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
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)
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.
- variables that shadow vers declared earlier
- Py_Fatal print an error to the stderr
- gcc was complaining about the order of initialized vars (for classes)
- const return values for ints and bools didnt do anything.
- braces for ambiguous if statements
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
Grease Pencil is a tool which allows you to draw freehand in some views, allowing you to annotate/scribble over the contents of that view in either 2d or 3d. This facilitates many easier communication and planning abilities.
To use, simply enable it from the View menu (choose 'Grease Pencil...' and click 'Use Grease Pencil'). Then, click+drag using the left-mouse button and the shift-key held to draw a stroke.
For more information, check the following page on the wiki:
http://wiki.blender.org/index.php/User:Aligorith/247_Grease_Pencil
First batch of optimizaton of the bullet adaptation layer in the BGE.
- remove circular motion state update.
- optimization of physic adaptation layer for bullet: bypass
unecessary conversion of rotation matrix to quaternion and back.
- remove double updates during object replication.
This patch introduces two options for the motion actuator:
damping: number of frames to reach the target velocity. It takes
into account the startup velocityin the target velocity direction
and add 1/damping fraction of target velocity until the full
velocity is reached. Works only with linear and angular velocity.
It will be extended to delta and force motion method in a future
release.
clamping: apply the force and torque as long as the target velocity
is not reached. If this option is set, the velocity specified
in linV or angV are not applied to the object but used as target
velocity. You should also specify a force in force or torque field:
the force will be applied as long as the velocity along the axis of
the vector set in linV or angV is not reached. Works best in low
friction environment.
AddObject actuator forces last created object to hang in memory even after object is removed from scene => bad link between object and physic controller that causes Blender to crash in case a python script tries to use it (bad programming anyway).
This patch avoids the crash by maintaining consistent links at all time.
added raycast support for bullet (no triangle-mesh support, soon)
added python methods for 'getHitObject', getRayDirection, getHitPosition and getHitNormal for mouse over sensor,
which makes it easy for a shootout.blend demo :)
