Contents
How does a rigid body work in Box2D?
Bodies are always rigid bodies in Box2D. That means that two fixtures attached to the same rigid body never move relative to each other and fixtures attached to the same body don’t collide. Fixtures have collision geometry and density. Normally, bodies acquire their mass properties from the fixtures.
How does Box2D copy data out of the body definition?
Box2D copies the data out of the body definition; it does not keep a pointer to the body definition. This means you can recycle a body definition to create multiple bodies. Let’s go over some of the key members of the body definition.
When does a body wake up in Box2D?
When Box2D determines that a body (or group of bodies) has come to rest, the body enters a sleep state which has very little CPU overhead. If a body is awake and collides with a sleeping body, then the sleeping body wakes up. Bodies will also wake up if a joint or contact attached to them is destroyed. You can also wake a body manually.
Which is the most complex part of Box2D?
The Dynamics module is the most complex part of Box2D and is the part you likely interact with the most. The Dynamics module sits on top of the Common and Collision modules, so you should be somewhat familiar with those by now. The Dynamics module contains: fixture class rigid body class contact class joint classes world class listener classes
How big should an object be in Box2D?
Caution: Box2D is tuned for MKS units. Keep the size of moving objects roughly between 0.1 and 10 meters. You’ll need to use some scaling system when you render your environment and actors. The Box2D testbed does this by using an OpenGL viewport transform.
Can a Physics World be created in Box2D?
A physics world is a collection of bodies, fixtures, and constraints that interact together. Box2D supports the creation of multiple worlds, but this is usually not necessary or desirable.
How is Box2D used in a game engine?
Box2D is a 2D rigid body simulation library for games. Programmers can use it in their games to make objects move in realistic ways and make the game world more interactive. From the game engine’s point of view, a physics engine is just a system for procedural animation. Box2D is written in portable C++.
Can a dynamic body collide with all body types?
A dynamic body can collide with all body types. A dynamic body always has finite, non-zero mass. If you try to set the mass of a dynamic body to zero, it will automatically acquire a mass of one kilogram and it won’t rotate. Bodies are the backbone for fixtures (shapes).