505 lines
11 KiB
C
505 lines
11 KiB
C
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/* Copyright (c) Mark J. Kilgard, 1997. */
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/* This program is freely distributable without licensing fees
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and is provided without guarantee or warrantee expressed or
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implied. This program is -not- in the public domain. */
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/* This example demonstrates how to render particle effects
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with OpenGL. A cloud of pinkish/orange particles explodes with the
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particles bouncing off the ground. When the EXT_point_parameters
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is present , the particle size is attenuated based on eye distance. */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <math.h> /* for cos(), sin(), and sqrt() */
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#ifdef _WIN32
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#include <windows.h>
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#endif
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#include <GL/glew.h>
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#include <GL/glut.h>
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/* Some <math.h> files do not define M_PI... */
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#ifndef M_PI
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#define M_PI 3.14159265
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#endif
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#if 0 /* For debugging. */
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#undef GL_EXT_point_parameters
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#endif
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static GLfloat angle = -150; /* in degrees */
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static int spin = 0;
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static int moving, begin;
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static int newModel = 1;
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static float theTime;
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static int repeat = 1;
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static int blend = 1;
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int useMipmaps = 1;
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int linearFiltering = 1;
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static GLfloat constant[3] = { 1/5.0, 0.0, 0.0 };
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static GLfloat linear[3] = { 0.0, 1/5.0, 0.0 };
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static GLfloat theQuad[3] = { 0.25, 0.0, 1/60.0 };
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#define MAX_POINTS 2000
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static int numPoints = 200;
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static GLfloat pointList[MAX_POINTS][3];
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static GLfloat pointTime[MAX_POINTS];
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static GLfloat pointVelocity[MAX_POINTS][2];
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static GLfloat pointDirection[MAX_POINTS][2];
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static int colorList[MAX_POINTS];
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static int animate = 1, motion = 0;
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static GLfloat colorSet[][4] = {
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/* Shades of red. */
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{ 0.7, 0.2, 0.4, 0.5 },
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{ 0.8, 0.0, 0.7, 0.5 },
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{ 1.0, 0.0, 0.0, 0.5 },
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{ 0.9, 0.3, 0.6, 0.5 },
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{ 1.0, 0.4, 0.0, 0.5 },
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{ 1.0, 0.0, 0.5, 0.5 },
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};
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#define NUM_COLORS (sizeof(colorSet)/sizeof(colorSet[0]))
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#define DEAD (NUM_COLORS+1)
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#if 0 /* drand48 might be better on Unix machines */
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#define RANDOM_RANGE(lo, hi) ((lo) + (hi - lo) * drand48())
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#else
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static float float_rand(void) { return rand() / (float) RAND_MAX; }
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#define RANDOM_RANGE(lo, hi) ((lo) + (hi - lo) * float_rand())
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#endif
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#define MEAN_VELOCITY 3.0
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#define GRAVITY 2.0
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/* Modeling units of ground extent in each X and Z direction. */
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#define EDGE 12
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static void
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makePointList(void)
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{
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float angle, velocity, direction;
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int i;
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motion = 1;
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for (i=0; i<numPoints; i++) {
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pointList[i][0] = 0.0;
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pointList[i][1] = 0.0;
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pointList[i][2] = 0.0;
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pointTime[i] = 0.0;
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angle = (RANDOM_RANGE(60.0, 70.0)) * M_PI/180.0;
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direction = RANDOM_RANGE(0.0, 360.0) * M_PI/180.0;
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pointDirection[i][0] = cos(direction);
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pointDirection[i][1] = sin(direction);
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velocity = MEAN_VELOCITY + RANDOM_RANGE(-0.8, 1.0);
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pointVelocity[i][0] = velocity * cos(angle);
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pointVelocity[i][1] = velocity * sin(angle);
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colorList[i] = rand() % NUM_COLORS;
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}
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theTime = 0.0;
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}
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static void
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updatePointList(void)
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{
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float distance;
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int i;
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static double t0 = -1.;
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double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
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if (t0 < 0.0)
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t0 = t;
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dt = t - t0;
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t0 = t;
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motion = 0;
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for (i=0; i<numPoints; i++) {
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distance = pointVelocity[i][0] * theTime;
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/* X and Z */
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pointList[i][0] = pointDirection[i][0] * distance;
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pointList[i][2] = pointDirection[i][1] * distance;
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/* Z */
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pointList[i][1] =
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(pointVelocity[i][1] - 0.5 * GRAVITY * pointTime[i])*pointTime[i];
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/* If we hit the ground, bounce the point upward again. */
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if (pointList[i][1] <= 0.0) {
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if (distance > EDGE) {
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/* Particle has hit ground past the distance duration of
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the particles. Mark particle as dead. */
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colorList[i] = NUM_COLORS; /* Not moving. */
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continue;
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}
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pointVelocity[i][1] *= 0.8; /* 80% of previous up velocity. */
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pointTime[i] = 0.0; /* Reset the particles sense of up time. */
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}
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motion = 1;
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pointTime[i] += dt;
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}
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theTime += dt;
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if (!motion && !spin) {
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if (repeat) {
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makePointList();
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} else {
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glutIdleFunc(NULL);
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}
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}
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}
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static void
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idle(void)
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{
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updatePointList();
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if (spin) {
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angle += 0.3;
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newModel = 1;
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}
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glutPostRedisplay();
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}
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static void
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visible(int vis)
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{
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if (vis == GLUT_VISIBLE) {
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if (animate && (motion || spin)) {
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glutIdleFunc(idle);
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}
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} else {
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glutIdleFunc(NULL);
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}
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}
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static void
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recalcModelView(void)
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{
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glPopMatrix();
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glPushMatrix();
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glRotatef(angle, 0.0, 1.0, 0.0);
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newModel = 0;
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}
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static void
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redraw(void)
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{
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int i;
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glDepthMask(GL_TRUE);
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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if (newModel)
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recalcModelView();
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/* Draw the floor. */
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/* glEnable(GL_TEXTURE_2D);*/
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glColor3f(0.5, 1.0, 0.5);
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glBegin(GL_QUADS);
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glTexCoord2f(0.0, 0.0);
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glVertex3f(-EDGE, -0.05, -EDGE);
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glTexCoord2f(20.0, 0.0);
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glVertex3f(EDGE, -0.05, -EDGE);
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glTexCoord2f(20.0, 20.0);
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glVertex3f(EDGE, -0.05, EDGE);
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glTexCoord2f(0.0, 20.0);
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glVertex3f(-EDGE, -0.05, EDGE);
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glEnd();
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/* Allow particles to blend with each other. */
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glDepthMask(GL_FALSE);
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if (blend)
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glEnable(GL_BLEND);
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glDisable(GL_TEXTURE_2D);
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glBegin(GL_POINTS);
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for (i=0; i<numPoints; i++) {
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/* Draw alive particles. */
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if (colorList[i] != DEAD) {
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glColor4fv(colorSet[colorList[i]]);
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glVertex3fv(pointList[i]);
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}
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}
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glEnd();
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glDisable(GL_BLEND);
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glutSwapBuffers();
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}
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/* ARGSUSED2 */
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static void
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mouse(int button, int state, int x, int y)
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{
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/* Scene can be spun around Y axis using left
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mouse button movement. */
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if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
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moving = 1;
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begin = x;
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}
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if (button == GLUT_LEFT_BUTTON && state == GLUT_UP) {
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moving = 0;
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}
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}
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/* ARGSUSED1 */
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static void
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mouseMotion(int x, int y)
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{
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if (moving) {
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angle = angle + (x - begin);
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begin = x;
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newModel = 1;
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glutPostRedisplay();
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}
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}
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static void
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menu(int option)
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{
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switch (option) {
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case 0:
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makePointList();
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break;
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#ifdef GL_ARB_point_parameters
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case 1:
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glPointParameterfvARB(GL_POINT_DISTANCE_ATTENUATION_ARB, constant);
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break;
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case 2:
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glPointParameterfvARB(GL_POINT_DISTANCE_ATTENUATION_ARB, linear);
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break;
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case 3:
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glPointParameterfvARB(GL_POINT_DISTANCE_ATTENUATION_ARB, theQuad);
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break;
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#endif
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case 4:
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blend = 1;
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break;
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case 5:
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blend = 0;
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break;
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#ifdef GL_ARB_point_parameters
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case 6:
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glPointParameterfARB(GL_POINT_FADE_THRESHOLD_SIZE_ARB, 1.0);
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break;
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case 7:
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glPointParameterfARB(GL_POINT_FADE_THRESHOLD_SIZE_ARB, 10.0);
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break;
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#endif
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case 8:
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glEnable(GL_POINT_SMOOTH);
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break;
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case 9:
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glDisable(GL_POINT_SMOOTH);
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break;
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case 10:
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glPointSize(2.0);
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break;
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case 11:
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glPointSize(4.0);
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break;
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case 12:
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glPointSize(8.0);
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break;
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case 13:
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spin = 1 - spin;
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if (animate && (spin || motion)) {
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glutIdleFunc(idle);
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} else {
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glutIdleFunc(NULL);
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}
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break;
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case 14:
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numPoints = 200;
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break;
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case 15:
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numPoints = 500;
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break;
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case 16:
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numPoints = 1000;
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break;
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case 17:
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numPoints = 2000;
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break;
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case 666:
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exit(0);
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}
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glutPostRedisplay();
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}
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/* ARGSUSED1 */
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static void
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key(unsigned char c, int x, int y)
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{
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switch (c) {
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case 13:
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animate = 1 - animate; /* toggle. */
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if (animate && (motion || spin)) {
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glutIdleFunc(idle);
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} else {
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glutIdleFunc(NULL);
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}
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break;
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case ' ':
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animate = 1;
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makePointList();
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glutIdleFunc(idle);
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break;
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case 27:
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exit(0);
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}
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}
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/* Nice floor texture tiling pattern. */
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static char *circles[] = {
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"....xxxx........",
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"..xxxxxxxx......",
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".xxxxxxxxxx.....",
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".xxx....xxx.....",
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"xxx......xxx....",
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"xxx......xxx....",
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"xxx......xxx....",
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"xxx......xxx....",
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".xxx....xxx.....",
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".xxxxxxxxxx.....",
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"..xxxxxxxx......",
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"....xxxx........",
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"................",
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"................",
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"................",
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"................",
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};
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static void
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makeFloorTexture(void)
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{
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GLubyte floorTexture[16][16][3];
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GLubyte *loc;
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int s, t;
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/* Setup RGB image for the texture. */
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loc = (GLubyte*) floorTexture;
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for (t = 0; t < 16; t++) {
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for (s = 0; s < 16; s++) {
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if (circles[t][s] == 'x') {
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/* Nice blue. */
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loc[0] = 0x1f;
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loc[1] = 0x1f;
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loc[2] = 0x8f;
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} else {
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/* Light gray. */
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loc[0] = 0xca;
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loc[1] = 0xca;
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loc[2] = 0xca;
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}
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loc += 3;
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}
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}
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glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
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if (useMipmaps) {
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
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GL_LINEAR_MIPMAP_LINEAR);
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gluBuild2DMipmaps(GL_TEXTURE_2D, 3, 16, 16,
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GL_RGB, GL_UNSIGNED_BYTE, floorTexture);
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} else {
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if (linearFiltering) {
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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} else {
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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}
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glTexImage2D(GL_TEXTURE_2D, 0, 3, 16, 16, 0,
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GL_RGB, GL_UNSIGNED_BYTE, floorTexture);
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}
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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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int i;
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glutInitWindowSize(300, 300);
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glutInit(&argc, argv);
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glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH | GLUT_MULTISAMPLE);
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for (i=1; i<argc; i++) {
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if(!strcmp("-noms", argv[i])) {
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glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
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printf("forcing no multisampling\n");
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} else if(!strcmp("-nomipmaps", argv[i])) {
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useMipmaps = 0;
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} else if(!strcmp("-nearest", argv[i])) {
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linearFiltering = 0;
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}
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}
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glutCreateWindow("point burst");
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glewInit();
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glutDisplayFunc(redraw);
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glutMouseFunc(mouse);
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glutMotionFunc(mouseMotion);
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glutVisibilityFunc(visible);
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glutKeyboardFunc(key);
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glutCreateMenu(menu);
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glutAddMenuEntry("Reset time", 0);
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glutAddMenuEntry("Constant", 1);
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glutAddMenuEntry("Linear", 2);
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glutAddMenuEntry("Quadratic", 3);
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glutAddMenuEntry("Blend on", 4);
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glutAddMenuEntry("Blend off", 5);
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glutAddMenuEntry("Threshold 1", 6);
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glutAddMenuEntry("Threshold 10", 7);
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glutAddMenuEntry("Point smooth on", 8);
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glutAddMenuEntry("Point smooth off", 9);
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glutAddMenuEntry("Point size 2", 10);
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glutAddMenuEntry("Point size 4", 11);
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glutAddMenuEntry("Point size 8", 12);
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glutAddMenuEntry("Toggle spin", 13);
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glutAddMenuEntry("200 points ", 14);
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glutAddMenuEntry("500 points ", 15);
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glutAddMenuEntry("1000 points ", 16);
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glutAddMenuEntry("2000 points ", 17);
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glutAddMenuEntry("Quit", 666);
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glutAttachMenu(GLUT_RIGHT_BUTTON);
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if (!glutExtensionSupported("GL_ARB_point_parameters")) {
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fprintf(stderr, "Sorry, GL_ARB_point_parameters is not supported.\n");
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return -1;
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}
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glShadeModel(GL_FLAT);
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glEnable(GL_DEPTH_TEST);
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glEnable(GL_POINT_SMOOTH);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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glPointSize(8.0);
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#if GL_ARB_point_parameters
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glPointParameterfvARB(GL_POINT_DISTANCE_ATTENUATION_ARB, theQuad);
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#endif
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glMatrixMode(GL_PROJECTION);
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gluPerspective( /* field of view in degree */ 40.0,
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/* aspect ratio */ 1.0,
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/* Z near */ 0.5, /* Z far */ 40.0);
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glMatrixMode(GL_MODELVIEW);
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gluLookAt(0.0, 1.0, 8.0, /* eye location */
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0.0, 1.0, 0.0, /* center is at (0,0,0) */
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0.0, 1.0, 0.); /* up is in postivie Y direction */
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glPushMatrix(); /* dummy push so we can pop on model
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recalc */
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makePointList();
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makeFloorTexture();
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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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