153 lines
4.5 KiB
C
153 lines
4.5 KiB
C
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/* Copyright (c) Mark J. Kilgard, 1994. */
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/*
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* (c) Copyright 1993, Silicon Graphics, Inc.
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* ALL RIGHTS RESERVED
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* Permission to use, copy, modify, and distribute this software for
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* any purpose and without fee is hereby granted, provided that the above
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* copyright notice appear in all copies and that both the copyright notice
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* and this permission notice appear in supporting documentation, and that
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* the name of Silicon Graphics, Inc. not be used in advertising
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* or publicity pertaining to distribution of the software without specific,
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* written prior permission.
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*
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* THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
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* AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
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* INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
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* FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON
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* GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
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* SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
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* KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
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* LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
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* THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC. HAS BEEN
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* ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
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* POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* US Government Users Restricted Rights
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* Use, duplication, or disclosure by the Government is subject to
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* restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
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* (c)(1)(ii) of the Rights in Technical Data and Computer Software
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* clause at DFARS 252.227-7013 and/or in similar or successor
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* clauses in the FAR or the DOD or NASA FAR Supplement.
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* Unpublished-- rights reserved under the copyright laws of the
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* United States. Contractor/manufacturer is Silicon Graphics,
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* Inc., 2011 N. Shoreline Blvd., Mountain View, CA 94039-7311.
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*
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* OpenGL(TM) is a trademark of Silicon Graphics, Inc.
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*/
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/*
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* fogindex.c
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* This program demonstrates fog in color index mode.
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* Three cones are drawn at different z values in a linear
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* fog. 32 contiguous colors (from 16 to 47) are loaded
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* with a color ramp.
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*/
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#include <stdlib.h>
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#include <GL/glut.h>
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/* Initialize color map and fog. Set screen clear color
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* to end of color ramp.
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*/
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#define NUM_COLORS 32
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#define RAMPSTART 16
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static void
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myinit(void)
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{
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int i;
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glEnable(GL_DEPTH_TEST);
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glDepthFunc(GL_LESS);
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for (i = 0; i < NUM_COLORS; i++) {
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GLfloat shade;
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shade = (GLfloat) (NUM_COLORS - i) / (GLfloat) NUM_COLORS;
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glutSetColor(16 + i, shade, shade, shade);
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}
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glEnable(GL_FOG);
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glFogi(GL_FOG_MODE, GL_LINEAR);
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glFogi(GL_FOG_INDEX, NUM_COLORS);
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glFogf(GL_FOG_START, 0.0);
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glFogf(GL_FOG_END, 4.0);
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glHint(GL_FOG_HINT, GL_NICEST);
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glClearIndex((GLfloat) (NUM_COLORS + RAMPSTART - 1));
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}
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/* display() renders 3 cones at different z positions.
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*/
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static void
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display(void)
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{
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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glPushMatrix();
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glTranslatef(-1.0, -1.0, -1.0);
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glRotatef(-90.0, 1.0, 0.0, 0.0);
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glIndexi(RAMPSTART);
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glutSolidCone(1.0, 2.0, 10, 10);
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glPopMatrix();
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glPushMatrix();
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glTranslatef(0.0, -1.0, -2.25);
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glRotatef(-90.0, 1.0, 0.0, 0.0);
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glIndexi(RAMPSTART);
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glutSolidCone(1.0, 2.0, 10, 10);
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glPopMatrix();
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glPushMatrix();
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glTranslatef(1.0, -1.0, -3.5);
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glRotatef(-90.0, 1.0, 0.0, 0.0);
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glIndexi(RAMPSTART);
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glutSolidCone(1.0, 2.0, 10, 10);
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glPopMatrix();
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glFlush();
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}
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static void
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myReshape(int w, int h)
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{
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glViewport(0, 0, w, h);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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if (w <= h)
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glOrtho(-2.0, 2.0, -2.0 * (GLfloat) h / (GLfloat) w,
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2.0 * (GLfloat) h / (GLfloat) w, 0.0, 10.0);
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else
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glOrtho(-2.0 * (GLfloat) w / (GLfloat) h,
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2.0 * (GLfloat) w / (GLfloat) h, -2.0, 2.0, 0.0, 10.0);
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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}
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static void
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key(unsigned char k, int x, int y)
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{
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switch (k) {
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case 27: /* Escape */
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exit(0);
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break;
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default:
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return;
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}
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glutPostRedisplay();
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}
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/* Main Loop
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* Open window with initial window size, title bar,
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* RGBA display mode, depth buffer, and handle input events.
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*/
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int
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main(int argc, char **argv)
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{
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glutInit(&argc, argv);
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glutInitDisplayMode(GLUT_SINGLE | GLUT_INDEX | GLUT_DEPTH);
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glutCreateWindow(argv[0]);
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myinit();
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glutReshapeFunc(myReshape);
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glutDisplayFunc(display);
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glutKeyboardFunc(key);
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glutMainLoop();
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return 0; /* ANSI C requires main to return int. */
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}
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