1/*
2 * GL_ARB_texture_cube_map demo
3 *
4 * Brian Paul
5 * May 2000
6 *
7 *
8 * Copyright (C) 2000  Brian Paul   All Rights Reserved.
9 *
10 * Permission is hereby granted, free of charge, to any person obtaining a
11 * copy of this software and associated documentation files (the "Software"),
12 * to deal in the Software without restriction, including without limitation
13 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
14 * and/or sell copies of the Software, and to permit persons to whom the
15 * Software is furnished to do so, subject to the following conditions:
16 *
17 * The above copyright notice and this permission notice shall be included
18 * in all copies or substantial portions of the Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
21 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
23 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
24 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
25 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
26 */
27
28
29/*
30 * This is a pretty minimalistic demo for now.  Eventually, use some
31 * interesting cube map textures and 3D objects.
32 * For now, we use 6 checkerboard "walls" and a sphere (good for
33 * verification purposes).
34 */
35
36
37#include <assert.h>
38#include <math.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <string.h>
42#include <GL/glew.h>
43#include "glut_wrap.h"
44#include "readtex.h"
45
46#ifndef GL_TEXTURE_CUBE_MAP_SEAMLESS
47#define GL_TEXTURE_CUBE_MAP_SEAMLESS 0x884F
48#endif
49
50static GLfloat Xrot = 0, Yrot = 0;
51static GLfloat EyeDist = 10;
52static GLboolean use_vertex_arrays = GL_FALSE;
53static GLboolean anim = GL_TRUE;
54static GLboolean NoClear = GL_FALSE;
55static GLint FrameParity = 0;
56static GLenum FilterIndex = 0;
57static GLint ClampIndex = 0;
58static GLboolean supportFBO = GL_FALSE;
59static GLboolean supportSeamless = GL_FALSE;
60static GLboolean seamless = GL_FALSE;
61static GLuint TexObj = 0;
62static GLint T0 = 0;
63static GLint Frames = 0;
64
65
66static struct {
67   GLenum mode;
68   const char *name;
69} ClampModes[] = {
70   { GL_CLAMP_TO_EDGE, "GL_CLAMP_TO_EDGE" },
71   { GL_CLAMP_TO_BORDER, "GL_CLAMP_TO_BORDER" },
72   { GL_CLAMP, "GL_CLAMP" },
73   { GL_REPEAT, "GL_REPEAT" }
74};
75
76#define NUM_CLAMP_MODES (sizeof(ClampModes) / sizeof(ClampModes[0]))
77
78
79static struct {
80   GLenum mag_mode, min_mode;
81   const char *name;
82} FilterModes[] = {
83   { GL_NEAREST, GL_NEAREST, "GL_NEAREST, GL_NEAREST" },
84   { GL_NEAREST, GL_LINEAR, "GL_NEAREST, GL_LINEAR" },
85   { GL_NEAREST, GL_NEAREST_MIPMAP_NEAREST, "GL_NEAREST, GL_NEAREST_MIPMAP_NEAREST" },
86   { GL_NEAREST, GL_NEAREST_MIPMAP_LINEAR, "GL_NEAREST, GL_NEAREST_MIPMAP_LINEAR" },
87   { GL_NEAREST, GL_LINEAR_MIPMAP_NEAREST, "GL_NEAREST, GL_LINEAR_MIPMAP_NEAREST" },
88   { GL_NEAREST, GL_LINEAR_MIPMAP_LINEAR, "GL_NEAREST, GL_LINEAR_MIPMAP_LINEAR" },
89
90   { GL_LINEAR, GL_NEAREST, "GL_LINEAR, GL_NEAREST" },
91   { GL_LINEAR, GL_LINEAR, "GL_LINEAR, GL_LINEAR" },
92   { GL_LINEAR, GL_NEAREST_MIPMAP_NEAREST, "GL_LINEAR, GL_NEAREST_MIPMAP_NEAREST" },
93   { GL_LINEAR, GL_NEAREST_MIPMAP_LINEAR, "GL_LINEAR, GL_NEAREST_MIPMAP_LINEAR" },
94   { GL_LINEAR, GL_LINEAR_MIPMAP_NEAREST, "GL_LINEAR, GL_LINEAR_MIPMAP_NEAREST" },
95   { GL_LINEAR, GL_LINEAR_MIPMAP_LINEAR, "GL_LINEAR, GL_LINEAR_MIPMAP_LINEAR" }
96};
97
98#define NUM_FILTER_MODES (sizeof(FilterModes) / sizeof(FilterModes[0]))
99
100
101
102/* The effects of GL_ARB_seamless_cube_map don't show up unless eps1 is 1.0.
103 */
104#define eps1 1.0 /*0.99*/
105#define br   20.0  /* box radius */
106
107static const GLfloat tex_coords[] = {
108   /* +X side */
109   1.0, -eps1, -eps1,
110   1.0, -eps1,  eps1,
111   1.0,  eps1,  eps1,
112   1.0,  eps1, -eps1,
113
114   /* -X side */
115   -1.0,  eps1, -eps1,
116   -1.0,  eps1,  eps1,
117   -1.0, -eps1,  eps1,
118   -1.0, -eps1, -eps1,
119
120   /* +Y side */
121   -eps1, 1.0, -eps1,
122   -eps1, 1.0,  eps1,
123    eps1, 1.0,  eps1,
124    eps1, 1.0, -eps1,
125
126   /* -Y side */
127   -eps1, -1.0, -eps1,
128   -eps1, -1.0,  eps1,
129    eps1, -1.0,  eps1,
130    eps1, -1.0, -eps1,
131
132   /* +Z side */
133    eps1, -eps1, 1.0,
134   -eps1, -eps1, 1.0,
135   -eps1,  eps1, 1.0,
136    eps1,  eps1, 1.0,
137
138   /* -Z side */
139    eps1,  eps1, -1.0,
140   -eps1,  eps1, -1.0,
141   -eps1, -eps1, -1.0,
142    eps1, -eps1, -1.0,
143};
144
145static const GLfloat vtx_coords[] = {
146   /* +X side */
147   br, -br, -br,
148   br, -br,  br,
149   br,  br,  br,
150   br,  br, -br,
151
152   /* -X side */
153   -br,  br, -br,
154   -br,  br,  br,
155   -br, -br,  br,
156   -br, -br, -br,
157
158   /* +Y side */
159   -br,  br, -br,
160   -br,  br,  br,
161    br,  br,  br,
162    br,  br, -br,
163
164   /* -Y side */
165   -br, -br, -br,
166   -br, -br,  br,
167    br, -br,  br,
168    br, -br, -br,
169
170   /* +Z side */
171    br, -br, br,
172   -br, -br, br,
173   -br,  br, br,
174    br,  br, br,
175
176   /* -Z side */
177    br,  br, -br,
178   -br,  br, -br,
179   -br, -br, -br,
180    br, -br, -br,
181};
182
183static void draw_skybox( void )
184{
185   if ( use_vertex_arrays ) {
186      glTexCoordPointer( 3, GL_FLOAT, 0, tex_coords );
187      glVertexPointer(   3, GL_FLOAT, 0, vtx_coords );
188
189      glEnableClientState( GL_TEXTURE_COORD_ARRAY );
190      glEnableClientState( GL_VERTEX_ARRAY );
191
192      glDrawArrays( GL_QUADS, 0, 24 );
193
194      glDisableClientState( GL_TEXTURE_COORD_ARRAY );
195      glDisableClientState( GL_VERTEX_ARRAY );
196   }
197   else {
198      unsigned   i;
199
200      glBegin(GL_QUADS);
201      for ( i = 0 ; i < 24 ; i++ ) {
202	 glTexCoord3fv( & tex_coords[ i * 3 ] );
203	 glVertex3fv  ( & vtx_coords[ i * 3 ] );
204      }
205      glEnd();
206   }
207}
208
209
210static void draw( void )
211{
212   GLenum wrap;
213
214   if (NoClear) {
215      /* This demonstrates how we can avoid calling glClear.
216       * This method only works if every pixel in the window is painted for
217       * every frame.
218       * We can simply skip clearing of the color buffer in this case.
219       * For the depth buffer, we alternately use a different subrange of
220       * the depth buffer for each frame.  For the odd frame use the range
221       * [0, 0.5] with GL_LESS.  For the even frames, use the range [1, 0.5]
222       * with GL_GREATER.
223       */
224      FrameParity = 1 - FrameParity;
225      if (FrameParity) {
226         glDepthRange(0.0, 0.5);
227         glDepthFunc(GL_LESS);
228      }
229      else {
230         glDepthRange(1.0, 0.5);
231         glDepthFunc(GL_GREATER);
232      }
233   }
234   else {
235      /* ordinary clearing */
236      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
237   }
238
239   glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER,
240                   FilterModes[FilterIndex].min_mode);
241   glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER,
242                   FilterModes[FilterIndex].mag_mode);
243
244   if (supportSeamless) {
245      if (seamless) {
246	 glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
247      } else {
248	 glDisable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
249      }
250   }
251   wrap = ClampModes[ClampIndex].mode;
252   glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, wrap);
253   glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, wrap);
254   glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_R, wrap);
255
256   glPushMatrix(); /*MODELVIEW*/
257      glTranslatef( 0.0, 0.0, -EyeDist );
258
259      /* skybox */
260      glDisable(GL_TEXTURE_GEN_S);
261      glDisable(GL_TEXTURE_GEN_T);
262      glDisable(GL_TEXTURE_GEN_R);
263
264      glMatrixMode(GL_MODELVIEW);
265      glPushMatrix();
266         glRotatef(Xrot, 1, 0, 0);
267         glRotatef(Yrot, 0, 1, 0);
268         draw_skybox();
269      glPopMatrix();
270
271      /* sphere */
272      glMatrixMode(GL_TEXTURE);
273      glLoadIdentity();
274      glRotatef(-Yrot, 0, 1, 0);
275      glRotatef(-Xrot, 1, 0, 0);
276
277      glEnable(GL_TEXTURE_GEN_S);
278      glEnable(GL_TEXTURE_GEN_T);
279      glEnable(GL_TEXTURE_GEN_R);
280      glutSolidSphere(2.0, 20, 20);
281
282      glLoadIdentity(); /* texture */
283
284      glMatrixMode(GL_MODELVIEW);
285   glPopMatrix();
286
287   glutSwapBuffers();
288
289   Frames++;
290
291   {
292      GLint t = glutGet(GLUT_ELAPSED_TIME);
293      if (t - T0 >= 5000) {
294	 GLfloat seconds = (t - T0) / 1000.0;
295	 GLfloat fps = Frames / seconds;
296	 printf("%d frames in %6.3f seconds = %6.3f FPS\n", Frames, seconds, fps);
297	 fflush(stdout);
298	 T0 = t;
299	 Frames = 0;
300      }
301   }
302}
303
304
305static void idle(void)
306{
307   GLfloat t = 0.05 * glutGet(GLUT_ELAPSED_TIME);
308   Yrot = t;
309   glutPostRedisplay();
310}
311
312
313static void set_mode(GLuint mode)
314{
315   if (mode == 0) {
316      glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_ARB);
317      glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_ARB);
318      glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_REFLECTION_MAP_ARB);
319      printf("GL_REFLECTION_MAP_ARB mode\n");
320   }
321   else if (mode == 1) {
322      glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_NORMAL_MAP_ARB);
323      glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_NORMAL_MAP_ARB);
324      glTexGeni(GL_R, GL_TEXTURE_GEN_MODE, GL_NORMAL_MAP_ARB);
325      printf("GL_NORMAL_MAP_ARB mode\n");
326   }
327}
328
329
330static void key(unsigned char k, int x, int y)
331{
332   static GLuint mode = 0;
333   (void) x;
334   (void) y;
335   switch (k) {
336      case ' ':
337         anim = !anim;
338         if (anim)
339            glutIdleFunc(idle);
340         else
341            glutIdleFunc(NULL);
342         break;
343      case 'f':
344         FilterIndex = (FilterIndex + 1) % NUM_FILTER_MODES;
345         printf("Tex filter: %s\n", FilterModes[FilterIndex].name);
346         break;
347      case 'c':
348         ClampIndex = (ClampIndex + 1) % NUM_CLAMP_MODES;
349         printf("Tex wrap mode: %s\n", ClampModes[ClampIndex].name);
350         break;
351      case 'm':
352         mode = !mode;
353         set_mode(mode);
354         break;
355      case 's':
356	 seamless = ! seamless;
357	 printf("Seamless cube map filtering is %sabled\n",
358		(seamless) ? "en" : "dis" );
359	 break;
360      case 'v':
361         use_vertex_arrays = ! use_vertex_arrays;
362         printf( "Vertex arrays are %sabled\n",
363		 (use_vertex_arrays) ? "en" : "dis" );
364         break;
365      case 'z':
366         EyeDist -= 0.5;
367         if (EyeDist < 6.0)
368            EyeDist = 6.0;
369         break;
370      case 'Z':
371         EyeDist += 0.5;
372         if (EyeDist > 90.0)
373            EyeDist = 90;
374         break;
375      case 27:
376         exit(0);
377   }
378   fflush(stdout);
379   glutPostRedisplay();
380}
381
382
383static void specialkey(int key, int x, int y)
384{
385   GLfloat step = 5;
386   (void) x;
387   (void) y;
388   switch (key) {
389      case GLUT_KEY_UP:
390         Xrot += step;
391         break;
392      case GLUT_KEY_DOWN:
393         Xrot -= step;
394         break;
395      case GLUT_KEY_LEFT:
396         Yrot -= step;
397         break;
398      case GLUT_KEY_RIGHT:
399         Yrot += step;
400         break;
401   }
402   glutPostRedisplay();
403}
404
405
406/* new window size or exposure */
407static void reshape(int width, int height)
408{
409   GLfloat ar = (float) width / (float) height;
410   glViewport(0, 0, (GLint)width, (GLint)height);
411   glMatrixMode(GL_PROJECTION);
412   glLoadIdentity();
413   glFrustum( -2.0*ar, 2.0*ar, -2.0, 2.0, 4.0, 100.0 );
414   glMatrixMode(GL_MODELVIEW);
415   glLoadIdentity();
416}
417
418
419static void init_checkers( void )
420{
421#define CUBE_TEX_SIZE 64
422   GLubyte image[CUBE_TEX_SIZE][CUBE_TEX_SIZE][4];
423   static const GLubyte colors[6][3] = {
424      { 255,   0,   0 },	/* face 0 - red */
425      {   0, 255, 255 },	/* face 1 - cyan */
426      {   0, 255,   0 },	/* face 2 - green */
427      { 255,   0, 255 },	/* face 3 - purple */
428      {   0,   0, 255 },	/* face 4 - blue */
429      { 255, 255,   0 }		/* face 5 - yellow */
430   };
431   static const GLenum targets[6] = {
432      GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB,
433      GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB,
434      GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB,
435      GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB,
436      GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB,
437      GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB
438   };
439
440   GLint i, j, f;
441
442   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
443
444   if (!supportFBO)
445      glTexParameteri(GL_TEXTURE_CUBE_MAP_ARB, GL_GENERATE_MIPMAP_SGIS, GL_TRUE);
446
447
448   /* make colored checkerboard cube faces */
449   for (f = 0; f < 6; f++) {
450      for (i = 0; i < CUBE_TEX_SIZE; i++) {
451         for (j = 0; j < CUBE_TEX_SIZE; j++) {
452            if ((i/4 + j/4) & 1) {
453               image[i][j][0] = colors[f][2];
454               image[i][j][1] = colors[f][1];
455               image[i][j][2] = colors[f][0];
456               image[i][j][3] = 255;
457            }
458            else {
459               image[i][j][0] = 255;
460               image[i][j][1] = 255;
461               image[i][j][2] = 255;
462               image[i][j][3] = 255;
463            }
464         }
465      }
466
467      glTexImage2D(targets[f], 0, GL_RGBA8, CUBE_TEX_SIZE, CUBE_TEX_SIZE, 0,
468                   GL_BGRA, GL_UNSIGNED_BYTE, image);
469   }
470
471   if (supportFBO)
472      glGenerateMipmapEXT(GL_TEXTURE_CUBE_MAP_ARB);
473}
474
475
476static void load(GLenum target, const char *filename,
477                 GLboolean flipTB, GLboolean flipLR)
478{
479   GLint w, h;
480   GLenum format;
481   GLubyte *img = LoadRGBImage( filename, &w, &h, &format );
482   if (!img) {
483      printf("Error: couldn't load texture image %s\n", filename);
484      exit(1);
485   }
486   assert(format == GL_RGB);
487
488   /* <sigh> the way the texture cube mapping works, we have to flip
489    * images to make things look right.
490    */
491   if (flipTB) {
492      const int stride = 3 * w;
493      GLubyte temp[3*1024];
494      int i;
495      for (i = 0; i < h / 2; i++) {
496         memcpy(temp, img + i * stride, stride);
497         memcpy(img + i * stride, img + (h - i - 1) * stride, stride);
498         memcpy(img + (h - i - 1) * stride, temp, stride);
499      }
500   }
501   if (flipLR) {
502      const int stride = 3 * w;
503      GLubyte temp[3];
504      GLubyte *row;
505      int i, j;
506      for (i = 0; i < h; i++) {
507         row = img + i * stride;
508         for (j = 0; j < w / 2; j++) {
509            int k = w - j - 1;
510            temp[0] = row[j*3+0];
511            temp[1] = row[j*3+1];
512            temp[2] = row[j*3+2];
513            row[j*3+0] = row[k*3+0];
514            row[j*3+1] = row[k*3+1];
515            row[j*3+2] = row[k*3+2];
516            row[k*3+0] = temp[0];
517            row[k*3+1] = temp[1];
518            row[k*3+2] = temp[2];
519         }
520      }
521   }
522
523   gluBuild2DMipmaps(target, GL_RGB, w, h, format, GL_UNSIGNED_BYTE, img);
524   free(img);
525}
526
527
528static void load_envmaps(void)
529{
530   load(GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB, "right.rgb", GL_TRUE, GL_FALSE);
531   load(GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB, "left.rgb", GL_TRUE, GL_FALSE);
532   load(GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB, "top.rgb", GL_FALSE, GL_TRUE);
533   load(GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB, "bottom.rgb", GL_FALSE, GL_TRUE);
534   load(GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB, "front.rgb", GL_TRUE, GL_FALSE);
535   load(GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB, "back.rgb", GL_TRUE, GL_FALSE);
536}
537
538
539static void init( GLboolean useImageFiles )
540{
541   /* check for extensions */
542   if (!GLEW_ARB_texture_cube_map) {
543      printf("Sorry, this demo requires GL_ARB_texture_cube_map\n");
544      exit(0);
545   }
546
547   /* Needed for glGenerateMipmapEXT / auto mipmapping
548    */
549   supportFBO = GLEW_EXT_framebuffer_object;
550
551   if (!supportFBO && !GLEW_SGIS_generate_mipmap) {
552      printf("Sorry, this demo requires GL_EXT_framebuffer_object or "
553	     "GL_SGIS_generate_mipmap\n");
554      exit(0);
555   }
556
557   /* GLEW doesn't know about this extension yet, so use the old GLUT function
558    * to check for availability.
559    */
560   supportSeamless = glutExtensionSupported("GL_ARB_seamless_cube_map");
561
562   printf("GL_RENDERER: %s\n", (char *) glGetString(GL_RENDERER));
563
564
565   glGenTextures(1, &TexObj);
566   glBindTexture(GL_TEXTURE_CUBE_MAP_ARB, TexObj);
567
568   if (useImageFiles) {
569      load_envmaps();
570   }
571   else {
572      init_checkers();
573   }
574
575   glEnable(GL_TEXTURE_CUBE_MAP_ARB);
576   glEnable(GL_DEPTH_TEST);
577
578   glClearColor(.3, .3, .3, 0);
579   glColor3f( 1.0, 1.0, 1.0 );
580
581   set_mode(0);
582}
583
584
585static void usage(void)
586{
587   printf("keys:\n");
588   printf("  SPACE - toggle animation\n");
589   printf("  CURSOR KEYS - rotation\n");
590   printf("  c - toggle texture clamp/wrap mode\n");
591   printf("  f - toggle texture filter mode\n");
592   printf("  m - toggle texgen reflection mode\n");
593   printf("  z/Z - change viewing distance\n");
594   fflush(stdout);
595}
596
597
598static void parse_args(int argc, char *argv[])
599{
600   int initFlag = 0;
601   int i;
602
603   for (i = 1; i < argc; i++) {
604      if (strcmp(argv[i], "-i") == 0)
605         initFlag = 1;
606      else if (strcmp(argv[i], "--noclear") == 0)
607         NoClear = GL_TRUE;
608      else {
609         fprintf(stderr, "Bad option: %s\n", argv[i]);
610         exit(1);
611      }
612   }
613   init (initFlag);
614}
615
616int main( int argc, char *argv[] )
617{
618   glutInitWindowSize(600, 500);
619   glutInit(&argc, argv);
620   glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
621   glutCreateWindow("Texture Cube Mapping");
622   glewInit();
623   glutReshapeFunc( reshape );
624   glutKeyboardFunc( key );
625   glutSpecialFunc( specialkey );
626   glutDisplayFunc( draw );
627   if (anim)
628      glutIdleFunc(idle);
629   parse_args(argc, argv);
630   usage();
631   glutMainLoop();
632   return 0;
633}
634