;; Example 3-7 Robot Arm (use gl) (use gl.glut) (define *shoulder* 0) (define *elbow* 0) (define (init) (gl-clear-color 0.0 0.0 0.0 0.0) (gl-shade-model GL_FLAT) ) (define (disp) (gl-clear GL_COLOR_BUFFER_BIT) (gl-push-matrix) (gl-translate -1.0 0.0 0.0) (gl-rotate *shoulder* 0.0 0.0 1.0) (gl-translate 1.0 0.0 0.0) (gl-push-matrix) (gl-scale 2.0 0.4 1.0) (glut-wire-cube 1.0) (gl-pop-matrix) (gl-translate 1.0 0.0 0.0) (gl-rotate *elbow* 0.0 0.0 1.0) (gl-translate 1.0 0.0 0.0) (gl-push-matrix) (gl-scale 2.0 0.4 1.0) (glut-wire-cube 1.0) (gl-pop-matrix) (gl-pop-matrix) (glut-swap-buffers) ) (define (reshape w h) (gl-viewport 0 0 w h) (gl-matrix-mode GL_PROJECTION) (gl-load-identity) (glu-perspective 60.0 (/ w h) 1.0 20.0) (gl-matrix-mode GL_MODELVIEW) (gl-load-identity) (gl-translate 0 0 -5.0) ) (define (keyboard key x y) (cond ((= key (char->integer #\s)) (set! *shoulder* (modulo (+ *shoulder* 5) 360)) (glut-post-redisplay)) ((= key (char->integer #\S)) (set! *shoulder* (modulo (- *shoulder* 5) 360)) (glut-post-redisplay)) ((= key (char->integer #\e)) (set! *elbow* (modulo (+ *elbow* 5) 360)) (glut-post-redisplay)) ((= key (char->integer #\E)) (set! *elbow* (modulo (- *elbow* 5) 360)) (glut-post-redisplay)) ((= key 27) (exit 0)) )) (define (main args) (glut-init args) (glut-init-display-mode (logior GLUT_DOUBLE 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)