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Diffstat (limited to 'progs/redbook/fogcoord.c')
| -rw-r--r-- | progs/redbook/fogcoord.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/progs/redbook/fogcoord.c b/progs/redbook/fogcoord.c new file mode 100644 index 0000000000..39e4689948 --- /dev/null +++ b/progs/redbook/fogcoord.c @@ -0,0 +1,194 @@ +/* + * 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 Unpublished - rights + * reserved under the copyright laws of the United States.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. + */ + +#define GL_GLEXT_PROTOTYPES + +#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]); + init(); + glutReshapeFunc (reshape); + glutKeyboardFunc (keyboard); + glutDisplayFunc (display); + glutMainLoop(); + return 0; +} |