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

Change-Id: I7fe90c0a0033b4d9a341a4f0b8356d7f7133e93e

1 files changed, 71 insertions, 0 deletions

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: */