From: Javier Sancho <jsf@jsancho.org>
Date: Mon, 24 Apr 2017 15:48:12 +0000 (+0200)
Subject: Composing scenes
X-Git-Url: https://git.jsancho.org/?a=commitdiff_plain;h=f5a68f317089a2b52f787322d5384b0afadeb7cd;p=gacela.git

Composing scenes
---

diff --git a/gacela/image.scm b/gacela/image.scm
index e6c8f4e..2af2b4b 100644
--- a/gacela/image.scm
+++ b/gacela/image.scm
@@ -25,7 +25,8 @@
   #:use-module (gl)
   #:export (image
             move
-            scale))
+            scale
+            over))
 
 (define (calculate proc-or-value)
   (if (procedure? proc-or-value)
@@ -72,3 +73,13 @@
    (lambda ()
      (gl-scale x y z)
      (display-scene scene))))
+
+(define (over . scenes)
+  (make-scene
+   "over"
+   (lambda ()
+     (let display ((sc scenes))
+       (cond ((not (null? sc))
+              (with-gl-push-matrix
+               (display-scene (car sc)))
+              (display (cdr sc))))))))