[1963] | 1 | /* |
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| 2 | Bullet Continuous Collision Detection and Physics Library |
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| 3 | Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/ |
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| 4 | |
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| 5 | This software is provided 'as-is', without any express or implied warranty. |
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| 6 | In no event will the authors be held liable for any damages arising from the use of this software. |
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| 7 | Permission is granted to anyone to use this software for any purpose, |
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| 8 | including commercial applications, and to alter it and redistribute it freely, |
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| 9 | subject to the following restrictions: |
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| 10 | |
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| 11 | 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required. |
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| 12 | 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. |
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| 13 | 3. This notice may not be removed or altered from any source distribution. |
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| 14 | */ |
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| 15 | |
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| 16 | |
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| 17 | #include "btHingeConstraint.h" |
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| 18 | #include "BulletDynamics/Dynamics/btRigidBody.h" |
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| 19 | #include "LinearMath/btTransformUtil.h" |
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| 20 | #include "LinearMath/btMinMax.h" |
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| 21 | #include <new> |
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[2882] | 22 | #include "btSolverBody.h" |
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[1963] | 23 | |
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| 24 | |
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[7983] | 25 | |
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| 26 | //#define HINGE_USE_OBSOLETE_SOLVER false |
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[2882] | 27 | #define HINGE_USE_OBSOLETE_SOLVER false |
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| 28 | |
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[7983] | 29 | #define HINGE_USE_FRAME_OFFSET true |
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[2882] | 30 | |
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[7983] | 31 | #ifndef __SPU__ |
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[2882] | 32 | |
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[1963] | 33 | |
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[2882] | 34 | |
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[7983] | 35 | |
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| 36 | |
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[1963] | 37 | btHingeConstraint::btHingeConstraint(btRigidBody& rbA,btRigidBody& rbB, const btVector3& pivotInA,const btVector3& pivotInB, |
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[7983] | 38 | const btVector3& axisInA,const btVector3& axisInB, bool useReferenceFrameA) |
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[1963] | 39 | :btTypedConstraint(HINGE_CONSTRAINT_TYPE, rbA,rbB), |
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| 40 | m_angularOnly(false), |
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[2882] | 41 | m_enableAngularMotor(false), |
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| 42 | m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER), |
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[7983] | 43 | m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET), |
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| 44 | m_useReferenceFrameA(useReferenceFrameA), |
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| 45 | m_flags(0) |
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[1963] | 46 | { |
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| 47 | m_rbAFrame.getOrigin() = pivotInA; |
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| 48 | |
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| 49 | // since no frame is given, assume this to be zero angle and just pick rb transform axis |
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| 50 | btVector3 rbAxisA1 = rbA.getCenterOfMassTransform().getBasis().getColumn(0); |
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| 51 | |
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| 52 | btVector3 rbAxisA2; |
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| 53 | btScalar projection = axisInA.dot(rbAxisA1); |
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| 54 | if (projection >= 1.0f - SIMD_EPSILON) { |
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| 55 | rbAxisA1 = -rbA.getCenterOfMassTransform().getBasis().getColumn(2); |
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| 56 | rbAxisA2 = rbA.getCenterOfMassTransform().getBasis().getColumn(1); |
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| 57 | } else if (projection <= -1.0f + SIMD_EPSILON) { |
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| 58 | rbAxisA1 = rbA.getCenterOfMassTransform().getBasis().getColumn(2); |
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| 59 | rbAxisA2 = rbA.getCenterOfMassTransform().getBasis().getColumn(1); |
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| 60 | } else { |
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| 61 | rbAxisA2 = axisInA.cross(rbAxisA1); |
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| 62 | rbAxisA1 = rbAxisA2.cross(axisInA); |
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| 63 | } |
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| 64 | |
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| 65 | m_rbAFrame.getBasis().setValue( rbAxisA1.getX(),rbAxisA2.getX(),axisInA.getX(), |
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| 66 | rbAxisA1.getY(),rbAxisA2.getY(),axisInA.getY(), |
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| 67 | rbAxisA1.getZ(),rbAxisA2.getZ(),axisInA.getZ() ); |
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| 68 | |
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| 69 | btQuaternion rotationArc = shortestArcQuat(axisInA,axisInB); |
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| 70 | btVector3 rbAxisB1 = quatRotate(rotationArc,rbAxisA1); |
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| 71 | btVector3 rbAxisB2 = axisInB.cross(rbAxisB1); |
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| 72 | |
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| 73 | m_rbBFrame.getOrigin() = pivotInB; |
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[2882] | 74 | m_rbBFrame.getBasis().setValue( rbAxisB1.getX(),rbAxisB2.getX(),axisInB.getX(), |
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| 75 | rbAxisB1.getY(),rbAxisB2.getY(),axisInB.getY(), |
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| 76 | rbAxisB1.getZ(),rbAxisB2.getZ(),axisInB.getZ() ); |
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[1963] | 77 | |
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| 78 | //start with free |
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[7983] | 79 | m_lowerLimit = btScalar(1.0f); |
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| 80 | m_upperLimit = btScalar(-1.0f); |
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[1963] | 81 | m_biasFactor = 0.3f; |
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| 82 | m_relaxationFactor = 1.0f; |
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| 83 | m_limitSoftness = 0.9f; |
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| 84 | m_solveLimit = false; |
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[2882] | 85 | m_referenceSign = m_useReferenceFrameA ? btScalar(-1.f) : btScalar(1.f); |
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[1963] | 86 | } |
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| 87 | |
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| 88 | |
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[7983] | 89 | |
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| 90 | btHingeConstraint::btHingeConstraint(btRigidBody& rbA,const btVector3& pivotInA,const btVector3& axisInA, bool useReferenceFrameA) |
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[2882] | 91 | :btTypedConstraint(HINGE_CONSTRAINT_TYPE, rbA), m_angularOnly(false), m_enableAngularMotor(false), |
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| 92 | m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER), |
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[7983] | 93 | m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET), |
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| 94 | m_useReferenceFrameA(useReferenceFrameA), |
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| 95 | m_flags(0) |
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[1963] | 96 | { |
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| 97 | |
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| 98 | // since no frame is given, assume this to be zero angle and just pick rb transform axis |
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| 99 | // fixed axis in worldspace |
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| 100 | btVector3 rbAxisA1, rbAxisA2; |
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| 101 | btPlaneSpace1(axisInA, rbAxisA1, rbAxisA2); |
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| 102 | |
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| 103 | m_rbAFrame.getOrigin() = pivotInA; |
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| 104 | m_rbAFrame.getBasis().setValue( rbAxisA1.getX(),rbAxisA2.getX(),axisInA.getX(), |
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| 105 | rbAxisA1.getY(),rbAxisA2.getY(),axisInA.getY(), |
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| 106 | rbAxisA1.getZ(),rbAxisA2.getZ(),axisInA.getZ() ); |
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| 107 | |
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[2882] | 108 | btVector3 axisInB = rbA.getCenterOfMassTransform().getBasis() * axisInA; |
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[1963] | 109 | |
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| 110 | btQuaternion rotationArc = shortestArcQuat(axisInA,axisInB); |
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| 111 | btVector3 rbAxisB1 = quatRotate(rotationArc,rbAxisA1); |
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| 112 | btVector3 rbAxisB2 = axisInB.cross(rbAxisB1); |
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| 113 | |
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| 114 | |
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| 115 | m_rbBFrame.getOrigin() = rbA.getCenterOfMassTransform()(pivotInA); |
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| 116 | m_rbBFrame.getBasis().setValue( rbAxisB1.getX(),rbAxisB2.getX(),axisInB.getX(), |
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| 117 | rbAxisB1.getY(),rbAxisB2.getY(),axisInB.getY(), |
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| 118 | rbAxisB1.getZ(),rbAxisB2.getZ(),axisInB.getZ() ); |
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| 119 | |
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| 120 | //start with free |
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[7983] | 121 | m_lowerLimit = btScalar(1.0f); |
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| 122 | m_upperLimit = btScalar(-1.0f); |
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[1963] | 123 | m_biasFactor = 0.3f; |
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| 124 | m_relaxationFactor = 1.0f; |
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| 125 | m_limitSoftness = 0.9f; |
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| 126 | m_solveLimit = false; |
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[2882] | 127 | m_referenceSign = m_useReferenceFrameA ? btScalar(-1.f) : btScalar(1.f); |
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[1963] | 128 | } |
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| 129 | |
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[2882] | 130 | |
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[7983] | 131 | |
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[1963] | 132 | btHingeConstraint::btHingeConstraint(btRigidBody& rbA,btRigidBody& rbB, |
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[2882] | 133 | const btTransform& rbAFrame, const btTransform& rbBFrame, bool useReferenceFrameA) |
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[1963] | 134 | :btTypedConstraint(HINGE_CONSTRAINT_TYPE, rbA,rbB),m_rbAFrame(rbAFrame),m_rbBFrame(rbBFrame), |
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| 135 | m_angularOnly(false), |
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[2882] | 136 | m_enableAngularMotor(false), |
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| 137 | m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER), |
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[7983] | 138 | m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET), |
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| 139 | m_useReferenceFrameA(useReferenceFrameA), |
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| 140 | m_flags(0) |
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[1963] | 141 | { |
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| 142 | //start with free |
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[7983] | 143 | m_lowerLimit = btScalar(1.0f); |
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| 144 | m_upperLimit = btScalar(-1.0f); |
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[1963] | 145 | m_biasFactor = 0.3f; |
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| 146 | m_relaxationFactor = 1.0f; |
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| 147 | m_limitSoftness = 0.9f; |
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| 148 | m_solveLimit = false; |
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[2882] | 149 | m_referenceSign = m_useReferenceFrameA ? btScalar(-1.f) : btScalar(1.f); |
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[1963] | 150 | } |
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| 151 | |
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| 152 | |
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[7983] | 153 | |
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[2882] | 154 | btHingeConstraint::btHingeConstraint(btRigidBody& rbA, const btTransform& rbAFrame, bool useReferenceFrameA) |
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[1963] | 155 | :btTypedConstraint(HINGE_CONSTRAINT_TYPE, rbA),m_rbAFrame(rbAFrame),m_rbBFrame(rbAFrame), |
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| 156 | m_angularOnly(false), |
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[2882] | 157 | m_enableAngularMotor(false), |
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| 158 | m_useSolveConstraintObsolete(HINGE_USE_OBSOLETE_SOLVER), |
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[7983] | 159 | m_useOffsetForConstraintFrame(HINGE_USE_FRAME_OFFSET), |
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| 160 | m_useReferenceFrameA(useReferenceFrameA), |
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| 161 | m_flags(0) |
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[1963] | 162 | { |
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| 163 | ///not providing rigidbody B means implicitly using worldspace for body B |
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| 164 | |
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| 165 | m_rbBFrame.getOrigin() = m_rbA.getCenterOfMassTransform()(m_rbAFrame.getOrigin()); |
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| 166 | |
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| 167 | //start with free |
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[7983] | 168 | m_lowerLimit = btScalar(1.0f); |
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| 169 | m_upperLimit = btScalar(-1.0f); |
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[1963] | 170 | m_biasFactor = 0.3f; |
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| 171 | m_relaxationFactor = 1.0f; |
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| 172 | m_limitSoftness = 0.9f; |
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| 173 | m_solveLimit = false; |
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[2882] | 174 | m_referenceSign = m_useReferenceFrameA ? btScalar(-1.f) : btScalar(1.f); |
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[1963] | 175 | } |
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| 176 | |
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[2882] | 177 | |
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[7983] | 178 | |
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[1963] | 179 | void btHingeConstraint::buildJacobian() |
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| 180 | { |
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[2882] | 181 | if (m_useSolveConstraintObsolete) |
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[1963] | 182 | { |
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[2882] | 183 | m_appliedImpulse = btScalar(0.); |
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[7983] | 184 | m_accMotorImpulse = btScalar(0.); |
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[1963] | 185 | |
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[2882] | 186 | if (!m_angularOnly) |
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[1963] | 187 | { |
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[2882] | 188 | btVector3 pivotAInW = m_rbA.getCenterOfMassTransform()*m_rbAFrame.getOrigin(); |
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| 189 | btVector3 pivotBInW = m_rbB.getCenterOfMassTransform()*m_rbBFrame.getOrigin(); |
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| 190 | btVector3 relPos = pivotBInW - pivotAInW; |
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[1963] | 191 | |
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[2882] | 192 | btVector3 normal[3]; |
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| 193 | if (relPos.length2() > SIMD_EPSILON) |
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| 194 | { |
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| 195 | normal[0] = relPos.normalized(); |
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| 196 | } |
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| 197 | else |
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| 198 | { |
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| 199 | normal[0].setValue(btScalar(1.0),0,0); |
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| 200 | } |
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[1963] | 201 | |
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[2882] | 202 | btPlaneSpace1(normal[0], normal[1], normal[2]); |
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| 203 | |
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| 204 | for (int i=0;i<3;i++) |
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| 205 | { |
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| 206 | new (&m_jac[i]) btJacobianEntry( |
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[1963] | 207 | m_rbA.getCenterOfMassTransform().getBasis().transpose(), |
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| 208 | m_rbB.getCenterOfMassTransform().getBasis().transpose(), |
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| 209 | pivotAInW - m_rbA.getCenterOfMassPosition(), |
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| 210 | pivotBInW - m_rbB.getCenterOfMassPosition(), |
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| 211 | normal[i], |
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| 212 | m_rbA.getInvInertiaDiagLocal(), |
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| 213 | m_rbA.getInvMass(), |
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| 214 | m_rbB.getInvInertiaDiagLocal(), |
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| 215 | m_rbB.getInvMass()); |
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[2882] | 216 | } |
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[1963] | 217 | } |
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| 218 | |
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[2882] | 219 | //calculate two perpendicular jointAxis, orthogonal to hingeAxis |
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| 220 | //these two jointAxis require equal angular velocities for both bodies |
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[1963] | 221 | |
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[2882] | 222 | //this is unused for now, it's a todo |
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| 223 | btVector3 jointAxis0local; |
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| 224 | btVector3 jointAxis1local; |
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[1963] | 225 | |
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[2882] | 226 | btPlaneSpace1(m_rbAFrame.getBasis().getColumn(2),jointAxis0local,jointAxis1local); |
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[1963] | 227 | |
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[2882] | 228 | btVector3 jointAxis0 = getRigidBodyA().getCenterOfMassTransform().getBasis() * jointAxis0local; |
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| 229 | btVector3 jointAxis1 = getRigidBodyA().getCenterOfMassTransform().getBasis() * jointAxis1local; |
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| 230 | btVector3 hingeAxisWorld = getRigidBodyA().getCenterOfMassTransform().getBasis() * m_rbAFrame.getBasis().getColumn(2); |
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| 231 | |
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| 232 | new (&m_jacAng[0]) btJacobianEntry(jointAxis0, |
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| 233 | m_rbA.getCenterOfMassTransform().getBasis().transpose(), |
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| 234 | m_rbB.getCenterOfMassTransform().getBasis().transpose(), |
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| 235 | m_rbA.getInvInertiaDiagLocal(), |
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| 236 | m_rbB.getInvInertiaDiagLocal()); |
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[1963] | 237 | |
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[2882] | 238 | new (&m_jacAng[1]) btJacobianEntry(jointAxis1, |
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| 239 | m_rbA.getCenterOfMassTransform().getBasis().transpose(), |
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| 240 | m_rbB.getCenterOfMassTransform().getBasis().transpose(), |
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| 241 | m_rbA.getInvInertiaDiagLocal(), |
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| 242 | m_rbB.getInvInertiaDiagLocal()); |
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[1963] | 243 | |
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[2882] | 244 | new (&m_jacAng[2]) btJacobianEntry(hingeAxisWorld, |
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| 245 | m_rbA.getCenterOfMassTransform().getBasis().transpose(), |
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| 246 | m_rbB.getCenterOfMassTransform().getBasis().transpose(), |
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| 247 | m_rbA.getInvInertiaDiagLocal(), |
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| 248 | m_rbB.getInvInertiaDiagLocal()); |
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[1963] | 249 | |
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[2882] | 250 | // clear accumulator |
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| 251 | m_accLimitImpulse = btScalar(0.); |
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[1963] | 252 | |
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[2882] | 253 | // test angular limit |
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[7983] | 254 | testLimit(m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform()); |
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[1963] | 255 | |
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[2882] | 256 | //Compute K = J*W*J' for hinge axis |
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| 257 | btVector3 axisA = getRigidBodyA().getCenterOfMassTransform().getBasis() * m_rbAFrame.getBasis().getColumn(2); |
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| 258 | m_kHinge = 1.0f / (getRigidBodyA().computeAngularImpulseDenominator(axisA) + |
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| 259 | getRigidBodyB().computeAngularImpulseDenominator(axisA)); |
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| 260 | |
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| 261 | } |
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| 262 | } |
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| 263 | |
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| 264 | |
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[7983] | 265 | #endif //__SPU__ |
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| 266 | |
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| 267 | |
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[2882] | 268 | void btHingeConstraint::getInfo1(btConstraintInfo1* info) |
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| 269 | { |
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| 270 | if (m_useSolveConstraintObsolete) |
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[1963] | 271 | { |
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[2882] | 272 | info->m_numConstraintRows = 0; |
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| 273 | info->nub = 0; |
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| 274 | } |
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| 275 | else |
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| 276 | { |
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| 277 | info->m_numConstraintRows = 5; // Fixed 3 linear + 2 angular |
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| 278 | info->nub = 1; |
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[7983] | 279 | //always add the row, to avoid computation (data is not available yet) |
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[2882] | 280 | //prepare constraint |
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[7983] | 281 | testLimit(m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform()); |
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[2882] | 282 | if(getSolveLimit() || getEnableAngularMotor()) |
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[1963] | 283 | { |
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[2882] | 284 | info->m_numConstraintRows++; // limit 3rd anguar as well |
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| 285 | info->nub--; |
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[1963] | 286 | } |
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[7983] | 287 | |
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[1963] | 288 | } |
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[7983] | 289 | } |
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[1963] | 290 | |
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[7983] | 291 | void btHingeConstraint::getInfo1NonVirtual(btConstraintInfo1* info) |
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| 292 | { |
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| 293 | if (m_useSolveConstraintObsolete) |
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| 294 | { |
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| 295 | info->m_numConstraintRows = 0; |
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| 296 | info->nub = 0; |
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| 297 | } |
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| 298 | else |
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| 299 | { |
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| 300 | //always add the 'limit' row, to avoid computation (data is not available yet) |
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| 301 | info->m_numConstraintRows = 6; // Fixed 3 linear + 2 angular |
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| 302 | info->nub = 0; |
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| 303 | } |
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| 304 | } |
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[1963] | 305 | |
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[2882] | 306 | void btHingeConstraint::getInfo2 (btConstraintInfo2* info) |
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| 307 | { |
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[7983] | 308 | if(m_useOffsetForConstraintFrame) |
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| 309 | { |
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| 310 | getInfo2InternalUsingFrameOffset(info, m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform(),m_rbA.getAngularVelocity(),m_rbB.getAngularVelocity()); |
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| 311 | } |
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| 312 | else |
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| 313 | { |
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| 314 | getInfo2Internal(info, m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform(),m_rbA.getAngularVelocity(),m_rbB.getAngularVelocity()); |
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| 315 | } |
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| 316 | } |
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| 317 | |
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| 318 | |
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| 319 | void btHingeConstraint::getInfo2NonVirtual (btConstraintInfo2* info,const btTransform& transA,const btTransform& transB,const btVector3& angVelA,const btVector3& angVelB) |
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| 320 | { |
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| 321 | ///the regular (virtual) implementation getInfo2 already performs 'testLimit' during getInfo1, so we need to do it now |
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| 322 | testLimit(transA,transB); |
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| 323 | |
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| 324 | getInfo2Internal(info,transA,transB,angVelA,angVelB); |
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| 325 | } |
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| 326 | |
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| 327 | |
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| 328 | void btHingeConstraint::getInfo2Internal(btConstraintInfo2* info, const btTransform& transA,const btTransform& transB,const btVector3& angVelA,const btVector3& angVelB) |
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| 329 | { |
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| 330 | |
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[2882] | 331 | btAssert(!m_useSolveConstraintObsolete); |
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[7983] | 332 | int i, skip = info->rowskip; |
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[2882] | 333 | // transforms in world space |
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[7983] | 334 | btTransform trA = transA*m_rbAFrame; |
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| 335 | btTransform trB = transB*m_rbBFrame; |
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[2882] | 336 | // pivot point |
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| 337 | btVector3 pivotAInW = trA.getOrigin(); |
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| 338 | btVector3 pivotBInW = trB.getOrigin(); |
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[7983] | 339 | #if 0 |
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| 340 | if (0) |
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| 341 | { |
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| 342 | for (i=0;i<6;i++) |
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| 343 | { |
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| 344 | info->m_J1linearAxis[i*skip]=0; |
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| 345 | info->m_J1linearAxis[i*skip+1]=0; |
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| 346 | info->m_J1linearAxis[i*skip+2]=0; |
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| 347 | |
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| 348 | info->m_J1angularAxis[i*skip]=0; |
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| 349 | info->m_J1angularAxis[i*skip+1]=0; |
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| 350 | info->m_J1angularAxis[i*skip+2]=0; |
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| 351 | |
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| 352 | info->m_J2angularAxis[i*skip]=0; |
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| 353 | info->m_J2angularAxis[i*skip+1]=0; |
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| 354 | info->m_J2angularAxis[i*skip+2]=0; |
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| 355 | |
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| 356 | info->m_constraintError[i*skip]=0.f; |
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| 357 | } |
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| 358 | } |
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| 359 | #endif //#if 0 |
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[2882] | 360 | // linear (all fixed) |
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[7983] | 361 | |
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| 362 | if (!m_angularOnly) |
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[2882] | 363 | { |
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[7983] | 364 | info->m_J1linearAxis[0] = 1; |
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| 365 | info->m_J1linearAxis[skip + 1] = 1; |
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| 366 | info->m_J1linearAxis[2 * skip + 2] = 1; |
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| 367 | } |
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| 368 | |
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| 369 | |
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| 370 | |
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| 371 | |
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| 372 | btVector3 a1 = pivotAInW - transA.getOrigin(); |
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| 373 | { |
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[2882] | 374 | btVector3* angular0 = (btVector3*)(info->m_J1angularAxis); |
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[7983] | 375 | btVector3* angular1 = (btVector3*)(info->m_J1angularAxis + skip); |
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| 376 | btVector3* angular2 = (btVector3*)(info->m_J1angularAxis + 2 * skip); |
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[2882] | 377 | btVector3 a1neg = -a1; |
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| 378 | a1neg.getSkewSymmetricMatrix(angular0,angular1,angular2); |
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| 379 | } |
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[7983] | 380 | btVector3 a2 = pivotBInW - transB.getOrigin(); |
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[2882] | 381 | { |
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| 382 | btVector3* angular0 = (btVector3*)(info->m_J2angularAxis); |
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[7983] | 383 | btVector3* angular1 = (btVector3*)(info->m_J2angularAxis + skip); |
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| 384 | btVector3* angular2 = (btVector3*)(info->m_J2angularAxis + 2 * skip); |
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[2882] | 385 | a2.getSkewSymmetricMatrix(angular0,angular1,angular2); |
---|
| 386 | } |
---|
| 387 | // linear RHS |
---|
| 388 | btScalar k = info->fps * info->erp; |
---|
[7983] | 389 | if (!m_angularOnly) |
---|
| 390 | { |
---|
| 391 | for(i = 0; i < 3; i++) |
---|
| 392 | { |
---|
| 393 | info->m_constraintError[i * skip] = k * (pivotBInW[i] - pivotAInW[i]); |
---|
| 394 | } |
---|
| 395 | } |
---|
[2882] | 396 | // make rotations around X and Y equal |
---|
| 397 | // the hinge axis should be the only unconstrained |
---|
| 398 | // rotational axis, the angular velocity of the two bodies perpendicular to |
---|
| 399 | // the hinge axis should be equal. thus the constraint equations are |
---|
| 400 | // p*w1 - p*w2 = 0 |
---|
| 401 | // q*w1 - q*w2 = 0 |
---|
| 402 | // where p and q are unit vectors normal to the hinge axis, and w1 and w2 |
---|
| 403 | // are the angular velocity vectors of the two bodies. |
---|
| 404 | // get hinge axis (Z) |
---|
| 405 | btVector3 ax1 = trA.getBasis().getColumn(2); |
---|
| 406 | // get 2 orthos to hinge axis (X, Y) |
---|
| 407 | btVector3 p = trA.getBasis().getColumn(0); |
---|
| 408 | btVector3 q = trA.getBasis().getColumn(1); |
---|
| 409 | // set the two hinge angular rows |
---|
| 410 | int s3 = 3 * info->rowskip; |
---|
| 411 | int s4 = 4 * info->rowskip; |
---|
| 412 | |
---|
| 413 | info->m_J1angularAxis[s3 + 0] = p[0]; |
---|
| 414 | info->m_J1angularAxis[s3 + 1] = p[1]; |
---|
| 415 | info->m_J1angularAxis[s3 + 2] = p[2]; |
---|
| 416 | info->m_J1angularAxis[s4 + 0] = q[0]; |
---|
| 417 | info->m_J1angularAxis[s4 + 1] = q[1]; |
---|
| 418 | info->m_J1angularAxis[s4 + 2] = q[2]; |
---|
| 419 | |
---|
| 420 | info->m_J2angularAxis[s3 + 0] = -p[0]; |
---|
| 421 | info->m_J2angularAxis[s3 + 1] = -p[1]; |
---|
| 422 | info->m_J2angularAxis[s3 + 2] = -p[2]; |
---|
| 423 | info->m_J2angularAxis[s4 + 0] = -q[0]; |
---|
| 424 | info->m_J2angularAxis[s4 + 1] = -q[1]; |
---|
| 425 | info->m_J2angularAxis[s4 + 2] = -q[2]; |
---|
| 426 | // compute the right hand side of the constraint equation. set relative |
---|
| 427 | // body velocities along p and q to bring the hinge back into alignment. |
---|
| 428 | // if ax1,ax2 are the unit length hinge axes as computed from body1 and |
---|
| 429 | // body2, we need to rotate both bodies along the axis u = (ax1 x ax2). |
---|
| 430 | // if `theta' is the angle between ax1 and ax2, we need an angular velocity |
---|
| 431 | // along u to cover angle erp*theta in one step : |
---|
| 432 | // |angular_velocity| = angle/time = erp*theta / stepsize |
---|
| 433 | // = (erp*fps) * theta |
---|
| 434 | // angular_velocity = |angular_velocity| * (ax1 x ax2) / |ax1 x ax2| |
---|
| 435 | // = (erp*fps) * theta * (ax1 x ax2) / sin(theta) |
---|
| 436 | // ...as ax1 and ax2 are unit length. if theta is smallish, |
---|
| 437 | // theta ~= sin(theta), so |
---|
| 438 | // angular_velocity = (erp*fps) * (ax1 x ax2) |
---|
| 439 | // ax1 x ax2 is in the plane space of ax1, so we project the angular |
---|
| 440 | // velocity to p and q to find the right hand side. |
---|
| 441 | btVector3 ax2 = trB.getBasis().getColumn(2); |
---|
| 442 | btVector3 u = ax1.cross(ax2); |
---|
| 443 | info->m_constraintError[s3] = k * u.dot(p); |
---|
| 444 | info->m_constraintError[s4] = k * u.dot(q); |
---|
| 445 | // check angular limits |
---|
| 446 | int nrow = 4; // last filled row |
---|
| 447 | int srow; |
---|
| 448 | btScalar limit_err = btScalar(0.0); |
---|
| 449 | int limit = 0; |
---|
| 450 | if(getSolveLimit()) |
---|
| 451 | { |
---|
| 452 | limit_err = m_correction * m_referenceSign; |
---|
| 453 | limit = (limit_err > btScalar(0.0)) ? 1 : 2; |
---|
| 454 | } |
---|
| 455 | // if the hinge has joint limits or motor, add in the extra row |
---|
| 456 | int powered = 0; |
---|
| 457 | if(getEnableAngularMotor()) |
---|
| 458 | { |
---|
| 459 | powered = 1; |
---|
| 460 | } |
---|
| 461 | if(limit || powered) |
---|
| 462 | { |
---|
| 463 | nrow++; |
---|
| 464 | srow = nrow * info->rowskip; |
---|
| 465 | info->m_J1angularAxis[srow+0] = ax1[0]; |
---|
| 466 | info->m_J1angularAxis[srow+1] = ax1[1]; |
---|
| 467 | info->m_J1angularAxis[srow+2] = ax1[2]; |
---|
| 468 | |
---|
| 469 | info->m_J2angularAxis[srow+0] = -ax1[0]; |
---|
| 470 | info->m_J2angularAxis[srow+1] = -ax1[1]; |
---|
| 471 | info->m_J2angularAxis[srow+2] = -ax1[2]; |
---|
| 472 | |
---|
| 473 | btScalar lostop = getLowerLimit(); |
---|
| 474 | btScalar histop = getUpperLimit(); |
---|
| 475 | if(limit && (lostop == histop)) |
---|
| 476 | { // the joint motor is ineffective |
---|
| 477 | powered = 0; |
---|
| 478 | } |
---|
| 479 | info->m_constraintError[srow] = btScalar(0.0f); |
---|
[7983] | 480 | btScalar currERP = (m_flags & BT_HINGE_FLAGS_ERP_STOP) ? m_stopERP : info->erp; |
---|
[2882] | 481 | if(powered) |
---|
| 482 | { |
---|
[7983] | 483 | if(m_flags & BT_HINGE_FLAGS_CFM_NORM) |
---|
| 484 | { |
---|
| 485 | info->cfm[srow] = m_normalCFM; |
---|
| 486 | } |
---|
| 487 | btScalar mot_fact = getMotorFactor(m_hingeAngle, lostop, histop, m_motorTargetVelocity, info->fps * currERP); |
---|
[2882] | 488 | info->m_constraintError[srow] += mot_fact * m_motorTargetVelocity * m_referenceSign; |
---|
| 489 | info->m_lowerLimit[srow] = - m_maxMotorImpulse; |
---|
| 490 | info->m_upperLimit[srow] = m_maxMotorImpulse; |
---|
| 491 | } |
---|
| 492 | if(limit) |
---|
| 493 | { |
---|
[7983] | 494 | k = info->fps * currERP; |
---|
[2882] | 495 | info->m_constraintError[srow] += k * limit_err; |
---|
[7983] | 496 | if(m_flags & BT_HINGE_FLAGS_CFM_STOP) |
---|
| 497 | { |
---|
| 498 | info->cfm[srow] = m_stopCFM; |
---|
| 499 | } |
---|
[2882] | 500 | if(lostop == histop) |
---|
| 501 | { |
---|
| 502 | // limited low and high simultaneously |
---|
| 503 | info->m_lowerLimit[srow] = -SIMD_INFINITY; |
---|
| 504 | info->m_upperLimit[srow] = SIMD_INFINITY; |
---|
| 505 | } |
---|
| 506 | else if(limit == 1) |
---|
| 507 | { // low limit |
---|
| 508 | info->m_lowerLimit[srow] = 0; |
---|
| 509 | info->m_upperLimit[srow] = SIMD_INFINITY; |
---|
| 510 | } |
---|
| 511 | else |
---|
| 512 | { // high limit |
---|
| 513 | info->m_lowerLimit[srow] = -SIMD_INFINITY; |
---|
| 514 | info->m_upperLimit[srow] = 0; |
---|
| 515 | } |
---|
| 516 | // bounce (we'll use slider parameter abs(1.0 - m_dampingLimAng) for that) |
---|
| 517 | btScalar bounce = m_relaxationFactor; |
---|
| 518 | if(bounce > btScalar(0.0)) |
---|
| 519 | { |
---|
[7983] | 520 | btScalar vel = angVelA.dot(ax1); |
---|
| 521 | vel -= angVelB.dot(ax1); |
---|
[2882] | 522 | // only apply bounce if the velocity is incoming, and if the |
---|
| 523 | // resulting c[] exceeds what we already have. |
---|
| 524 | if(limit == 1) |
---|
| 525 | { // low limit |
---|
| 526 | if(vel < 0) |
---|
| 527 | { |
---|
| 528 | btScalar newc = -bounce * vel; |
---|
| 529 | if(newc > info->m_constraintError[srow]) |
---|
| 530 | { |
---|
| 531 | info->m_constraintError[srow] = newc; |
---|
| 532 | } |
---|
| 533 | } |
---|
| 534 | } |
---|
| 535 | else |
---|
| 536 | { // high limit - all those computations are reversed |
---|
| 537 | if(vel > 0) |
---|
| 538 | { |
---|
| 539 | btScalar newc = -bounce * vel; |
---|
| 540 | if(newc < info->m_constraintError[srow]) |
---|
| 541 | { |
---|
| 542 | info->m_constraintError[srow] = newc; |
---|
| 543 | } |
---|
| 544 | } |
---|
| 545 | } |
---|
| 546 | } |
---|
| 547 | info->m_constraintError[srow] *= m_biasFactor; |
---|
| 548 | } // if(limit) |
---|
| 549 | } // if angular limit or powered |
---|
[1963] | 550 | } |
---|
| 551 | |
---|
[2882] | 552 | |
---|
[1963] | 553 | |
---|
| 554 | |
---|
| 555 | |
---|
| 556 | |
---|
| 557 | void btHingeConstraint::updateRHS(btScalar timeStep) |
---|
| 558 | { |
---|
| 559 | (void)timeStep; |
---|
| 560 | |
---|
| 561 | } |
---|
| 562 | |
---|
[2882] | 563 | |
---|
[1963] | 564 | btScalar btHingeConstraint::getHingeAngle() |
---|
| 565 | { |
---|
[7983] | 566 | return getHingeAngle(m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform()); |
---|
| 567 | } |
---|
| 568 | |
---|
| 569 | btScalar btHingeConstraint::getHingeAngle(const btTransform& transA,const btTransform& transB) |
---|
| 570 | { |
---|
| 571 | const btVector3 refAxis0 = transA.getBasis() * m_rbAFrame.getBasis().getColumn(0); |
---|
| 572 | const btVector3 refAxis1 = transA.getBasis() * m_rbAFrame.getBasis().getColumn(1); |
---|
| 573 | const btVector3 swingAxis = transB.getBasis() * m_rbBFrame.getBasis().getColumn(1); |
---|
| 574 | // btScalar angle = btAtan2Fast(swingAxis.dot(refAxis0), swingAxis.dot(refAxis1)); |
---|
| 575 | btScalar angle = btAtan2(swingAxis.dot(refAxis0), swingAxis.dot(refAxis1)); |
---|
[2882] | 576 | return m_referenceSign * angle; |
---|
[1963] | 577 | } |
---|
| 578 | |
---|
[2882] | 579 | |
---|
[7983] | 580 | #if 0 |
---|
[2882] | 581 | void btHingeConstraint::testLimit() |
---|
| 582 | { |
---|
| 583 | // Compute limit information |
---|
| 584 | m_hingeAngle = getHingeAngle(); |
---|
| 585 | m_correction = btScalar(0.); |
---|
| 586 | m_limitSign = btScalar(0.); |
---|
| 587 | m_solveLimit = false; |
---|
| 588 | if (m_lowerLimit <= m_upperLimit) |
---|
| 589 | { |
---|
| 590 | if (m_hingeAngle <= m_lowerLimit) |
---|
| 591 | { |
---|
| 592 | m_correction = (m_lowerLimit - m_hingeAngle); |
---|
| 593 | m_limitSign = 1.0f; |
---|
| 594 | m_solveLimit = true; |
---|
| 595 | } |
---|
| 596 | else if (m_hingeAngle >= m_upperLimit) |
---|
| 597 | { |
---|
| 598 | m_correction = m_upperLimit - m_hingeAngle; |
---|
| 599 | m_limitSign = -1.0f; |
---|
| 600 | m_solveLimit = true; |
---|
| 601 | } |
---|
| 602 | } |
---|
| 603 | return; |
---|
[7983] | 604 | } |
---|
| 605 | #else |
---|
[2882] | 606 | |
---|
[7983] | 607 | |
---|
| 608 | void btHingeConstraint::testLimit(const btTransform& transA,const btTransform& transB) |
---|
| 609 | { |
---|
| 610 | // Compute limit information |
---|
| 611 | m_hingeAngle = getHingeAngle(transA,transB); |
---|
| 612 | m_correction = btScalar(0.); |
---|
| 613 | m_limitSign = btScalar(0.); |
---|
| 614 | m_solveLimit = false; |
---|
| 615 | if (m_lowerLimit <= m_upperLimit) |
---|
| 616 | { |
---|
| 617 | m_hingeAngle = btAdjustAngleToLimits(m_hingeAngle, m_lowerLimit, m_upperLimit); |
---|
| 618 | if (m_hingeAngle <= m_lowerLimit) |
---|
| 619 | { |
---|
| 620 | m_correction = (m_lowerLimit - m_hingeAngle); |
---|
| 621 | m_limitSign = 1.0f; |
---|
| 622 | m_solveLimit = true; |
---|
| 623 | } |
---|
| 624 | else if (m_hingeAngle >= m_upperLimit) |
---|
| 625 | { |
---|
| 626 | m_correction = m_upperLimit - m_hingeAngle; |
---|
| 627 | m_limitSign = -1.0f; |
---|
| 628 | m_solveLimit = true; |
---|
| 629 | } |
---|
| 630 | } |
---|
| 631 | return; |
---|
| 632 | } |
---|
| 633 | #endif |
---|
| 634 | |
---|
| 635 | static btVector3 vHinge(0, 0, btScalar(1)); |
---|
| 636 | |
---|
| 637 | void btHingeConstraint::setMotorTarget(const btQuaternion& qAinB, btScalar dt) |
---|
| 638 | { |
---|
| 639 | // convert target from body to constraint space |
---|
| 640 | btQuaternion qConstraint = m_rbBFrame.getRotation().inverse() * qAinB * m_rbAFrame.getRotation(); |
---|
| 641 | qConstraint.normalize(); |
---|
| 642 | |
---|
| 643 | // extract "pure" hinge component |
---|
| 644 | btVector3 vNoHinge = quatRotate(qConstraint, vHinge); vNoHinge.normalize(); |
---|
| 645 | btQuaternion qNoHinge = shortestArcQuat(vHinge, vNoHinge); |
---|
| 646 | btQuaternion qHinge = qNoHinge.inverse() * qConstraint; |
---|
| 647 | qHinge.normalize(); |
---|
| 648 | |
---|
| 649 | // compute angular target, clamped to limits |
---|
| 650 | btScalar targetAngle = qHinge.getAngle(); |
---|
| 651 | if (targetAngle > SIMD_PI) // long way around. flip quat and recalculate. |
---|
| 652 | { |
---|
| 653 | qHinge = operator-(qHinge); |
---|
| 654 | targetAngle = qHinge.getAngle(); |
---|
| 655 | } |
---|
| 656 | if (qHinge.getZ() < 0) |
---|
| 657 | targetAngle = -targetAngle; |
---|
| 658 | |
---|
| 659 | setMotorTarget(targetAngle, dt); |
---|
| 660 | } |
---|
| 661 | |
---|
| 662 | void btHingeConstraint::setMotorTarget(btScalar targetAngle, btScalar dt) |
---|
| 663 | { |
---|
| 664 | if (m_lowerLimit < m_upperLimit) |
---|
| 665 | { |
---|
| 666 | if (targetAngle < m_lowerLimit) |
---|
| 667 | targetAngle = m_lowerLimit; |
---|
| 668 | else if (targetAngle > m_upperLimit) |
---|
| 669 | targetAngle = m_upperLimit; |
---|
| 670 | } |
---|
| 671 | |
---|
| 672 | // compute angular velocity |
---|
| 673 | btScalar curAngle = getHingeAngle(m_rbA.getCenterOfMassTransform(),m_rbB.getCenterOfMassTransform()); |
---|
| 674 | btScalar dAngle = targetAngle - curAngle; |
---|
| 675 | m_motorTargetVelocity = dAngle / dt; |
---|
| 676 | } |
---|
| 677 | |
---|
| 678 | |
---|
| 679 | |
---|
| 680 | void btHingeConstraint::getInfo2InternalUsingFrameOffset(btConstraintInfo2* info, const btTransform& transA,const btTransform& transB,const btVector3& angVelA,const btVector3& angVelB) |
---|
| 681 | { |
---|
| 682 | btAssert(!m_useSolveConstraintObsolete); |
---|
| 683 | int i, s = info->rowskip; |
---|
| 684 | // transforms in world space |
---|
| 685 | btTransform trA = transA*m_rbAFrame; |
---|
| 686 | btTransform trB = transB*m_rbBFrame; |
---|
| 687 | // pivot point |
---|
| 688 | btVector3 pivotAInW = trA.getOrigin(); |
---|
| 689 | btVector3 pivotBInW = trB.getOrigin(); |
---|
| 690 | #if 1 |
---|
| 691 | // difference between frames in WCS |
---|
| 692 | btVector3 ofs = trB.getOrigin() - trA.getOrigin(); |
---|
| 693 | // now get weight factors depending on masses |
---|
| 694 | btScalar miA = getRigidBodyA().getInvMass(); |
---|
| 695 | btScalar miB = getRigidBodyB().getInvMass(); |
---|
| 696 | bool hasStaticBody = (miA < SIMD_EPSILON) || (miB < SIMD_EPSILON); |
---|
| 697 | btScalar miS = miA + miB; |
---|
| 698 | btScalar factA, factB; |
---|
| 699 | if(miS > btScalar(0.f)) |
---|
| 700 | { |
---|
| 701 | factA = miB / miS; |
---|
| 702 | } |
---|
| 703 | else |
---|
| 704 | { |
---|
| 705 | factA = btScalar(0.5f); |
---|
| 706 | } |
---|
| 707 | factB = btScalar(1.0f) - factA; |
---|
| 708 | // get the desired direction of hinge axis |
---|
| 709 | // as weighted sum of Z-orthos of frameA and frameB in WCS |
---|
| 710 | btVector3 ax1A = trA.getBasis().getColumn(2); |
---|
| 711 | btVector3 ax1B = trB.getBasis().getColumn(2); |
---|
| 712 | btVector3 ax1 = ax1A * factA + ax1B * factB; |
---|
| 713 | ax1.normalize(); |
---|
| 714 | // fill first 3 rows |
---|
| 715 | // we want: velA + wA x relA == velB + wB x relB |
---|
| 716 | btTransform bodyA_trans = transA; |
---|
| 717 | btTransform bodyB_trans = transB; |
---|
| 718 | int s0 = 0; |
---|
| 719 | int s1 = s; |
---|
| 720 | int s2 = s * 2; |
---|
| 721 | int nrow = 2; // last filled row |
---|
| 722 | btVector3 tmpA, tmpB, relA, relB, p, q; |
---|
| 723 | // get vector from bodyB to frameB in WCS |
---|
| 724 | relB = trB.getOrigin() - bodyB_trans.getOrigin(); |
---|
| 725 | // get its projection to hinge axis |
---|
| 726 | btVector3 projB = ax1 * relB.dot(ax1); |
---|
| 727 | // get vector directed from bodyB to hinge axis (and orthogonal to it) |
---|
| 728 | btVector3 orthoB = relB - projB; |
---|
| 729 | // same for bodyA |
---|
| 730 | relA = trA.getOrigin() - bodyA_trans.getOrigin(); |
---|
| 731 | btVector3 projA = ax1 * relA.dot(ax1); |
---|
| 732 | btVector3 orthoA = relA - projA; |
---|
| 733 | btVector3 totalDist = projA - projB; |
---|
| 734 | // get offset vectors relA and relB |
---|
| 735 | relA = orthoA + totalDist * factA; |
---|
| 736 | relB = orthoB - totalDist * factB; |
---|
| 737 | // now choose average ortho to hinge axis |
---|
| 738 | p = orthoB * factA + orthoA * factB; |
---|
| 739 | btScalar len2 = p.length2(); |
---|
| 740 | if(len2 > SIMD_EPSILON) |
---|
| 741 | { |
---|
| 742 | p /= btSqrt(len2); |
---|
| 743 | } |
---|
| 744 | else |
---|
| 745 | { |
---|
| 746 | p = trA.getBasis().getColumn(1); |
---|
| 747 | } |
---|
| 748 | // make one more ortho |
---|
| 749 | q = ax1.cross(p); |
---|
| 750 | // fill three rows |
---|
| 751 | tmpA = relA.cross(p); |
---|
| 752 | tmpB = relB.cross(p); |
---|
| 753 | for (i=0; i<3; i++) info->m_J1angularAxis[s0+i] = tmpA[i]; |
---|
| 754 | for (i=0; i<3; i++) info->m_J2angularAxis[s0+i] = -tmpB[i]; |
---|
| 755 | tmpA = relA.cross(q); |
---|
| 756 | tmpB = relB.cross(q); |
---|
| 757 | if(hasStaticBody && getSolveLimit()) |
---|
| 758 | { // to make constraint between static and dynamic objects more rigid |
---|
| 759 | // remove wA (or wB) from equation if angular limit is hit |
---|
| 760 | tmpB *= factB; |
---|
| 761 | tmpA *= factA; |
---|
| 762 | } |
---|
| 763 | for (i=0; i<3; i++) info->m_J1angularAxis[s1+i] = tmpA[i]; |
---|
| 764 | for (i=0; i<3; i++) info->m_J2angularAxis[s1+i] = -tmpB[i]; |
---|
| 765 | tmpA = relA.cross(ax1); |
---|
| 766 | tmpB = relB.cross(ax1); |
---|
| 767 | if(hasStaticBody) |
---|
| 768 | { // to make constraint between static and dynamic objects more rigid |
---|
| 769 | // remove wA (or wB) from equation |
---|
| 770 | tmpB *= factB; |
---|
| 771 | tmpA *= factA; |
---|
| 772 | } |
---|
| 773 | for (i=0; i<3; i++) info->m_J1angularAxis[s2+i] = tmpA[i]; |
---|
| 774 | for (i=0; i<3; i++) info->m_J2angularAxis[s2+i] = -tmpB[i]; |
---|
| 775 | |
---|
| 776 | btScalar k = info->fps * info->erp; |
---|
| 777 | |
---|
| 778 | if (!m_angularOnly) |
---|
| 779 | { |
---|
| 780 | for (i=0; i<3; i++) info->m_J1linearAxis[s0+i] = p[i]; |
---|
| 781 | for (i=0; i<3; i++) info->m_J1linearAxis[s1+i] = q[i]; |
---|
| 782 | for (i=0; i<3; i++) info->m_J1linearAxis[s2+i] = ax1[i]; |
---|
| 783 | |
---|
| 784 | // compute three elements of right hand side |
---|
| 785 | |
---|
| 786 | btScalar rhs = k * p.dot(ofs); |
---|
| 787 | info->m_constraintError[s0] = rhs; |
---|
| 788 | rhs = k * q.dot(ofs); |
---|
| 789 | info->m_constraintError[s1] = rhs; |
---|
| 790 | rhs = k * ax1.dot(ofs); |
---|
| 791 | info->m_constraintError[s2] = rhs; |
---|
| 792 | } |
---|
| 793 | // the hinge axis should be the only unconstrained |
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| 794 | // rotational axis, the angular velocity of the two bodies perpendicular to |
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| 795 | // the hinge axis should be equal. thus the constraint equations are |
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| 796 | // p*w1 - p*w2 = 0 |
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| 797 | // q*w1 - q*w2 = 0 |
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| 798 | // where p and q are unit vectors normal to the hinge axis, and w1 and w2 |
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| 799 | // are the angular velocity vectors of the two bodies. |
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| 800 | int s3 = 3 * s; |
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| 801 | int s4 = 4 * s; |
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| 802 | info->m_J1angularAxis[s3 + 0] = p[0]; |
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| 803 | info->m_J1angularAxis[s3 + 1] = p[1]; |
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| 804 | info->m_J1angularAxis[s3 + 2] = p[2]; |
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| 805 | info->m_J1angularAxis[s4 + 0] = q[0]; |
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| 806 | info->m_J1angularAxis[s4 + 1] = q[1]; |
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| 807 | info->m_J1angularAxis[s4 + 2] = q[2]; |
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| 808 | |
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| 809 | info->m_J2angularAxis[s3 + 0] = -p[0]; |
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| 810 | info->m_J2angularAxis[s3 + 1] = -p[1]; |
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| 811 | info->m_J2angularAxis[s3 + 2] = -p[2]; |
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| 812 | info->m_J2angularAxis[s4 + 0] = -q[0]; |
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| 813 | info->m_J2angularAxis[s4 + 1] = -q[1]; |
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| 814 | info->m_J2angularAxis[s4 + 2] = -q[2]; |
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| 815 | // compute the right hand side of the constraint equation. set relative |
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| 816 | // body velocities along p and q to bring the hinge back into alignment. |
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| 817 | // if ax1A,ax1B are the unit length hinge axes as computed from bodyA and |
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| 818 | // bodyB, we need to rotate both bodies along the axis u = (ax1 x ax2). |
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| 819 | // if "theta" is the angle between ax1 and ax2, we need an angular velocity |
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| 820 | // along u to cover angle erp*theta in one step : |
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| 821 | // |angular_velocity| = angle/time = erp*theta / stepsize |
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| 822 | // = (erp*fps) * theta |
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| 823 | // angular_velocity = |angular_velocity| * (ax1 x ax2) / |ax1 x ax2| |
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| 824 | // = (erp*fps) * theta * (ax1 x ax2) / sin(theta) |
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| 825 | // ...as ax1 and ax2 are unit length. if theta is smallish, |
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| 826 | // theta ~= sin(theta), so |
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| 827 | // angular_velocity = (erp*fps) * (ax1 x ax2) |
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| 828 | // ax1 x ax2 is in the plane space of ax1, so we project the angular |
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| 829 | // velocity to p and q to find the right hand side. |
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| 830 | k = info->fps * info->erp; |
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| 831 | btVector3 u = ax1A.cross(ax1B); |
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| 832 | info->m_constraintError[s3] = k * u.dot(p); |
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| 833 | info->m_constraintError[s4] = k * u.dot(q); |
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| 834 | #endif |
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| 835 | // check angular limits |
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| 836 | nrow = 4; // last filled row |
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| 837 | int srow; |
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| 838 | btScalar limit_err = btScalar(0.0); |
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| 839 | int limit = 0; |
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| 840 | if(getSolveLimit()) |
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| 841 | { |
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| 842 | limit_err = m_correction * m_referenceSign; |
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| 843 | limit = (limit_err > btScalar(0.0)) ? 1 : 2; |
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| 844 | } |
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| 845 | // if the hinge has joint limits or motor, add in the extra row |
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| 846 | int powered = 0; |
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| 847 | if(getEnableAngularMotor()) |
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| 848 | { |
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| 849 | powered = 1; |
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| 850 | } |
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| 851 | if(limit || powered) |
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| 852 | { |
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| 853 | nrow++; |
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| 854 | srow = nrow * info->rowskip; |
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| 855 | info->m_J1angularAxis[srow+0] = ax1[0]; |
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| 856 | info->m_J1angularAxis[srow+1] = ax1[1]; |
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| 857 | info->m_J1angularAxis[srow+2] = ax1[2]; |
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| 858 | |
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| 859 | info->m_J2angularAxis[srow+0] = -ax1[0]; |
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| 860 | info->m_J2angularAxis[srow+1] = -ax1[1]; |
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| 861 | info->m_J2angularAxis[srow+2] = -ax1[2]; |
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| 862 | |
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| 863 | btScalar lostop = getLowerLimit(); |
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| 864 | btScalar histop = getUpperLimit(); |
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| 865 | if(limit && (lostop == histop)) |
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| 866 | { // the joint motor is ineffective |
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| 867 | powered = 0; |
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| 868 | } |
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| 869 | info->m_constraintError[srow] = btScalar(0.0f); |
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| 870 | btScalar currERP = (m_flags & BT_HINGE_FLAGS_ERP_STOP) ? m_stopERP : info->erp; |
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| 871 | if(powered) |
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| 872 | { |
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| 873 | if(m_flags & BT_HINGE_FLAGS_CFM_NORM) |
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| 874 | { |
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| 875 | info->cfm[srow] = m_normalCFM; |
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| 876 | } |
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| 877 | btScalar mot_fact = getMotorFactor(m_hingeAngle, lostop, histop, m_motorTargetVelocity, info->fps * currERP); |
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| 878 | info->m_constraintError[srow] += mot_fact * m_motorTargetVelocity * m_referenceSign; |
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| 879 | info->m_lowerLimit[srow] = - m_maxMotorImpulse; |
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| 880 | info->m_upperLimit[srow] = m_maxMotorImpulse; |
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| 881 | } |
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| 882 | if(limit) |
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| 883 | { |
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| 884 | k = info->fps * currERP; |
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| 885 | info->m_constraintError[srow] += k * limit_err; |
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| 886 | if(m_flags & BT_HINGE_FLAGS_CFM_STOP) |
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| 887 | { |
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| 888 | info->cfm[srow] = m_stopCFM; |
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| 889 | } |
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| 890 | if(lostop == histop) |
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| 891 | { |
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| 892 | // limited low and high simultaneously |
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| 893 | info->m_lowerLimit[srow] = -SIMD_INFINITY; |
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| 894 | info->m_upperLimit[srow] = SIMD_INFINITY; |
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| 895 | } |
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| 896 | else if(limit == 1) |
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| 897 | { // low limit |
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| 898 | info->m_lowerLimit[srow] = 0; |
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| 899 | info->m_upperLimit[srow] = SIMD_INFINITY; |
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| 900 | } |
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| 901 | else |
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| 902 | { // high limit |
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| 903 | info->m_lowerLimit[srow] = -SIMD_INFINITY; |
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| 904 | info->m_upperLimit[srow] = 0; |
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| 905 | } |
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| 906 | // bounce (we'll use slider parameter abs(1.0 - m_dampingLimAng) for that) |
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| 907 | btScalar bounce = m_relaxationFactor; |
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| 908 | if(bounce > btScalar(0.0)) |
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| 909 | { |
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| 910 | btScalar vel = angVelA.dot(ax1); |
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| 911 | vel -= angVelB.dot(ax1); |
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| 912 | // only apply bounce if the velocity is incoming, and if the |
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| 913 | // resulting c[] exceeds what we already have. |
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| 914 | if(limit == 1) |
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| 915 | { // low limit |
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| 916 | if(vel < 0) |
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| 917 | { |
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| 918 | btScalar newc = -bounce * vel; |
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| 919 | if(newc > info->m_constraintError[srow]) |
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| 920 | { |
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| 921 | info->m_constraintError[srow] = newc; |
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| 922 | } |
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| 923 | } |
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| 924 | } |
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| 925 | else |
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| 926 | { // high limit - all those computations are reversed |
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| 927 | if(vel > 0) |
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| 928 | { |
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| 929 | btScalar newc = -bounce * vel; |
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| 930 | if(newc < info->m_constraintError[srow]) |
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| 931 | { |
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| 932 | info->m_constraintError[srow] = newc; |
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| 933 | } |
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| 934 | } |
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| 935 | } |
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| 936 | } |
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| 937 | info->m_constraintError[srow] *= m_biasFactor; |
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| 938 | } // if(limit) |
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| 939 | } // if angular limit or powered |
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| 940 | } |
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| 941 | |
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| 942 | |
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| 943 | ///override the default global value of a parameter (such as ERP or CFM), optionally provide the axis (0..5). |
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| 944 | ///If no axis is provided, it uses the default axis for this constraint. |
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| 945 | void btHingeConstraint::setParam(int num, btScalar value, int axis) |
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| 946 | { |
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| 947 | if((axis == -1) || (axis == 5)) |
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| 948 | { |
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| 949 | switch(num) |
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| 950 | { |
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| 951 | case BT_CONSTRAINT_STOP_ERP : |
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| 952 | m_stopERP = value; |
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| 953 | m_flags |= BT_HINGE_FLAGS_ERP_STOP; |
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| 954 | break; |
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| 955 | case BT_CONSTRAINT_STOP_CFM : |
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| 956 | m_stopCFM = value; |
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| 957 | m_flags |= BT_HINGE_FLAGS_CFM_STOP; |
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| 958 | break; |
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| 959 | case BT_CONSTRAINT_CFM : |
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| 960 | m_normalCFM = value; |
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| 961 | m_flags |= BT_HINGE_FLAGS_CFM_NORM; |
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| 962 | break; |
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| 963 | default : |
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| 964 | btAssertConstrParams(0); |
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| 965 | } |
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| 966 | } |
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| 967 | else |
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| 968 | { |
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| 969 | btAssertConstrParams(0); |
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| 970 | } |
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| 971 | } |
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| 972 | |
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| 973 | ///return the local value of parameter |
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| 974 | btScalar btHingeConstraint::getParam(int num, int axis) const |
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| 975 | { |
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| 976 | btScalar retVal = 0; |
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| 977 | if((axis == -1) || (axis == 5)) |
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| 978 | { |
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| 979 | switch(num) |
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| 980 | { |
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| 981 | case BT_CONSTRAINT_STOP_ERP : |
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| 982 | btAssertConstrParams(m_flags & BT_HINGE_FLAGS_ERP_STOP); |
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| 983 | retVal = m_stopERP; |
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| 984 | break; |
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| 985 | case BT_CONSTRAINT_STOP_CFM : |
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| 986 | btAssertConstrParams(m_flags & BT_HINGE_FLAGS_CFM_STOP); |
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| 987 | retVal = m_stopCFM; |
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| 988 | break; |
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| 989 | case BT_CONSTRAINT_CFM : |
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| 990 | btAssertConstrParams(m_flags & BT_HINGE_FLAGS_CFM_NORM); |
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| 991 | retVal = m_normalCFM; |
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| 992 | break; |
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| 993 | default : |
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| 994 | btAssertConstrParams(0); |
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| 995 | } |
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| 996 | } |
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| 997 | else |
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| 998 | { |
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| 999 | btAssertConstrParams(0); |
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| 1000 | } |
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| 1001 | return retVal; |
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| 1002 | } |
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| 1003 | |
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| 1004 | |
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