Display images using OpenGL and textures

[gacela.git] / gacela / image.scm

diff --git a/gacela/image.scm b/gacela/image.scm
index cd0d27351277e3a29cfca446b30ba2bb1c6d0e6a..40d407560a0b4a06e2aa2f26087569e3dd98a215 100644 (file)
--- a/gacela/image.scm
+++ b/gacela/image.scm
@@ -22,6 +22,7 @@
   #:use-module ((sdl2 image) #:prefix sdl2:)
   #:use-module ((sdl2 render) #:prefix sdl2:)
   #:use-module ((sdl2 surface) #:prefix sdl2:)
+  #:use-module (gl)
   #:export (bitmap
             move-xy))
 
@@ -29,14 +30,26 @@
   (make-scene
    "bitmap"
    (let ((image (sdl2:load-image filename))
-         (texture #f))
-     (let ((a 0))
-       (lambda* (#:key (xy '(0 0)))
-         (if (not texture)
-             (set! texture (sdl2:surface->texture %sdl-renderer image)))
-         (sdl2:clear-renderer %sdl-renderer)
-         (sdl2:render-copy %sdl-renderer texture #:dest-rect (sdl2:make-rect (car xy) (cadr xy) (sdl2:surface-width image) (sdl2:surface-height image)))
-         (sdl2:present-renderer %sdl-renderer))))))
+         (texture #f)
+         (w/2 0)
+         (h/2 0))
+     (lambda* ()
+       (when (not texture)
+         (set! texture (sdl2:surface->texture %sdl-renderer image))
+         (set! w/2 (/ (sdl2:surface-width image) 2))
+         (set! h/2 (/ (sdl2:surface-height image) 2)))
+       (gl-enable (oes-framebuffer-object texture-2d))
+       (sdl2:bind-texture texture)
+       (gl-begin (begin-mode quads)
+         (gl-texture-coordinates 0 0)
+         (gl-vertex (- w/2) h/2 0)
+         (gl-texture-coordinates 1 0)
+         (gl-vertex w/2 h/2 0)
+         (gl-texture-coordinates 1 1)
+         (gl-vertex w/2 (- h/2) 0)
+         (gl-texture-coordinates 0 1)
+         (gl-vertex (- w/2) (- h/2) 0))
+       (gl-disable (oes-framebuffer-object texture-2d))))))
 
 (define (move-xy x y scene)
   (define (to-integer n)