add glut demo

* examples/glut/demo.scm: Copied GLUT demo from Daniel Hartwig.

diff --git a/examples/glut/demo.scm b/examples/glut/demo.scm
new file mode 100644 (file)
index 0000000..c24c669
--- /dev/null
+++ b/examples/glut/demo.scm
@@ -0,0 +1,44 @@
+#!/usr/bin/env guile
+!#
+
+(use-modules (figl glut low-level)
+             (figl glut)
+             (figl gl low-level)
+             (system foreign))
+
+(define GLUT_RGB #x0000)
+(define GLUT_RGBA #x0000)
+(define GLUT_INDEX #x0001)
+(define GLUT_SINGLE #x0000)
+(define GLUT_DOUBLE #x0002)
+(define GLUT_ACCUM #x0004)
+(define GLUT_ALPHA #x0008)
+(define GLUT_DEPTH #x0010)
+(define GLUT_STENCIL #x0020)
+(define GLUT_MULTISAMPLE #x0080)
+(define GLUT_STEREO #x0100)
+(define GLUT_LUMINANCE #x0200)
+
+(define GL_COLOR_BUFFER_BIT #x4000)
+(define GL_DEPTH_BUFFER_BIT #x0100)
+(define GL_TRIANGLES #x0004)
+
+(define (render-scene)
+  (glClear (logior GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT))
+  (glBegin GL_TRIANGLES)
+  (glVertex3f -0.5 -0.5 0.0)
+  (glVertex3f 0.5 0.0 0.0)
+  (glVertex3f 0.0 0.5 0.0)
+  (glEnd)
+
+  (glutSwapBuffers))
+
+(glutInitWindowSize 320 200)
+(glutInitDisplayMode (logior GLUT_RGB GLUT_DOUBLE GLUT_DEPTH))
+
+(glut-init (program-arguments))
+
+(define main-window (glutCreateWindow "glut"))
+
+(glutDisplayFunc (procedure->pointer void render-scene (list)))
+(glutMainLoop)