| 1 | /* | 
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| 2 |  * Copyright (c) 2005 Erwin Coumans http://continuousphysics.com/Bullet/ | 
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| 3 |  * | 
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| 4 |  * Permission to use, copy, modify, distribute and sell this software | 
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| 5 |  * and its documentation for any purpose is hereby granted without fee, | 
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| 6 |  * provided that the above copyright notice appear in all copies. | 
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| 7 |  * Erwin Coumans makes no representations about the suitability  | 
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| 8 |  * of this software for any purpose.   | 
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| 9 |  * It is provided "as is" without express or implied warranty. | 
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| 10 | */ | 
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| 11 | #include "btWheelInfo.h" | 
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| 12 | #include "BulletDynamics/Dynamics/btRigidBody.h" // for pointvelocity | 
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| 13 |  | 
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| 14 |  | 
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| 15 | btScalar btWheelInfo::getSuspensionRestLength() const | 
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| 16 | { | 
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| 17 |  | 
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| 18 |         return m_suspensionRestLength1; | 
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| 19 |  | 
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| 20 | } | 
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| 21 |  | 
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| 22 | void    btWheelInfo::updateWheel(const btRigidBody& chassis,RaycastInfo& raycastInfo) | 
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| 23 | { | 
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| 24 |         (void)raycastInfo; | 
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| 25 |  | 
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| 26 |          | 
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| 27 |         if (m_raycastInfo.m_isInContact) | 
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| 28 |  | 
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| 29 |         { | 
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| 30 |                 btScalar        project= m_raycastInfo.m_contactNormalWS.dot( m_raycastInfo.m_wheelDirectionWS ); | 
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| 31 |                 btVector3        chassis_velocity_at_contactPoint; | 
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| 32 |                 btVector3 relpos = m_raycastInfo.m_contactPointWS - chassis.getCenterOfMassPosition(); | 
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| 33 |                 chassis_velocity_at_contactPoint = chassis.getVelocityInLocalPoint( relpos ); | 
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| 34 |                 btScalar projVel = m_raycastInfo.m_contactNormalWS.dot( chassis_velocity_at_contactPoint ); | 
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| 35 |                 if ( project >= btScalar(-0.1)) | 
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| 36 |                 { | 
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| 37 |                         m_suspensionRelativeVelocity = btScalar(0.0); | 
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| 38 |                         m_clippedInvContactDotSuspension = btScalar(1.0) / btScalar(0.1); | 
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| 39 |                 } | 
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| 40 |                 else | 
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| 41 |                 { | 
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| 42 |                         btScalar inv = btScalar(-1.) / project; | 
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| 43 |                         m_suspensionRelativeVelocity = projVel * inv; | 
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| 44 |                         m_clippedInvContactDotSuspension = inv; | 
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| 45 |                 } | 
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| 46 |                  | 
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| 47 |         } | 
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| 48 |  | 
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| 49 |         else    // Not in contact : position wheel in a nice (rest length) position | 
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| 50 |         { | 
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| 51 |                 m_raycastInfo.m_suspensionLength = this->getSuspensionRestLength(); | 
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| 52 |                 m_suspensionRelativeVelocity = btScalar(0.0); | 
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| 53 |                 m_raycastInfo.m_contactNormalWS = -m_raycastInfo.m_wheelDirectionWS; | 
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| 54 |                 m_clippedInvContactDotSuspension = btScalar(1.0); | 
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| 55 |         } | 
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| 56 | } | 
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