X-Git-Url: https://git.jsancho.org/?p=gacela.git;a=blobdiff_plain;f=gacela%2Fimage.scm;fp=gacela%2Fimage.scm;h=236ac744fd420e83bf770e606346c46c02cf0d3a;hp=e6c8f4ef74a38fbf24a59213656ec51d8645facf;hb=bd985fa207b6aef6ed73096e9ea0e0db52a5f21c;hpb=6cc07be7e64e74546bf295ad42b5d2475624e3fc

diff --git a/gacela/image.scm b/gacela/image.scm
index e6c8f4e..236ac74 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)
@@ -46,6 +47,9 @@
          (set! h/2 (/ (sdl2:surface-height image) 2)))
        (gl-enable (oes-framebuffer-object texture-2d))
        (sdl2:bind-texture texture)
+       (gl-enable (oes-framebuffer-object blend))
+       (set-gl-blend-function (blending-factor-src src-alpha)
+                              (blending-factor-dest one-minus-src-alpha))
        (gl-begin (begin-mode quads)
          (gl-texture-coordinates 0 0)
          (gl-vertex (- w/2) h/2 0)
@@ -55,6 +59,7 @@
          (gl-vertex w/2 (- h/2) 0)
          (gl-texture-coordinates 0 1)
          (gl-vertex (- w/2) (- h/2) 0))
+       (gl-disable (oes-framebuffer-object blend))
        (gl-disable (oes-framebuffer-object texture-2d))))))
 
 (define* (move scene x y #:optional (z 0))
@@ -70,5 +75,17 @@
   (make-scene
    "scale"
    (lambda ()
-     (gl-scale x y z)
+     (gl-scale (calculate x)
+               (calculate y)
+               (calculate 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))))))))