+
+/**
+ * gl_renderbuffer is a base class which we subclass. The Class field
+ * is used for simple run-time type checking.
+ */
+#define INTEL_RB_CLASS 0x12345678
+
+
+/**
+ * Return a gl_renderbuffer ptr casted to intel_renderbuffer.
+ * NULL will be returned if the rb isn't really an intel_renderbuffer.
+ * This is determined by checking the ClassID.
+ */
+static INLINE struct intel_renderbuffer *
+intel_renderbuffer(struct gl_renderbuffer *rb)
+{
+ struct intel_renderbuffer *irb = (struct intel_renderbuffer *) rb;
+ if (irb && irb->Base.ClassID == INTEL_RB_CLASS) {
+ /*_mesa_warning(NULL, "Returning non-intel Rb\n");*/
+ return irb;
+ }
+ else
+ return NULL;
+}
+
+
+/**
+ * Return a framebuffer's renderbuffer, named by a BUFFER_x index.
+ */
+static INLINE struct intel_renderbuffer *
+intel_get_renderbuffer(struct gl_framebuffer *fb, int attIndex)
+{
+ if (attIndex >= 0)
+ return intel_renderbuffer(fb->Attachment[attIndex].Renderbuffer);
+ else
+ return NULL;
+}
+