BulletSim/Functionality
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Revision as of 11:19, 17 January 2013 by Misterblue (Talk | contribs)
BulletSim Functionality
This page lists OpenSimulator physics operations and, in particular, the detailed vehicle parameters. The BulletSim implementation state is listed as well as some comments about the functionality.
| Function | Impl | Commentary |
|---|---|---|
| linksets | Y | BulletSim has two implementations of linksets: constraints and compound. The default is "compound". The type is selected by an INI file setting. "Constraint" creates the linkset by creating static physical constraints between the objects of the linkset. This is good for small linksets and will be extended in the future to allow other than static constraints (hinges, sliders, ...). "Compound" creates the linkset by combining all the children meshes into one compound physical shape. This creates a very stable physical shape and works well for large linksets. |
| llApplyImpulse | Y | |
| llApplyRotationalImpulse | N | |
| llMoveToTarget | Y/N | what it does |
| llCastRay | N | |
| llGetAccel | N | |
| llGetBoundingBox | semi | Current implementation (20130117) computes the bounding box of the root prim or the avatar. Linksets are not implemented. This computation is done in the LSL implementation code and is not done by the physics engine. |
| llGetCenterOfMass | Y | As per tradition, this actually returns the geometric center of the prim or linkset. Not the actual center-of-mass. |
| llGetForce | Y | |
| llGetGeometricCenter | Y | |
| llGetMass | Y | |
| llGetMassMKS | N | This function is not yet implemented in OpenSimulator (20130117). |
| PRIM_TYPE_* | Y | The OpenSimulator meshmerizer creates meshes for all types of prim shapes including sculpties. For better storage and performance, BulletSim uses physics engine native shapes for cubes, rectangles and spheres. The mesh shapes are shared once created so having many toruses of the same size creates only one mesh that is shared by all the instances. |
| PRIM_SLICE | N | |
| PRIM_PHYSICS_SHAPE_CONVEX | semi | OpenSimulator does not set or return this value. BulletSim internally converts all physical shapes to convex hulls for performance. This is done with the | HACD : Hierarchical Approximate Convex Decomposition algorithm. Currently (20130117), the code is in C# and checked into OpenSimulator core but future versions will use the version included in Bullet. Future implementations should us any convex hull shipped with the mesh. |
| PRIM_MATERIAL_* | Y | Setting materials modifies the friction and restitution of the physical prim. Density is not changed. |
| PRIM_PHANTOM | Y | |
| object collisions | Y | |
| linkset child collisions | N |
