opengl: texture atlas impl. to efficiently packs textures

Change-Id: I66b3eddadb172da26aa1a62f2a795895769db93b

2 files changed, 176 insertions, 8 deletions

diff --git a/vcl/opengl/FixedTextureAtlas.cxx b/vcl/opengl/FixedTextureAtlas.cxx
index 80c1cfe496c7..1ed83111d293 100644
--- a/vcl/opengl/FixedTextureAtlas.cxx
+++ b/vcl/opengl/FixedTextureAtlas.cxx
@@ -42,7 +42,7 @@ void FixedTextureAtlasManager::CreateNewTexture()
     mpTextures.back()->InitializeSlots(mWidthFactor * mHeightFactor);
 }
 
-OpenGLTexture FixedTextureAtlasManager::InsertBuffer(int nWidth, int nHeight, int nFormat, int nType, sal_uInt8* pData)
+OpenGLTexture FixedTextureAtlasManager::Reserve(int nWidth, int nHeight)
 {
     ImplOpenGLTexture* pTexture = nullptr;
 
@@ -71,14 +71,18 @@ OpenGLTexture FixedTextureAtlasManager::InsertBuffer(int nWidth, int nHeight, in
 
     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);
 }
 
+OpenGLTexture FixedTextureAtlasManager::InsertBuffer(int nWidth, int nHeight, int nFormat, int nType, sal_uInt8* 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: */
diff --git a/vcl/opengl/PackedTextureAtlas.cxx b/vcl/opengl/PackedTextureAtlas.cxx
new file mode 100644
index 000000000000..60fa1e98fc41
--- /dev/null
+++ b/vcl/opengl/PackedTextureAtlas.cxx
@@ -0,0 +1,164 @@
+/* -*- 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/PackedTextureAtlas.hxx"
+
+struct Node
+{
+    Rectangle mRectangle;
+    std::unique_ptr<Node> mLeftNode;
+    std::unique_ptr<Node> mRightNode;
+    bool mOccupied;
+
+    Node(Rectangle& aRectangle);
+
+    bool isLeaf();
+    Node* insert(int nWidth, int nHeight, int nPadding);
+};
+
+Node::Node(Rectangle& aRectangle)
+    : mRectangle(aRectangle)
+    , mLeftNode()
+    , mRightNode()
+    , mOccupied(false)
+{}
+
+bool Node::isLeaf()
+{
+    return mLeftNode.get()  == nullptr &&
+           mRightNode.get() == nullptr;
+}
+
+Node* Node::insert(int nWidth, int nHeight, int nPadding)
+{
+    if (!isLeaf())
+    {
+        Node* pNewNode = mLeftNode->insert(nWidth, nHeight, nPadding);
+
+        if (pNewNode != nullptr)
+            return pNewNode;
+
+        return mRightNode->insert(nWidth, nHeight, nPadding);
+    }
+    else
+    {
+        if (mOccupied)
+        {
+            return nullptr;
+        }
+
+        if (nWidth > mRectangle.GetWidth() || nHeight > mRectangle.GetHeight())
+        {   // does not fit
+            return nullptr;
+        }
+
+        if (nWidth == mRectangle.GetWidth() && nHeight == mRectangle.GetHeight())
+        {   // perfect fit
+            mOccupied = true;
+            return this;
+        }
+
+        int dw = mRectangle.GetWidth() - nWidth;
+        int dh = mRectangle.GetHeight() - nHeight;
+
+        Rectangle aLeftRect;
+        Rectangle aRightRect;
+        if (dw > dh)
+        {
+            aLeftRect = Rectangle(Point(mRectangle.Left(), mRectangle.Top()),
+                                  Size(nWidth, mRectangle.GetHeight()));
+            aRightRect = Rectangle(Point(nPadding + mRectangle.Left() + nWidth, mRectangle.Top()),
+                                   Size(mRectangle.GetWidth() - nWidth - nPadding, mRectangle.GetHeight()));
+        }
+        else
+        {
+            aLeftRect = Rectangle(Point(mRectangle.Left(), mRectangle.Top()),
+                                  Size(mRectangle.GetWidth(), nHeight));
+            aRightRect = Rectangle(Point(mRectangle.Left(), nPadding + mRectangle.Top() + nHeight),
+                                   Size(mRectangle.GetWidth(), mRectangle.GetHeight() - nHeight - nPadding));
+        }
+
+        mLeftNode.reset(new Node(aLeftRect));
+        mRightNode.reset(new Node(aRightRect));
+
+        return mLeftNode->insert(nWidth, nHeight, nPadding);
+    }
+}
+
+struct PackedTexture
+{
+    std::unique_ptr<Node> mpRootNode;
+    ImplOpenGLTexture* mpTexture;
+};
+
+PackedTextureAtlasManager::PackedTextureAtlasManager(int nTextureWidth, int nTextureHeight)
+    : mnTextureWidth(nTextureWidth)
+    , mnTextureHeight(nTextureHeight)
+{
+}
+
+PackedTextureAtlasManager::~PackedTextureAtlasManager()
+{
+    for (std::unique_ptr<PackedTexture>& pPackedTexture : maPackedTextures)
+    {
+        // Free texture early in VCL shutdown while we have a context.
+        pPackedTexture->mpTexture->Dispose();
+        pPackedTexture->mpTexture->DecreaseRefCount(0);
+    }
+}
+
+void PackedTextureAtlasManager::CreateNewTexture()
+{
+    std::unique_ptr<PackedTexture> pPackedTexture(new PackedTexture);
+    pPackedTexture->mpTexture = new ImplOpenGLTexture(mnTextureWidth, mnTextureHeight, true);
+    Rectangle aInitialRect(Point(0, 0), Size(mnTextureWidth, mnTextureHeight));
+    pPackedTexture->mpRootNode.reset(new Node(aInitialRect));
+    maPackedTextures.push_back(std::move(pPackedTexture));
+}
+
+OpenGLTexture PackedTextureAtlasManager::Reserve(int nWidth, int nHeight)
+{
+    for (std::unique_ptr<PackedTexture>& pPackedTexture : maPackedTextures)
+    {
+        Node* pNode = pPackedTexture->mpRootNode->insert(nWidth, nHeight, 1);
+        if (pNode != nullptr)
+        {
+            return OpenGLTexture(pPackedTexture->mpTexture, pNode->mRectangle, -1);
+        }
+    }
+    CreateNewTexture();
+    std::unique_ptr<PackedTexture>& pPackedTexture = maPackedTextures.back();
+    Node* pNode = pPackedTexture->mpRootNode->insert(nWidth, nHeight, 1);
+    if (pNode != nullptr)
+    {
+        return OpenGLTexture(pPackedTexture->mpTexture, pNode->mRectangle, -1);
+    }
+    return OpenGLTexture();
+}
+
+OpenGLTexture PackedTextureAtlasManager::InsertBuffer(int nWidth, int nHeight, int nFormat, int nType, sal_uInt8* pData)
+{
+    OpenGLTexture aTexture = Reserve(nWidth, nHeight);
+    if (aTexture && pData == nullptr)
+        return aTexture;
+
+    aTexture.CopyData(nWidth, nHeight, nFormat, nType, pData);
+
+    return aTexture;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */