ExtendedPhysics - Revision history

Misterblue: Add description of axis lock functions

2023-05-25T17:28:55Z

Add description of axis lock functions

Misterblue: ExtendedPhysics module documentation

2023-05-25T14:52:58Z

ExtendedPhysics module documentation

New page

= ExtendedPhysics =

'''ExtendedPhysics''' is an OpenSimulator module that adds
LSL functions and constants that provide
physics engine extension functions.

The module is designed so to work with any physics engine
but, at the moment, only '''BulletSim''' implements these functions.
These functions can be called when using any physics engine but
nothing will change.

The OpenSimulator default configuration has '''ExtendedPhysics'''
disabled. To enable '''ExtendedPhysics''', add the following
to any of the configuration INI files:

<pre>
[ExtendedPhysics]
Enabled = true
</pre>

== Informational Functions ==

This request returns the type of the physics engine.
This function returns the same as <code>osGetPhysicsEngineType</code>
which is a string identifying the type of the physics engine.

The BulletSim physics engine returns the string "BulletSim".

The function <code>osGetPhysicsEngineName</code> returns a string
that has additional information than just the type.
For instance, version numbers or types of accelerators being used.

<pre>
string physType = physGetEngineType();
string morePhysType = osGetPhysicsEngineName();
llOwnerSay(0, "Physics engine type = " + physType);
llOwnerSay(0, "Physics engine type again = " + morePhysType);
</pre>

== Disable Deactivation Function ==

Disable physics deactivation on the containing physical object.

The Bullet physics engine saves CPU cycles by only
checking "active" physical objects. Physical objects start out
active and are deactivated when their linear or angular velocity
falls below some threshold. For instance, if a scene has 100
physical balls that are dropped and roll around, the physics
engine has to test each of the 100 balls multiple times a second
to compute their movement. As some of the balls slow down and
stop moving, the balls are stopped and "deactivated" and thus
the physics engine doesn't need to check the stopped physical
object any more.

Physical objects are re-activated when another physical object
bumps into them but otherwise, they stay still.

This deactivation is usually a great CPU saver but there are cases
where it causes objects with small movements or movements that are
effected by non-physical objects. A ball on a tilting surface, for
instance.

This function disables deactivation -- setting "true" means the object
will never be deactivated.

<code>
<pre>
physDisableDeactivation(TRUE);
</pre>
</code>

== Axis Lock Functions ==

<pre>
physAxisLock(int lockFlags, ...)
PHYS_AXIS_LOCK_LINEAR = 14700;
PHYS_AXIS_LOCK_LINEAR_X = 14701;
PHYS_AXIS_LIMIT_LINEAR_X = 14702;
PHYS_AXIS_LOCK_LINEAR_Y = 14703;
PHYS_AXIS_LIMIT_LINEAR_Y = 14704;
PHYS_AXIS_LOCK_LINEAR_Z = 14705;
PHYS_AXIS_LIMIT_LINEAR_Z = 14706;
PHYS_AXIS_LOCK_ANGULAR = 14707;
PHYS_AXIS_LOCK_ANGULAR_X = 14708;
PHYS_AXIS_LIMIT_ANGULAR_X = 14709;
PHYS_AXIS_LOCK_ANGULAR_Y = 14710;
PHYS_AXIS_LIMIT_ANGULAR_Y = 14711;
PHYS_AXIS_LOCK_ANGULAR_Z = 14712;
PHYS_AXIS_LIMIT_ANGULAR_Z = 14713;
PHYS_AXIS_UNLOCK_LINEAR = 14714;
PHYS_AXIS_UNLOCK_LINEAR_X = 14715;
PHYS_AXIS_UNLOCK_LINEAR_Y = 14716;
PHYS_AXIS_UNLOCK_LINEAR_Z = 14717;
PHYS_AXIS_UNLOCK_ANGULAR = 14718;
PHYS_AXIS_UNLOCK_ANGULAR_X = 14719;
PHYS_AXIS_UNLOCK_ANGULAR_Y = 14720;
PHYS_AXIS_UNLOCK_ANGULAR_Z = 14721;
PHYS_AXIS_UNLOCK = 14722;
</pre>

== Linkset Manipulation Functions ==

<pre>
PHYS_LINKSET_TYPE_CONSTRAINT = 0;
PHYS_LINKSET_TYPE_COMPOUND = 1;
PHYS_LINKSET_TYPE_MANUAL = 2;

public int physSetLinksetType(int linksetType)

int lsType = physGetLinksetType();

PHYS_LINK_TYPE_FIXED = 1234;
PHYS_LINK_TYPE_HINGE = 4;
PHYS_LINK_TYPE_SPRING = 9;
PHYS_LINK_TYPE_6DOF = 6;
PHYS_LINK_TYPE_SLIDER = 7;

physChangeLinkType(int linkNum, int lType)

physGetLinkType(int linkNum)

physChangeLinkFixed(int linkNum)

PHYS_PARAM_FRAMEINA_LOC = 14401;
PHYS_PARAM_FRAMEINA_ROT = 14402;
PHYS_PARAM_FRAMEINB_LOC = 14403;
PHYS_PARAM_FRAMEINB_ROT = 14404;
PHYS_PARAM_LINEAR_LIMIT_LOW = 14405;
PHYS_PARAM_LINEAR_LIMIT_HIGH = 14406;
PHYS_PARAM_ANGULAR_LIMIT_LOW = 14407;
PHYS_PARAM_ANGULAR_LIMIT_HIGH = 14408;
PHYS_PARAM_USE_FRAME_OFFSET = 14409;
PHYS_PARAM_ENABLE_TRANSMOTOR = 14410;
PHYS_PARAM_TRANSMOTOR_MAXVEL = 14411;
PHYS_PARAM_TRANSMOTOR_MAXFORCE = 14412;
PHYS_PARAM_CFM = 14413;
PHYS_PARAM_ERP = 14414;
PHYS_PARAM_SOLVER_ITERATIONS = 14415;
PHYS_PARAM_SPRING_AXIS_ENABLE = 14416;
PHYS_PARAM_SPRING_DAMPING = 14417;
PHYS_PARAM_SPRING_STIFFNESS = 14418;
PHYS_PARAM_LINK_TYPE = 14419;
PHYS_PARAM_USE_LINEAR_FRAMEA = 14420;
PHYS_PARAM_SPRING_EQUILIBRIUM_POINT = 14421;

PHYS_AXIS_ALL = -1;
PHYS_AXIS_LINEAR_ALL = -2;
PHYS_AXIS_ANGULAR_ALL = -3;
PHYS_AXIS_LINEAR_X = 0;
PHYS_AXIS_LINEAR_Y = 1;
PHYS_AXIS_LINEAR_Z = 2;
PHYS_AXIS_ANGULAR_X = 3;
PHYS_AXIS_ANGULAR_Y = 4;
PHYS_AXIS_ANGULAR_Z = 5;

physChangeLinkParams(params ....)
</pre>

@@ Line 72: / Line 72: @@
 == Axis Lock Functions ==
 <pre>
-physAxisLock(int lockFlags, ...)
+    physAxisLock(PHYS_AXIS_LOCK_ANGULAR, PHYS_AXIS_LOCK_LINEAR_Y, PHYS_AXIS_LOCK_LINEAR_X);
-        PHYS_AXIS_LOCK_LINEAR     = 14700;
-        PHYS_AXIS_LOCK_LINEAR_X   = 14701;
-        PHYS_AXIS_LIMIT_LINEAR_X  = 14702;
-        PHYS_AXIS_LOCK_LINEAR_Y   = 14703;
-        PHYS_AXIS_LIMIT_LINEAR_Y  = 14704;
-        PHYS_AXIS_LOCK_LINEAR_Z   = 14705;
-        PHYS_AXIS_LIMIT_LINEAR_Z  = 14706;
-        PHYS_AXIS_LOCK_ANGULAR    = 14707;
-        PHYS_AXIS_LOCK_ANGULAR_X  = 14708;
-        PHYS_AXIS_LIMIT_ANGULAR_X = 14709;
-        PHYS_AXIS_LOCK_ANGULAR_Y  = 14710;
-        PHYS_AXIS_LIMIT_ANGULAR_Y = 14711;
-        PHYS_AXIS_LOCK_ANGULAR_Z  = 14712;
-        PHYS_AXIS_LIMIT_ANGULAR_Z = 14713;
-        PHYS_AXIS_UNLOCK_LINEAR   = 14714;
-        PHYS_AXIS_UNLOCK_LINEAR_X = 14715;
-        PHYS_AXIS_UNLOCK_LINEAR_Y = 14716;
-        PHYS_AXIS_UNLOCK_LINEAR_Z = 14717;
-        PHYS_AXIS_UNLOCK_ANGULAR  = 14718;
-        PHYS_AXIS_UNLOCK_ANGULAR_X = 14719;
-        PHYS_AXIS_UNLOCK_ANGULAR_Y = 14720;
-        PHYS_AXIS_UNLOCK_ANGULAR_Z = 14721;
-        PHYS_AXIS_UNLOCK           = 14722;
 </pre>
 == Linkset Manipulation Functions ==