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A constraint. More...
#include <PxConstraintDesc.h>
Public Attributes | |
| PxVec3 | linear0 |
| linear component of velocity jacobian in world space More... | |
| PxReal | geometricError |
| geometric error of the constraint along this axis More... | |
| PxVec3 | angular0 |
| angular component of velocity jacobian in world space More... | |
| PxReal | velocityTarget |
| velocity target for the constraint along this axis More... | |
| PxVec3 | linear1 |
| linear component of velocity jacobian in world space More... | |
| PxReal | minImpulse |
| minimum impulse the solver may apply to enforce this constraint More... | |
| PxVec3 | angular1 |
| angular component of velocity jacobian in world space More... | |
| PxReal | maxImpulse |
| maximum impulse the solver may apply to enforce this constraint More... | |
| union { | |
| struct SpringModifiers { | |
| PxReal stiffness | |
| spring parameter, for spring constraints More... | |
| PxReal damping | |
| damping parameter, for spring constraints More... | |
| } spring | |
| struct RestitutionModifiers { | |
| PxReal restitution | |
| restitution parameter for determining additional "bounce" More... | |
| PxReal velocityThreshold | |
| minimum impact velocity for bounce More... | |
| } bounce | |
| } | mods |
| PxReal | forInternalUse |
| for internal use only More... | |
| PxU16 | flags |
| a set of Px1DConstraintFlags More... | |
| PxU16 | solveHint |
| constraint optimization hint, should be an element of PxConstraintSolveHint More... | |
A constraint.
A constraint is expressed as a set of 1-dimensional constraint rows which define the required constraint on the objects' velocities.
Each constraint is either a hard constraint or a spring. We define the velocity at the constraint to be the quantity
v = body0vel.dot(lin0,ang0) - body1vel.dot(lin1, ang1)
For a hard constraint, the solver attempts to generate
1. a set of velocities for the objects which, when integrated, respect the constraint errors:
v + (geometricError / timestep) = velocityTarget
2. a set of velocities for the objects which respect the constraints:
v = velocityTarget
Hard constraints support restitution: if the impact velocity exceeds the bounce threshold, then the target velocity of the constraint will be set to restitution * -v
Alternatively, the solver can attempt to resolve the velocity constraint as an implicit spring:
F = stiffness * -geometricError + damping * (velocityTarget - v)
where F is the constraint force or acceleration. Springs are fully implicit: that is, the force or acceleration is a function of the position and velocity after the solve.
All constraints support limits on the minimum or maximum impulse applied.
| PxVec3 Px1DConstraint::angular0 |
angular component of velocity jacobian in world space
| PxVec3 Px1DConstraint::angular1 |
angular component of velocity jacobian in world space
| struct { ... } ::RestitutionModifiers Px1DConstraint::bounce |
| PxReal Px1DConstraint::damping |
damping parameter, for spring constraints
| PxU16 Px1DConstraint::flags |
a set of Px1DConstraintFlags
| PxReal Px1DConstraint::forInternalUse |
for internal use only
| PxReal Px1DConstraint::geometricError |
geometric error of the constraint along this axis
| PxVec3 Px1DConstraint::linear0 |
linear component of velocity jacobian in world space
| PxVec3 Px1DConstraint::linear1 |
linear component of velocity jacobian in world space
| PxReal Px1DConstraint::maxImpulse |
maximum impulse the solver may apply to enforce this constraint
| PxReal Px1DConstraint::minImpulse |
minimum impulse the solver may apply to enforce this constraint
| union { ... } Px1DConstraint::mods |
| PxReal Px1DConstraint::restitution |
restitution parameter for determining additional "bounce"
| PxU16 Px1DConstraint::solveHint |
constraint optimization hint, should be an element of PxConstraintSolveHint
| struct { ... } ::SpringModifiers Px1DConstraint::spring |
| PxReal Px1DConstraint::stiffness |
spring parameter, for spring constraints
| PxReal Px1DConstraint::velocityTarget |
velocity target for the constraint along this axis
| PxReal Px1DConstraint::velocityThreshold |
minimum impact velocity for bounce