[gegl/gsoc2009-gpu] Implement proper texture read-backs

[Jerson Michael Perpetua <jperpetua src gnome org>]

commit 9407820d1d0e5919cf871ed21c7edc54d9d0cfc8
Author: Jerson Michael Perpetua <jersonperpetua gmail com>
Date:   Thu Jul 9 03:51:04 2009 +0800

    Implement proper texture read-backs
    
    Implement proper texture read-backs through an offscreen
    framebuffer.

 gegl/gpu/gegl-gpu-texture.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/gegl/gpu/gegl-gpu-texture.c b/gegl/gpu/gegl-gpu-texture.c
index 7083cf0..c366ace 100644
--- a/gegl/gpu/gegl-gpu-texture.c
+++ b/gegl/gpu/gegl-gpu-texture.c
@@ -93,6 +93,14 @@ gegl_gpu_texture_get (const GeglGpuTexture *texture,
   else
     buf = dest;
 
+  glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, 
+                            GL_COLOR_ATTACHMENT0_EXT, 
+                            GL_TEXTURE_RECTANGLE_ARB,
+                            texture->handle,
+                            0);
+
+  glReadBuffer(GL_COLOR_ATTACHMENT0_EXT);
+
   if (roi == NULL || (roi->x == 0 && roi->y == 0
                       && roi->width == texture->width
                       && roi->height == texture->height))