box2d

How to detect if body collides other body but do not react on this collision. By default i - detect collision and bodies collide. If i set fixtureDef filter - bodies do not collide but i can not detect collision. Help please! If the fixture never needs to collide with anything you could make it a sensor. If you need it to collide with some things but not others you could do contact->SetEnabled(false) in the PreSolve of the collision listener, depending on what it collided with. What you want here is a sensor fixture on a body. From the box2d manual: Sometimes game logic needs to know when two

I'm attempting to create a "U" shape in Box2d (in Cocos2d) by joining 3 rectangles like so: |_| It sounds like joints are not the correct solution here since I don't want any movement so I have created a main body which is the middle bit and 2 fixtures for the sides. I've added the two sides to the middle bit like this: mainBody->CreateFixture(&leftFixtureDef); mainBody->CreateFixture(&rightFixtureDef); This works, however both side fixtures get added to the center of the mainBody. I can't seem to work out how to position the fixtures relative to the main body. Attaching a sprite/node to the

I'm newbie in box2d. Can you help me? I want to make gun (touch, move, stopped, ball flew). I make detection and rotation of gun, but I can't make popping of ball. How can I count velocity, which I need to set to the ball? Thank you very much The easiest way is to look at the direction the gun is pointing when you define the body, and use GetWorldVector to see how it has changed. For example if the gun is pointing directly upwards when you create the body, this would be the direction (0,1). Then you can use GetWorldVector at any time to get the current direction of that vector in world

I have been creating my own very simple test game based on Breakout while learning SpriteKit (using iOS Games by Tutorials by Ray Wenderlich et al.) to see if I can apply concepts that I have learned. I have decided to simplify my code by using an .sks file to create the sprite nodes and replacing my manual bounds checking and collision with physics bodies. However, my ball keeps running parallel to walls/other rectangles (as in, simply sliding up and down them) any time it collides with them at a steep angle. Here is the relevant code--I have moved the physics body properties into code to