1 files changed, 783 insertions, 0 deletions

diff --git a/vcl/opengl/salbmp.cxx b/vcl/opengl/salbmp.cxx
new file mode 100644
index 000000000..e9b1bca73
--- /dev/null
+++ b/vcl/opengl/salbmp.cxx
@@ -0,0 +1,783 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <memory>
+#include <sal/config.h>
+#include <sal/log.hxx>
+#include <osl/diagnose.h>
+#include <tools/debug.hxx>
+
+#include <vcl/opengl/OpenGLHelper.hxx>
+
+#include <vcl/bitmap.hxx>
+#include <vcl/checksum.hxx>
+#include <vcl/outdev.hxx>
+#include <svdata.hxx>
+#include <salgdi.hxx>
+#include <vcleventlisteners.hxx>
+#include <vcl/lazydelete.hxx>
+#include <scanlinewriter.hxx>
+
+#include <o3tl/make_shared.hxx>
+
+#include <opengl/zone.hxx>
+#include <opengl/program.hxx>
+#include <opengl/salbmp.hxx>
+#include <opengl/RenderState.hxx>
+#include <opengl/FixedTextureAtlas.hxx>
+
+#if OSL_DEBUG_LEVEL > 0
+#  define CANARY "tex-canary"
+#endif
+
+namespace
+{
+
+bool determineTextureFormat(sal_uInt16 nBits, GLenum& nFormat, GLenum& nType)
+{
+    switch(nBits)
+    {
+    case 8:
+        nFormat = GL_LUMINANCE;
+        nType = GL_UNSIGNED_BYTE;
+        return true;
+    case 24:
+        nFormat = GL_RGB;
+        nType = GL_UNSIGNED_BYTE;
+        return true;
+    case 32:
+        nFormat = GL_RGBA;
+        nType = GL_UNSIGNED_BYTE;
+        return true;
+    default:
+        break;
+    }
+    SAL_WARN("vcl.opengl", "Could not determine the appropriate texture format for input bits '" << nBits << "'");
+    return false;
+}
+
+bool isValidBitCount( sal_uInt16 nBitCount )
+{
+    return (nBitCount == 1) || (nBitCount == 4) || (nBitCount == 8) || (nBitCount == 24) || (nBitCount == 32);
+}
+
+sal_uInt32 lclBytesPerRow(sal_uInt16 nBits, int nWidth)
+{
+    switch(nBits)
+    {
+    case 1:  return (nWidth + 7) >> 3;
+    case 4:  return (nWidth + 1) >> 1;
+    case 8:  return  nWidth;
+    case 24: return  nWidth * 3;
+    case 32: return  nWidth * 4;
+    default:
+        OSL_FAIL("vcl::OpenGLSalBitmap::AllocateUserData(), illegal bitcount!");
+    }
+    return 0;
+}
+}
+
+OpenGLSalBitmap::OpenGLSalBitmap()
+: mbDirtyTexture(true)
+, mnBits(0)
+, mnBytesPerRow(0)
+, mnWidth(0)
+, mnHeight(0)
+{
+}
+
+OpenGLSalBitmap::~OpenGLSalBitmap()
+{
+    Destroy();
+    VCL_GL_INFO( "~OpenGLSalBitmap" );
+}
+
+void OpenGLSalBitmap::Create( const OpenGLTexture& rTex, long nX, long nY, long nWidth, long nHeight )
+{
+    DBG_TESTSOLARMUTEX();
+    static const BitmapPalette aEmptyPalette;
+    OpenGLVCLContextZone aContextZone;
+
+    Destroy();
+    VCL_GL_INFO( "OpenGLSalBitmap::Create from FBO: ["
+                  << nX << ", " << nY << "] " << nWidth << "x" << nHeight );
+
+    GLint nMaxTextureSize;
+    glGetIntegerv( GL_MAX_TEXTURE_SIZE, &nMaxTextureSize );
+    if ( nWidth > nMaxTextureSize )
+    {
+        nWidth = nMaxTextureSize;
+        VCL_GL_INFO( "Width limited to " << nMaxTextureSize );
+    }
+
+    if ( nHeight > nMaxTextureSize )
+    {
+        nHeight = nMaxTextureSize;
+        VCL_GL_INFO( "Height limited to " << nMaxTextureSize );
+    }
+
+    mnWidth = nWidth;
+    mnHeight = nHeight;
+
+    // TODO Check the framebuffer configuration
+    mnBits = 32;
+    maPalette = aEmptyPalette;
+
+    if( rTex )
+        maTexture = OpenGLTexture( rTex, nX, nY, nWidth, nHeight );
+    else
+        maTexture = OpenGLTexture( nX, nY, nWidth, nHeight );
+    mbDirtyTexture = false;
+    VCL_GL_INFO( "Created texture " << maTexture.Id() );
+
+    assert(mnWidth == maTexture.GetWidth() &&
+           mnHeight == maTexture.GetHeight());
+}
+
+bool OpenGLSalBitmap::Create( const Size& rSize, sal_uInt16 nBits, const BitmapPalette& rBitmapPalette )
+{
+    DBG_TESTSOLARMUTEX();
+    OpenGLVCLContextZone aContextZone;
+
+    Destroy();
+    VCL_GL_INFO( "OpenGLSalBitmap::Create with size: " << rSize );
+
+    if( !isValidBitCount( nBits ) )
+        return false;
+    maPalette = rBitmapPalette;
+    mnBits = nBits;
+    mnWidth = rSize.Width();
+    mnHeight = rSize.Height();
+
+    // Limit size to what GL allows, so later glTexImage2D() won't fail.
+    GLint nMaxTextureSize;
+    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &nMaxTextureSize);
+    if (mnWidth > nMaxTextureSize)
+        mnWidth = nMaxTextureSize;
+    if (mnHeight > nMaxTextureSize)
+        mnHeight = nMaxTextureSize;
+
+    return false;
+}
+
+bool OpenGLSalBitmap::Create( const SalBitmap& rSalBmp )
+{
+    DBG_TESTSOLARMUTEX();
+    return Create( rSalBmp, rSalBmp.GetBitCount() );
+}
+
+bool OpenGLSalBitmap::Create( const SalBitmap& rSalBmp, SalGraphics* pGraphics )
+{
+    DBG_TESTSOLARMUTEX();
+    return Create( rSalBmp, pGraphics ? pGraphics->GetBitCount() : rSalBmp.GetBitCount() );
+}
+
+bool OpenGLSalBitmap::Create( const SalBitmap& rSalBmp, sal_uInt16 nNewBitCount )
+{
+    DBG_TESTSOLARMUTEX();
+    OpenGLZone aZone;
+
+    // check that carefully only in the debug mode
+    assert(dynamic_cast<const OpenGLSalBitmap*>(&rSalBmp));
+
+    const OpenGLSalBitmap& rSourceBitmap = static_cast<const OpenGLSalBitmap&>(rSalBmp);
+
+    VCL_GL_INFO("OpenGLSalBitmap::Create from BMP: "
+                << rSourceBitmap.mnWidth << "x" << rSourceBitmap.mnHeight
+                << " Bits old: " << mnBits << " new:" << nNewBitCount );
+
+    if( isValidBitCount( nNewBitCount ) )
+    {
+        // TODO: lfrb: What about the pending operations?!
+        mnBits = nNewBitCount;
+        mnBytesPerRow = rSourceBitmap.mnBytesPerRow;
+        mnWidth = rSourceBitmap.mnWidth;
+        mnHeight = rSourceBitmap.mnHeight;
+        maPalette = rSourceBitmap.maPalette;
+        // execute any pending operations on the source bitmap
+        maTexture = rSourceBitmap.GetTexture();
+        mbDirtyTexture = false;
+
+        // be careful here, we are share & reference-count the
+        // mpUserBuffer, BUT this Create() is called from
+        // Bitmap::ImplMakeUnique().
+        // Consequently, there might be cases when this needs to be made
+        // unique later (when we don't do that right away here), like when
+        // using the BitmapWriteAccess.
+        mpUserBuffer = rSourceBitmap.mpUserBuffer;
+
+        return true;
+    }
+    return false;
+}
+
+bool OpenGLSalBitmap::Create( const css::uno::Reference< css::rendering::XBitmapCanvas >& /*xBitmapCanvas*/, Size& /*rSize*/, bool /*bMask*/ )
+{
+    DBG_TESTSOLARMUTEX();
+    // TODO Is this method needed?
+    return false;
+}
+
+OpenGLTexture& OpenGLSalBitmap::GetTexture() const
+{
+    OpenGLSalBitmap* pThis = const_cast<OpenGLSalBitmap*>(this);
+    if( !maTexture || mbDirtyTexture )
+        pThis->CreateTexture();
+    VCL_GL_INFO( "Got texture " << maTexture.Id() );
+    return pThis->maTexture;
+}
+
+void OpenGLSalBitmap::Destroy()
+{
+    OpenGLZone aZone;
+
+    VCL_GL_INFO("Destroy OpenGLSalBitmap texture:" << maTexture.Id());
+    maTexture = OpenGLTexture();
+    DeallocateUserData();
+}
+
+bool OpenGLSalBitmap::AllocateUserData()
+{
+    VCL_GL_INFO( "OpenGLSalBitmap::AllocateUserData" );
+
+    if( mnWidth && mnHeight )
+    {
+        mnBytesPerRow = lclBytesPerRow(mnBits, mnWidth);
+    }
+
+    bool alloc = false;
+    if (mnBytesPerRow != 0 && mnHeight &&
+        mnBytesPerRow <= std::numeric_limits<sal_uInt32>::max() / mnHeight)
+    {
+        try
+        {
+            size_t nToAllocate = mnBytesPerRow * mnHeight;
+#if OSL_DEBUG_LEVEL > 0
+            nToAllocate += sizeof(CANARY);
+#endif
+            mpUserBuffer = o3tl::make_shared_array<sal_uInt8>(nToAllocate);
+#if OSL_DEBUG_LEVEL > 0
+            memcpy(mpUserBuffer.get() + nToAllocate - sizeof(CANARY),
+                   CANARY, sizeof(CANARY));
+#endif
+            alloc = true;
+        }
+        catch (const std::bad_alloc &) {}
+    }
+    if (!alloc)
+    {
+        SAL_WARN("vcl.opengl", "bad alloc " << mnBytesPerRow << "x" << mnHeight);
+        DeallocateUserData();
+    }
+#ifdef DBG_UTIL
+    else
+    {
+        for (size_t i = 0; i < size_t(mnBytesPerRow * mnHeight); i++)
+            mpUserBuffer.get()[i] = (i & 0xFF);
+    }
+#endif
+
+    return mpUserBuffer != nullptr;
+}
+
+void OpenGLSalBitmap::DeallocateUserData()
+{
+    mpUserBuffer.reset();
+    mnBytesPerRow = 0;
+}
+
+namespace {
+
+void lclInstantiateTexture(OpenGLTexture& rTexture, const int nWidth, const int nHeight,
+                           const GLenum nFormat, const GLenum nType, sal_uInt8 const * pData)
+{
+    if (nWidth == nHeight)
+    {
+        typedef std::vector<std::unique_ptr<FixedTextureAtlasManager>> TextureAtlasVector;
+        static vcl::DeleteOnDeinit<TextureAtlasVector> aTextureAtlases([]() {
+            TextureAtlasVector* p = new TextureAtlasVector;
+            p->reserve(5);
+            p->push_back(std::make_unique<FixedTextureAtlasManager>(8, 8, 16));
+            p->push_back(std::make_unique<FixedTextureAtlasManager>(8, 8, 24));
+            p->push_back(std::make_unique<FixedTextureAtlasManager>(8, 8, 32));
+            p->push_back(std::make_unique<FixedTextureAtlasManager>(8, 8, 48));
+            p->push_back(std::make_unique<FixedTextureAtlasManager>(8, 8, 64));
+            return p;
+        }());
+        for (std::unique_ptr<FixedTextureAtlasManager>& pTextureAtlas : *aTextureAtlases.get())
+        {
+            if (nWidth == pTextureAtlas->GetSubtextureSize())
+            {
+                rTexture = pTextureAtlas->InsertBuffer(nWidth, nHeight, nFormat, nType, pData);
+                return;
+            }
+        }
+    }
+    rTexture = OpenGLTexture (nWidth, nHeight, nFormat, nType, pData);
+}
+
+} // end anonymous namespace
+
+Size OpenGLSalBitmap::GetSize() const
+{
+    return Size(mnWidth, mnHeight);
+}
+
+GLuint OpenGLSalBitmap::CreateTexture()
+{
+    VCL_GL_INFO( "::CreateTexture bits: " << mnBits);
+    GLenum nFormat = GL_RGBA;
+    GLenum nType = GL_UNSIGNED_BYTE;
+    sal_uInt8* pData( nullptr );
+    bool bAllocated( false );
+
+    if (mpUserBuffer != nullptr)
+    {
+        if( mnBits == 24 || mnBits == 32 )
+        {
+            // no conversion needed for truecolor
+            pData = mpUserBuffer.get();
+
+            determineTextureFormat(mnBits, nFormat, nType);
+        }
+        else if( mnBits == 8 && maPalette.IsGreyPalette8Bit() )
+        {
+            // no conversion needed for 8bit grayscale
+            pData = mpUserBuffer.get();
+            nFormat = GL_LUMINANCE;
+            nType = GL_UNSIGNED_BYTE;
+        }
+        else
+        {
+            VCL_GL_INFO( "::CreateTexture - convert from " << mnBits << " to 24 bits" );
+            // convert to 24 bits RGB using palette
+            determineTextureFormat(24, nFormat, nType);
+            pData = convertDataBitCount( mpUserBuffer.get(), mnWidth, mnHeight,
+                mnBits, mnBytesPerRow, maPalette,
+                nFormat == GL_BGR ? BitConvert::BGR : BitConvert::RGB ).release();
+            bAllocated = true;
+        }
+    }
+
+    OpenGLVCLContextZone aContextZone;
+
+    lclInstantiateTexture(maTexture, mnWidth, mnHeight, nFormat, nType, pData);
+
+    VCL_GL_INFO("Created texture " << maTexture.Id() << " bits: " << mnBits);
+
+    if( bAllocated )
+        delete[] pData;
+
+    mbDirtyTexture = false;
+
+    CHECK_GL_ERROR();
+    return maTexture.Id();
+}
+
+bool OpenGLSalBitmap::ReadTexture()
+{
+    sal_uInt8* pData = mpUserBuffer.get();
+
+    GLenum nFormat = GL_RGBA;
+    GLenum nType = GL_UNSIGNED_BYTE;
+
+    VCL_GL_INFO( "::ReadTexture " << mnWidth << "x" << mnHeight << " bits: " << mnBits);
+
+    if( pData == nullptr )
+        return false;
+
+    OpenGLVCLContextZone aContextZone;
+
+    rtl::Reference<OpenGLContext> xContext = OpenGLContext::getVCLContext();
+    xContext->state().scissor().disable();
+    xContext->state().stencil().disable();
+
+    if ((mnBits == 8 && maPalette.IsGreyPalette8Bit()) || mnBits == 24 || mnBits == 32)
+    {
+        determineTextureFormat(mnBits, nFormat, nType);
+
+#if OSL_DEBUG_LEVEL > 0
+        // help valgrind & drmemory rescue us - touch last and first bits.
+        pData[0] = 0;
+        pData[mnBits/8*mnWidth*mnHeight-1] = 0;
+        // if this fails we can read too much into pData
+        assert(mnWidth == maTexture.GetWidth() &&
+               mnHeight == maTexture.GetHeight());
+#endif
+
+        maTexture.Read(nFormat, nType, pData);
+
+#if OSL_DEBUG_LEVEL > 0 && !defined NDEBUG
+        // If we read over the end of pData we have a real hidden memory
+        // corruption problem !
+        size_t nCanary = mnBytesPerRow * mnHeight;
+        assert(!memcmp(pData + nCanary, CANARY, sizeof (CANARY)));
+#endif
+        return true;
+    }
+    else if (mnBits == 1 || mnBits == 4 || mnBits == 8)
+    {   // convert buffers from 24-bit RGB to 1,4 or 8-bit buffer
+        std::vector<sal_uInt8> aBuffer(mnWidth * mnHeight * 3);
+
+        sal_uInt8* pBuffer = aBuffer.data();
+        determineTextureFormat(24, nFormat, nType);
+        maTexture.Read(nFormat, nType, pBuffer);
+        sal_uInt32 nSourceBytesPerRow = lclBytesPerRow(24, mnWidth);
+
+        std::unique_ptr<vcl::ScanlineWriter> pWriter = vcl::ScanlineWriter::Create(mnBits, maPalette);
+        for (int y = 0; y < mnHeight; ++y)
+        {
+            sal_uInt8* pSource = &pBuffer[y * nSourceBytesPerRow];
+            sal_uInt8* pDestination = &pData[y * mnBytesPerRow];
+
+            pWriter->nextLine(pDestination);
+
+            for (int x = 0; x < mnWidth; ++x)
+            {
+                // read source
+                sal_uInt8 nR = *pSource++;
+                sal_uInt8 nG = *pSource++;
+                sal_uInt8 nB = *pSource++;
+
+                pWriter->writeRGB(nR, nG, nB);
+            }
+        }
+        return true;
+    }
+
+    SAL_WARN("vcl.opengl", "::ReadTexture - tx:" << maTexture.Id() << " @ "
+             << mnWidth << "x" << mnHeight << "- unimplemented bit depth: "
+             << mnBits);
+    return false;
+}
+
+sal_uInt16 OpenGLSalBitmap::GetBitCount() const
+{
+    return mnBits;
+}
+
+bool OpenGLSalBitmap::calcChecksumGL(OpenGLTexture& rInputTexture, BitmapChecksum& rChecksum) const
+{
+    OUString FragShader("areaHashCRC64TFragmentShader");
+
+    rtl::Reference< OpenGLContext > xContext = OpenGLContext::getVCLContext();
+    xContext->state().scissor().disable();
+    xContext->state().stencil().disable();
+
+    static vcl::DeleteOnDeinit<OpenGLTexture> gCRCTableTexture(
+        new OpenGLTexture(512, 1, GL_RGBA, GL_UNSIGNED_BYTE,
+                           vcl_get_crc64_table()));
+    OpenGLTexture &rCRCTableTexture = *gCRCTableTexture.get();
+
+    // First Pass
+
+    int nWidth = rInputTexture.GetWidth();
+    int nHeight = rInputTexture.GetHeight();
+
+    OpenGLProgram* pProgram = xContext->UseProgram("textureVertexShader", FragShader);
+    if (pProgram == nullptr)
+        return false;
+
+    int nNewWidth = ceil( nWidth / 4.0 );
+    int nNewHeight = ceil( nHeight / 4.0 );
+
+    OpenGLTexture aFirstPassTexture(nNewWidth, nNewHeight);
+    OpenGLFramebuffer* pFramebuffer = xContext->AcquireFramebuffer(aFirstPassTexture);
+
+    pProgram->SetUniform1f( "xstep", 1.0 / mnWidth );
+    pProgram->SetUniform1f( "ystep", 1.0 / mnHeight );
+
+    pProgram->SetTexture("crc_table", rCRCTableTexture);
+    pProgram->SetTexture("sampler", rInputTexture);
+    pProgram->DrawTexture(rInputTexture);
+    pProgram->Clean();
+
+    OpenGLContext::ReleaseFramebuffer(pFramebuffer);
+
+    CHECK_GL_ERROR();
+
+    // Second Pass
+
+    nWidth = aFirstPassTexture.GetWidth();
+    nHeight = aFirstPassTexture.GetHeight();
+
+    pProgram = xContext->UseProgram("textureVertexShader", FragShader);
+    if (pProgram == nullptr)
+        return false;
+
+    nNewWidth = ceil( nWidth / 4.0 );
+    nNewHeight = ceil( nHeight / 4.0 );
+
+    OpenGLTexture aSecondPassTexture(nNewWidth, nNewHeight);
+    pFramebuffer = xContext->AcquireFramebuffer(aSecondPassTexture);
+
+    pProgram->SetUniform1f( "xstep", 1.0 / mnWidth );
+    pProgram->SetUniform1f( "ystep", 1.0 / mnHeight );
+
+    pProgram->SetTexture("crc_table", rCRCTableTexture);
+    pProgram->SetTexture("sampler", aFirstPassTexture);
+    pProgram->DrawTexture(aFirstPassTexture);
+    pProgram->Clean();
+
+    OpenGLContext::ReleaseFramebuffer(pFramebuffer);
+
+    CHECK_GL_ERROR();
+
+    // Final CRC on CPU
+    OpenGLTexture& aFinalTexture = aSecondPassTexture;
+    std::vector<sal_uInt8> aBuf( aFinalTexture.GetWidth() * aFinalTexture.GetHeight() * 4 );
+    aFinalTexture.Read(GL_RGBA, GL_UNSIGNED_BYTE, aBuf.data());
+
+    BitmapChecksum nCrc = vcl_get_checksum(0, aBuf.data(), aBuf.size());
+
+    rChecksum = nCrc;
+    return true;
+}
+
+void OpenGLSalBitmap::updateChecksum() const
+{
+    if (mbChecksumValid)
+        return;
+
+    if( (mnWidth * mnHeight) < (1024*768) || mnWidth < 128 || mnHeight < 128 )
+    {
+        SalBitmap::updateChecksum();
+        return;
+    }
+
+    OpenGLSalBitmap* pThis = const_cast<OpenGLSalBitmap*>(this);
+
+    OpenGLVCLContextZone aContextZone;
+    OpenGLTexture& rInputTexture = GetTexture();
+    pThis->mbChecksumValid = calcChecksumGL(rInputTexture, pThis->mnChecksum);
+    if (!pThis->mbChecksumValid)
+        SalBitmap::updateChecksum();
+}
+
+BitmapBuffer* OpenGLSalBitmap::AcquireBuffer( BitmapAccessMode nMode )
+{
+    OpenGLVCLContextZone aContextZone;
+
+    if( nMode != BitmapAccessMode::Info )
+    {
+        if (!mpUserBuffer)
+        {
+            if( !AllocateUserData() )
+                return nullptr;
+            if( maTexture && !ReadTexture() )
+            {
+                DeallocateUserData();
+                return nullptr;
+            }
+        }
+    }
+
+    // mpUserBuffer must be unique when we are doing the write access
+    if (nMode == BitmapAccessMode::Write && mpUserBuffer && mpUserBuffer.use_count() > 1)
+    {
+        std::shared_ptr<sal_uInt8> aBuffer(mpUserBuffer);
+
+        mpUserBuffer.reset();
+        AllocateUserData();
+        memcpy(mpUserBuffer.get(), aBuffer.get(), mnBytesPerRow * mnHeight);
+    }
+
+    BitmapBuffer* pBuffer = new BitmapBuffer;
+    pBuffer->mnWidth = mnWidth;
+    pBuffer->mnHeight = mnHeight;
+    pBuffer->maPalette = maPalette;
+    pBuffer->mnScanlineSize = mnBytesPerRow;
+    pBuffer->mpBits = mpUserBuffer.get();
+    pBuffer->mnBitCount = mnBits;
+
+    switch (mnBits)
+    {
+        case 1:
+            pBuffer->mnFormat = ScanlineFormat::N1BitMsbPal;
+            break;
+        case 4:
+            pBuffer->mnFormat = ScanlineFormat::N4BitMsnPal;
+            break;
+        case 8:
+            pBuffer->mnFormat = ScanlineFormat::N8BitPal;
+            break;
+        case 24:
+        {
+            pBuffer->mnFormat = ScanlineFormat::N24BitTcRgb;
+            break;
+        }
+        case 32:
+        {
+            pBuffer->mnFormat = ScanlineFormat::N32BitTcRgba;
+            ColorMaskElement aRedMask(0xff000000);
+            aRedMask.CalcMaskShift();
+            ColorMaskElement aGreenMask(0x00ff0000);
+            aGreenMask.CalcMaskShift();
+            ColorMaskElement aBlueMask(0x0000ff00);
+            aBlueMask.CalcMaskShift();
+            pBuffer->maColorMask  = ColorMask(aRedMask, aGreenMask, aBlueMask);
+            break;
+        }
+        default: assert(false);
+    }
+
+    return pBuffer;
+}
+
+void OpenGLSalBitmap::ReleaseBuffer( BitmapBuffer* pBuffer, BitmapAccessMode nMode )
+{
+    OpenGLVCLContextZone aContextZone;
+
+    if( nMode == BitmapAccessMode::Write )
+    {
+        maTexture = OpenGLTexture();
+        mbDirtyTexture = true;
+        mbChecksumValid = false;
+    }
+    // The palette is modified on read during the BitmapWriteAccess,
+    // but of course, often it is not modified; interesting.
+    maPalette = pBuffer->maPalette;
+
+    // Are there any more ground movements underneath us ?
+    assert( pBuffer->mnWidth == mnWidth );
+    assert( pBuffer->mnHeight == mnHeight );
+    assert( pBuffer->mnBitCount == mnBits );
+
+    delete pBuffer;
+}
+
+bool OpenGLSalBitmap::GetSystemData( BitmapSystemData& /*rData*/ )
+{
+    SAL_WARN( "vcl.opengl", "*** NOT IMPLEMENTED *** GetSystemData" );
+#if 0
+    // TODO Implement for ANDROID/OSX/IOS/WIN32
+    X11SalBitmap rBitmap;
+    BitmapBuffer* pBuffer;
+
+    rBitmap.Create( GetSize(), mnBits, maPalette );
+    pBuffer = rBitmap.AcquireBuffer( false );
+    if( pBuffer == NULL )
+        return false;
+
+    if (!mpUserBuffer.get())
+    {
+        if( !AllocateUserData() || !ReadTexture() )
+        {
+            rBitmap.ReleaseBuffer( pBuffer, false );
+            DeallocateUserData();
+            return false;
+        }
+    }
+
+    // TODO Might be more efficient to add a static method to SalBitmap
+    //      to get system data from a buffer
+    memcpy( pBuffer->mpBits, mpUserBuffer.get(), mnBytesPerRow * mnHeight );
+
+    rBitmap.ReleaseBuffer( pBuffer, false );
+    return rBitmap.GetSystemData( rData );
+#else
+    return false;
+#endif
+}
+
+bool OpenGLSalBitmap::Replace( const Color& rSearchColor, const Color& rReplaceColor, sal_uInt8 nTol )
+{
+    VCL_GL_INFO("::Replace");
+
+    OpenGLZone aZone;
+    rtl::Reference<OpenGLContext> xContext = OpenGLContext::getVCLContext();
+    xContext->state().scissor().disable();
+    xContext->state().stencil().disable();
+
+    OpenGLFramebuffer* pFramebuffer;
+    OpenGLProgram* pProgram;
+
+    GetTexture();
+    pProgram = xContext->UseProgram( "textureVertexShader",
+                                     "replaceColorFragmentShader" );
+    if( !pProgram )
+        return false;
+
+    OpenGLTexture aNewTex( mnWidth, mnHeight );
+    pFramebuffer = xContext->AcquireFramebuffer( aNewTex );
+
+    pProgram->SetTexture( "sampler", maTexture );
+    pProgram->SetColor( "search_color", rSearchColor );
+    pProgram->SetColor( "replace_color", rReplaceColor );
+    pProgram->SetUniform1f( "epsilon", nTol / 255.0f );
+    pProgram->DrawTexture( maTexture );
+    pProgram->Clean();
+
+    OpenGLContext::ReleaseFramebuffer( pFramebuffer );
+    maTexture = aNewTex;
+
+    CHECK_GL_ERROR();
+    return true;
+}
+
+// Convert texture to greyscale and adjust bitmap metadata
+bool OpenGLSalBitmap::ConvertToGreyscale()
+{
+    VCL_GL_INFO("::ConvertToGreyscale");
+
+    // avoid re-converting to 8bits.
+    if ( mnBits == 8 && maPalette.IsGreyPalette8Bit())
+        return true;
+
+    OpenGLZone aZone;
+    rtl::Reference<OpenGLContext> xContext = OpenGLContext::getVCLContext();
+    xContext->state().scissor().disable();
+    xContext->state().stencil().disable();
+
+    OpenGLFramebuffer* pFramebuffer;
+    OpenGLProgram* pProgram;
+
+    GetTexture();
+    pProgram = xContext->UseProgram("textureVertexShader", "greyscaleFragmentShader");
+
+    if (!pProgram)
+        return false;
+
+    OpenGLTexture aNewTex(mnWidth, mnHeight);
+    pFramebuffer = xContext->AcquireFramebuffer(aNewTex);
+    pProgram->SetTexture("sampler", maTexture);
+    pProgram->DrawTexture(maTexture);
+    pProgram->Clean();
+
+    OpenGLContext::ReleaseFramebuffer( pFramebuffer );
+    maTexture = aNewTex;
+    mnBits = 8;
+    maPalette = Bitmap::GetGreyPalette(256);
+
+    // AllocateUserData will handle the rest.
+    DeallocateUserData();
+    mbDirtyTexture = false;
+
+    CHECK_GL_ERROR();
+    return true;
+}
+
+// This is needed to just make the bitmap usable as an alpha channel.
+// Converting to 8bit grey will do.
+bool OpenGLSalBitmap::InterpretAs8Bit()
+{
+    return ConvertToGreyscale();
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */