From 062d9c7b8af0557398f399af0a4d4709b0c7d304 Mon Sep 17 00:00:00 2001
From: Markus Mohrhard <markus.mohrhard@collabora.co.uk>
Date: Fri, 8 Aug 2014 05:28:02 +0200
Subject: reimplement custom sprite rendering with FBO

Change-Id: I8d7a54fac61a3072d4f34615e71e37c70dec4e50
---
 canvas/source/opengl/ogl_buffercontext.hxx      |  9 ++++++--
 canvas/source/opengl/ogl_canvascustomsprite.cxx |  7 +++---
 canvas/source/opengl/ogl_spritedevicehelper.cxx | 30 ++++++++++++++++++-------
 3 files changed, 33 insertions(+), 13 deletions(-)

diff --git a/canvas/source/opengl/ogl_buffercontext.hxx b/canvas/source/opengl/ogl_buffercontext.hxx
index 7d85e9a3791d..a99446b7ad2c 100644
--- a/canvas/source/opengl/ogl_buffercontext.hxx
+++ b/canvas/source/opengl/ogl_buffercontext.hxx
@@ -10,20 +10,25 @@
 #ifndef INCLUDED_CANVAS_SOURCE_OPENGL_OGL_BUFFERCONTEXT_HXX
 #define INCLUDED_CANVAS_SOURCE_OPENGL_OGL_BUFFERCONTEXT_HXX
 
+#include <GL/glew.h>
+
 #include <sal/config.h>
 #include <boost/shared_ptr.hpp>
 
+
 namespace oglcanvas
 {
     struct IBufferContext
     {
         virtual ~IBufferContext() {}
 
-        /// start render to buffer. changes gl current context
+        /// start render to buffer. changes current framebuffer
         virtual bool startBufferRendering() = 0;
 
-        /// end render to buffer. switches to window context, and selects rendered texture
+        /// end render to buffer. switches to default framebuffer
         virtual bool endBufferRendering() = 0;
+
+        virtual GLuint getTextureId() = 0;
     };
 
     typedef ::boost::shared_ptr<IBufferContext> IBufferContextSharedPtr;
diff --git a/canvas/source/opengl/ogl_canvascustomsprite.cxx b/canvas/source/opengl/ogl_canvascustomsprite.cxx
index 86cbac6902dd..2f2853e78543 100644
--- a/canvas/source/opengl/ogl_canvascustomsprite.cxx
+++ b/canvas/source/opengl/ogl_canvascustomsprite.cxx
@@ -159,9 +159,8 @@ namespace oglcanvas
                 // composite that to screen
 
                 // TODO(P3): buffer texture
-                // TODO: moggi: reimplement as FBO with rendering to texture
-                pBufferContext = NULL;
-                // pBufferContext->startBufferRendering();
+                pBufferContext = maCanvasHelper.getDeviceHelper()->createBufferContext(aSpriteSizePixel);
+                pBufferContext->startBufferRendering();
             }
 
             // this ends up in pBufferContext, if that one's "current"
@@ -174,6 +173,8 @@ namespace oglcanvas
                 // screen now. Calls below switches us back to window
                 // context, and binds to generated, dynamic texture
                 pBufferContext->endBufferRendering();
+                GLuint nTexture = pBufferContext->getTextureId();
+                glBindTexture(GL_TEXTURE_2D, nTexture);
 
                 glEnable(GL_TEXTURE_2D);
                 glTexParameteri(GL_TEXTURE_2D,
diff --git a/canvas/source/opengl/ogl_spritedevicehelper.cxx b/canvas/source/opengl/ogl_spritedevicehelper.cxx
index cd29f37f5352..3f6b53482aed 100644
--- a/canvas/source/opengl/ogl_spritedevicehelper.cxx
+++ b/canvas/source/opengl/ogl_spritedevicehelper.cxx
@@ -537,21 +537,29 @@ namespace oglcanvas
     namespace
     {
 
-        /*
-         * TODO: mogg: reimplement through FBO with texture as backend
         class BufferContextImpl : public IBufferContext
         {
             ::basegfx::B2IVector       maSize;
             const SpriteDeviceHelper&  mrDeviceHelper;
+            GLuint mnFrambufferId;
+            GLuint mnDepthId;
+            GLuint mnTextureId;
 
             virtual bool startBufferRendering() SAL_OVERRIDE
             {
-                return false;
+                glBindFramebuffer(GL_FRAMEBUFFER, mnFrambufferId);
+                return true;
             }
 
             virtual bool endBufferRendering() SAL_OVERRIDE
             {
-                return false;
+                glBindFramebuffer(GL_FRAMEBUFFER, 0);
+                return true;
+            }
+
+            virtual GLuint getTextureId() SAL_OVERRIDE
+            {
+                return mnTextureId;
             }
 
         public:
@@ -559,20 +567,26 @@ namespace oglcanvas
                               const ::basegfx::B2IVector& rSize) :
                 maSize(rSize),
                 mrDeviceHelper(rDeviceHelper),
-                mnTexture(0)
+                mnFrambufferId(0),
+                mnDepthId(0),
+                mnTextureId(0)
             {
+                OpenGLHelper::createFramebuffer(maSize.getX(), maSize.getY(), mnFrambufferId,
+                        mnDepthId, mnTextureId, false);
             }
 
             virtual ~BufferContextImpl()
             {
+                glDeleteTextures(1, &mnTextureId);
+                glDeleteRenderbuffers(1, &mnDepthId);
+                glDeleteFramebuffers(1, &mnFrambufferId);
             }
         };
-        */
     }
 
-    IBufferContextSharedPtr SpriteDeviceHelper::createBufferContext(const ::basegfx::B2IVector& ) const
+    IBufferContextSharedPtr SpriteDeviceHelper::createBufferContext(const ::basegfx::B2IVector& rSize) const
     {
-        return NULL;
+        return IBufferContextSharedPtr(new BufferContextImpl(*this, rSize));
     }
 
     TextureCache& SpriteDeviceHelper::getTextureCache() const
-- 
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