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

Change-Id: I7fe90c0a0033b4d9a341a4f0b8356d7f7133e93e

2 files changed, 80 insertions, 2 deletions

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 );