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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 Unpublished - rights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;
+}