progs/redbook/shadowmap.c

   1 /*
   2  * Copyright (c) 1993-2003, Silicon Graphics, Inc.
   3  * All Rights Reserved
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose and without fee is hereby granted, provided that the above
   7  * copyright notice appear in all copies and that both the copyright
   8  * notice and this permission notice appear in supporting documentation,
   9  * and that the name of Silicon Graphics, Inc. not be used in
  10  * advertising or publicity pertaining to distribution of the software
  11  * without specific, written prior permission.
  12  *
  13  * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" AND
  14  * WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
  16  * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
  17  * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
  18  * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  19  * OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, LOSS OF
  20  * PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF THIRD
  21  * PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN ADVISED OF
  22  * THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON ANY THEORY OF
  23  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE POSSESSION, USE
  24  * OR PERFORMANCE OF THIS SOFTWARE.
  25  *
  26  * US Government Users Restricted Rights
  27  * Use, duplication, or disclosure by the Government is subject to
  28  * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
  29  * (c)(1)(ii) of the Rights in Technical Data and Computer Software
  30  * clause at DFARS 252.227-7013 and/or in similar or successor clauses
  31  * in the FAR or the DOD or NASA FAR Supplement.  Unpublished - rights
  32  * reserved under the copyright laws of the United States.
  33  *
  34  * Contractor/manufacturer is:
  35  *      Silicon Graphics, Inc.
  36  *      1500 Crittenden Lane
  37  *      Mountain View, CA  94043
  38  *      United State of America
  39  *
  40  * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
  41  */
  42
  43 #include <math.h>
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <GL/glew.h>
  47 #include <GL/glut.h>
  48 /*#include "helpers.h"*/
  49
  50 #define SHADOW_MAP_WIDTH      256
  51 #define SHADOW_MAP_HEIGHT     256
  52
  53 #define PI       3.14159265359
  54
  55 GLdouble    fovy      = 60.0;
  56 GLdouble    nearPlane = 10.0;
  57 GLdouble    farPlane  = 100.0;
  58
  59 GLfloat     angle = 0.0;
  60 GLfloat     torusAngle = 0.0;
  61
  62 GLfloat     lightPos[] = { 25.0, 25.0, 25.0, 1.0 };
  63 GLfloat     lookat[] = { 0.0, 0.0, 0.0 };
  64 GLfloat     up[] = { 0.0, 0.0, 1.0 };
  65
  66 GLboolean showShadow = GL_FALSE;
  67
  68 static void
  69 init( void )
  70 {
  71     GLfloat  white[] = { 1.0, 1.0, 1.0, 1.0 };
  72
  73     glTexImage2D( GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT,
  74                   SHADOW_MAP_WIDTH, SHADOW_MAP_HEIGHT, 0,
  75                   GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, NULL );
  76
  77     glLightfv( GL_LIGHT0, GL_POSITION, lightPos );
  78     glLightfv( GL_LIGHT0, GL_SPECULAR, white );
  79     glLightfv( GL_LIGHT0, GL_DIFFUSE, white );
  80
  81     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
  82     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
  83     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
  84     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
  85     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL );
  86     glTexParameteri( GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE, GL_LUMINANCE );
  87     glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE,
  88                      GL_COMPARE_R_TO_TEXTURE );
  89
  90     glTexGeni( GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
  91     glTexGeni( GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
  92     glTexGeni( GL_R, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
  93     glTexGeni( GL_Q, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR );
  94
  95     glColorMaterial( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE );
  96
  97     glCullFace( GL_BACK );
  98
  99     glEnable( GL_DEPTH_TEST );
 100     glEnable( GL_LIGHT0 );
 101     glEnable( GL_LIGHTING );
 102     glEnable( GL_TEXTURE_2D );
 103     glEnable( GL_TEXTURE_GEN_S );
 104     glEnable( GL_TEXTURE_GEN_T );
 105     glEnable( GL_TEXTURE_GEN_R );
 106     glEnable( GL_TEXTURE_GEN_Q );
 107     glEnable( GL_COLOR_MATERIAL );
 108     glEnable( GL_CULL_FACE );
 109 }
 110
 111 static void
 112 reshape( int width, int height )
 113 {
 114     glViewport( 0, 0, width, height );
 115
 116     glMatrixMode( GL_PROJECTION );
 117     glLoadIdentity();
 118     gluPerspective( fovy, (GLdouble) width/height, nearPlane, farPlane );
 119     glMatrixMode( GL_MODELVIEW );
 120 }
 121
 122 static void
 123 idle( void )
 124 {
 125     angle += PI / 10000;
 126     torusAngle += .1;
 127     glutPostRedisplay();
 128 }
 129
 130 static void
 131 keyboard( unsigned char key, int x, int y )
 132 {
 133     switch( key ) {
 134     case 27:  /* Escape */
 135       exit( 0 );
 136       break;
 137
 138     case 't': {
 139         static GLboolean textureOn = GL_TRUE;
 140         textureOn = !textureOn;
 141         if ( textureOn )
 142         glEnable( GL_TEXTURE_2D );
 143         else
 144         glDisable( GL_TEXTURE_2D );
 145       }
 146       break;
 147
 148     case 'm': {
 149         static GLboolean compareMode = GL_TRUE;
 150         compareMode = !compareMode;
 151         printf( "Compare mode %s\n", compareMode ? "On" : "Off" );
 152         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE,
 153                          compareMode ? GL_COMPARE_R_TO_TEXTURE : GL_NONE );
 154       }
 155       break;
 156
 157     case 'f': {
 158         static GLboolean funcMode = GL_TRUE;
 159         funcMode = !funcMode;
 160         printf( "Operator %s\n", funcMode ? "GL_LEQUAL" : "GL_GEQUAL" );
 161         glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC,
 162                          funcMode ? GL_LEQUAL : GL_GEQUAL );
 163       }
 164       break;
 165
 166     case 's':
 167       showShadow = !showShadow;
 168       break;
 169
 170     case 'p': {
 171         static GLboolean  animate = GL_TRUE;
 172         animate = !animate;
 173         glutIdleFunc( animate ? idle : NULL );
 174       }
 175       break;
 176     }
 177
 178     glutPostRedisplay();
 179 }
 180
 181 static void
 182 transposeMatrix( GLfloat m[16] )
 183 {
 184     GLfloat  tmp;
 185 #define Swap( a, b )    tmp = a; a = b; b = tmp
 186     Swap( m[1],  m[4]  );
 187     Swap( m[2],  m[8]  );
 188     Swap( m[3],  m[12] );
 189     Swap( m[6],  m[9]  );
 190     Swap( m[7],  m[13] );
 191     Swap( m[11], m[14] );
 192 #undef Swap
 193 }
 194
 195 static void
 196 drawObjects( GLboolean shadowRender )
 197 {
 198     GLboolean textureOn = glIsEnabled( GL_TEXTURE_2D );
 199
 200     if ( shadowRender )
 201         glDisable( GL_TEXTURE_2D );
 202
 203     if ( !shadowRender ) {
 204         glNormal3f( 0, 0, 1 );
 205         glColor3f( 1, 1, 1 );
 206         glRectf( -20.0, -20.0, 20.0, 20.0 );
 207     }
 208
 209     glPushMatrix();
 210     glTranslatef( 11, 11, 11 );
 211     glRotatef( 54.73, -5, 5, 0 );
 212     glRotatef( torusAngle, 1, 0, 0 );
 213     glColor3f( 1, 0, 0 );
 214     glutSolidTorus( 1, 4, 8, 36 );
 215     glPopMatrix();
 216
 217     glPushMatrix();
 218     glTranslatef( 2, 2, 2 );
 219     glColor3f( 0, 0, 1 );
 220     glutSolidCube( 4 );
 221     glPopMatrix();
 222
 223     glPushMatrix();
 224     glTranslatef( lightPos[0], lightPos[1], lightPos[2] );
 225     glColor3f( 1, 1, 1 );
 226     glutWireSphere( 0.5, 6, 6 );
 227     glPopMatrix();
 228
 229     if ( shadowRender && textureOn )
 230         glEnable( GL_TEXTURE_2D );
 231 }
 232
 233 static void
 234 generateShadowMap( void )
 235 {
 236     GLint    viewport[4];
 237     GLfloat  lightPos[4];
 238
 239     glGetLightfv( GL_LIGHT0, GL_POSITION, lightPos );
 240     glGetIntegerv( GL_VIEWPORT, viewport );
 241
 242     glViewport( 0, 0, SHADOW_MAP_WIDTH, SHADOW_MAP_HEIGHT );
 243
 244     glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
 245
 246     glMatrixMode( GL_PROJECTION );
 247     glPushMatrix();
 248     glLoadIdentity();
 249     gluPerspective( 80.0, 1.0, 10.0, 1000.0 );
 250     glMatrixMode( GL_MODELVIEW );
 251
 252     glPushMatrix();
 253     glLoadIdentity();
 254     gluLookAt( lightPos[0], lightPos[1], lightPos[2],
 255                lookat[0], lookat[1], lookat[2],
 256                up[0], up[1], up[2] );
 257
 258     drawObjects( GL_TRUE );
 259
 260     glPopMatrix();
 261     glMatrixMode( GL_PROJECTION );
 262     glPopMatrix();
 263     glMatrixMode( GL_MODELVIEW );
 264
 265     glCopyTexImage2D( GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, 0, 0,
 266                       SHADOW_MAP_WIDTH, SHADOW_MAP_HEIGHT, 0 );
 267
 268     glViewport( viewport[0], viewport[1], viewport[2], viewport[3] );
 269
 270     if ( showShadow ) {
 271       GLfloat depthImage[SHADOW_MAP_WIDTH][SHADOW_MAP_HEIGHT];
 272       glReadPixels( 0, 0, SHADOW_MAP_WIDTH, SHADOW_MAP_HEIGHT,
 273                     GL_DEPTH_COMPONENT, GL_FLOAT, depthImage );
 274       glWindowPos2f( viewport[2]/2, 0 );
 275       glDrawPixels( SHADOW_MAP_WIDTH, SHADOW_MAP_HEIGHT, GL_LUMINANCE,
 276                     GL_FLOAT, depthImage );
 277       glutSwapBuffers();
 278     }
 279 }
 280
 281 static void
 282 generateTextureMatrix( void )
 283 {
 284     GLfloat  tmpMatrix[16];
 285
 286     /*
 287      *  Set up projective texture matrix.  We use the GL_MODELVIEW matrix
 288      *    stack and OpenGL matrix commands to make the matrix.
 289      */
 290     glPushMatrix();
 291     glLoadIdentity();
 292     glTranslatef( 0.5, 0.5, 0.0 );
 293     glScalef( 0.5, 0.5, 1.0 );
 294     gluPerspective( 60.0, 1.0, 1.0, 1000.0 );
 295     gluLookAt( lightPos[0], lightPos[1], lightPos[2],
 296                lookat[0], lookat[1], lookat[2],
 297                up[0], up[1], up[2] );
 298     glGetFloatv( GL_MODELVIEW_MATRIX, tmpMatrix );
 299     glPopMatrix();
 300
 301     transposeMatrix( tmpMatrix );
 302
 303     glTexGenfv( GL_S, GL_OBJECT_PLANE, &tmpMatrix[0] );
 304     glTexGenfv( GL_T, GL_OBJECT_PLANE, &tmpMatrix[4] );
 305     glTexGenfv( GL_R, GL_OBJECT_PLANE, &tmpMatrix[8] );
 306     glTexGenfv( GL_Q, GL_OBJECT_PLANE, &tmpMatrix[12] );
 307 }
 308
 309 static void
 310 display( void )
 311 {
 312     GLfloat  radius = 30;
 313
 314     generateShadowMap();
 315     generateTextureMatrix();
 316
 317     if ( showShadow )
 318       return;
 319
 320     glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
 321
 322     glPushMatrix();
 323     gluLookAt( radius*cos(angle), radius*sin(angle), 30,
 324                lookat[0], lookat[1], lookat[2],
 325                up[0], up[1], up[2] );
 326     drawObjects( GL_FALSE );
 327     glPopMatrix();
 328
 329     glutSwapBuffers();
 330 }
 331
 332 int
 333 main( int argc, char** argv )
 334 {
 335     glutInit( &argc, argv );
 336     glutInitDisplayMode( GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE );
 337     glutInitWindowSize( 512, 512 );
 338     glutInitWindowPosition( 100, 100 );
 339     glutCreateWindow( argv[0] );
 340     glewInit();
 341
 342     init();
 343
 344     glutDisplayFunc( display );
 345     glutReshapeFunc( reshape );
 346     glutKeyboardFunc( keyboard );
 347     glutIdleFunc( idle );
 348
 349     glutMainLoop();
 350
 351     return 0;
 352 }