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/* 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* Unpublished-- rights reserved under the copyright laws of the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. */
}
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