Control number of PShapes in scene with key input - processing

Question

I am trying to make a certain ammount of PShapes display in the scene, this is done by using keys from 0-9. The objects themselves do appear, but respawn endlesly. I am using an arrayList to store them. I suspect there is something wrong with the for loop that reads the shapes from the array... but I cannot figure it out...
import java.io.*;
import java.util.Random;
import java.util.ArrayList;
Random rnd = new Random();
PShape torus;
int nTorus;
ArrayList<PShape> toruses;
void settings() {
size(640, 480, P3D);
}
void setup() {
toruses = new ArrayList();
}
void draw() {
background(0);
for (PShape torus : toruses) {
pushMatrix();
translate((int)(rnd.nextDouble() * 1000-1000), (int)(rnd.nextDouble() * 1000-1000), (int)(rnd.nextDouble() * 1000-1000));
shape(torus);
popMatrix();
}
}
void keyPressed() {
if (key == '1') {
nTorus = 1;
} else if (key == '2') {
nTorus = 2;
} else if (key == '3') {
nTorus = 3;
} else if (key == '4') {
nTorus = 4;
} else if (key == '5') {
nTorus = 5;
} else if (key == '6') {
nTorus = 6;
} else if (key == '7') {
nTorus = 7;
} else if (key == '8') {
nTorus = 8;
} else if (key == '9') {
nTorus = 9;
} else if (key == '0') {
nTorus = 0;
}
toruses.clear();
for (int i = 0; i < nTorus; i++) {
PShape tShape = getTorus((int)(rnd.nextDouble() * 200+50), (int)(rnd.nextDouble() * 100+50), 32, 32);
toruses.add(tShape);
}
}

Answer 1

You've got a few things going on in your code:
Why are you constantly checking the key every time the draw() function is called?
You actually check it twice, since you also call the createTorus() function from draw() for some reason.
The key variable holds the last pressed key, so that big if statement in your draw() function will always be entered.
Instead of constantly checking from the draw() function, you'll be better off using the keyPressed() function. That way you can take action only when the user actually presses a key. Then from the draw() function, the only thing you need to do is actually draw what's in the ArrayList.
Here is a small example that takes that approach to draw points based on user input:
ArrayList<PVector> points = new ArrayList<PVector>();
void setup() {
size(500, 500);
}
void keyPressed() {
int pointCount = 0;
if (key == '1') {
pointCount = 1;
} else if (key == '2') {
pointCount = 2;
} else if (key == '3') {
pointCount = 3;
} else if (key == '4') {
pointCount = 4;
} else if (key == '5') {
pointCount = 5;
} else if (key == '6') {
pointCount = 6;
} else if (key == '7') {
pointCount = 7;
} else if (key == '8') {
pointCount = 8;
} else if (key == '9') {
pointCount = 9;
}
points.clear();
for (int i = 0; i < pointCount; i++) {
points.add(new PVector(random(width), random(height)));
}
}
void draw() {
background(0);
for (PVector point : points) {
ellipse(point.x, point.y, 10, 10);
}
}