// calculate the x-direction on collision
public void bounceX() {
double tx = vel * Math.cos(theta);
double ty = vel * Math.sin(theta);
theta = Math.atan2(ty, -tx);
if (x < 0) {
x = -x;
}
if (x > Engine.getGameWidth()) {
x = Engine.getGameWidth() * 2 - x;
}
if (x < 0 || x > Engine.getGameWidth()) {
x = Math.random() * Engine.getGameWidth();
}
}
public Entity(boolean left) {
this();
theta = (Math.random() - .5) * Math.PI;
vel = Math.random() * 3;
if (left) x = 1;
else x = Engine.getGameWidth() - 1;
theta += Math.PI;
}
public Entity() {
x = Math.random() * Engine.getGameWidth();
y = Math.random() * Engine.getGameHeight();
fTheta = Math.random() * Math.PI * 2;
pTheta = Math.random() * Math.PI * 2;
dFTheta = (Math.random() * 2 - 1) * Math.PI / 50;
dPTheta = (Math.random() * 2 - 1) * Math.PI / 50;
mass = 100;
}