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().
Clamp objects min/max velocity.
Accessed with bullet physics from the advanced button with dynamic and rigid body objects.
- useful for preventing unstable physics in cases where objects move too fast.
- can add linear velocity with the motion actuator to give smooth motion transitions, without moving too fast.
- minimum velocity means objects don't stop moving.
- python scripts can adjust these values speedup or throttle velocity in the existing direction.
Also made copy properties from an object with no properties work (in case you want to clear all props)
Added occlusion culling capability in the BGE.
More info: http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.49/Game_Engine#BGE_Scenegraph_improvement
MSVC, scons, cmake, Makefile updated.
Other minor performance improvements:
- The rasterizer was computing the openGL model matrix of the objects too many times
- DBVT view frustrum culling was not properly culling behind the near plane:
Large objects behind the camera were sent to the GPU
- Remove all references to mesh split/join feature as it is not yet functional
This commit contains a number of performance improvements for the
BGE in the Scenegraph (parent relation between objects in the
scene) and view frustrum culling.
The scenegraph improvement consists in avoiding position update
if the object has not moved since last update and the removal
of redundant updates and synchronization with the physics engine.
The view frustrum culling improvement consists in using the DBVT
broadphase facility of Bullet to build a tree of graphical objects
in the scene. The elements of the tree are Aabb boxes (Aligned
Axis Bounding Boxes) enclosing the objects. This provides good
precision in closed and opened scenes. This new culling system
is enabled by default but just in case, it can be disabled with
a button in the World settings. There is no do_version in this
commit but it will be added before the 2.49 release. For now you
must manually enable the DBVT culling option in World settings
when you open an old file.
The above improvements speed up scenegraph and culling up to 5x.
However, this performance improvement is only visible when
you have hundreds or thousands of objects.
The main interest of the DBVT tree is to allow easy occlusion
culling and automatic LOD system. This will be the object of further
improvements.
* giving compileflags, cc_compileflags and cxx_compileflags to BlenderLib() now actually overrides any other setting (so there's no unclarity when ie. conflicting options are being specified in REL_CFLAGS et al). These are set after either release or debug flags, but before any *_WARN flags (so those stay maintained).
* add cxx_compileflags for GE parts on win32-vc to have better performance.
* NOTE: if platform maintainers (OSX and Linux) could check and do the same for their systems. Not vital, but probably very, very much welcomed by GE users.
This patch modifies the way the setParent actuator and KX_GameObject::setParent() function
works when parenting to a compound object: the collision shape of the object being parented
is dynamically added to the coumpound shape.
Similarly, unparenting an object from a compound object will cause the child collision shape
to be dynamically removed from the parent shape provided that is was previously added with
setParent.
Note: * This also works if the object is parented to a child of a compound object: the
collision shape is added to the compound shape of the top parent.
* The collision shape is added with the transformation (position, scale and orientation)
it had at the time of the parenting.
* The child shape is rigidly attached to the compound shape, the transformation is not
affected by any further change in position/scale/orientation of the child object.
* While the child shape is added to the compound shape, the child object is removed from
the dynamic world to avoid superposition of shapes (one for the object itself and
one for the compound child shape). This means that collision sensors on the child
object are disabled while the child object is parent to a compound object.
* There is no difference when setParent is used on a non-compound object: the child
object is automatically changed to a static ghost object to avoid bad interaction
with the parent shape; collision sensors on the child object continue to be active
while the object is parented.
* The child shape dynamically added to a compound shape modifies the inertia of the
compound object but not the mass. It participates to collision detection as any other
"static" child shape.
Implementation of the PHY_IPhysicsController::SetMargin(),
GetMargin(), SetRadius() and GetRadius() for Bullet and Sumo
to allow resetting the Near sensor radius. For bullet use
the new setUnscaledRadius() function to change sphere radius.
In pPreparation of a Fh constraint actuator:
- Add KX_IPhysicsController::GetRadius()
- Fix implementation of KX_BulletPhysicsController::GetVelocity()
(velocity at a point in geometric coordinate)
- Don't try to set velocity on static object (Bullet will assert)
- Add KX_GameObject::GetVelocity() for C access to local velocity
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.
The root cause of this bug is the fact that Bullet shapes
are shared between duplicated game objects. As the physics
object scale is stored in the shape, all duplicas must
have the same scale otherwise the physics representation
is incorrect.
This fix introduces a mechanism to duplicate shapes at
runtime so that Bullet shapes are not shared anymore.
The drawback is an increased memory consuption.
A reference count mechanism will be introduced in a
later revision to keep Bullet shape shared between
duplicas that have the same scale.
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.
Note: Visual Studio projectfiles and other buildsystems need to add extern/bullet2/src/BulletDynamics/ConstraintSolver/btConeTwistConstraint.cpp to the project!
+ 'scons blenderplayer' builds blender AND blenderplayer now (tested on Linux
only, but was only linking issue, so should work on other platforms too).
NOTE: I noticed some compileflags for GE specific libs that were left out -
I re-enabled them in the SConscripts, but I'm going to do a test build my-
self now, so if there are problems with them on win32, I probably already
know about them :)
* This commit is all of the rewrite work done on the SCons system. For
documentation see doc/blender-scons.txt and doc/blender-scons-dev.txt.
Also http://mediawiki.blender.org/index.php/BlenderDev/SconsRefactoring
contains valuable information, along with what still needs to be done.
- linux, os x and windows compile now.
- files are compiled to BF_INSTALLDIR (see config/(platform)-config.py)
- NOTE: Jean-Luc P will commit sometime during the weekend proper
appit() for OS X. For now, copy the resulting binary to an
existing .app bundle.
- features:
- cleaner structure for better maintenance
- cleaner output during compile
- better handling of build options
- general overall speed increase
- see the wiki for more info
Cygwin, FreeBSD and Solaris systems still need work. For these systems:
1) copy a config/(platform)-config.py to ie. config/cygwin-config.py
2) set the proper defaults for your platform
3) mail me at jesterking at letwory dot net with you configuration. if
you need any modifications to the system, do send a patch, too.
I'll be giving first-aid today and tomorrow, after that it'll be all
regular development work :)
/Nathan
fixed a python related bug with physics contraints
fixed some line-ending problem with blenderbuttons.c
makefile/scons/projectfiles need to add source/gameengine/Ketsji/KX_VehicleWrapper.cpp
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,
comma at end of enumerator list
If this change causes problems, feel free to back it out.
I am trying to get gcc to complain about mixed declarations and
code since that breaks on platforms that only support C89/C90.
* Blender static now links. By default this option is disabled on all
platforms. Simply set the option in config.opts to 'true'.
* Added the following flags to config.opts:
- HOST_CC. This is the C compiler for the host platform. This value is the
same as TARGET_CC when not cross compiling.
- HOST_CXX. This is the C++ compiler for the host platform. This value is
the same as TARGET_CXX when not cross compiling.
- TARGET_CC. This is the C compiler for the target platform.
- TARGET_CXX. This is the C++ compiler for the target platform.
- TARGET_AR. This is the linker command for linking libraries.
- PATH This is the standard search path
All SConscript files have been updated to reflect these changes. Now it's
possible to change only the root SConstruct file, and all compiler specific
variables are passed automatically to all SConscript files. Of course, this
does not apply to makesdna because there the host and target platform is
different from all other libraries.
To pass a variable that applies to all platforms, all we now have to do is
set the correct value in library_env
Note: as usual, to get the latest options in the config.opts file, first
remove your version.
