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export contact friction/damping through URDF and API

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convert from contact friction/damping to cfm/erp
btCollisionObject::setContactFrictionAndDamping
This commit is contained in:
Erwin Coumans
2016-09-02 16:40:56 -07:00
parent 23f7293a25
commit ecd814c9c5
19 changed files with 269 additions and 125 deletions
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4
src/BulletCollision/CollisionDispatch/btCollisionObject.cpp
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@@ -33,6 +33,8 @@ btCollisionObject::btCollisionObject()
m_friction(btScalar(0.5)),
m_restitution(btScalar(0.)),
m_rollingFriction(0.0f),
m_contactDamping(.1),
m_contactStiffness(1e4),
m_internalType(CO_COLLISION_OBJECT),
m_userObjectPointer(0),
m_userIndex2(-1),
@@ -92,6 +94,8 @@ const char* btCollisionObject::serialize(void* dataBuffer, btSerializer* seriali
dataOut->m_deactivationTime = m_deactivationTime;
dataOut->m_friction = m_friction;
dataOut->m_rollingFriction = m_rollingFriction;
dataOut->m_contactDamping = m_contactDamping;
dataOut->m_contactStiffness = m_contactStiffness;
dataOut->m_restitution = m_restitution;
dataOut->m_internalType = m_internalType;

38
src/BulletCollision/CollisionDispatch/btCollisionObject.h
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@@ -86,6 +86,10 @@ protected:
btScalar m_friction;
btScalar m_restitution;
btScalar m_rollingFriction;
btScalar m_contactDamping;
btScalar m_contactStiffness;
///m_internalType is reserved to distinguish Bullet's btCollisionObject, btRigidBody, btSoftBody, btGhostObject etc.
///do not assign your own m_internalType unless you write a new dynamics object class.
@@ -129,7 +133,8 @@ public:
CF_CUSTOM_MATERIAL_CALLBACK = 8,//this allows per-triangle material (friction/restitution)
CF_CHARACTER_OBJECT = 16,
CF_DISABLE_VISUALIZE_OBJECT = 32, //disable debug drawing
CF_DISABLE_SPU_COLLISION_PROCESSING = 64//disable parallel/SPU processing
CF_DISABLE_SPU_COLLISION_PROCESSING = 64,//disable parallel/SPU processing
CF_HAS_CONTACT_STIFFNESS_DAMPING = 128
};
enum CollisionObjectTypes
@@ -319,7 +324,31 @@ public:
return m_rollingFriction;
}
void setContactStiffnessAndDamping(btScalar stiffness, btScalar damping)
{
m_updateRevision++;
m_contactStiffness = stiffness;
m_contactDamping = damping;
m_collisionFlags |=CF_HAS_CONTACT_STIFFNESS_DAMPING;
//avoid divisions by zero...
if (m_contactStiffness< SIMD_EPSILON)
{
m_contactStiffness = SIMD_EPSILON;
}
}
btScalar getContactStiffness() const
{
return m_contactStiffness;
}
btScalar getContactDamping() const
{
return m_contactDamping;
}
///reserved for Bullet internal usage
int getInternalType() const
{
@@ -541,6 +570,8 @@ struct btCollisionObjectDoubleData
double m_deactivationTime;
double m_friction;
double m_rollingFriction;
double m_contactDamping;
double m_contactStiffness;
double m_restitution;
double m_hitFraction;
double m_ccdSweptSphereRadius;
@@ -574,7 +605,8 @@ struct btCollisionObjectFloatData
float m_deactivationTime;
float m_friction;
float m_rollingFriction;
float m_contactDamping;
float m_contactStiffness;
float m_restitution;
float m_hitFraction;
float m_ccdSweptSphereRadius;

27
src/BulletCollision/CollisionDispatch/btManifoldResult.cpp
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@@ -25,7 +25,7 @@ ContactAddedCallback gContactAddedCallback=0;
///User can override this material combiner by implementing gContactAddedCallback and setting body0->m_collisionFlags |= btCollisionObject::customMaterialCallback;
inline btScalar calculateCombinedRollingFriction(const btCollisionObject* body0,const btCollisionObject* body1)
btScalar btManifoldResult::calculateCombinedRollingFriction(const btCollisionObject* body0,const btCollisionObject* body1)
{
btScalar friction = body0->getRollingFriction() * body1->getRollingFriction();
@@ -58,6 +58,22 @@ btScalar btManifoldResult::calculateCombinedRestitution(const btCollisionObject*
return body0->getRestitution() * body1->getRestitution();
}
btScalar btManifoldResult::calculateCombinedContactDamping(const btCollisionObject* body0,const btCollisionObject* body1)
{
return body0->getContactDamping() + body1->getContactDamping();
}
btScalar btManifoldResult::calculateCombinedContactStiffness(const btCollisionObject* body0,const btCollisionObject* body1)
{
btScalar s0 = body0->getContactStiffness();
btScalar s1 = body1->getContactStiffness();
btScalar tmp0 = btScalar(1)/s0;
btScalar tmp1 = btScalar(1)/s1;
btScalar combinedStiffness = btScalar(1) / (tmp0+tmp1);
return combinedStiffness;
}
btManifoldResult::btManifoldResult(const btCollisionObjectWrapper* body0Wrap,const btCollisionObjectWrapper* body1Wrap)
@@ -109,6 +125,15 @@ void btManifoldResult::addContactPoint(const btVector3& normalOnBInWorld,const b
newPt.m_combinedFriction = calculateCombinedFriction(m_body0Wrap->getCollisionObject(),m_body1Wrap->getCollisionObject());
newPt.m_combinedRestitution = calculateCombinedRestitution(m_body0Wrap->getCollisionObject(),m_body1Wrap->getCollisionObject());
newPt.m_combinedRollingFriction = calculateCombinedRollingFriction(m_body0Wrap->getCollisionObject(),m_body1Wrap->getCollisionObject());
if ( (m_body0Wrap->getCollisionObject()->getCollisionFlags()& btCollisionObject::CF_HAS_CONTACT_STIFFNESS_DAMPING) ||
(m_body1Wrap->getCollisionObject()->getCollisionFlags()& btCollisionObject::CF_HAS_CONTACT_STIFFNESS_DAMPING))
{
newPt.m_combinedContactDamping1 = calculateCombinedContactDamping(m_body0Wrap->getCollisionObject(),m_body1Wrap->getCollisionObject());
newPt.m_combinedContactStiffness1 = calculateCombinedContactStiffness(m_body0Wrap->getCollisionObject(),m_body1Wrap->getCollisionObject());
newPt.m_contactPointFlags |= BT_CONTACT_FLAG_CONTACT_STIFFNESS_DAMPING;
}
btPlaneSpace1(newPt.m_normalWorldOnB,newPt.m_lateralFrictionDir1,newPt.m_lateralFrictionDir2);

3
src/BulletCollision/CollisionDispatch/btManifoldResult.h
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@@ -145,6 +145,9 @@ public:
/// in the future we can let the user override the methods to combine restitution and friction
static btScalar calculateCombinedRestitution(const btCollisionObject* body0,const btCollisionObject* body1);
static btScalar calculateCombinedFriction(const btCollisionObject* body0,const btCollisionObject* body1);
static btScalar calculateCombinedRollingFriction(const btCollisionObject* body0,const btCollisionObject* body1);
static btScalar calculateCombinedContactDamping(const btCollisionObject* body0,const btCollisionObject* body1);
static btScalar calculateCombinedContactStiffness(const btCollisionObject* body0,const btCollisionObject* body1);
};
#endif //BT_MANIFOLD_RESULT_H

15
src/BulletCollision/NarrowPhaseCollision/btManifoldPoint.h
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@@ -40,6 +40,7 @@ enum btContactPointFlags
BT_CONTACT_FLAG_LATERAL_FRICTION_INITIALIZED=1,
BT_CONTACT_FLAG_HAS_CONTACT_CFM=2,
BT_CONTACT_FLAG_HAS_CONTACT_ERP=4,
BT_CONTACT_FLAG_CONTACT_STIFFNESS_DAMPING = 8,
};
/// ManifoldContactPoint collects and maintains persistent contactpoints.
@@ -116,8 +117,18 @@ class btManifoldPoint
btScalar m_appliedImpulseLateral2;
btScalar m_contactMotion1;
btScalar m_contactMotion2;
btScalar m_contactCFM;
btScalar m_contactERP;
union
{
btScalar m_contactCFM;
btScalar m_combinedContactStiffness1;
};
union
{
btScalar m_contactERP;
btScalar m_combinedContactDamping1;
};
btScalar m_frictionCFM;