Ball.java

import processing.core.*;

public class Ball extends Simulatable implements ShapeCircle, Drawable{

	public float kAtrito = 17f;

	public float getMass(){
		return 0.300f;
	}
	public float getRadius(){
		return 0.05f;
	}

	public float getKFactor(){
		return 1.0f;
	}

	public boolean canCollide(Simulatable s){
		if(s instanceof Goal && !(s instanceof GoalWall))
			return false;

		return true;
	}

	boolean isOn = true;
	public boolean isOn(){
		return isOn;
	}

	public void setOn(boolean on){
		isOn = on;
	}

	// public boolean colliding(Simulatable b){
		
	// 	return is;
	// }

	/*
		Sets position of Ball and reset's speed, acceleration and force
	*/
	public void setPosition(PVector p){
		force.set(0,0);
		accel.set(0,0);
		speed.set(0,0);
		position.set(p.x,p.y);
	}

	public PVector getForce(float dt){
		PVector forceSum = super.getForce(dt);
		PVector atrito = getRealSpeed();
		atrito.mult(dt);
		atrito.mult(-1 * kAtrito);

		forceSum.add(atrito);
		return forceSum;
	}

	int ds = 0;
	public void draw(PApplet canvas, float scale){

		if(isOn())
			canvas.fill(255,255,0);
		else
			canvas.fill(100,100,100);

		canvas.stroke(0);
		float size = getRadius() * scale * 2;
		canvas.ellipse(position.x * scale, position.y * scale, size, size);
	}

}