For my uni project I am trying to switch between 3 webcam feeds that are plugged into my computer, using physical switches, but I'm having some trouble:

I've got the webcam working & have started using the key release programme, but I'm having trouble getting rid of the black square (representing another camera) when I initially press the key, &  the camera only takes pictures, not a live feed which I don't want!
And how would I add another two cameras?

here's my code so far:

import processing.video.*;
Capture myCapture;

void setup()
{
size(200, 200);
 myCapture = new Capture (this, width, height, 30);
 myCapture.frameRate(30);

}
int value = 0;

void draw() {
fill(value);
rect(25, 2, 50, 50);
}

void keyReleased() {
if (value == 0) {
 if(myCapture.available()) {
 myCapture.read();
}
 image(myCapture, 0, 0);
} else {
 value = 0;
}
}

any suggestions would be great!

Thanks