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Diffstat (limited to 'progs/redbook/fog.c')
| -rw-r--r-- | progs/redbook/fog.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/progs/redbook/fog.c b/progs/redbook/fog.c new file mode 100644 index 00000000000..14c7700eccf --- /dev/null +++ b/progs/redbook/fog.c @@ -0,0 +1,200 @@ + +/* Copyright (c) Mark J. Kilgard, 1994. */ + +/** + * (c) Copyright 1993, 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 + * Unpublished-- rights reserved under the copyright laws of the + * United States.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., 2011 N. Shoreline Blvd., Mountain View, CA 94039-7311. + * + * OpenGL(TM) is a trademark of Silicon Graphics, Inc. + */ +/* + * fog.c + * This program draws 5 red teapots, each at a different + * z distance from the eye, in different types of fog. + * Pressing the left mouse button chooses between 3 types of + * fog: exponential, exponential squared, and linear. + * In this program, there is a fixed density value, as well + * as fixed start and end values for the linear fog. + */ +#include <stdlib.h> +#include <math.h> +#include <GL/glut.h> + +GLint fogMode; + +void +selectFog(int mode) +{ + switch(mode) { + case GL_LINEAR: + glFogf(GL_FOG_START, 1.0); + glFogf(GL_FOG_END, 5.0); + /* falls through */ + case GL_EXP2: + case GL_EXP: + glFogi(GL_FOG_MODE, mode); + glutPostRedisplay(); + break; + case 0: + exit(0); + } +} + +/* Initialize z-buffer, projection matrix, light source, + * and lighting model. Do not specify a material property here. + */ +void +myinit(void) +{ + GLfloat position[] = + {0.0, 3.0, 3.0, 0.0}; + GLfloat local_view[] = + {0.0}; + + glEnable(GL_DEPTH_TEST); + glDepthFunc(GL_LESS); + + glLightfv(GL_LIGHT0, GL_POSITION, position); + glLightModelfv(GL_LIGHT_MODEL_LOCAL_VIEWER, local_view); + + glFrontFace(GL_CW); + glEnable(GL_LIGHTING); + glEnable(GL_LIGHT0); + glEnable(GL_AUTO_NORMAL); + glEnable(GL_NORMALIZE); + glEnable(GL_FOG); + { + GLfloat fogColor[4] = + {0.5, 0.5, 0.5, 1.0}; + + fogMode = GL_EXP; + glFogi(GL_FOG_MODE, fogMode); + glFogfv(GL_FOG_COLOR, fogColor); + glFogf(GL_FOG_DENSITY, 0.35); + glHint(GL_FOG_HINT, GL_DONT_CARE); + glClearColor(0.5, 0.5, 0.5, 1.0); + } +} + +void +renderRedTeapot(GLfloat x, GLfloat y, GLfloat z) +{ + float mat[4]; + + glPushMatrix(); + glTranslatef(x, y, z); + mat[0] = 0.1745; + mat[1] = 0.01175; + mat[2] = 0.01175; + mat[3] = 1.0; + glMaterialfv(GL_FRONT, GL_AMBIENT, mat); + mat[0] = 0.61424; + mat[1] = 0.04136; + mat[2] = 0.04136; + glMaterialfv(GL_FRONT, GL_DIFFUSE, mat); + mat[0] = 0.727811; + mat[1] = 0.626959; + mat[2] = 0.626959; + glMaterialfv(GL_FRONT, GL_SPECULAR, mat); + glMaterialf(GL_FRONT, GL_SHININESS, 0.6 * 128.0); + glutSolidTeapot(1.0); + glPopMatrix(); +} + +/* display() draws 5 teapots at different z positions. + */ +void +display(void) +{ + glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); + renderRedTeapot(-4.0, -0.5, -1.0); + renderRedTeapot(-2.0, -0.5, -2.0); + renderRedTeapot(0.0, -0.5, -3.0); + renderRedTeapot(2.0, -0.5, -4.0); + renderRedTeapot(4.0, -0.5, -5.0); + glFlush(); +} + +void +myReshape(int w, int h) +{ + glViewport(0, 0, w, h); + glMatrixMode(GL_PROJECTION); + glLoadIdentity(); + if (w <= (h * 3)) + glOrtho(-6.0, 6.0, -2.0 * ((GLfloat) h * 3) / (GLfloat) w, + 2.0 * ((GLfloat) h * 3) / (GLfloat) w, 0.0, 10.0); + else + glOrtho(-6.0 * (GLfloat) w / ((GLfloat) h * 3), + 6.0 * (GLfloat) w / ((GLfloat) h * 3), -2.0, 2.0, 0.0, 10.0); + glMatrixMode(GL_MODELVIEW); + glLoadIdentity(); +} + +static void +key(unsigned char k, int x, int y) +{ + switch (k) { + case 27: /* Escape */ + exit(0); + break; + default: + return; + } + glutPostRedisplay(); +} + +/* 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_SINGLE | GLUT_RGB | GLUT_DEPTH); + glutInitWindowSize(450, 150); + glutCreateWindow(argv[0]); + myinit(); + glutReshapeFunc(myReshape); + glutDisplayFunc(display); + glutCreateMenu(selectFog); + glutAddMenuEntry("Fog EXP", GL_EXP); + glutAddMenuEntry("Fog EXP2", GL_EXP2); + glutAddMenuEntry("Fog LINEAR", GL_LINEAR); + glutAddMenuEntry("Quit", 0); + glutAttachMenu(GLUT_RIGHT_BUTTON); + glutKeyboardFunc(key); + glutMainLoop(); + return 0; /* ANSI C requires main to return int. */ +} |