src/redbook/combiner.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  Unpublished - rights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 /*  combiner.c
  44  *  This program renders a variety of quads showing different
  45  *  effects of texture combiner functions.
  46  *
  47  *  The first row renders an untextured polygon (so you can
  48  *  compare the fragment colors) and then the 2 textures.
  49  *  The second row shows several different combiner functions
  50  *  on a single texture:  replace, modulate, add, add-signed,
  51  *  and subtract.
  52  *  The third row shows the interpolate combiner function
  53  *  on a single texture with a constant color/alpha value,
  54  *  varying the amount of interpolation.
  55  *  The fourth row uses multitexturing with two textures
  56  *  and different combiner functions.
  57  *  The fifth row are some combiner experiments:  using the
  58  *  scaling factor and reversing the order of subtraction
  59  *  for a combination function.
  60  */
  61 #include <glad/glad.h>
  62 #include "glut_wrap.h"
  63 #include <stdlib.h>
  64 #include <stdio.h>
  65
  66 #define imageWidth 8
  67 #define imageHeight 8
  68 /*     arrays for two textures      */
  69 static GLubyte image0[imageHeight][imageWidth][4];
  70 static GLubyte image1[imageHeight][imageWidth][4];
  71
  72 static GLuint texName[4];
  73
  74 static void makeImages(void)
  75 {
  76    int i, j, c;
  77    for (i = 0; i < imageHeight; i++) {
  78       for (j = 0; j < imageWidth; j++) {
  79          c = ((i&2)==0)*255;   /*  horiz b & w stripes  */
  80          image0[i][j][0] = (GLubyte) c;
  81          image0[i][j][1] = (GLubyte) c;
  82          image0[i][j][2] = (GLubyte) c;
  83          image0[i][j][3] = (GLubyte) 255;
  84          c = ((j&4)!=0)*128;   /*  wider vertical 50% cyan and black stripes  */
  85          image1[i][j][0] = (GLubyte) 0;
  86          image1[i][j][1] = (GLubyte) c;
  87          image1[i][j][2] = (GLubyte) c;
  88          image1[i][j][3] = (GLubyte) 255;
  89       }
  90    }
  91 }
  92
  93 static void init(void)
  94 {
  95    glClearColor (0.0, 0.0, 0.0, 0.0);
  96    glShadeModel(GL_SMOOTH);
  97
  98    makeImages();
  99    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 100
 101    glGenTextures(4, texName);
 102
 103    glBindTexture(GL_TEXTURE_2D, texName[0]);
 104    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 105    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 106    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 107    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 108    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageWidth, imageHeight,
 109                 0, GL_RGBA, GL_UNSIGNED_BYTE, image0);
 110
 111    glBindTexture(GL_TEXTURE_2D, texName[1]);
 112    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 113    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 114    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 115    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 116    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageWidth, imageHeight,
 117                 0, GL_RGBA, GL_UNSIGNED_BYTE, image1);
 118
 119 /*  smooth-shaded polygon with multiple texture coordinates  */
 120    glNewList (1, GL_COMPILE);
 121    glBegin(GL_QUADS);
 122    glMultiTexCoord2fARB(GL_TEXTURE0_ARB, 0.0, 0.0);
 123    glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0.0, 0.0);
 124    glColor3f (0.5, 1.0, 0.25);
 125    glVertex3f(0.0, 0.0, 0.0);
 126    glMultiTexCoord2fARB(GL_TEXTURE0_ARB, 0.0, 2.0);
 127    glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0.0, 2.0);
 128    glColor3f (1.0, 1.0, 1.0);
 129    glVertex3f(0.0, 1.0, 0.0);
 130    glMultiTexCoord2fARB(GL_TEXTURE0_ARB, 2.0, 2.0);
 131    glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 2.0, 2.0);
 132    glColor3f (1.0, 1.0, 1.0);
 133    glVertex3f(1.0, 1.0, 0.0);
 134    glMultiTexCoord2fARB(GL_TEXTURE0_ARB, 2.0, 0.0);
 135    glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 2.0, 0.0);
 136    glColor3f (1.0, 0.5, 0.25);
 137    glVertex3f(1.0, 0.0, 0.0);
 138    glEnd();
 139    glEndList ();
 140 }
 141
 142 static void display(void)
 143 {
 144    static GLfloat constColor[4] = {0.0, 0.0, 0.0, 0.0};  /*  for use as constant texture color  */
 145
 146    glClear(GL_COLOR_BUFFER_BIT);
 147
 148    glDisable(GL_TEXTURE_2D);  /*  untextured polygon--see the "fragment" colors  */
 149    glPushMatrix();
 150    glTranslatef(0.0, 5.0, 0.0);
 151    glCallList(1);
 152    glPopMatrix();
 153
 154    glEnable(GL_TEXTURE_2D);
 155 /*  draw ordinary textured polys; 1 texture unit; combine mode disabled  */
 156    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 157    glPushMatrix();
 158    glBindTexture(GL_TEXTURE_2D, texName[0]);
 159    glTranslatef(1.0, 5.0, 0.0);
 160    glCallList(1);
 161    glPopMatrix();
 162
 163    glPushMatrix();
 164    glBindTexture(GL_TEXTURE_2D, texName[1]);
 165    glTranslatef(2.0, 5.0, 0.0);
 166    glCallList(1);
 167    glPopMatrix();
 168
 169 /*  different combine modes enabled; 1 texture unit
 170  *  defaults are:
 171  *  glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE);
 172  *  glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);
 173  *  glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB);
 174  *  glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR);
 175  */
 176    glBindTexture(GL_TEXTURE_2D, texName[0]);
 177    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
 178    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE);
 179    glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE);
 180    glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);
 181    glPushMatrix();
 182    glTranslatef(1.0, 4.0, 0.0);
 183    glCallList(1);
 184    glPopMatrix();
 185
 186    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_MODULATE);
 187    glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB);
 188    glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR);
 189    glPushMatrix();
 190    glTranslatef(2.0, 4.0, 0.0);
 191    glCallList(1);
 192    glPopMatrix();
 193
 194    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD);
 195    glPushMatrix();
 196    glTranslatef(3.0, 4.0, 0.0);
 197    glCallList(1);
 198    glPopMatrix();
 199
 200    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD_SIGNED_ARB);
 201    glPushMatrix();
 202    glTranslatef(4.0, 4.0, 0.0);
 203    glCallList(1);
 204    glPopMatrix();
 205
 206    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_SUBTRACT_ARB);
 207    glPushMatrix();
 208    glTranslatef(5.0, 4.0, 0.0);
 209    glCallList(1);
 210    glPopMatrix();
 211
 212 /*  interpolate combine with constant color; 1 texture unit
 213  *  use different alpha values for constant color
 214  *  defaults are:
 215  *  glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE);
 216  *  glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);
 217  *  glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB);
 218  *  glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR);
 219  *  glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE2_RGB_ARB, GL_CONSTANT_ARB);
 220  *  glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND2_RGB_ARB, GL_SRC_ALPHA);
 221  */
 222    constColor[3] = 0.2;
 223    glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, constColor);
 224    glBindTexture(GL_TEXTURE_2D, texName[0]);
 225    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
 226    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_INTERPOLATE_ARB);
 227    glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE);
 228    glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);
 229    glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB);
 230    glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR);
 231    glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE2_RGB_ARB, GL_CONSTANT_ARB);
 232    glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND2_RGB_ARB, GL_SRC_ALPHA);
 233    glPushMatrix();
 234    glTranslatef(1.0, 3.0, 0.0);
 235    glCallList(1);
 236    glPopMatrix();
 237
 238    constColor[3] = 0.4;
 239    glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, constColor);
 240    glPushMatrix();
 241    glTranslatef(2.0, 3.0, 0.0);
 242    glCallList(1);
 243    glPopMatrix();
 244
 245    constColor[3] = 0.6;
 246    glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, constColor);
 247    glPushMatrix();
 248    glTranslatef(3.0, 3.0, 0.0);
 249    glCallList(1);
 250    glPopMatrix();
 251
 252    constColor[3] = 0.8;
 253    glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, constColor);
 254    glPushMatrix();
 255    glTranslatef(4.0, 3.0, 0.0);
 256    glCallList(1);
 257    glPopMatrix();
 258
 259 /*  combine textures 0 & 1
 260  *  defaults are:
 261  *  glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE);
 262  *  glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);
 263  *  glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB);
 264  *  glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR);
 265  */
 266
 267    glActiveTextureARB (GL_TEXTURE0_ARB);
 268    glEnable (GL_TEXTURE_2D);
 269    glBindTexture(GL_TEXTURE_2D, texName[0]);
 270    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 271
 272    glActiveTextureARB (GL_TEXTURE1_ARB);
 273    glEnable (GL_TEXTURE_2D);
 274    glBindTexture(GL_TEXTURE_2D, texName[1]);
 275    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
 276    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE);
 277    glPushMatrix();
 278    glTranslatef(1.0, 2.0, 0.0);
 279    glCallList(1);
 280    glPopMatrix();
 281
 282    /*  try different combiner modes of texture unit 1  */
 283    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_MODULATE);
 284    glPushMatrix();
 285    glTranslatef(2.0, 2.0, 0.0);
 286    glCallList(1);
 287    glPopMatrix();
 288
 289    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD);
 290    glPushMatrix();
 291    glTranslatef(3.0, 2.0, 0.0);
 292    glCallList(1);
 293    glPopMatrix();
 294
 295    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD_SIGNED_ARB);
 296    glPushMatrix();
 297    glTranslatef(4.0, 2.0, 0.0);
 298    glCallList(1);
 299    glPopMatrix();
 300
 301    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_SUBTRACT_ARB);
 302    glPushMatrix();
 303    glTranslatef(5.0, 2.0, 0.0);
 304    glCallList(1);
 305    glPopMatrix();
 306
 307 /*  some experiments */
 308
 309 /*  see the effect of RGB_SCALE   */
 310    glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 2.0);
 311    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE);
 312    glPushMatrix();
 313    glTranslatef(1.0, 1.0, 0.0);
 314    glCallList(1);
 315    glPopMatrix();
 316
 317    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_MODULATE);
 318    glPushMatrix();
 319    glTranslatef(2.0, 1.0, 0.0);
 320    glCallList(1);
 321    glPopMatrix();
 322    glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 1.0);
 323
 324 /*  using SOURCE0 and SOURCE1, reverse the order of subtraction Arg1-Arg0  */
 325
 326    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB);
 327    glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_SUBTRACT_ARB);
 328    glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_PREVIOUS_ARB);
 329    glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);
 330    glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_TEXTURE);
 331    glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR);
 332    glPushMatrix();
 333    glTranslatef(5.0, 1.0, 0.0);
 334    glCallList(1);
 335    glPopMatrix();
 336
 337    glActiveTextureARB (GL_TEXTURE1_ARB);  /*  deactivate multitexturing  */
 338    glDisable (GL_TEXTURE_2D);
 339    glActiveTextureARB (GL_TEXTURE0_ARB);  /*  activate single texture unit  */
 340
 341    glFlush();
 342 }
 343
 344 static void reshape(int w, int h)
 345 {
 346    glViewport(0, 0, (GLsizei) w, (GLsizei) h);
 347    glMatrixMode(GL_PROJECTION);
 348    glLoadIdentity();
 349    gluOrtho2D(0.0, 7.0, 0.0, 7.0);
 350    glMatrixMode(GL_MODELVIEW);
 351    glLoadIdentity();
 352 }
 353
 354 static void keyboard (unsigned char key, int x, int y)
 355 {
 356    switch (key) {
 357       case 27:
 358          exit(0);
 359          break;
 360       default:
 361          break;
 362    }
 363 }
 364
 365 int main(int argc, char** argv)
 366 {
 367    glutInit(&argc, argv);
 368    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
 369    glutInitWindowSize(400, 400);
 370    glutInitWindowPosition(100, 100);
 371    glutCreateWindow(argv[0]);
 372    gladLoadGL();
 373    init();
 374    glutDisplayFunc(display);
 375    glutReshapeFunc(reshape);
 376    glutKeyboardFunc(keyboard);
 377    glutMainLoop();
 378    return 0;
 379 }