color samples.
                const bool mixedSamples = state.getExtensions().framebufferMixedSamples;
                if (!mixedSamples)
                    return GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_ANGLE;
    
                const int colorSamples = samples ? samples : 1;
                const int depthSamples = depthAttachment.getSamples();
                if ((depthSamples % colorSamples) != 0)
                    return GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_ANGLE;
            }
        }
    
        const FramebufferAttachment &stencilAttachment = mState.mStencilAttachment;
        if (stencilAttachment.isAttached())
        {
            const Extents &size = stencilAttachment.getSize();
            if (size.width == 0 || size.height == 0)
            {
                return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
            }
    
            const InternalFormat &format = *stencilAttachment.getFormat().info;
    
            if (!format.renderSupport(context->getClientVersion(), context->getExtensions()))
            {
                return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
            }
    
            if (format.stencilBits == 0)
            {
                return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
            }
    
            if (missingAttachment)
            {
                samples = stencilAttachment.getSamples();
                missingAttachment = false;
            }
            else if (samples != stencilAttachment.getSamples())
            {
                // see the comments in depth attachment check.
                const bool mixedSamples = state.getExtensions().framebufferMixedSamples;
                if (!mixedSamples)
                    return GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_ANGLE;
    
                const int colorSamples   = samples ? samples : 1;
                const int stencilSamples = stencilAttachment.getSamples();
                if ((stencilSamples % colorSamples) != 0)
                    return GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_ANGLE;
            }
    
            // Starting from ES 3.0 stencil and depth, if present, should be the same image
            if (state.getClientMajorVersion() >= 3 && depthAttachment.isAttached() &&
                stencilAttachment != depthAttachment)
            {
                return GL_FRAMEBUFFER_UNSUPPORTED;
            }
        }
    
        // Special additional validation for WebGL 1 DEPTH/STENCIL/DEPTH_STENCIL.
        if (state.isWebGL1())
        {
            if (!mState.mWebGLDepthStencilConsistent)
            {
                return GL_FRAMEBUFFER_UNSUPPORTED;
            }
    
            if (mState.mWebGLDepthStencilAttachment.isAttached())
            {
                if (mState.mWebGLDepthStencilAttachment.getDepthSize() == 0 ||
                    mState.mWebGLDepthStencilAttachment.getStencilSize() == 0)
                {
                    return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                }
            }
            else if (mState.mStencilAttachment.isAttached() &&
                     mState.mStencilAttachment.getDepthSize() > 0)
            {
                return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
            }
            else if (mState.mDepthAttachment.isAttached() &&
                     mState.mDepthAttachment.getStencilSize() > 0)
            {
                return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
            }
        }
    
        // ES3.1(section 9.4) requires that if no image is attached to the
        // framebuffer, and either the value of the framebuffer's FRAMEBUFFER_DEFAULT_WIDTH
        // or FRAMEBUFFER_DEFAULT_HEIGHT parameters is zero, the framebuffer is
        // considered incomplete.
        GLint defaultWidth  = mState.getDefaultWidth();
        GLint defaultHeight = mState.getDefaultHeight();
    
        if (missingAttachment && (defaultWidth == 0 || defaultHeight == 0))
        {
            return GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT;
        }
    
        // In ES 2.0 and WebGL, all color attachments must have the same width and height.
        // In ES 3.0, there is no such restriction.
        if ((state.getClientMajorVersion() < 3 || state.getExtensions().webglCompatibility) &&
            !mState.attachmentsHaveSameDimensions())
        {
            return GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS;
        }
    
        // ES3.1(section 9.4) requires that if the attached images are a mix of renderbuffers
        // and textures, the value of TEXTURE_FIXED_SAMPLE_LOCATIONS must be TRUE for all
        // attached textures.
        if (fixedSampleLocations.valid() && hasRenderbuffer && !fixedSampleLocations.value())
        {
            return GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE;
        }
    
        syncState(context);
        if (!mImpl->checkStatus())
        {
            return GL_FRAMEBUFFER_UNSUPPORTED;
        }
    
        return GL_FRAMEBUFFER_COMPLETE;
    }
    
    Error Framebuffer::discard(size_t count, const GLenum *attachments)
    {
        return mImpl->discard(count, attachments);
    }
    
    Error Framebuffer::invalidate(size_t count, const GLenum *attachments)
    {
        return mImpl->invalidate(count, attachments);
    }
    
    Error Framebuffer::invalidateSub(size_t count, const GLenum *attachments, const gl::Rectangle &area)
    {
        return mImpl->invalidateSub(count, attachments, area);
    }
    
    Error Framebuffer::clear(rx::ContextImpl *context, GLbitfield mask)
    {
        if (context->getGLState().isRasterizerDiscardEnabled())
        {
            return gl::NoError();
        }
    
        return mImpl->clear(context, mask);
    }
    
    Error Framebuffer::clearBufferfv(rx::ContextImpl *context,
                                     GLenum buffer,
                                     GLint drawbuffer,
                                     const GLfloat *values)
    {
        if (context->getGLState().isRasterizerDiscardEnabled())
        {
            return gl::NoError();
        }
    
        return mImpl->clearBufferfv(context, buffer, drawbuffer, values);
    }
    
    Error Framebuffer::clearBufferuiv(rx::ContextImpl *context,
                                      GLenum buffer,
                                      GLint drawbuffer,
                                      const GLuint *values)
    {
        if (context->getGLState().isRasterizerDiscardEnabled())
        {
            return gl::NoError();
        }
    
        return mImpl->clearBufferuiv(context, buffer, drawbuffer, values);
    }
    
    Error Framebuffer::clearBufferiv(rx::ContextImpl *context,
                                     GLenum buffer,
                                     GLint drawbuffer,
                                     const GLint *values)
    {
        if (context->getGLState().isRasterizerDiscardEnabled())
        {
            return gl::NoError();
        }
    
        return mImpl->clearBufferiv(context, buffer, drawbuffer, values);
    }
    
    Error Framebuffer::clearBufferfi(rx::ContextImpl *context,
                                     GLenum buffer,
                                     GLint drawbuffer,
                                     GLfloat depth,
                                     GLint stencil)
    {
        if (context->getGLState().isRasterizerDiscardEnabled())
        {
            return gl::NoError();
        }
    
        return mImpl->clearBufferfi(context, buffer, drawbuffer, depth, stencil);
    }
    
    GLenum Framebuffer::getImplementationColorReadFormat() const
    {
        return mImpl->getImplementationColorReadFormat();
    }
    
    GLenum Framebuffer::getImplementationColorReadType() const
    {
        return mImpl->getImplementationColorReadType();
    }
    
    Error Framebuffer::readPixels(rx::ContextImpl *context,
                                  const Rectangle &area,
                                  GLenum format,
                                  GLenum type,
                                  void *pixels) const
    {
        ANGLE_TRY(mImpl->readPixels(context, area, format, type, pixels));
    
        Buffer *unpackBuffer = context->getGLState().getUnpackState().pixelBuffer.get();
        if (unpackBuffer)
        {
            unpackBuffer->onPixelUnpack();
        }
    
        return NoError();
    }
    
    Error Framebuffer::blit(rx::ContextImpl *context,
                            const Rectangle &sourceArea,
                            const Rectangle &destArea,
                            GLbitfield mask,
                            GLenum filter)
    {
        GLbitfield blitMask = mask;
    
        // Note that blitting is called against draw framebuffer.
        // See the code in gl::Context::blitFramebuffer.
        if ((mask & GL_COLOR_BUFFER_BIT) && !hasEnabledDrawBuffer())
        {
            blitMask &= ~GL_COLOR_BUFFER_BIT;
        }
    
        if ((mask & GL_STENCIL_BUFFER_BIT) && mState.getStencilAttachment() == nullptr)
        {
            blitMask &= ~GL_STENCIL_BUFFER_BIT;
        }
    
        if ((mask & GL_DEPTH_BUFFER_BIT) && mState.getDepthAttachment() == nullptr)
        {
            blitMask &= ~GL_DEPTH_BUFFER_BIT;
        }
    
        if (!blitMask)
        {
            return NoError();
        }
    
        return mImpl->blit(context, sourceArea, destArea, blitMask, filter);
    }
    
    int Framebuffer::getSamples(const Context *context)
    {
        if (complete(context))
        {
            // For a complete framebuffer, all attachments must have the same sample count.
            // In this case return the first nonzero sample size.
            const auto *firstColorAttachment = mState.getFirstColorAttachment();
            if (firstColorAttachment)
            {
                ASSERT(firstColorAttachment->isAttached());
                return firstColorAttachment->getSamples();
            }
        }
    
        return 0;
    }
    
    Error Framebuffer::getSamplePosition(size_t index, GLfloat *xy) const
    {
        ANGLE_TRY(mImpl->getSamplePosition(index, xy));
        return gl::NoError();
    }
    
    bool Framebuffer::hasValidDepthStencil() const
    {
        return mState.getDepthStencilAttachment() != nullptr;
    }
    
    void Framebuffer::setAttachment(const Context *context,
                                    GLenum type,
                                    GLenum binding,
                                    const ImageIndex &textureIndex,
                                    FramebufferAttachmentObject *resource)
    {
        // Context may be null in unit tests.
        if (!context || !context->isWebGL1())
        {
            setAttachmentImpl(type, binding, textureIndex, resource);
            return;
        }
    
        switch (binding)
        {
            case GL_DEPTH_STENCIL:
            case GL_DEPTH_STENCIL_ATTACHMENT:
                mState.mWebGLDepthStencilAttachment.attach(type, binding, textureIndex, resource);
                break;
            case GL_DEPTH:
            case GL_DEPTH_ATTACHMENT:
                mState.mWebGLDepthAttachment.attach(type, binding, textureIndex, resource);
                break;
            case GL_STENCIL:
            case GL_STENCIL_ATTACHMENT:
                mState.mWebGLStencilAttachment.attach(type, binding, textureIndex, resource);
                break;
            default:
                setAttachmentImpl(type, binding, textureIndex, resource);
                return;
        }
    
        commitWebGL1DepthStencilIfConsistent();
    }
    
    void Framebuffer::commitWebGL1DepthStencilIfConsistent()
    {
        int count = 0;
    
        std::array<FramebufferAttachment *, 3> attachments = {{&mState.mWebGLDepthStencilAttachment,
                                                               &mState.mWebGLDepthAttachment,
                                                               &mState.mWebGLStencilAttachment}};
        for (FramebufferAttachment *attachment : attachments)
        {
            if (attachment->isAttached())
            {
                count++;
            }
        }
    
        mState.mWebGLDepthStencilConsistent = (count <= 1);
        if (!mState.mWebGLDepthStencilConsistent)
        {
            // Inconsistent.
            return;
        }
    
        auto getImageIndexIfTextureAttachment = [](const FramebufferAttachment &attachment) {
            if (attachment.type() == GL_TEXTURE)
            {
                return attachment.getTextureImageIndex();
            }
            else
            {
                return ImageIndex::MakeInvalid();
            }
        };
    
        if (mState.mWebGLDepthAttachment.isAttached())
        {
            const auto &depth = mState.mWebGLDepthAttachment;
            setAttachmentImpl(depth.type(), GL_DEPTH_ATTACHMENT,
                              getImageIndexIfTextureAttachment(depth), depth.getResource());
            setAttachmentImpl(GL_NONE, GL_STENCIL_ATTACHMENT, ImageIndex::MakeInvalid(), nullptr);
        }
        else if (mState.mWebGLStencilAttachment.isAttached())
        {
            const auto &stencil = mState.mWebGLStencilAttachment;
            setAttachmentImpl(GL_NONE, GL_DEPTH_ATTACHMENT, ImageIndex::MakeInvalid(), nullptr);
            setAttachmentImpl(stencil.type(), GL_STENCIL_ATTACHMENT,
                              getImageIndexIfTextureAttachment(stencil), stencil.getResource());
        }
        else if (mState.mWebGLDepthStencilAttachment.isAttached())
        {
            const auto &depthStencil = mState.mWebGLDepthStencilAttachment;
            setAttachmentImpl(depthStencil.type(), GL_DEPTH_ATTACHMENT,
                              getImageIndexIfTextureAttachment(depthStencil),
                              depthStencil.getResource());
            setAttachmentImpl(depthStencil.type(), GL_STENCIL_ATTACHMENT,
                              getImageIndexIfTextureAttachment(depthStencil),
                              depthStencil.getResource());
        }
        else
        {
            setAttachmentImpl(GL_NONE, GL_DEPTH_ATTACHMENT, ImageIndex::MakeInvalid(), nullptr);
            setAttachmentImpl(GL_NONE, GL_STENCIL_ATTACHMENT, ImageIndex::MakeInvalid(), nullptr);
        }
    }
    
    void Framebuffer::setAttachmentImpl(GLenum type,
                                        GLenum binding,
                                        const ImageIndex &textureIndex,
                                        FramebufferAttachmentObject *resource)
    {
        switch (binding)
        {
            case GL_DEPTH_STENCIL:
            case GL_DEPTH_STENCIL_ATTACHMENT:
            {
                // ensure this is a legitimate depth+stencil format
                FramebufferAttachmentObject *attachmentObj = resource;
                if (resource)
                {
                    const Format &format = resource->getAttachmentFormat(binding, textureIndex);
                    if (format.info->depthBits == 0 || format.info->stencilBits == 0)
                    {
                        // Attaching nullptr detaches the current attachment.
                        attachmentObj = nullptr;
                    }
                }
    
                updateAttachment(&mState.mDepthAttachment, DIRTY_BIT_DEPTH_ATTACHMENT,
                                 &mDirtyDepthAttachmentBinding, type, binding, textureIndex,
                                 attachmentObj);
                updateAttachment(&mState.mStencilAttachment, DIRTY_BIT_STENCIL_ATTACHMENT,
                                 &mDirtyStencilAttachmentBinding, type, binding, textureIndex,
                                 attachmentObj);
                return;
            }
    
            case GL_DEPTH:
            case GL_DEPTH_ATTACHMENT:
                updateAttachment(&mState.mDepthAttachment, DIRTY_BIT_DEPTH_ATTACHMENT,
                                 &mDirtyDepthAttachmentBinding, type, binding, textureIndex, resource);
                break;
    
            case GL_STENCIL:
            case GL_STENCIL_ATTACHMENT:
                updateAttachment(&mState.mStencilAttachment, DIRTY_BIT_STENCIL_ATTACHMENT,
                                 &mDirtyStencilAttachmentBinding, type, binding, textureIndex,
                                 resource);
                break;
    
            case GL_BACK:
                mState.mColorAttachments[0].attach(type, binding, textureIndex, resource);
                mDirtyBits.set(DIRTY_BIT_COLOR_ATTACHMENT_0);
                // No need for a resource binding for the default FBO, it's always complete.
                break;
    
            default:
            {
                size_t colorIndex = binding - GL_COLOR_ATTACHMENT0;
                ASSERT(colorIndex < mState.mColorAttachments.size());
                size_t dirtyBit = DIRTY_BIT_COLOR_ATTACHMENT_0 + colorIndex;
                updateAttachment(&mState.mColorAttachments[colorIndex], dirtyBit,
                                 &mDirtyColorAttachmentBindings[colorIndex], type, binding,
                                 textureIndex, resource);
    
                bool enabled = (type != GL_NONE && getDrawBufferState(colorIndex) != GL_NONE);
                mState.mEnabledDrawBuffers.set(colorIndex, enabled);
            }
            break;
        }
    }
    
    void Framebuffer::updateAttachment(FramebufferAttachment *attachment,
                                       size_t dirtyBit,
                                       OnAttachmentDirtyBinding *onDirtyBinding,
                                       GLenum type,
                                       GLenum binding,
                                       const ImageIndex &textureIndex,
                                       FramebufferAttachmentObject *resource)
    {
        attachment->attach(type, binding, textureIndex, resource);
        mDirtyBits.set(dirtyBit);
        BindResourceChannel(onDirtyBinding, resource);
    }
    
    void Framebuffer::resetAttachment(const Context *context, GLenum binding)
    {
        setAttachment(context, GL_NONE, binding, ImageIndex::MakeInvalid(), nullptr);
    }
    
    void Framebuffer::syncState(const Context *context)
    {
        if (mDirtyBits.any())
        {
            mImpl->syncState(rx::SafeGetImpl(context), mDirtyBits);
            mDirtyBits.reset();
            if (mId != 0)
            {
                mCachedStatus.reset();
            }
        }
    }
    
    void Framebuffer::signal(uint32_t token)
    {
        // TOOD(jmadill): Make this only update individual attachments to do less work.
        mCachedStatus.reset();
    }
    
    bool Framebuffer::complete(const Context *context)
    {
        return (checkStatus(context) == GL_FRAMEBUFFER_COMPLETE);
    }
    
    bool Framebuffer::cachedComplete() const
    {
        return (mCachedStatus.valid() && mCachedStatus == GL_FRAMEBUFFER_COMPLETE);
    }
    
    bool Framebuffer::formsRenderingFeedbackLoopWith(const State &state) const
    {
        const Program *program = state.getProgram();
    
        // TODO(jmadill): Default framebuffer feedback loops.
        if (mId == 0)
        {
            return false;
        }
    
        // The bitset will skip inactive draw buffers.
        for (size_t drawIndex : mState.mEnabledDrawBuffers)
        {
            const FramebufferAttachment *attachment = getDrawBuffer(drawIndex);
            if (attachment && attachment->type() == GL_TEXTURE)
            {
                // Validate the feedback loop.
                if (program->samplesFromTexture(state, attachment->id()))
                {
                    return true;
                }
            }
        }
    
        // Validate depth-stencil feedback loop.
        const auto &dsState = state.getDepthStencilState();
    
        // We can skip the feedback loop checks if depth/stencil is masked out or disabled.
        const FramebufferAttachment *depth = getDepthbuffer();
        if (depth && depth->type() == GL_TEXTURE && dsState.depthTest && dsState.depthMask)
        {
            if (program->samplesFromTexture(state, depth->id()))
            {
                return true;
            }
        }
    
        // Note: we assume the front and back masks are the same for WebGL.
        const FramebufferAttachment *stencil = getStencilbuffer();
        ASSERT(dsState.stencilBackWritemask == dsState.stencilWritemask);
        if (stencil && stencil->type() == GL_TEXTURE && dsState.stencilTest &&
            dsState.stencilWritemask != 0)
        {
            // Skip the feedback loop check if depth/stencil point to the same resource.
            if (!depth || *stencil != *depth)
            {
                if (program->samplesFromTexture(state, stencil->id()))
                {
                    return true;
                }
            }
        }
    
        return false;
    }
    
    bool Framebuffer::formsCopyingFeedbackLoopWith(GLuint copyTextureID,
                                                   GLint copyTextureLevel,
                                                   GLint copyTextureLayer) const
    {
        if (mId == 0)
        {
            // It seems impossible to form a texture copying feedback loop with the default FBO.
            return false;
        }
    
        const FramebufferAttachment *readAttachment = getReadColorbuffer();
        ASSERT(readAttachment);
    
        if (readAttachment->isTextureWithId(copyTextureID))
        {
            const auto &imageIndex = readAttachment->getTextureImageIndex();
            if (imageIndex.mipIndex == copyTextureLevel)
            {
                // Check 3D/Array texture layers.
                return imageIndex.layerIndex == ImageIndex::ENTIRE_LEVEL ||
                       copyTextureLayer == ImageIndex::ENTIRE_LEVEL ||
                       imageIndex.layerIndex == copyTextureLayer;
            }
        }
        return false;
    }
    
    GLint Framebuffer::getDefaultWidth() const
    {
        return mState.getDefaultWidth();
    }
    
    GLint Framebuffer::getDefaultHeight() const
    {
        return mState.getDefaultHeight();
    }
    
    GLint Framebuffer::getDefaultSamples() const
    {
        return mState.getDefaultSamples();
    }
    
    GLboolean Framebuffer::getDefaultFixedSampleLocations() const
    {
        return mState.getDefaultFixedSampleLocations();
    }
    
    void Framebuffer::setDefaultWidth(GLint defaultWidth)
    {
        mState.mDefaultWidth = defaultWidth;
        mDirtyBits.set(DIRTY_BIT_DEFAULT_WIDTH);
    }
    
    void Framebuffer::setDefaultHeight(GLint defaultHeight)
    {
        mState.mDefaultHeight = defaultHeight;
        mDirtyBits.set(DIRTY_BIT_DEFAULT_HEIGHT);
    }
    
    void Framebuffer::setDefaultSamples(GLint defaultSamples)
    {
        mState.mDefaultSamples = defaultSamples;
        mDirtyBits.set(DIRTY_BIT_DEFAULT_SAMPLES);
    }
    
    void Framebuffer::setDefaultFixedSampleLocations(GLboolean defaultFixedSampleLocations)
    {
        mState.mDefaultFixedSampleLocations = defaultFixedSampleLocations;
        mDirtyBits.set(DIRTY_BIT_DEFAULT_FIXED_SAMPLE_LOCATIONS);
    }
    
    // TODO(jmadill): Remove this kludge.
    GLenum Framebuffer::checkStatus(const ValidationContext *context)
    {
        return checkStatus(static_cast<const Context *>(context));
    }
    
    int Framebuffer::getSamples(const ValidationContext *context)
    {
        return getSamples(static_cast<const Context *>(context));
    }
    
    }  // namespace gl