;; Example 4-1 Drawing a Smooth-Shaded Triangle (use gl) (use gl.glut) (define (init) (gl-clear-color 0.0 0.0 0.0 0.0) (gl-shade-model GL_SMOOTH)) (define (triangle) (gl-begin GL_TRIANGLES) (gl-color '#f32(1.0 0.0 0.0)) (gl-vertex '#f32(5.0 5.0)) (gl-color '#f32(0.0 1.0 0.0)) (gl-vertex '#f32(25.0 5.0)) (gl-color '#f32(0.0 0.0 1.0)) (gl-vertex '#f32(5.0 25.0)) (gl-end)) (define (disp) (gl-clear GL_COLOR_BUFFER_BIT) (triangle) (gl-flush) ) (define (reshape w h) (gl-viewport 0 0 w h) (gl-matrix-mode GL_PROJECTION) (gl-load-identity) (if (<= w h) (glu-ortho-2d 0.0 30.0 0.0 (* 30.0 (/ h w))) (glu-ortho-2d 0.0 (* 30.0 (/ w h)) 0.0 30.0)) (gl-matrix-mode GL_MODELVIEW) ) (define (keyboard key x y) (when (= key 27) (exit 0))) (define (main args) (glut-init args) (glut-init-display-mode (logior GLUT_SINGLE GLUT_RGB)) (glut-init-window-size 500 500) (glut-init-window-position 100 100) (glut-create-window *program-name*) (init) (glut-display-func disp) (glut-reshape-func reshape) (glut-keyboard-func keyboard) (glut-main-loop) 0)