1 files changed, 137 insertions, 0 deletions
diff --git a/vcl/opengl/FixedTextureAtlas.cxx b/vcl/opengl/FixedTextureAtlas.cxx
new file mode 100644
index 000000000..7425942d1
--- /dev/null
+++ b/vcl/opengl/FixedTextureAtlas.cxx
@@ -0,0 +1,137 @@
+/* -*- 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 <memory>
+#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>
+
+struct FixedTexture
+{
+    std::shared_ptr<ImplOpenGLTexture> mpTexture;
+    int mnFreeSlots;
+    std::vector<bool> maAllocatedSlots;
+
+    FixedTexture(int nTextureWidth, int nTextureHeight, int nNumberOfSlots)
+        : mpTexture(std::make_shared<ImplOpenGLTexture>(nTextureWidth, nTextureHeight, true))
+        , mnFreeSlots(nNumberOfSlots)
+        , maAllocatedSlots(nNumberOfSlots, false)
+    {
+        auto aDeallocateFunction = [this] (int nSlotNumber)
+        {
+            deallocateSlot(nSlotNumber);
+        };
+
+        mpTexture->SetSlotDeallocateCallback(aDeallocateFunction);
+        mpTexture->InitializeSlotMechanism(nNumberOfSlots);
+    }
+
+    ~FixedTexture()
+    {
+        mpTexture->ResetSlotDeallocateCallback();
+    }
+
+    void allocateSlot(int nSlot)
+    {
+        maAllocatedSlots[nSlot] = true;
+        mnFreeSlots--;
+    }
+
+    void deallocateSlot(int nSlot)
+    {
+        maAllocatedSlots[nSlot] = false;
+        mnFreeSlots++;
+    }
+
+    int findAndAllocateFreeSlot()
+    {
+        for (size_t i = 0; i < maAllocatedSlots.size(); ++i)
+        {
+            if (!maAllocatedSlots[i])
+            {
+                allocateSlot(i);
+                return i;
+            }
+        }
+        return -1;
+    }
+
+private:
+    FixedTexture(const FixedTexture&) = delete;
+    FixedTexture& operator=(const FixedTexture&) = delete;
+};
+
+FixedTextureAtlasManager::FixedTextureAtlasManager(int nWidthFactor, int nHeightFactor, int nSubTextureSize)
+    : mWidthFactor(nWidthFactor)
+    , mHeightFactor(nHeightFactor)
+    , mSubTextureSize(nSubTextureSize)
+{
+}
+
+FixedTextureAtlasManager::~FixedTextureAtlasManager()
+{
+}
+
+void FixedTextureAtlasManager::CreateNewTexture()
+{
+    int nTextureWidth = mWidthFactor  * mSubTextureSize;
+    int nTextureHeight = mHeightFactor * mSubTextureSize;
+    maFixedTextures.push_back(std::make_unique<FixedTexture>(nTextureWidth, nTextureHeight, mWidthFactor * mHeightFactor));
+}
+
+OpenGLTexture FixedTextureAtlasManager::Reserve(int nWidth, int nHeight)
+{
+    FixedTexture* pFixedTexture = nullptr;
+
+    auto funFreeSlot = [] (std::unique_ptr<FixedTexture>& inFixedTexture)
+    {
+        return inFixedTexture->mnFreeSlots > 0;
+    };
+
+    auto it = std::find_if(maFixedTextures.begin(), maFixedTextures.end(), funFreeSlot);
+
+    if (it != maFixedTextures.end())
+    {
+        pFixedTexture = (*it).get();
+    }
+    else
+    {
+        CreateNewTexture();
+        pFixedTexture = maFixedTextures.back().get();
+    }
+
+    int nSlot = pFixedTexture->findAndAllocateFreeSlot();
+
+    // Calculate coordinates in texture
+    int nX = (nSlot % mWidthFactor) * mSubTextureSize;
+    int nY = (nSlot / mWidthFactor) * mSubTextureSize;
+
+    tools::Rectangle aRectangle(Point(nX, nY), Size(nWidth, nHeight));
+
+    return OpenGLTexture(pFixedTexture->mpTexture, aRectangle, nSlot);
+}
+
+OpenGLTexture FixedTextureAtlasManager::InsertBuffer(int nWidth, int nHeight, int nFormat, int nType, sal_uInt8 const * pData)
+{
+    OpenGLTexture aTexture = Reserve(nWidth, nHeight);
+    if (pData == nullptr)
+        return aTexture;
+
+    aTexture.CopyData(nWidth, nHeight, nFormat, nType, pData);
+
+    return aTexture;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */