1 files changed, 9 insertions, 1 deletions
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index f205864191..9080c83da4 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -2236,7 +2236,15 @@ struct gl_renderbuffer_attachment
 struct gl_framebuffer
 {
    _glthread_Mutex Mutex;  /**< for thread safety */
-   GLuint Name;            /**< if zero, this is a window system framebuffer */
+   /**
+    * If zero, this is a window system framebuffer.  If non-zero, this
+    * is a FBO framebuffer; note that for some devices (i.e. those with
+    * a natural pixel coordinate system for FBOs that differs from the 
+    * OpenGL/Mesa coordinate system), this means that both the viewport
+    * and polygon face orientation will have to be inverted.
+    */
+   GLuint Name;
+
    GLint RefCount;
    GLboolean DeletePending;