Blender Git Loki

BGE patch: new force field constraint actuator

A new type of constraint actuator is available: Force field.
It provides a very similar service to the Fh material feature
but with some specificities:
- It is defined at the object level: each object can have
different settings and you don't need to use material.
- It can be applied in all 6 directions and not just -Z.
- It can be enabled/disabled easily (it's an actuator).
- You can have multiple force fields active at the same time
on the same object in different direction (think of a
space ship in a tunnel with a repulsive force field
on each wall).
- You can have a different damping for the rotation.

Besides that it provides the same dynamic behavior and the
parameters are self explanatory.
It works by adapting the linear and angular velocity: the
dynamic is independent of the mass. It is compatible with
all other motion actuators.

Note: linear and anysotropic friction is not yet implemented,
the only friction will come from the object damping parameters.
Support for friction will be added in a future revision.