[cogl] cogl-pipeline: Fix comparing the texture data state for NULL textures

[Neil Roberts <nroberts src gnome org>]

commit d2a35a1e2227c27dde84610ffbad3d593c32d096
Author: Neil Roberts <neil linux intel com>
Date:   Thu Feb 9 13:56:40 2012 +0000

    cogl-pipeline: Fix comparing the texture data state for NULL textures
    
    When comparing the texture data for a pipeline layer it tries to get
    the GL texture handle out of the texture object. However it's valid
    for a layer to have a NULL texture object but in that case the code
    would just crash. This patch fixes it to compare the texture types
    when the texture object is NULL.
    
    Reviewed-by: Robert Bragg <robert linux intel com>

 cogl/cogl-pipeline-layer-state.c |   21 +++++++++++++++++----
 1 files changed, 17 insertions(+), 4 deletions(-)
---
diff --git a/cogl/cogl-pipeline-layer-state.c b/cogl/cogl-pipeline-layer-state.c
index 12ee87b..e6506a8 100644
--- a/cogl/cogl-pipeline-layer-state.c
+++ b/cogl/cogl-pipeline-layer-state.c
@@ -877,12 +877,25 @@ _cogl_pipeline_layer_texture_data_equal (CoglPipelineLayer *authority0,
                                          CoglPipelineLayer *authority1,
                                          CoglPipelineEvalFlags flags)
 {
-  GLuint gl_handle0, gl_handle1;
+  if (authority0->texture == NULL)
+    {
+      if (authority1->texture == NULL)
+        return (_cogl_pipeline_layer_get_texture_type (authority0) ==
+                _cogl_pipeline_layer_get_texture_type (authority1));
+      else
+        return FALSE;
+    }
+  else if (authority1->texture == NULL)
+    return FALSE;
+  else
+    {
+      GLuint gl_handle0, gl_handle1;
 
-  cogl_texture_get_gl_texture (authority0->texture, &gl_handle0, NULL);
-  cogl_texture_get_gl_texture (authority1->texture, &gl_handle1, NULL);
+      cogl_texture_get_gl_texture (authority0->texture, &gl_handle0, NULL);
+      cogl_texture_get_gl_texture (authority1->texture, &gl_handle1, NULL);
 
-  return gl_handle0 == gl_handle1;
+      return gl_handle0 == gl_handle1;
+    }
 }
 
 gboolean