;; Example 6-2 Three-Dimensional Blending (use gl) (use gl.glut) (define MAXZ 8.0) (define MINZ -8.0) (define ZINC 0.4) (define *solid-z* MAXZ) (define *transparent-z* MINZ) (define *sphere-list* #f) (define *cube-list* #f) (define (init) (gl-material GL_FRONT GL_SPECULAR '#f32(1.0 1.0 1.0 0.15)) (gl-material GL_FRONT GL_SHININESS 100.0) (gl-light GL_LIGHT0 GL_POSITION '#f32(0.5 0.5 1.0 0.0)) (gl-enable GL_LIGHTING) (gl-enable GL_LIGHT0) (gl-enable GL_DEPTH_TEST) (set! *sphere-list* (gl-gen-lists 1)) (gl-new-list *sphere-list* GL_COMPILE) (glut-solid-sphere 0.4 16 16) (gl-end-list) (set! *cube-list* (gl-gen-lists 1)) (gl-new-list *cube-list* GL_COMPILE) (glut-solid-cube 0.6) (gl-end-list) ) (define (disp) (gl-clear (logior GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT)) (gl-push-matrix) (gl-translate -0.15 -0.15 *solid-z*) (gl-material GL_FRONT GL_EMISSION '#f32(0.0 0.0 0.0 1.0)) (gl-material GL_FRONT GL_DIFFUSE '#f32(0.75 0.75 0.0 1.0)) (gl-call-list *sphere-list*) (gl-pop-matrix) (gl-push-matrix) (gl-translate 0.15 0.15 *transparent-z*) (gl-rotate 15.0 1.0 1.0 0.0) (gl-rotate 30.0 0.0 1.0 0.0) (gl-material GL_FRONT GL_EMISSION '#f32(0.0 0.3 0.3 0.6)) (gl-material GL_FRONT GL_DIFFUSE '#f32(0.0 0.8 0.8 0.6)) (gl-enable GL_BLEND) (gl-depth-mask #f) (gl-blend-func GL_SRC_ALPHA GL_ONE) (gl-call-list *cube-list*) (gl-depth-mask #t) (gl-disable GL_BLEND) (gl-pop-matrix) (glut-swap-buffers) ) (define (reshape w h) (gl-viewport 0 0 w h) (gl-matrix-mode GL_PROJECTION) (gl-load-identity) (if (<= w h) (gl-ortho -1.5 1.5 (* -1.5 (/ h w)) (* 1.5 (/ h w)) -10.0 10.0) (gl-ortho (* -1.5 (/ w h)) (* 1.5 (/ w h)) -1.5 1.5 -10.0 10.0)) (gl-matrix-mode GL_MODELVIEW) (gl-load-identity) ) (define (animate) (if (or (<= *solid-z* MINZ) (>= *transparent-z* MAXZ)) (glut-idle-func #f) (begin (dec! *solid-z* ZINC) (inc! *transparent-z* ZINC) (glut-post-redisplay))) ) (define (keyboard key x y) (cond ((or (= key (char->integer #\a)) (= key (char->integer #\A))) (set! *solid-z* MAXZ) (set! *transparent-z* MINZ) (glut-idle-func animate)) ((or (= key (char->integer #\r)) (= key (char->integer #\R))) (set! *solid-z* MAXZ) (set! *transparent-z* MINZ) (glut-post-redisplay)) ((= key 27) (exit 0))) ) (define (main args) (glut-init args) (glut-init-display-mode (logior GLUT_DOUBLE GLUT_RGB GLUT_DEPTH)) (glut-init-window-size 500 500) (glut-create-window *program-name*) (init) (glut-reshape-func reshape) (glut-keyboard-func keyboard) (glut-display-func disp) (glut-main-loop) 0)