From: Javier Sancho <jsf@jsancho.org>
Date: Mon, 24 Apr 2017 15:59:15 +0000 (+0200)
Subject: Enable transparency
X-Git-Url: https://git.jsancho.org/?p=gacela.git;a=commitdiff_plain;h=7fb1ff434787d12f8e4111a44dfc684a0b94eac3

Enable transparency
---

diff --git a/gacela/image.scm b/gacela/image.scm
index 2af2b4b..6acff1d 100644
--- a/gacela/image.scm
+++ b/gacela/image.scm
@@ -47,6 +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)
@@ -56,6 +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))