how can i move static box2d object

Question

how can i move static box2d sprites. i have tried this tutorial from . http://www.raywenderlich.com/475/how-to-create-a-simple-breakout-game-with-box2d-and-cocos2d-tutorial-part-12.

I managed to add another "paddle" object with box2d body, but i can seam to be able to make the code to move the second "paddle" body. Can anyone direct me how to do it?

Is there a way to move a "b2_staticBody" box 2d object? i have tried, but i can only move it when i use "b2_dynamicBody" if i used "b2_staticBody" i can move it at all.

Answer 1

You want to use a dynamic body, if you want bodies to move in your physics. That is, the nature of bodies in box2d. You make a dynamic body, and apply impulse or force to it in the direction you want it to move.

I recently wrote this very basic tutorial to create a pong game using Farseer physics engine (which is a C# port of Box2d), so the same things would apply.

Also, it would help to know what kind of a game are you making ?

Answer 2

I'm not sure which version you are working with, but version 2.1.0 has 'kinematic bodies'.

Instead of bodyDef.type = b2_dynamicBody; you would put bodyDef.type = b2_kinematicBody;.

They are sort of like static bodies, only you can move them. They only move how you tell them to, so they aren't affected by collisions or other forces (like gravity).

From the box2d docs at http://www.box2d.org/manual.html

A kinematic body moves under simulation according to its velocity. Kinematic bodies do not respond to forces. They can be moved manually by the user, but normally a kinematic body is moved by setting its velocity. A kinematic body behaves as if it has infinite mass, however, Box2D stores zero for the mass and the inverse mass. Kinematic bodies do not collide with other static or kinematic bodies.