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
This function sets the maximum number of logic frame executed per render frame.
Valid values: 1..5
This function is useful to control the amount of processing consumed by logic.
By default, up to 5 logic frames can be executed per render frame. This is fine
as long as the time spent on logic is negligible compared to the render time.
If it's not the case, the default value will drag the performance of the game
down by executing unnecessary logic frames that take up most of the CPU time.
You can avoid that by lowering the value with this function.
The drawback is less precision in the logic system to physics and I/O activity.
Note that it does not affect the physics system: physics will still run
at full frame rate (actually up to 5 times the ticrate).
You can further control the render frame rate with GameLogic.setLogicTicRate().
rayCast(to,from,dist,prop,face,xray,poly):
The face paremeter determines the orientation of the normal:
0 or omitted => hit normal is always oriented towards the ray origin (as if you casted the ray from outside)
1 => hit normal is the real face normal (only for mesh object, otherwise face has no effect)
The ray has X-Ray capability if xray parameter is 1, otherwise the first object hit (other than self object) stops the ray.
The prop and xray parameters interact as follow:
prop off, xray off: return closest hit or no hit if there is no object on the full extend of the ray.
prop off, xray on : idem.
prop on, xray off: return closest hit if it matches prop, no hit otherwise.
prop on, xray on : return closest hit matching prop or no hit if there is no object matching prop on the full extend of the ray.
if poly is 0 or omitted, returns a 3-tuple with object reference, hit point and hit normal or (None,None,None) if no hit.
if poly is 1, returns a 4-tuple with in addition a KX_PolyProxy as 4th element.
The KX_PolyProxy object holds information on the polygon hit by the ray: the index of the vertex forming the poylgon, material, etc.
Attributes (read-only):
matname: The name of polygon material, empty if no material.
material: The material of the polygon
texture: The texture name of the polygon.
matid: The material index of the polygon, use this to retrieve vertex proxy from mesh proxy
v1: vertex index of the first vertex of the polygon, use this to retrieve vertex proxy from mesh proxy
v2: vertex index of the second vertex of the polygon, use this to retrieve vertex proxy from mesh proxy
v3: vertex index of the third vertex of the polygon, use this to retrieve vertex proxy from mesh proxy
v4: vertex index of the fourth vertex of the polygon, 0 if polygon has only 3 vertex
use this to retrieve vertex proxy from mesh proxy
visible: visible state of the polygon: 1=visible, 0=invisible
collide: collide state of the polygon: 1=receives collision, 0=collision free.
Methods:
getMaterialName(): Returns the polygon material name with MA prefix
getMaterial(): Returns the polygon material
getTextureName(): Returns the polygon texture name
getMaterialIndex(): Returns the material bucket index of the polygon.
getNumVertex(): Returns the number of vertex of the polygon.
isVisible(): Returns whether the polygon is visible or not
isCollider(): Returns whether the polygon is receives collision or not
getVertexIndex(vertex): Returns the mesh vertex index of a polygon vertex
getMesh(): Returns a mesh proxy
New methods of KX_MeshProxy have been implemented to retrieve KX_PolyProxy objects:
getNumPolygons(): Returns the number of polygon in the mesh.
getPolygon(index): Gets the specified polygon from the mesh.
More details in PyDoc.
With this patch, only sensors that are connected to
active states are actually registered in the logic
manager. Inactive sensors won't take any CPU,
especially the Radar and Near sensors that use a
physical object for the detection: these objects
are removed from the physics engine.
To take advantage of this optimization patch, you
need to define very light idle state when the
objects are inactive: make them transparent, suspend
the physics, keep few sensors active (e,g a message
sensor to wake up), etc.
remove constraint fixed,
Bullet timestep now subdivides Blender game engine timestep, so it runs 60 hertz,
SphereShape reverted to old style, so no support for non-uniform scaled spheres for now,
I got rid of a few warnings about blah shadows a previous declaration.
In the gameengine files I fix the following:
removed some unused vars
removed dos style line breaks
added newlines to last line in a couple of files to remove warnings.
Kent
Keyboard sensors can now hook escape key. Ctrl-Break can be used from within blender if you've forgotten an end game actuator.
Fixed a stupid bug preventing some actuators working (like TrackTo).
Consider:
gameobj->getClientInfo()->m_auxilary_info = (matname ? (void*)(matname+2) : NULL);
It works if matname is "MAblah", but not if matname is "".
2. Added constructor for struct RAS_CameraData.
3. Added initializers to the struct KX_ClientObjectInfo constructor
4. Collision sensors won't detect near sensors.
5. A stack of minor tweaks, adjusting whitespace, using ++it for stl stuff.
[SCons] Build with Solid as default when enabling the gameengine in the build process
[SCons] Build solid and qhull from the extern directory and link statically against them
That was about it.
There are a few things that needs double checking:
* Makefiles
* Projectfiles
* All the other systems than Linux and Windows on which the build (with scons) has been successfully tested.
