Hey people,

I have managed to combine two sources to make a colourful ripple effect with a continuous flow but I am now stuck as to how I make the background transparent.

This is to be projected on to a wall, hence the desire for it to be see through. Here is the source code for what I already have....


//ring.pde
ArrayList ripples;
color bg = 0;

int c1 = 255; // Color array
int c2 = 127;
color[] c = {
color(c1, c2, 0), color(c1, 0, c2), color(c2, c1, 0), color(c2, 0, c1), color(0, c2, c1), };

void setup() {
size(500, 500);
ripples = new ArrayList();
smooth();
stroke(255);
strokeWeight(3);
noFill();
}

void draw() {
background(bg);
for( int i = ripples.size()-1; i >= 0;i--){
Ripple ripple = (Ripple) ripples.get(i);
ripple.resize();
ripple.display();
if(!ripple.on)ripples.remove(i);
}

}

void mouseDragged() {
int which = round(random(4)); // pick a color, any color (or the number associateing to that color in the array)
ripples.add(new Ripple(mouseX, mouseY, which));
}



void keyPressed() {
if (keyCode == ' ') {
if (bg == 0) {
bg = 255;
} else {
bg = 0;
}
}
}

//ripple class
class Ripple { // The ripple class
float x, y; //
float diameter, alph;
boolean on;
boolean finished = false;
color colors;

public Ripple(float xpos, float ypos, color shade) {
x = xpos;
y = ypos;
on = true;
diameter = 1;
colors = shade;

}

void resize() {
if (on) {
if (diameter < 200) {
diameter++;
alph = abs((diameter*1.275)-255);
} else {
on = false;
}
}
}

void display() {
noFill();
stroke(c[colors], alph);
strokeWeight(3);
ellipse(x, y, diameter, diameter);
}
}



Thanks in advance for any help.