;; Example 6-5 Five Fogged Spheres in RGBA Mode (use gl) (use gl.glut) (define *fog-mode* GL_EXP) (define (init) (gl-enable GL_DEPTH_TEST) (gl-light GL_LIGHT0 GL_POSITION '#f32(0.5 0.5 3.0 0.0)) (gl-enable GL_LIGHTING) (gl-enable GL_LIGHT0) (gl-material GL_FRONT GL_AMBIENT '#f32(0.1745 0.01175 0.01175 0.0)) (gl-material GL_FRONT GL_DIFFUSE '#f32(0.61424 0.04136 0.04136 0.0)) (gl-material GL_FRONT GL_SPECULAR '#f32(0.727811 0.626959 0.626959 0.0)) (gl-material GL_FRONT GL_SHININESS (* 0.6 128)) (gl-enable GL_FOG) (gl-fog GL_FOG_MODE GL_EXP) (gl-fog GL_FOG_COLOR '#f32(0.5 0.5 0.5 1.0)) (gl-fog GL_FOG_DENSITY 0.35) (gl-hint GL_FOG_HINT GL_DONT_CARE) (gl-fog GL_FOG_START 1.0) (gl-fog GL_FOG_END 5.0) (gl-clear-color 0.5 0.5 0.5 1.0) ) (define (render-sphere x y z) (gl-push-matrix) (gl-translate x y z) (glut-solid-sphere 0.4 16 16) (gl-pop-matrix)) (define (disp) (gl-clear (logior GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT)) (render-sphere -2.0 -0.5 -1.0) (render-sphere -1.0 -0.5 -2.0) (render-sphere 0.0 -0.5 -3.0) (render-sphere 1.0 -0.5 -4.0) (render-sphere 2.0 -0.5 -5.0) (gl-flush) ) (define (reshape w h) (gl-viewport 0 0 w h) (gl-matrix-mode GL_PROJECTION) (gl-load-identity) (if (<= w h) (gl-ortho -2.5 2.5 (* -2.5 (/ h w)) (* 2.5 (/ h w)) -10.0 10.0) (gl-ortho (* -2.5 (/ w h)) (* 2.5 (/ w h)) -2.5 2.5 -10.0 10.0)) (gl-matrix-mode GL_MODELVIEW) (gl-load-identity) ) (define (keyboard key x y) (cond ((or (= key (char->integer #\f)) (= key (char->integer #\F))) (receive (next-mode next-mode-name) (apply values (cdr (assv *fog-mode* `((,GL_EXP ,GL_EXP2 GL_EXP2) (,GL_EXP2 ,GL_LINEAR GL_LINEAR) (,GL_LINEAR ,GL_EXP GL_EXP))))) (print #`"Fog mode is ,|next-mode-name|") (set! *fog-mode* next-mode) (gl-fog GL_FOG_MODE *fog-mode*)) (glut-post-redisplay)) ((= key 27) ;ESC (exit 0))) ) (define (main args) (glut-init args) (glut-init-display-mode (logior GLUT_SINGLE GLUT_RGB GLUT_DEPTH)) (glut-init-window-size 500 500) (glut-create-window (car args)) (init) (glut-reshape-func reshape) (glut-keyboard-func keyboard) (glut-display-func disp) (glut-main-loop) 0)