blender/source/gameengine/SceneGraph
Benoit Bolsee 3ea1c1b4b6 BGE: new sensor object to generalize Near and Radar sensor, static-static collision capbility.
A new type of "Sensor" physics object is available in the GE for advanced
collision management. It's called Sensor for its similarities with the
physics objects that underlie the Near and Radar sensors.
Like the Near and Radar object it is:
- static and ghost
- invisible by default
- always active to ensure correct collision detection
- capable of detecting both static and dynamic objects
- ignoring collision with their parent
- capable of broadphase filtering based on:
  * Actor option: the collisioning object must have the Actor flag set to be detected
  * property/material: as specified in the collision sensors attached to it
  Broadphase filtering is important for performance reason: the collision points
  will be computed only for the objects that pass the broahphase filter.
- automatically removed from the simulation when no collision sensor is active on it

Unlike the Near and Radar object it can:
- take any shape, including triangle mesh
- be made visible for debugging (just use the Visible actuator)
- have multiple collision sensors using it

Other than that, the sensor objects are ordinary objects. You can move them
freely or parent them. When parented to a dynamic object, they can provide
advanced collision control to this object.

The type of collision capability depends on the shape:
- box, sphere, cylinder, cone, convex hull provide volume detection.
- triangle mesh provides surface detection but you can give some volume
  to the suface by increasing the margin in the Advanced Settings panel.
  The margin applies on both sides of the surface.

Performance tip:
- Sensor objects perform better than Near and Radar: they do less synchronizations
  because of the Scenegraph optimizations and they can have multiple collision sensors
  on them (with different property filtering for example).
- Always prefer simple shape (box, sphere) to complex shape whenever possible.
- Always use broadphase filtering (avoid collision sensor with empty propery/material)
- Use collision sensor only when you need them. When no collision sensor is active
  on the sensor object, it is removed from the simulation and consume no CPU.

Known limitations:
- When running Blender in debug mode, you will see one warning line of the console:
  "warning btCollisionDispatcher::needsCollision: static-static collision!"
  In release mode this message is not printed.
- Collision margin has no effect on sphere, cone and cylinder shape.

Other performance improvements:
- Remove unnecessary interpolation for Near and Radar objects and by extension
  sensor objects.
- Use direct matrix copy instead of quaternion to synchronize orientation.

Other bug fix:
- Fix Near/Radar position error on newly activated objects. This was causing
  several detection problems in YoFrankie
- Fix margin not passed correctly to gImpact shape.
- Disable force/velocity actions on static objects
2009-05-17 12:51:51 +00:00
..
CMakeLists.txt Patch from GSR that a) fixes a whole bunch of GPL/BL license 2008-04-16 22:40:48 +00:00
Makefile Patch from GSR that a) fixes a whole bunch of GPL/BL license 2008-04-16 22:40:48 +00:00
SConscript SCons: 2009-02-15 23:26:00 +00:00
SG_BBox.cpp BGE Scenegraph and View frustrum culling improvement. 2009-04-07 22:14:06 +00:00
SG_BBox.h BGE Scenegraph and View frustrum culling improvement. 2009-04-07 22:14:06 +00:00
SG_Controller.cpp Patch from GSR that a) fixes a whole bunch of GPL/BL license 2008-04-16 22:40:48 +00:00
SG_Controller.h BGE logic patch: new "Add" mode for Ipo actuator, several corrections in state system. 2008-07-08 12:18:43 +00:00
SG_DList.h BGE performance, 4th round: logic 2009-05-10 20:53:58 +00:00
SG_IObject.cpp BGE performance: second round of scenegraph improvement. 2009-05-03 22:29:00 +00:00
SG_IObject.h BGE: new sensor object to generalize Near and Radar sensor, static-static collision capbility. 2009-05-17 12:51:51 +00:00
SG_Node.cpp Fix an undefined variable bug detected by valgrind. 2009-05-05 22:32:15 +00:00
SG_Node.h BGE performance: second round of scenegraph improvement. 2009-05-03 22:29:00 +00:00
SG_ParentRelation.h BGE Scenegraph and View frustrum culling improvement. 2009-04-07 22:14:06 +00:00
SG_QList.h BGE performance, 4th round: logic 2009-05-10 20:53:58 +00:00
SG_Spatial.cpp BGE performance, 3rd round: culling and rasterizer. 2009-05-07 09:13:01 +00:00
SG_Spatial.h BGE: new sensor object to generalize Near and Radar sensor, static-static collision capbility. 2009-05-17 12:51:51 +00:00
SG_Tree.cpp Patch from GSR that a) fixes a whole bunch of GPL/BL license 2008-04-16 22:40:48 +00:00
SG_Tree.h Patch from GSR that a) fixes a whole bunch of GPL/BL license 2008-04-16 22:40:48 +00:00