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

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  • Author : Jamie Madill
    Date : 2015-02-03 16:16:04
    Hash : b885e571
    Message : Implement ReadBuffer functionality. This enables ReadPixels from non-0 FBO attachments. Tested with: dEQP-GLES3.functional.negative_api.buffer.read_buffer (fails due to a possible error in dEQP) dEQP-GLES3.functional.shaders.fragdata.draw_buffers (passes) BUG=angle:903 Change-Id: Ib095e1d50b8fbbc6f197de25f19ec0993309145a Reviewed-on: https://chromium-review.googlesource.com/244841 Tested-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Zhenyao Mo <zmo@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 "libANGLE/formatutils.h"
    #include "libANGLE/Texture.h"
    #include "libANGLE/Context.h"
    #include "libANGLE/Renderbuffer.h"
    #include "libANGLE/FramebufferAttachment.h"
    #include "libANGLE/renderer/FramebufferImpl.h"
    #include "libANGLE/renderer/Renderer.h"
    #include "libANGLE/renderer/RenderbufferImpl.h"
    #include "libANGLE/renderer/Workarounds.h"
    
    #include "common/utilities.h"
    
    namespace gl
    {
    
    Framebuffer::Framebuffer(rx::FramebufferImpl *impl, GLuint id)
        : mImpl(impl),
          mId(id),
          mReadBufferState(GL_COLOR_ATTACHMENT0_EXT),
          mDepthbuffer(NULL),
          mStencilbuffer(NULL)
    {
        ASSERT(mImpl != nullptr);
    
        for (unsigned int colorAttachment = 0; colorAttachment < IMPLEMENTATION_MAX_DRAW_BUFFERS; colorAttachment++)
        {
            mColorbuffers[colorAttachment] = NULL;
            mDrawBufferStates[colorAttachment] = GL_NONE;
        }
        mDrawBufferStates[0] = GL_COLOR_ATTACHMENT0_EXT;
    }
    
    Framebuffer::~Framebuffer()
    {
        SafeDelete(mImpl);
        for (unsigned int colorAttachment = 0; colorAttachment < IMPLEMENTATION_MAX_DRAW_BUFFERS; colorAttachment++)
        {
            SafeDelete(mColorbuffers[colorAttachment]);
        }
        SafeDelete(mDepthbuffer);
        SafeDelete(mStencilbuffer);
    }
    
    void Framebuffer::detachTexture(GLuint textureId)
    {
        for (unsigned int colorAttachment = 0; colorAttachment < IMPLEMENTATION_MAX_DRAW_BUFFERS; colorAttachment++)
        {
            FramebufferAttachment *attachment = mColorbuffers[colorAttachment];
    
            if (attachment && attachment->isTextureWithId(textureId))
            {
                SafeDelete(mColorbuffers[colorAttachment]);
            }
        }
    
        if (mDepthbuffer && mDepthbuffer->isTextureWithId(textureId))
        {
            SafeDelete(mDepthbuffer);
        }
    
        if (mStencilbuffer && mStencilbuffer->isTextureWithId(textureId))
        {
            SafeDelete(mStencilbuffer);
        }
    }
    
    void Framebuffer::detachRenderbuffer(GLuint renderbufferId)
    {
        for (unsigned int colorAttachment = 0; colorAttachment < IMPLEMENTATION_MAX_DRAW_BUFFERS; colorAttachment++)
        {
            FramebufferAttachment *attachment = mColorbuffers[colorAttachment];
    
            if (attachment && attachment->isRenderbufferWithId(renderbufferId))
            {
                SafeDelete(mColorbuffers[colorAttachment]);
            }
        }
    
        if (mDepthbuffer && mDepthbuffer->isRenderbufferWithId(renderbufferId))
        {
            SafeDelete(mDepthbuffer);
        }
    
        if (mStencilbuffer && mStencilbuffer->isRenderbufferWithId(renderbufferId))
        {
            SafeDelete(mStencilbuffer);
        }
    }
    
    FramebufferAttachment *Framebuffer::getColorbuffer(unsigned int colorAttachment) const
    {
        ASSERT(colorAttachment < IMPLEMENTATION_MAX_DRAW_BUFFERS);
        return mColorbuffers[colorAttachment];
    }
    
    FramebufferAttachment *Framebuffer::getDepthbuffer() const
    {
        return mDepthbuffer;
    }
    
    FramebufferAttachment *Framebuffer::getStencilbuffer() const
    {
        return mStencilbuffer;
    }
    
    FramebufferAttachment *Framebuffer::getDepthStencilBuffer() const
    {
        return (hasValidDepthStencil() ? mDepthbuffer : NULL);
    }
    
    FramebufferAttachment *Framebuffer::getDepthOrStencilbuffer() const
    {
        FramebufferAttachment *depthstencilbuffer = mDepthbuffer;
        
        if (!depthstencilbuffer)
        {
            depthstencilbuffer = mStencilbuffer;
        }
    
        return depthstencilbuffer;
    }
    
    FramebufferAttachment *Framebuffer::getReadColorbuffer() const
    {
        size_t readIndex = (mReadBufferState == GL_BACK ? 0 : static_cast<size_t>(mReadBufferState - GL_COLOR_ATTACHMENT0));
        ASSERT(readIndex < IMPLEMENTATION_MAX_DRAW_BUFFERS);
        return mColorbuffers[readIndex];
    }
    
    GLenum Framebuffer::getReadColorbufferType() const
    {
        FramebufferAttachment *readAttachment = getReadColorbuffer();
        return (readAttachment ? readAttachment->type() : GL_NONE);
    }
    
    FramebufferAttachment *Framebuffer::getFirstColorbuffer() const
    {
        for (unsigned int colorAttachment = 0; colorAttachment < IMPLEMENTATION_MAX_DRAW_BUFFERS; colorAttachment++)
        {
            if (mColorbuffers[colorAttachment])
            {
                return mColorbuffers[colorAttachment];
            }
        }
    
        return NULL;
    }
    
    FramebufferAttachment *Framebuffer::getAttachment(GLenum attachment) const
    {
        if (attachment >= GL_COLOR_ATTACHMENT0 && attachment <= GL_COLOR_ATTACHMENT15)
        {
            return getColorbuffer(attachment - GL_COLOR_ATTACHMENT0);
        }
        else
        {
            switch (attachment)
            {
              case GL_COLOR:
              case GL_BACK:
                return getColorbuffer(0);
              case GL_DEPTH:
              case GL_DEPTH_ATTACHMENT:
                return getDepthbuffer();
              case GL_STENCIL:
              case GL_STENCIL_ATTACHMENT:
                return getStencilbuffer();
              case GL_DEPTH_STENCIL:
              case GL_DEPTH_STENCIL_ATTACHMENT:
                return getDepthStencilBuffer();
              default:
                UNREACHABLE();
                return NULL;
            }
        }
    }
    
    GLenum Framebuffer::getDrawBufferState(unsigned int colorAttachment) const
    {
        return mDrawBufferStates[colorAttachment];
    }
    
    void Framebuffer::setDrawBuffers(size_t count, const GLenum *buffers)
    {
        ASSERT(count <= ArraySize(mDrawBufferStates));
        std::copy(buffers, buffers + count, mDrawBufferStates);
        std::fill(mDrawBufferStates + count, mDrawBufferStates + ArraySize(mDrawBufferStates), GL_NONE);
        mImpl->setDrawBuffers(count, buffers);
    }
    
    GLenum Framebuffer::getReadBufferState() const
    {
        return mReadBufferState;
    }
    
    void Framebuffer::setReadBuffer(GLenum buffer)
    {
        ASSERT(buffer == GL_BACK || buffer == GL_NONE ||
               (buffer >= GL_COLOR_ATTACHMENT0 &&
                (buffer - GL_COLOR_ATTACHMENT0) < IMPLEMENTATION_MAX_DRAW_BUFFERS));
        mReadBufferState = buffer;
        mImpl->setReadBuffer(buffer);
    }
    
    bool Framebuffer::isEnabledColorAttachment(unsigned int colorAttachment) const
    {
        return (mColorbuffers[colorAttachment] && mDrawBufferStates[colorAttachment] != GL_NONE);
    }
    
    bool Framebuffer::hasEnabledColorAttachment() const
    {
        for (unsigned int colorAttachment = 0; colorAttachment < gl::IMPLEMENTATION_MAX_DRAW_BUFFERS; colorAttachment++)
        {
            if (isEnabledColorAttachment(colorAttachment))
            {
                return true;
            }
        }
    
        return false;
    }
    
    bool Framebuffer::hasStencil() const
    {
        return (mStencilbuffer && mStencilbuffer->getStencilSize() > 0);
    }
    
    bool Framebuffer::usingExtendedDrawBuffers() const
    {
        for (unsigned int colorAttachment = 1; colorAttachment < IMPLEMENTATION_MAX_DRAW_BUFFERS; colorAttachment++)
        {
            if (isEnabledColorAttachment(colorAttachment))
            {
                return true;
            }
        }
    
        return false;
    }
    
    GLenum Framebuffer::checkStatus(const gl::Data &data) const
    {
        // The default framebuffer *must* always be complete, though it may not be
        // subject to the same rules as application FBOs. ie, it could have 0x0 size.
        if (mId == 0)
        {
            return GL_FRAMEBUFFER_COMPLETE;
        }
    
        int width = 0;
        int height = 0;
        unsigned int colorbufferSize = 0;
        int samples = -1;
        bool missingAttachment = true;
    
        for (unsigned int colorAttachment = 0; colorAttachment < IMPLEMENTATION_MAX_DRAW_BUFFERS; colorAttachment++)
        {
            const FramebufferAttachment *colorbuffer = mColorbuffers[colorAttachment];
    
            if (colorbuffer)
            {
                if (colorbuffer->getWidth() == 0 || colorbuffer->getHeight() == 0)
                {
                    return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                }
    
                GLenum internalformat = colorbuffer->getInternalFormat();
                const TextureCaps &formatCaps = data.textureCaps->get(internalformat);
                const InternalFormat &formatInfo = GetInternalFormatInfo(internalformat);
                if (colorbuffer->type() == GL_TEXTURE)
                {
                    if (!formatCaps.renderable)
                    {
                        return GL_FRAMEBUFFER_UNSUPPORTED;
                    }
    
                    if (formatInfo.depthBits > 0 || formatInfo.stencilBits > 0)
                    {
                        return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                    }
                }
                else if (colorbuffer->type() == GL_RENDERBUFFER)
                {
                    if (!formatCaps.renderable || formatInfo.depthBits > 0 || formatInfo.stencilBits > 0)
                    {
                        return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                    }
                }
    
                if (!missingAttachment)
                {
                    // all color attachments must have the same width and height
                    if (colorbuffer->getWidth() != width || colorbuffer->getHeight() != height)
                    {
                        return GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS;
                    }
    
                    // 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 (colorbuffer->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 (data.clientVersion < 3)
                    {
                        if (formatInfo.pixelBytes != colorbufferSize)
                        {
                            return GL_FRAMEBUFFER_UNSUPPORTED;
                        }
                    }
                }
                else
                {
                    width = colorbuffer->getWidth();
                    height = colorbuffer->getHeight();
                    samples = colorbuffer->getSamples();
                    colorbufferSize = formatInfo.pixelBytes;
                    missingAttachment = false;
                }
            }
        }
    
        if (mDepthbuffer)
        {
            if (mDepthbuffer->getWidth() == 0 || mDepthbuffer->getHeight() == 0)
            {
                return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
            }
    
            GLenum internalformat = mDepthbuffer->getInternalFormat();
            const TextureCaps &formatCaps = data.textureCaps->get(internalformat);
            const InternalFormat &formatInfo = GetInternalFormatInfo(internalformat);
            if (mDepthbuffer->type() == GL_TEXTURE)
            {
                // depth texture attachments require OES/ANGLE_depth_texture
                if (!data.extensions->depthTextures)
                {
                    return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                }
    
                if (!formatCaps.renderable)
                {
                    return GL_FRAMEBUFFER_UNSUPPORTED;
                }
    
                if (formatInfo.depthBits == 0)
                {
                    return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                }
            }
            else if (mDepthbuffer->type() == GL_RENDERBUFFER)
            {
                if (!formatCaps.renderable || formatInfo.depthBits == 0)
                {
                    return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                }
            }
    
            if (missingAttachment)
            {
                width = mDepthbuffer->getWidth();
                height = mDepthbuffer->getHeight();
                samples = mDepthbuffer->getSamples();
                missingAttachment = false;
            }
            else if (width != mDepthbuffer->getWidth() || height != mDepthbuffer->getHeight())
            {
                return GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS;
            }
            else if (samples != mDepthbuffer->getSamples())
            {
                return GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_ANGLE;
            }
        }
    
        if (mStencilbuffer)
        {
            if (mStencilbuffer->getWidth() == 0 || mStencilbuffer->getHeight() == 0)
            {
                return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
            }
    
            GLenum internalformat = mStencilbuffer->getInternalFormat();
            const TextureCaps &formatCaps = data.textureCaps->get(internalformat);
            const InternalFormat &formatInfo = GetInternalFormatInfo(internalformat);
            if (mStencilbuffer->type() == GL_TEXTURE)
            {
                // texture stencil attachments come along as part
                // of OES_packed_depth_stencil + OES/ANGLE_depth_texture
                if (!data.extensions->depthTextures)
                {
                    return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                }
    
                if (!formatCaps.renderable)
                {
                    return GL_FRAMEBUFFER_UNSUPPORTED;
                }
    
                if (formatInfo.stencilBits == 0)
                {
                    return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                }
            }
            else if (mStencilbuffer->type() == GL_RENDERBUFFER)
            {
                if (!formatCaps.renderable || formatInfo.stencilBits == 0)
                {
                    return GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT;
                }
            }
    
            if (missingAttachment)
            {
                width = mStencilbuffer->getWidth();
                height = mStencilbuffer->getHeight();
                samples = mStencilbuffer->getSamples();
                missingAttachment = false;
            }
            else if (width != mStencilbuffer->getWidth() || height != mStencilbuffer->getHeight())
            {
                return GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS;
            }
            else if (samples != mStencilbuffer->getSamples())
            {
                return GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_ANGLE;
            }
        }
    
        // if we have both a depth and stencil buffer, they must refer to the same object
        // since we only support packed_depth_stencil and not separate depth and stencil
        if (mDepthbuffer && mStencilbuffer && !hasValidDepthStencil())
        {
            return GL_FRAMEBUFFER_UNSUPPORTED;
        }
    
        // we need to have at least one attachment to be complete
        if (missingAttachment)
        {
            return GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT;
        }
    
        return mImpl->checkStatus();
    }
    
    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(const State &state, GLbitfield mask)
    {
        return mImpl->clear(state, mask);
    }
    
    Error Framebuffer::clearBufferfv(const State &state, GLenum buffer, GLint drawbuffer, const GLfloat *values)
    {
        return mImpl->clearBufferfv(state, buffer, drawbuffer, values);
    }
    
    Error Framebuffer::clearBufferuiv(const State &state, GLenum buffer, GLint drawbuffer, const GLuint *values)
    {
        return mImpl->clearBufferuiv(state, buffer, drawbuffer, values);
    }
    
    Error Framebuffer::clearBufferiv(const State &state, GLenum buffer, GLint drawbuffer, const GLint *values)
    {
        return mImpl->clearBufferiv(state, buffer, drawbuffer, values);
    }
    
    Error Framebuffer::clearBufferfi(const State &state, GLenum buffer, GLint drawbuffer, GLfloat depth, GLint stencil)
    {
        return mImpl->clearBufferfi(state, buffer, drawbuffer, depth, stencil);
    }
    
    GLenum Framebuffer::getImplementationColorReadFormat() const
    {
        return mImpl->getImplementationColorReadFormat();
    }
    
    GLenum Framebuffer::getImplementationColorReadType() const
    {
        return mImpl->getImplementationColorReadType();
    }
    
    Error Framebuffer::readPixels(const gl::State &state, const gl::Rectangle &area, GLenum format, GLenum type, GLvoid *pixels) const
    {
        return mImpl->readPixels(state, area, format, type, pixels);
    }
    
    Error Framebuffer::blit(const gl::State &state, const gl::Rectangle &sourceArea, const gl::Rectangle &destArea,
                            GLbitfield mask, GLenum filter, const gl::Framebuffer *sourceFramebuffer)
    {
        return mImpl->blit(state, sourceArea, destArea, mask, filter, sourceFramebuffer);
    }
    
    int Framebuffer::getSamples(const gl::Data &data) const
    {
        if (checkStatus(data) == GL_FRAMEBUFFER_COMPLETE)
        {
            // for a complete framebuffer, all attachments must have the same sample count
            // in this case return the first nonzero sample size
            for (unsigned int colorAttachment = 0; colorAttachment < IMPLEMENTATION_MAX_DRAW_BUFFERS; colorAttachment++)
            {
                if (mColorbuffers[colorAttachment])
                {
                    return mColorbuffers[colorAttachment]->getSamples();
                }
            }
        }
    
        return 0;
    }
    
    bool Framebuffer::hasValidDepthStencil() const
    {
        // A valid depth-stencil attachment has the same resource bound to both the
        // depth and stencil attachment points.
        return (mDepthbuffer && mStencilbuffer &&
                mDepthbuffer->type() == mStencilbuffer->type() &&
                mDepthbuffer->id() == mStencilbuffer->id());
    }
    
    ColorbufferInfo Framebuffer::getColorbuffersForRender(const rx::Workarounds &workarounds) const
    {
        ColorbufferInfo colorbuffersForRender;
    
        for (size_t colorAttachment = 0; colorAttachment < IMPLEMENTATION_MAX_DRAW_BUFFERS; ++colorAttachment)
        {
            GLenum drawBufferState = mDrawBufferStates[colorAttachment];
            FramebufferAttachment *colorbuffer = mColorbuffers[colorAttachment];
    
            if (colorbuffer != NULL && drawBufferState != GL_NONE)
            {
                ASSERT(drawBufferState == GL_BACK || drawBufferState == (GL_COLOR_ATTACHMENT0_EXT + colorAttachment));
                colorbuffersForRender.push_back(colorbuffer);
            }
            else if (!workarounds.mrtPerfWorkaround)
            {
                colorbuffersForRender.push_back(NULL);
            }
        }
    
        return colorbuffersForRender;
    }
    
    void Framebuffer::setTextureAttachment(GLenum attachment, Texture *texture, const ImageIndex &imageIndex)
    {
        setAttachment(attachment, new TextureAttachment(attachment, texture, imageIndex));
    }
    
    void Framebuffer::setRenderbufferAttachment(GLenum attachment, Renderbuffer *renderbuffer)
    {
        setAttachment(attachment, new RenderbufferAttachment(attachment, renderbuffer));
    }
    
    void Framebuffer::setNULLAttachment(GLenum attachment)
    {
        setAttachment(attachment, NULL);
    }
    
    void Framebuffer::setAttachment(GLenum attachment, FramebufferAttachment *attachmentObj)
    {
        if (attachment >= GL_COLOR_ATTACHMENT0 && attachment < (GL_COLOR_ATTACHMENT0 + IMPLEMENTATION_MAX_DRAW_BUFFERS))
        {
            size_t colorAttachment = attachment - GL_COLOR_ATTACHMENT0;
            SafeDelete(mColorbuffers[colorAttachment]);
            mColorbuffers[colorAttachment] = attachmentObj;
            mImpl->setColorAttachment(colorAttachment, attachmentObj);
        }
        else if (attachment == GL_BACK)
        {
            SafeDelete(mColorbuffers[0]);
            mColorbuffers[0] = attachmentObj;
            mImpl->setColorAttachment(0, attachmentObj);
        }
        else if (attachment == GL_DEPTH_ATTACHMENT || attachment == GL_DEPTH)
        {
            SafeDelete(mDepthbuffer);
            mDepthbuffer = attachmentObj;
            mImpl->setDepthttachment(attachmentObj);
        }
        else if (attachment == GL_STENCIL_ATTACHMENT || attachment == GL_STENCIL)
        {
            SafeDelete(mStencilbuffer);
            mStencilbuffer = attachmentObj;
            mImpl->setStencilAttachment(attachmentObj);
        }
        else if (attachment == GL_DEPTH_STENCIL_ATTACHMENT || attachment == GL_DEPTH_STENCIL)
        {
            SafeDelete(mDepthbuffer);
            SafeDelete(mStencilbuffer);
    
            // ensure this is a legitimate depth+stencil format
            if (attachmentObj && attachmentObj->getDepthSize() > 0 && attachmentObj->getStencilSize() > 0)
            {
                mDepthbuffer = attachmentObj;
                mImpl->setDepthttachment(attachmentObj);
    
                // Make a new attachment object to ensure we do not double-delete
                // See angle issue 686
                if (attachmentObj->type() == GL_TEXTURE)
                {
                    mStencilbuffer = new TextureAttachment(GL_DEPTH_STENCIL_ATTACHMENT, attachmentObj->getTexture(),
                                                           *attachmentObj->getTextureImageIndex());
                    mImpl->setStencilAttachment(mStencilbuffer);
                }
                else if (attachmentObj->type() == GL_RENDERBUFFER)
                {
                    mStencilbuffer = new RenderbufferAttachment(GL_DEPTH_STENCIL_ATTACHMENT, attachmentObj->getRenderbuffer());
                    mImpl->setStencilAttachment(mStencilbuffer);
                }
                else
                {
                    UNREACHABLE();
                }
            }
        }
        else
        {
            UNREACHABLE();
        }
    }
    
    DefaultFramebuffer::DefaultFramebuffer(rx::FramebufferImpl *impl, rx::DefaultAttachmentImpl *colorAttachment,
                                           rx::DefaultAttachmentImpl *depthAttachment, rx::DefaultAttachmentImpl *stencilAttachment)
        : Framebuffer(impl, 0)
    {
        ASSERT(colorAttachment);
        setAttachment(GL_BACK, new DefaultAttachment(GL_BACK, colorAttachment));
    
        if (depthAttachment)
        {
            setAttachment(GL_DEPTH, new DefaultAttachment(GL_DEPTH, depthAttachment));
        }
        if (stencilAttachment)
        {
            setAttachment(GL_STENCIL, new DefaultAttachment(GL_STENCIL, stencilAttachment));
        }
    
        GLenum drawBufferState = GL_BACK;
        setDrawBuffers(1, &drawBufferState);
    
        setReadBuffer(GL_BACK);
    }
    
    }