I'm using Box2D and cocos2d-x but I can't figure the coordinate system out.
I know cocos2d-x uses P(0,0) as the bottom left part of the screen.
And Box2D uses P(0, 0) as the center of it's world.
I'm using debug draw for Box2D.
When creating a body with a polygon shape attached to it at P(0,0) in Box2D coordinates it shows up on the bottom left part of the screen.
Why doesn't it show up in the center?
When positioning any b2Body, use Sprite::getBoundingBox().getMidX() for the horizontal center, and for the vertical center use Sprite::getBoundingBox().getMidY().
You might want to wrap those calls in a Node::convertToWorldSpace(midX, midY) to make sure that your center coordinates are expanded into the cocos2d-x world coordinate system and hence the Box2D world coordinate space as it has to be consistent.
