render: framebuffer: Add framebuffer-null?

* sly/render/framebuffer.scm (framebuffer-null?): New procedure.

1 files changed, 5 insertions, 0 deletions

diff --git a/sly/render/framebuffer.scm b/sly/render/framebuffer.scm
index c3af36a..e533f7a 100644
--- a/sly/render/framebuffer.scm
+++ b/sly/render/framebuffer.scm
@@ -31,6 +31,7 @@
   #:use-module (sly wrappers gl)
   #:export (make-framebuffer
             framebuffer?
+            framebuffer-null?
             framebuffer-id framebuffer-renderbuffer-id
             framebuffer-texture
             null-framebuffer
@@ -58,6 +59,10 @@
 (define null-framebuffer
   (%make-framebuffer 0 0 #f))
 
+(define (framebuffer-null? framebuffer)
+  "Return #t if FRAMEBUFFER is the null framebuffer."
+  (eq? null-framebuffer framebuffer))
+
 (define make-framebuffer
   (let ((draw-buffers (u32vector (version-3-0 color-attachment0))))
     (lambda (width height)