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/*
* 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 Unpublished - rights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.
*/
/*
* pointp.c
* This program demonstrates point parameters and their effect
* on point primitives.
* 250 points are randomly generated within a 10 by 10 by 40
* region, centered at the origin. In some modes (including the
* default), points that are closer to the viewer will appear larger.
*
* Pressing the 'l', 'q', and 'c' keys switch the point
* parameters attenuation mode to linear, quadratic, or constant,
* respectively.
* Pressing the 'f' and 'b' keys move the viewer forward
* and backwards. In either linear or quadratic attenuation
* mode, the distance from the viewer to the point will change
* the size of the point primitive.
* Pressing the '+' and '-' keys will change the current point
* size. In this program, the point size is bounded, so it
* will not get less than 2.0, nor greater than GL_POINT_SIZE_MAX.
*/
#define GL_GLEXT_PROTOTYPES
#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>
static GLfloat psize = 7.0;
static GLfloat pmax[1];
static GLfloat constant[3] = {1.0, 0.0, 0.0};
static GLfloat linear[3] = {0.0, 0.12, 0.0};
static GLfloat quadratic[3] = {0.0, 0.0, 0.01};
static void init(void)
{
int i;
srand (12345);
glNewList(1, GL_COMPILE);
glBegin (GL_POINTS);
for (i = 0; i < 250; i++) {
glColor3f (1.0, ((rand()/(float) RAND_MAX) * 0.5) + 0.5,
rand()/(float) RAND_MAX);
/* randomly generated vertices:
-5 < x < 5; -5 < y < 5; -5 < z < -45 */
glVertex3f ( ((rand()/(float)RAND_MAX) * 10.0) - 5.0,
((rand()/(float)RAND_MAX) * 10.0) - 5.0,
((rand()/(float)RAND_MAX) * 40.0) - 45.0);
}
glEnd();
glEndList();
glEnable(GL_DEPTH_TEST);
glEnable(GL_POINT_SMOOTH);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glPointSize(psize);
glGetFloatv(GL_POINT_SIZE_MAX_EXT, pmax);
glPointParameterfvEXT (GL_DISTANCE_ATTENUATION_EXT, linear);
glPointParameterfEXT (GL_POINT_FADE_THRESHOLD_SIZE_EXT, 2.0);
}
static void display(void)
{
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glCallList (1);
glutSwapBuffers ();
}
static void reshape (int w, int h)
{
glViewport (0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode (GL_PROJECTION);
glLoadIdentity ();
gluPerspective (35.0, 1.0, 0.25, 200.0);
glMatrixMode (GL_MODELVIEW);
glTranslatef (0.0, 0.0, -10.0);
}
static void keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 'b':
glMatrixMode (GL_MODELVIEW);
glTranslatef (0.0, 0.0, -0.5);
glutPostRedisplay();
break;
case 'c':
glPointParameterfvEXT (GL_DISTANCE_ATTENUATION_EXT, constant);
glutPostRedisplay();
break;
case 'f':
glMatrixMode (GL_MODELVIEW);
glTranslatef (0.0, 0.0, 0.5);
glutPostRedisplay();
break;
case 'l':
glPointParameterfvEXT (GL_DISTANCE_ATTENUATION_EXT, linear);
glutPostRedisplay();
break;
case 'q':
glPointParameterfvEXT (GL_DISTANCE_ATTENUATION_EXT, quadratic);
glutPostRedisplay();
break;
case '+':
if (psize < (pmax[0] + 1.0))
psize = psize + 1.0;
glPointSize (psize);
glutPostRedisplay();
break;
case '-':
if (psize >= 2.0)
psize = psize - 1.0;
glPointSize (psize);
glutPostRedisplay();
break;
case 27:
exit(0);
break;
}
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH | GLUT_MULTISAMPLE);
glutInitWindowSize (500, 500);
glutInitWindowPosition (100, 100);
glutCreateWindow (argv[0]);
init ();
glutDisplayFunc (display);
glutReshapeFunc (reshape);
glutKeyboardFunc (keyboard);
glutMainLoop();
return 0;
}
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