| /* |
| * Copyright (c) 1993-2003, Silicon Graphics, Inc. |
| * All Rights Reserved |
| * |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose and without fee is hereby granted, provided that the above |
| * copyright notice appear in all copies and that both the copyright |
| * notice and this permission notice appear in supporting documentation, |
| * and that the name of Silicon Graphics, Inc. not be used in |
| * advertising or publicity pertaining to distribution of the software |
| * without specific, written prior permission. |
| * |
| * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" AND |
| * WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE, |
| * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR |
| * FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON |
| * GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT, |
| * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, |
| * OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, LOSS OF |
| * PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF THIRD |
| * PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC. HAS BEEN ADVISED OF |
| * THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON ANY THEORY OF |
| * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE POSSESSION, USE |
| * OR PERFORMANCE OF THIS SOFTWARE. |
| * |
| * US Government Users Restricted Rights |
| * Use, duplication, or disclosure by the Government is subject to |
| * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph |
| * (c)(1)(ii) of the Rights in Technical Data and Computer Software |
| * clause at DFARS 252.227-7013 and/or in similar or successor clauses |
| * in the FAR or the DOD or NASA FAR Supplement. Unpublished - rights |
| * reserved under the copyright laws of the United States. |
| * |
| * Contractor/manufacturer is: |
| * Silicon Graphics, Inc. |
| * 1500 Crittenden Lane |
| * Mountain View, CA 94043 |
| * United State of America |
| * |
| * OpenGL(R) is a registered trademark of Silicon Graphics, Inc. |
| */ |
| |
| /* combiner.c |
| * This program renders a variety of quads showing different |
| * effects of texture combiner functions. |
| * |
| * The first row renders an untextured polygon (so you can |
| * compare the fragment colors) and then the 2 textures. |
| * The second row shows several different combiner functions |
| * on a single texture: replace, modulate, add, add-signed, |
| * and subtract. |
| * The third row shows the interpolate combiner function |
| * on a single texture with a constant color/alpha value, |
| * varying the amount of interpolation. |
| * The fourth row uses multitexturing with two textures |
| * and different combiner functions. |
| * The fifth row are some combiner experiments: using the |
| * scaling factor and reversing the order of subtraction |
| * for a combination function. |
| */ |
| #include <GL/glew.h> |
| #include <GL/glut.h> |
| #include <stdlib.h> |
| #include <stdio.h> |
| |
| #define imageWidth 8 |
| #define imageHeight 8 |
| /* arrays for two textures */ |
| static GLubyte image0[imageHeight][imageWidth][4]; |
| static GLubyte image1[imageHeight][imageWidth][4]; |
| |
| static GLuint texName[4]; |
| |
| static void makeImages(void) |
| { |
| int i, j, c; |
| for (i = 0; i < imageHeight; i++) { |
| for (j = 0; j < imageWidth; j++) { |
| c = ((i&2)==0)*255; /* horiz b & w stripes */ |
| image0[i][j][0] = (GLubyte) c; |
| image0[i][j][1] = (GLubyte) c; |
| image0[i][j][2] = (GLubyte) c; |
| image0[i][j][3] = (GLubyte) 255; |
| c = ((j&4)!=0)*128; /* wider vertical 50% cyan and black stripes */ |
| image1[i][j][0] = (GLubyte) 0; |
| image1[i][j][1] = (GLubyte) c; |
| image1[i][j][2] = (GLubyte) c; |
| image1[i][j][3] = (GLubyte) 255; |
| } |
| } |
| } |
| |
| static void init(void) |
| { |
| glClearColor (0.0, 0.0, 0.0, 0.0); |
| glShadeModel(GL_SMOOTH); |
| |
| makeImages(); |
| glPixelStorei(GL_UNPACK_ALIGNMENT, 1); |
| |
| glGenTextures(4, texName); |
| |
| glBindTexture(GL_TEXTURE_2D, texName[0]); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); |
| glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageWidth, imageHeight, |
| 0, GL_RGBA, GL_UNSIGNED_BYTE, image0); |
| |
| glBindTexture(GL_TEXTURE_2D, texName[1]); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); |
| glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageWidth, imageHeight, |
| 0, GL_RGBA, GL_UNSIGNED_BYTE, image1); |
| |
| /* smooth-shaded polygon with multiple texture coordinates */ |
| glNewList (1, GL_COMPILE); |
| glBegin(GL_QUADS); |
| glMultiTexCoord2fARB(GL_TEXTURE0_ARB, 0.0, 0.0); |
| glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0.0, 0.0); |
| glColor3f (0.5, 1.0, 0.25); |
| glVertex3f(0.0, 0.0, 0.0); |
| glMultiTexCoord2fARB(GL_TEXTURE0_ARB, 0.0, 2.0); |
| glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0.0, 2.0); |
| glColor3f (1.0, 1.0, 1.0); |
| glVertex3f(0.0, 1.0, 0.0); |
| glMultiTexCoord2fARB(GL_TEXTURE0_ARB, 2.0, 2.0); |
| glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 2.0, 2.0); |
| glColor3f (1.0, 1.0, 1.0); |
| glVertex3f(1.0, 1.0, 0.0); |
| glMultiTexCoord2fARB(GL_TEXTURE0_ARB, 2.0, 0.0); |
| glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 2.0, 0.0); |
| glColor3f (1.0, 0.5, 0.25); |
| glVertex3f(1.0, 0.0, 0.0); |
| glEnd(); |
| glEndList (); |
| } |
| |
| static void display(void) |
| { |
| static GLfloat constColor[4] = {0.0, 0.0, 0.0, 0.0}; /* for use as constant texture color */ |
| |
| glClear(GL_COLOR_BUFFER_BIT); |
| |
| glDisable(GL_TEXTURE_2D); /* untextured polygon--see the "fragment" colors */ |
| glPushMatrix(); |
| glTranslatef(0.0, 5.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| glEnable(GL_TEXTURE_2D); |
| /* draw ordinary textured polys; 1 texture unit; combine mode disabled */ |
| glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); |
| glPushMatrix(); |
| glBindTexture(GL_TEXTURE_2D, texName[0]); |
| glTranslatef(1.0, 5.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| glPushMatrix(); |
| glBindTexture(GL_TEXTURE_2D, texName[1]); |
| glTranslatef(2.0, 5.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| /* different combine modes enabled; 1 texture unit |
| * defaults are: |
| * glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE); |
| * glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR); |
| * glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB); |
| * glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR); |
| */ |
| glBindTexture(GL_TEXTURE_2D, texName[0]); |
| glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB); |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE); |
| glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE); |
| glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR); |
| glPushMatrix(); |
| glTranslatef(1.0, 4.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_MODULATE); |
| glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB); |
| glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR); |
| glPushMatrix(); |
| glTranslatef(2.0, 4.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD); |
| glPushMatrix(); |
| glTranslatef(3.0, 4.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD_SIGNED_ARB); |
| glPushMatrix(); |
| glTranslatef(4.0, 4.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_SUBTRACT_ARB); |
| glPushMatrix(); |
| glTranslatef(5.0, 4.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| /* interpolate combine with constant color; 1 texture unit |
| * use different alpha values for constant color |
| * defaults are: |
| * glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE); |
| * glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR); |
| * glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB); |
| * glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR); |
| * glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE2_RGB_ARB, GL_CONSTANT_ARB); |
| * glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND2_RGB_ARB, GL_SRC_ALPHA); |
| */ |
| constColor[3] = 0.2; |
| glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, constColor); |
| glBindTexture(GL_TEXTURE_2D, texName[0]); |
| glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB); |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_INTERPOLATE_ARB); |
| glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE); |
| glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR); |
| glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB); |
| glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR); |
| glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE2_RGB_ARB, GL_CONSTANT_ARB); |
| glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND2_RGB_ARB, GL_SRC_ALPHA); |
| glPushMatrix(); |
| glTranslatef(1.0, 3.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| constColor[3] = 0.4; |
| glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, constColor); |
| glPushMatrix(); |
| glTranslatef(2.0, 3.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| constColor[3] = 0.6; |
| glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, constColor); |
| glPushMatrix(); |
| glTranslatef(3.0, 3.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| constColor[3] = 0.8; |
| glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, constColor); |
| glPushMatrix(); |
| glTranslatef(4.0, 3.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| /* combine textures 0 & 1 |
| * defaults are: |
| * glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE); |
| * glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR); |
| * glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB); |
| * glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR); |
| */ |
| |
| glActiveTextureARB (GL_TEXTURE0_ARB); |
| glEnable (GL_TEXTURE_2D); |
| glBindTexture(GL_TEXTURE_2D, texName[0]); |
| glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); |
| |
| glActiveTextureARB (GL_TEXTURE1_ARB); |
| glEnable (GL_TEXTURE_2D); |
| glBindTexture(GL_TEXTURE_2D, texName[1]); |
| glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB); |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE); |
| glPushMatrix(); |
| glTranslatef(1.0, 2.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| /* try different combiner modes of texture unit 1 */ |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_MODULATE); |
| glPushMatrix(); |
| glTranslatef(2.0, 2.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD); |
| glPushMatrix(); |
| glTranslatef(3.0, 2.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD_SIGNED_ARB); |
| glPushMatrix(); |
| glTranslatef(4.0, 2.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_SUBTRACT_ARB); |
| glPushMatrix(); |
| glTranslatef(5.0, 2.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| /* some experiments */ |
| |
| /* see the effect of RGB_SCALE */ |
| glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 2.0); |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE); |
| glPushMatrix(); |
| glTranslatef(1.0, 1.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_MODULATE); |
| glPushMatrix(); |
| glTranslatef(2.0, 1.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 1.0); |
| |
| /* using SOURCE0 and SOURCE1, reverse the order of subtraction Arg1-Arg0 */ |
| |
| glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB); |
| glTexEnvf(GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_SUBTRACT_ARB); |
| glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_PREVIOUS_ARB); |
| glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR); |
| glTexEnvf(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_TEXTURE); |
| glTexEnvf(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR); |
| glPushMatrix(); |
| glTranslatef(5.0, 1.0, 0.0); |
| glCallList(1); |
| glPopMatrix(); |
| |
| glActiveTextureARB (GL_TEXTURE1_ARB); /* deactivate multitexturing */ |
| glDisable (GL_TEXTURE_2D); |
| glActiveTextureARB (GL_TEXTURE0_ARB); /* activate single texture unit */ |
| |
| glFlush(); |
| } |
| |
| static void reshape(int w, int h) |
| { |
| glViewport(0, 0, (GLsizei) w, (GLsizei) h); |
| glMatrixMode(GL_PROJECTION); |
| glLoadIdentity(); |
| gluOrtho2D(0.0, 7.0, 0.0, 7.0); |
| glMatrixMode(GL_MODELVIEW); |
| glLoadIdentity(); |
| } |
| |
| static void keyboard (unsigned char key, int x, int y) |
| { |
| switch (key) { |
| case 27: |
| exit(0); |
| break; |
| default: |
| break; |
| } |
| } |
| |
| int main(int argc, char** argv) |
| { |
| glutInit(&argc, argv); |
| glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); |
| glutInitWindowSize(400, 400); |
| glutInitWindowPosition(100, 100); |
| glutCreateWindow(argv[0]); |
| glewInit(); |
| init(); |
| glutDisplayFunc(display); |
| glutReshapeFunc(reshape); |
| glutKeyboardFunc(keyboard); |
| glutMainLoop(); |
| return 0; |
| } |