Display images using OpenGL and textures

[gacela.git] / gacela / image.scm

diff --git a/gacela/image.scm b/gacela/image.scm
index 6a9710101009f7014360f0ca2ab21c69f2fa3655..40d407560a0b4a06e2aa2f26087569e3dd98a215 100644 (file)
--- a/gacela/image.scm
+++ b/gacela/image.scm
@@ -17,21 +17,46 @@
 
 (define-module (gacela image)
   #:use-module (gacela scene)
+  #:use-module (gacela game)
+  #:use-module ((sdl2) #:prefix sdl2:)
+  #:use-module ((sdl2 image) #:prefix sdl2:)
+  #:use-module ((sdl2 render) #:prefix sdl2:)
   #:use-module ((sdl2 surface) #:prefix sdl2:)
-  #:export (import-bitmap
-           move-xy))
+  #:use-module (gl)
+  #:export (bitmap
+            move-xy))
 
-(define-syntax-rule (import-bitmap filename)
+(define (bitmap filename)
   (make-scene
    "bitmap"
-   (let ((surface (sdl2:load-bmp filename)))
-     (let ((a 0))
-       (lambda ()
-        (set! a (+ a 1))
-        (format #t "Steps: ~a~%" a))))))
+   (let ((image (sdl2:load-image filename))
+         (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-syntax-rule (move-xy x y scene)
+(define (move-xy x y scene)
+  (define (to-integer n)
+    (inexact->exact (round n)))
   (make-scene
    "move-xy"
    (lambda ()
-     (display-scene scene))))
+     (let ((xy (list (to-integer (if (procedure? x) (x) x))
+                     (to-integer (if (procedure? y) (y) y)))))
+       (display-scene scene #:xy xy)))))