The following code is an update of a previous post which I removed. There appeared to be something not quite right with it. At any rate, this code works perfectly. You can try it in combination with this tutorial on how to set things up in OS X Lion. (spacebar = new shape, esc = toggle fullscreen).
/*
* harmonograph.cpp
*
* Created by Brecht Debackere on 24/04/12.
* 2012 Autofasurer.
*
*/
#include <GLUT/glut.h>
#include <iostream>
#include <math.h>
using namespace std;
//initialising variables
float fRed, fGreen, fBlue, fXpos, fYpos, fFrequency, fAmplitude, fPhase, fTime, fPointsize;
bool fullScreen = false;
//initialising states
void init()
{
glClearColor(0.0,0.0,0.0,1.);
//init some random values
fFrequency = (rand()%500-250)/5.0;
fPhase = (rand()%500-250)/5.0;
fAmplitude = (rand()%500-250)/5.0;
fRed = (rand()%100)/1000.0;
fGreen = (rand()%100)/1000.0;
fBlue = (rand()%100)/1000.0;
glEnable(GL_POINT_SMOOTH);
glPointSize(0.5f);
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_ONE);
}
//reshaping the viewport and projection
void reshape(int width, int height)
{
glViewport(0, 0, 640, 480);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(120.,(GLfloat) width/(GLfloat) height,0.1, 800.0);
gluLookAt(0.0,0.0,12.0, 0.0, 0.0, 0.0, 0,1,0);
glMatrixMode(GL_MODELVIEW);
}
//reading the keyboard input
void key(unsigned char key, int x, int y){
switch (key){
case 32://press spacebar for a new random figure
fFrequency = (rand()%500-250)/5.0;
fPhase = (rand()%500-250)/5.0;
fAmplitude = (rand()%500-250)/5.0;
fRed = (rand()%100)/1000.0;
fGreen = (rand()%100)/1000.0;
fBlue = (rand()%100)/1000.0;
fTime = 0.0;
break;
case 27://escape toggles fullscreen
fullScreen = !fullScreen;
if (fullScreen) {
glutFullScreen();
}
else {
glutReshapeWindow(640, 480);
glutPositionWindow(100, 100);
}
break;
}
}
//drawing and displaying
void display()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBegin(GL_POINTS);
while (fTime < 400.0) {
glColor4f(fRed, fGreen, fBlue, 0.1);
fXpos = -10*(cos(fFrequency * fTime) + cos(fPhase * fTime)*0.5 + cos(fAmplitude * fTime)*0.33);
fYpos = -10*(sin(fFrequency * fTime) + sin(fPhase * fTime)*0.5 + sin(fAmplitude * fTime)*0.33);
glVertex3f(fXpos, fYpos, 0);
fTime += 0.002;
}
glEnd();
fFrequency -= 0.00001;
fAmplitude += 0.00001;
fPhase += 0.00001;
fTime = 0.0;
glutSwapBuffers();
}
//main loop with initialising of window and glut, assigning functions
int main(int argc, char** argv)
{
srand(time(NULL));
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(640, 480);
glutCreateWindow("Harmonograph");
init();
glutDisplayFunc(display);
glutIdleFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(key);
glutMainLoop();
return 0;
}
]]>