abstract cinema – generative systems – interactive visuals

Vector from Brecht on Vimeo.

Software development and visualization for Dutch new media artist Marnix de Nijs’ Beijing Accelerator installation.

More info on this and his other works on his website.

Made with Processing

Vimeo’s compression screws up the details quite a bit so watch it in action in realtime here.

As there are some random values at work, refreshing will yield variations.

Based on the function designed by D. Sleator in 1976: f(x, y) = ((x ^ y) & ((y – 350) >> 3)) ** 2.

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;       
}