| /* |
| * 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 Unpublished - rights |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. |
| */ |
| |
| /* |
| * fogcoord.c |
| * |
| * This program demonstrates the use of explicit fog |
| * coordinates. You can press the keyboard and change |
| * the fog coordinate value at any vertex. You can |
| * also switch between using explicit fog coordinates |
| * and the default fog generation mode. |
| * |
| * Pressing the 'f' and 'b' keys move the viewer forward |
| * and backwards. |
| * Pressing 'c' initiates the default fog generation. |
| * Pressing capital 'C' restores explicit fog coordinates. |
| * Pressing '1', '2', '3', '8', '9', and '0' add or |
| * subtract from the fog coordinate values at one of the |
| * three vertices of the triangle. |
| */ |
| |
| #include <GL/glew.h> |
| #include <GL/glut.h> |
| #include <math.h> |
| #include <stdlib.h> |
| #include <stdio.h> |
| |
| static GLfloat f1, f2, f3; |
| |
| /* Initialize fog |
| */ |
| static void init(void) |
| { |
| GLfloat fogColor[4] = {0.0, 0.25, 0.25, 1.0}; |
| f1 = 1.0f; |
| f2 = 5.0f; |
| f3 = 10.0f; |
| |
| glEnable(GL_FOG); |
| glFogi (GL_FOG_MODE, GL_EXP); |
| glFogfv (GL_FOG_COLOR, fogColor); |
| glFogf (GL_FOG_DENSITY, 0.25); |
| glHint (GL_FOG_HINT, GL_DONT_CARE); |
| glFogi(GL_FOG_COORDINATE_SOURCE_EXT, GL_FOG_COORDINATE_EXT); |
| glClearColor(0.0, 0.25, 0.25, 1.0); /* fog color */ |
| } |
| |
| /* display() draws a triangle at an angle. |
| */ |
| static void display(void) |
| { |
| glClear(GL_COLOR_BUFFER_BIT); |
| |
| glColor3f (1.0f, 0.75f, 0.0f); |
| glBegin (GL_TRIANGLES); |
| glFogCoordfEXT (f1); |
| glVertex3f (2.0f, -2.0f, 0.0f); |
| glFogCoordfEXT (f2); |
| glVertex3f (-2.0f, 0.0f, -5.0f); |
| glFogCoordfEXT (f3); |
| glVertex3f (0.0f, 2.0f, -10.0f); |
| glEnd(); |
| |
| glutSwapBuffers(); |
| } |
| |
| static void reshape(int w, int h) |
| { |
| glViewport(0, 0, (GLsizei) w, (GLsizei) h); |
| glMatrixMode(GL_PROJECTION); |
| glLoadIdentity(); |
| gluPerspective (45.0, 1.0, 0.25, 25.0); |
| glMatrixMode(GL_MODELVIEW); |
| glLoadIdentity (); |
| glTranslatef (0.0, 0.0, -5.0); |
| } |
| |
| static void keyboard(unsigned char key, int x, int y) |
| { |
| switch (key) { |
| case 'c': |
| glFogi(GL_FOG_COORDINATE_SOURCE_EXT, GL_FRAGMENT_DEPTH_EXT); |
| glutPostRedisplay(); |
| break; |
| case 'C': |
| glFogi(GL_FOG_COORDINATE_SOURCE_EXT, GL_FOG_COORDINATE_EXT); |
| glutPostRedisplay(); |
| break; |
| case '1': |
| f1 = f1 + 0.25; |
| glutPostRedisplay(); |
| break; |
| case '2': |
| f2 = f2 + 0.25; |
| glutPostRedisplay(); |
| break; |
| case '3': |
| f3 = f3 + 0.25; |
| glutPostRedisplay(); |
| break; |
| case '8': |
| if (f1 > 0.25) { |
| f1 = f1 - 0.25; |
| glutPostRedisplay(); |
| } |
| break; |
| case '9': |
| if (f2 > 0.25) { |
| f2 = f2 - 0.25; |
| glutPostRedisplay(); |
| } |
| break; |
| case '0': |
| if (f3 > 0.25) { |
| f3 = f3 - 0.25; |
| glutPostRedisplay(); |
| } |
| break; |
| case 'b': |
| glMatrixMode (GL_MODELVIEW); |
| glTranslatef (0.0, 0.0, -0.25); |
| glutPostRedisplay(); |
| break; |
| case 'f': |
| glMatrixMode (GL_MODELVIEW); |
| glTranslatef (0.0, 0.0, 0.25); |
| glutPostRedisplay(); |
| break; |
| case 27: |
| exit(0); |
| break; |
| default: |
| break; |
| } |
| } |
| |
| |
| /* Main Loop |
| * Open window with initial window size, title bar, |
| * RGBA display mode, depth buffer, and handle input events. |
| */ |
| int main(int argc, char** argv) |
| { |
| glutInit(&argc, argv); |
| glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB); |
| glutInitWindowSize(500, 500); |
| glutCreateWindow(argv[0]); |
| glewInit(); |
| init(); |
| glutReshapeFunc (reshape); |
| glutKeyboardFunc (keyboard); |
| glutDisplayFunc (display); |
| glutMainLoop(); |
| return 0; |
| } |