1/*
2 * Copyright (c) 1993-2003, Silicon Graphics, Inc.
3 * All Rights Reserved
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose and without fee is hereby granted, provided that the above
7 * copyright notice appear in all copies and that both the copyright
8 * notice and this permission notice appear in supporting documentation,
9 * and that the name of Silicon Graphics, Inc. not be used in
10 * advertising or publicity pertaining to distribution of the software
11 * without specific, written prior permission.
12 *
13 * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" AND
14 * WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
15 * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
16 * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
17 * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
18 * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
19 * OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, LOSS OF
20 * PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF THIRD
21 * PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN ADVISED OF
22 * THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON ANY THEORY OF
23 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE POSSESSION, USE
24 * OR PERFORMANCE OF THIS SOFTWARE.
25 *
26 * US Government Users Restricted Rights
27 * Use, duplication, or disclosure by the Government is subject to
28 * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
29 * (c)(1)(ii) of the Rights in Technical Data and Computer Software
30 * clause at DFARS 252.227-7013 and/or in similar or successor clauses
31 * in the FAR or the DOD or NASA FAR Supplement.  Unpublished - rights
32 * reserved under the copyright laws of the United States.
33 *
34 * Contractor/manufacturer is:
35 *	Silicon Graphics, Inc.
36 *	1500 Crittenden Lane
37 *	Mountain View, CA  94043
38 *	United State of America
39 *
40 * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
41 */
42
43/*
44 *  pointp.c
45 *  This program demonstrates point parameters and their effect
46 *  on point primitives.
47 *  250 points are randomly generated within a 10 by 10 by 40
48 *  region, centered at the origin.  In some modes (including the
49 *  default), points that are closer to the viewer will appear larger.
50 *
51 *  Pressing the 'l', 'q', and 'c' keys switch the point
52 *  parameters attenuation mode to linear, quadratic, or constant,
53 *  respectively.
54 *  Pressing the 'f' and 'b' keys move the viewer forward
55 *  and backwards.  In either linear or quadratic attenuation
56 *  mode, the distance from the viewer to the point will change
57 *  the size of the point primitive.
58 *  Pressing the '+' and '-' keys will change the current point
59 *  size.  In this program, the point size is bounded, so it
60 *  will not get less than 2.0, nor greater than GL_POINT_SIZE_MAX.
61 */
62
63#include <GL/glew.h>
64#include "glut_wrap.h"
65#include <stdlib.h>
66#include <stdio.h>
67
68static GLfloat psize = 7.0;
69static GLfloat pmax[1];
70static GLfloat constant[3] = {1.0, 0.0, 0.0};
71static GLfloat linear[3] = {0.0, 0.12, 0.0};
72static GLfloat quadratic[3] = {0.0, 0.0, 0.01};
73
74static void init(void)
75{
76   int i;
77
78   srand (12345);
79
80   glNewList(1, GL_COMPILE);
81   glBegin (GL_POINTS);
82      for (i = 0; i < 250; i++) {
83          glColor3f (1.0, ((rand()/(float) RAND_MAX) * 0.5) + 0.5,
84                          rand()/(float) RAND_MAX);
85/*  randomly generated vertices:
86    -5 < x < 5;  -5 < y < 5;  -5 < z < -45  */
87          glVertex3f ( ((rand()/(float)RAND_MAX) * 10.0) - 5.0,
88                       ((rand()/(float)RAND_MAX) * 10.0) - 5.0,
89                       ((rand()/(float)RAND_MAX) * 40.0) - 45.0);
90      }
91   glEnd();
92   glEndList();
93
94   glEnable(GL_DEPTH_TEST);
95   glEnable(GL_POINT_SMOOTH);
96   glEnable(GL_BLEND);
97   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
98   glPointSize(psize);
99   glGetFloatv(GL_POINT_SIZE_MAX_EXT, pmax);
100
101   glPointParameterfvEXT (GL_DISTANCE_ATTENUATION_EXT, linear);
102   glPointParameterfEXT (GL_POINT_FADE_THRESHOLD_SIZE_EXT, 2.0);
103}
104
105static void display(void)
106{
107   glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
108   glCallList (1);
109   glutSwapBuffers ();
110}
111
112static void reshape (int w, int h)
113{
114   glViewport (0, 0, (GLsizei) w, (GLsizei) h);
115   glMatrixMode (GL_PROJECTION);
116   glLoadIdentity ();
117   gluPerspective (35.0, 1.0, 0.25, 200.0);
118   glMatrixMode (GL_MODELVIEW);
119   glTranslatef (0.0, 0.0, -10.0);
120}
121
122static void keyboard(unsigned char key, int x, int y)
123{
124   switch (key) {
125      case 'b':
126            glMatrixMode (GL_MODELVIEW);
127            glTranslatef (0.0, 0.0, -0.5);
128            glutPostRedisplay();
129         break;
130      case 'c':
131            glPointParameterfvEXT (GL_DISTANCE_ATTENUATION_EXT, constant);
132            glutPostRedisplay();
133         break;
134      case 'f':
135            glMatrixMode (GL_MODELVIEW);
136            glTranslatef (0.0, 0.0, 0.5);
137            glutPostRedisplay();
138         break;
139      case 'l':
140            glPointParameterfvEXT (GL_DISTANCE_ATTENUATION_EXT, linear);
141            glutPostRedisplay();
142         break;
143      case 'q':
144            glPointParameterfvEXT (GL_DISTANCE_ATTENUATION_EXT, quadratic);
145            glutPostRedisplay();
146         break;
147      case '+':
148            if (psize < (pmax[0] + 1.0))
149               psize = psize + 1.0;
150            glPointSize (psize);
151            glutPostRedisplay();
152         break;
153      case '-':
154            if (psize >= 2.0)
155               psize = psize - 1.0;
156            glPointSize (psize);
157            glutPostRedisplay();
158         break;
159      case 27:
160         exit(0);
161         break;
162   }
163}
164
165int main(int argc, char** argv)
166{
167   glutInit(&argc, argv);
168   glutInitDisplayMode (GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH | GLUT_MULTISAMPLE);
169   glutInitWindowSize (500, 500);
170   glutInitWindowPosition (100, 100);
171   glutCreateWindow (argv[0]);
172   glewInit();
173   init ();
174   glutDisplayFunc (display);
175   glutReshapeFunc (reshape);
176   glutKeyboardFunc (keyboard);
177   glutMainLoop();
178   return 0;
179}
180