Making sprite bounce in an angle in box2d

Question

In the game I'm trying to make, I have a ball sprite which bounces thanks to box2d. Here's how my current code looks:

-(id)init
{
    ball = [CCSprite spriteWithFile:@"ball.png"];
    ball.position = ccp(150, winSize.height * 0.78);
    [self addChild:ball];
    ball.tag = 2;

b2BodyDef ballBodyDef;
ballBodyDef.type = b2_dynamicBody;
ballBodyDef.position.Set(150/PTM_RATIO, 450/PTM_RATIO);
ballBodyDef.userData = ball;
_body = _world->CreateBody(&ballBodyDef);

b2CircleShape circle;
circle.m_radius = 26.0/PTM_RATIO;

b2FixtureDef ballShapeDef;
ballShapeDef.shape = &circle;
ballShapeDef.density = 0.5f;
ballShapeDef.friction = 1.0f;
ballShapeDef.restitution = 1.0f;
_ballFixture = _body->CreateFixture(&ballShapeDef);

b2Vec2 force = b2Vec2(160, 375);
_body->ApplyLinearImpulse(force, ballBodyDef.position);}

- (void)update:(ccTime) dt {
if(_isPaused == FALSE)
{
    _world->Step(dt, 10, 10);
    for(b2Body *b = _world->GetBodyList(); b; b=b->GetNext()) {
        if (b->GetUserData() != NULL) {
            CCSprite *sprite = (CCSprite *)b->GetUserData();
            if(sprite.tag == 2)
            {
                sprite.position = ccp(b->GetPosition().x * PTM_RATIO,
                              b->GetPosition().y * PTM_RATIO);
                sprite.rotation = -1 * CC_RADIANS_TO_DEGREES(b->GetAngle());
            }
        }
    }}

Bouncing itself works fine, my problem is there are instances wherein the ball would bounce on a straight line so to speak, either vertically or horizontally continuously which I am trying to avoid. So my question is, how can I make my ball sprite bounce at an angle instead of a straight line so it wouldn't get stuck bouncing infinitely in the same direction?

Benoît Lahoz Benoît Lahoz · Accepted Answer · 2013-03-09T08:34:48

You could apply a tiny force or gravity change to the body or the world, "randomly" or at equal intervals.

Making sprite bounce in an angle in box2d

1 Answers