Game Engine - Forces

Gravity

Gravity is automatically built into the world.
Gravity is a vertically downward vector.

Impulse

Impulse is force applied at a moment in time.

Vec2 impulse = new Vec2(2,4);   // 2-right, 4-down
box.applyImpulse(impulse, box.getWorldCenter());

Designing the Catapult Implementation

Impulse

I = C(catapult - ball)

Vec2 impulse = new Vec2();
impulse.set(catapultPos);
impulse = impulse.sub(boid.getWorldCenter());
impulse = impulse.mul(200);

 Collisions are handled by the physics engine.

• The key knowledge is to know when a collision happened

Collision handler function

void collision(Body b1, Body b2, float impulse) {
  // collision response goes here
}