opengl 编程指南 源代码

/* * 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 Unpublished - rights * reserved under the copyright laws of the United States.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/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]; 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; } } } void init(void) { GLint numunits[1]; 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 (); } 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(); /*