Fixed (fixed size) texture atlas for "caching" OpenGL texures

Change-Id: I7fe90c0a0033b4d9a341a4f0b8356d7f7133e93e

5 files changed, 233 insertions, 21 deletions

diff --git a/vcl/Library_vcl.mk b/vcl/Library_vcl.mk
index 2e6f8b02b40b..306178c4e794 100644
--- a/vcl/Library_vcl.mk
+++ b/vcl/Library_vcl.mk
@@ -132,6 +132,7 @@ $(eval $(call gb_Library_add_exception_objects,vcl,\
 	vcl/opengl/framebuffer \
 	vcl/opengl/program \
 	vcl/opengl/texture \
+	vcl/opengl/FixedTextureAtlas \
     vcl/source/opengl/OpenGLContext \
     vcl/source/opengl/OpenGLHelper \
     vcl/source/window/cairo_cairo \
diff --git a/vcl/inc/opengl/FixedTextureAtlas.hxx b/vcl/inc/opengl/FixedTextureAtlas.hxx
new file mode 100644
index 000000000000..c4f5d6065696
--- /dev/null
+++ b/vcl/inc/opengl/FixedTextureAtlas.hxx
@@ -0,0 +1,39 @@
+/* -*- 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/.
+ *
+ */
+
+#ifndef INCLUDED_VCL_INC_OPENGL_FIXED_TEXTURE_ATLAS_H
+#define INCLUDED_VCL_INC_OPENGL_FIXED_TEXTURE_ATLAS_H
+
+#include "opengl/texture.hxx"
+
+
+class VCL_PLUGIN_PUBLIC FixedTextureAtlasManager
+{
+    std::vector<std::unique_ptr<ImplOpenGLTexture>> mpTextures;
+
+    int mWidthFactor;
+    int mHeightFactor;
+    int mSubTextureSize;
+
+    void CreateNewTexture();
+
+public:
+    FixedTextureAtlasManager(int nWidthFactor, int nHeightFactor, int nTextureSize);
+    OpenGLTexture InsertBuffer(int nWidth, int nHeight, int nFormat, int nType, sal_uInt8* pData);
+
+    int GetSubtextureSize()
+    {
+        return mSubTextureSize;
+    }
+};
+
+#endif // INCLUDED_VCL_INC_OPENGL_FIXED_TEXTURE_ATLAS_H
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/inc/opengl/texture.hxx b/vcl/inc/opengl/texture.hxx
index b68397641326..51f7040ab9ef 100644
--- a/vcl/inc/opengl/texture.hxx
+++ b/vcl/inc/opengl/texture.hxx
@@ -26,6 +26,8 @@
 #include <rtl/ustring.hxx>
 #include <tools/gen.hxx>
 
+#include <memory>
+
 class ImplOpenGLTexture
 {
 public:
@@ -35,10 +37,45 @@ public:
     int    mnHeight;
     GLenum mnFilter;
 
+    std::unique_ptr<std::vector<int>> mpSlotReferences;
+    int mnFreeSlots;
+
     ImplOpenGLTexture( int nWidth, int nHeight, bool bAllocate );
     ImplOpenGLTexture( int nWidth, int nHeight, int nFormat, int nType, sal_uInt8* pData );
     ImplOpenGLTexture( int nX, int nY, int nWidth, int nHeight );
     ~ImplOpenGLTexture();
+
+    bool InsertBuffer(int nX, int nY, int nWidth, int nHeight, int nFormat, int nType, sal_uInt8* pData);
+
+    void IncreaseRefCount(int nSlotNumber)
+    {
+        mnRefCount++;
+        if (mpSlotReferences && nSlotNumber >= 0)
+        {
+            if (mpSlotReferences->at(nSlotNumber) == 0)
+                mnFreeSlots--;
+            mpSlotReferences->at(nSlotNumber)++;
+        }
+    }
+
+    void DecreaseRefCount(int nSlotNumber)
+    {
+        mnRefCount--;
+        if (mpSlotReferences && nSlotNumber >= 0)
+        {
+            mpSlotReferences->at(nSlotNumber)--;
+            if (mpSlotReferences->at(nSlotNumber) == 0)
+                mnFreeSlots++;
+        }
+    }
+
+    bool ExistRefs()
+    {
+        return mnRefCount > 0;
+    }
+
+    bool InitializeSlots(int nSlotSize);
+    int FindFreeSlot();
 };
 
 class VCL_PLUGIN_PUBLIC OpenGLTexture
@@ -46,12 +83,14 @@ class VCL_PLUGIN_PUBLIC OpenGLTexture
 private:
     // if the rect size doesn't match the mpImpl one, this instance
     // is a sub-area from the real OpenGL texture
-    Rectangle          maRect;
-
+    Rectangle maRect;
     ImplOpenGLTexture* mpImpl;
+    int mnSlotNumber;
 
 public:
                     OpenGLTexture();
+                    OpenGLTexture(ImplOpenGLTexture* pImpl, Rectangle aRectangle, int nSlotNumber = 0);
+
                     OpenGLTexture( int nWidth, int nHeight, bool bAllocate = true );
                     OpenGLTexture( int nWidth, int nHeight, int nFormat, int nType, sal_uInt8* pData );
                     OpenGLTexture( int nX, int nY, int nWidth, int nHeight );
diff --git a/vcl/opengl/FixedTextureAtlas.cxx b/vcl/opengl/FixedTextureAtlas.cxx
new file mode 100644
index 000000000000..c8ca50846b9d
--- /dev/null
+++ b/vcl/opengl/FixedTextureAtlas.cxx
@@ -0,0 +1,71 @@
+/* -*- 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/.
+ *
+ */
+
+#include <sal/config.h>
+#include <vcl/opengl/OpenGLContext.hxx>
+#include <vcl/opengl/OpenGLHelper.hxx>
+
+#include "opengl/framebuffer.hxx"
+#include "opengl/texture.hxx"
+
+#include "opengl/FixedTextureAtlas.hxx"
+
+FixedTextureAtlasManager::FixedTextureAtlasManager(int nWidthFactor, int nHeightFactor, int nSubTextureSize)
+    : mWidthFactor(nWidthFactor)
+    , mHeightFactor(nHeightFactor)
+    , mSubTextureSize(nSubTextureSize)
+{
+}
+
+void FixedTextureAtlasManager::CreateNewTexture()
+{
+    int nTextureWidth = mWidthFactor  * mSubTextureSize;
+    int nTextureHeight = mHeightFactor * mSubTextureSize;
+    mpTextures.push_back(std::move(std::unique_ptr<ImplOpenGLTexture>(new ImplOpenGLTexture(nTextureWidth, nTextureHeight, true))));
+    mpTextures.back()->InitializeSlots(mWidthFactor * mHeightFactor);
+}
+
+OpenGLTexture FixedTextureAtlasManager::InsertBuffer(int nWidth, int nHeight, int nFormat, int nType, sal_uInt8* pData)
+{
+    ImplOpenGLTexture* pTexture = nullptr;
+
+    for (size_t i = 0; i < mpTextures.size(); i++)
+    {
+        if (mpTextures[i]->mnFreeSlots > 0)
+        {
+            pTexture = mpTextures[i].get();
+        }
+    }
+
+    if (!pTexture)
+    {
+        CreateNewTexture();
+        pTexture = mpTextures.back().get();
+    }
+
+    int nSlot = pTexture->FindFreeSlot();
+
+    // Calculate coordinates in texture
+    int nX = (nSlot % mWidthFactor) * mSubTextureSize;
+    int nY = (nSlot / mWidthFactor) * mSubTextureSize;
+
+    Rectangle aRectangle(Point(nX, nY), Size(nWidth, nHeight));
+
+    // If available, copy the image data to the texture
+    if (pData)
+    {
+        if (!pTexture->InsertBuffer(nX, nY, nWidth, nHeight, nFormat, nType, pData))
+            return OpenGLTexture();
+    }
+
+    return OpenGLTexture(pTexture, aRectangle, nSlot);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/opengl/texture.cxx b/vcl/opengl/texture.cxx
index a527ceb98dd3..cbb8b076f38a 100644
--- a/vcl/opengl/texture.cxx
+++ b/vcl/opengl/texture.cxx
@@ -34,7 +34,8 @@ ImplOpenGLTexture::ImplOpenGLTexture( int nWidth, int nHeight, bool bAllocate )
     mnRefCount( 1 ),
     mnWidth( nWidth ),
     mnHeight( nHeight ),
-    mnFilter( GL_NEAREST )
+    mnFilter( GL_NEAREST ),
+    mnFreeSlots(-1)
 {
     glGenTextures( 1, &mnTexture );
     glBindTexture( GL_TEXTURE_2D, mnTexture );
@@ -57,7 +58,8 @@ ImplOpenGLTexture::ImplOpenGLTexture( int nX, int nY, int nWidth, int nHeight )
     mnTexture( 0 ),
     mnWidth( nWidth ),
     mnHeight( nHeight ),
-    mnFilter( GL_NEAREST )
+    mnFilter( GL_NEAREST ),
+    mnFreeSlots(-1)
 {
     // FIXME We need the window height here
     // nY = GetHeight() - nHeight - nY;
@@ -83,7 +85,8 @@ ImplOpenGLTexture::ImplOpenGLTexture( int nWidth, int nHeight, int nFormat, int
     mnTexture( 0 ),
     mnWidth( nWidth ),
     mnHeight( nHeight ),
-    mnFilter( GL_NEAREST )
+    mnFilter( GL_NEAREST ),
+    mnFreeSlots(-1)
 {
     if( !mnTexture )
         glGenTextures( 1, &mnTexture );
@@ -108,12 +111,64 @@ ImplOpenGLTexture::~ImplOpenGLTexture()
         glDeleteTextures( 1, &mnTexture );
 }
 
+bool ImplOpenGLTexture::InsertBuffer(int nX, int nY, int nWidth, int nHeight, int nFormat, int nType, sal_uInt8* pData)
+{
+    if (!pData || mnTexture == 0)
+        return false;
+    glBindTexture(GL_TEXTURE_2D, mnTexture);
+    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+    glTexSubImage2D(GL_TEXTURE_2D, 0, nX, mnHeight - nY - nHeight, nWidth, nHeight, nFormat, nType, pData);
+    glBindTexture(GL_TEXTURE_2D, 0);
+
+    SAL_INFO( "vcl.opengl", "OpenGLTexture " << mnTexture << " Insert buff. to " << nX << " " << nY
+                                             << " size " << nWidth << "x" << nHeight << " from data" );
+    CHECK_GL_ERROR();
+
+    return true;
+}
+
+bool ImplOpenGLTexture::InitializeSlots(int nSlotSize)
+{
+    if (mpSlotReferences)
+        return false;
+
+    mpSlotReferences.reset(new std::vector<int>(nSlotSize, 0));
+    mnFreeSlots = nSlotSize;
+
+    return true;
+}
+
+int ImplOpenGLTexture::FindFreeSlot()
+{
+    if (mnFreeSlots > 0 && mpSlotReferences)
+    {
+        for (size_t i = 0; i < mpSlotReferences->size(); i++)
+        {
+            if (mpSlotReferences->at(i) <= 0)
+            {
+                return i;
+            }
+        }
+    }
+    return -1;
+}
+
 OpenGLTexture::OpenGLTexture() :
     maRect( 0, 0, 0, 0 ),
-    mpImpl( NULL )
+    mpImpl(NULL),
+    mnSlotNumber(-1)
 {
 }
 
+OpenGLTexture::OpenGLTexture(ImplOpenGLTexture* pImpl, Rectangle aRectangle, int nSlotNumber)
+    : maRect(aRectangle)
+    , mpImpl(pImpl)
+    , mnSlotNumber(nSlotNumber)
+{
+    if (mpImpl)
+        mpImpl->IncreaseRefCount(nSlotNumber);
+}
+
 OpenGLTexture::OpenGLTexture( int nWidth, int nHeight, bool bAllocate ) :
     maRect( Point( 0, 0 ), Size( nWidth, nHeight ) )
 {
@@ -136,8 +191,10 @@ OpenGLTexture::OpenGLTexture( const OpenGLTexture& rTexture )
 {
     maRect = rTexture.maRect;
     mpImpl = rTexture.mpImpl;
-    if( mpImpl )
-        mpImpl->mnRefCount++;
+    mnSlotNumber = rTexture.mnSlotNumber;
+
+    if (mpImpl)
+        mpImpl->IncreaseRefCount(mnSlotNumber);
 }
 
 OpenGLTexture::OpenGLTexture( const OpenGLTexture& rTexture,
@@ -146,19 +203,19 @@ OpenGLTexture::OpenGLTexture( const OpenGLTexture& rTexture,
     maRect = Rectangle( Point( rTexture.maRect.Left() + nX, rTexture.maRect.Top() + nY ),
                         Size( nWidth, nHeight ) );
     mpImpl = rTexture.mpImpl;
-    if( mpImpl )
-        mpImpl->mnRefCount++;
+    mnSlotNumber = rTexture.mnSlotNumber;
+    if (mpImpl)
+        mpImpl->IncreaseRefCount(mnSlotNumber);
     SAL_INFO( "vcl.opengl", "Copying texture " << Id() << " [" << maRect.Left() << "," << maRect.Top() << "] " << GetWidth() << "x" << GetHeight() );
 }
 
 OpenGLTexture::~OpenGLTexture()
 {
-    if( mpImpl )
+    if (mpImpl)
     {
-        if( mpImpl->mnRefCount == 1 )
+        mpImpl->DecreaseRefCount(mnSlotNumber);
+        if (!mpImpl->ExistRefs())
             delete mpImpl;
-        else
-            mpImpl->mnRefCount--;
     }
 }
 
@@ -325,25 +382,30 @@ OpenGLTexture::operator bool() const
 
 OpenGLTexture&  OpenGLTexture::operator=( const OpenGLTexture& rTexture )
 {
-    if( rTexture.mpImpl )
-        rTexture.mpImpl->mnRefCount++;
-    if( mpImpl )
+    if (rTexture.mpImpl)
+    {
+        rTexture.mpImpl->IncreaseRefCount(rTexture.mnSlotNumber);
+    }
+
+    if (mpImpl)
     {
-        if( mpImpl->mnRefCount == 1 )
+        mpImpl->DecreaseRefCount(mnSlotNumber);
+        if (!mpImpl->ExistRefs())
             delete mpImpl;
-        else
-            mpImpl->mnRefCount--;
     }
 
     maRect = rTexture.maRect;
     mpImpl = rTexture.mpImpl;
+    mnSlotNumber = rTexture.mnSlotNumber;
 
     return *this;
 }
 
 bool OpenGLTexture::operator==( const OpenGLTexture& rTexture ) const
 {
-    return (mpImpl == rTexture.mpImpl && maRect == rTexture.maRect );
+    return (mpImpl == rTexture.mpImpl
+         && maRect == rTexture.maRect
+         && mnSlotNumber == rTexture.mnSlotNumber);
 }
 
 bool OpenGLTexture::operator!=( const OpenGLTexture& rTexture ) const