+ _mesa_reference_renderbuffer(&fb->Attachment[bufferName].Renderbuffer, rb);
+}
+
+
+/**
+ * Remove the named renderbuffer from the given framebuffer.
+ */
+void
+_mesa_remove_renderbuffer(struct gl_framebuffer *fb, GLuint bufferName)
+{
+ struct gl_renderbuffer *rb;
+
+ assert(bufferName < BUFFER_COUNT);
+
+ rb = fb->Attachment[bufferName].Renderbuffer;
+ if (!rb)
+ return;
+
+ _mesa_reference_renderbuffer(&rb, NULL);
+
+ fb->Attachment[bufferName].Renderbuffer = NULL;
+}
+
+
+/**
+ * Set *ptr to point to rb. If *ptr points to another renderbuffer,
+ * dereference that buffer first. The new renderbuffer's refcount will
+ * be incremented. The old renderbuffer's refcount will be decremented.
+ */
+void
+_mesa_reference_renderbuffer(struct gl_renderbuffer **ptr,
+ struct gl_renderbuffer *rb)
+{
+ assert(ptr);
+ if (*ptr == rb) {
+ /* no change */
+ return;
+ }
+
+ if (*ptr) {
+ /* Unreference the old renderbuffer */
+ GLboolean deleteFlag = GL_FALSE;
+ struct gl_renderbuffer *oldRb = *ptr;
+
+ assert(oldRb->Magic == RB_MAGIC);
+ _glthread_LOCK_MUTEX(oldRb->Mutex);
+ assert(oldRb->Magic == RB_MAGIC);
+ ASSERT(oldRb->RefCount > 0);
+ oldRb->RefCount--;
+ /*printf("RB DECR %p (%d) to %d\n", (void*) oldRb, oldRb->Name, oldRb->RefCount);*/
+ deleteFlag = (oldRb->RefCount == 0);
+ _glthread_UNLOCK_MUTEX(oldRb->Mutex);
+
+ if (deleteFlag) {
+ oldRb->Magic = 0; /* now invalid memory! */
+ oldRb->Delete(oldRb);
+ }
+
+ *ptr = NULL;
+ }
+ assert(!*ptr);
+
+ if (rb) {
+ assert(rb->Magic == RB_MAGIC);
+ /* reference new renderbuffer */
+ _glthread_LOCK_MUTEX(rb->Mutex);
+ rb->RefCount++;
+ /*printf("RB INCR %p (%d) to %d\n", (void*) rb, rb->Name, rb->RefCount);*/
+ _glthread_UNLOCK_MUTEX(rb->Mutex);
+ *ptr = rb;
+ }