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Diffstat (limited to 'Source/3rdParty/Box2D/Dynamics/Joints/b2FrictionJoint.cpp')
| -rw-r--r-- | Source/3rdParty/Box2D/Dynamics/Joints/b2FrictionJoint.cpp | 251 |
1 files changed, 0 insertions, 251 deletions
diff --git a/Source/3rdParty/Box2D/Dynamics/Joints/b2FrictionJoint.cpp b/Source/3rdParty/Box2D/Dynamics/Joints/b2FrictionJoint.cpp deleted file mode 100644 index cb122eb..0000000 --- a/Source/3rdParty/Box2D/Dynamics/Joints/b2FrictionJoint.cpp +++ /dev/null @@ -1,251 +0,0 @@ -/* -* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org -* -* This software is provided 'as-is', without any express or implied -* warranty. In no event will the authors be held liable for any damages -* arising from the use of this software. -* Permission is granted to anyone to use this software for any purpose, -* including commercial applications, and to alter it and redistribute it -* freely, subject to the following restrictions: -* 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. -* 2. Altered source versions must be plainly marked as such, and must not be -* misrepresented as being the original software. -* 3. This notice may not be removed or altered from any source distribution. -*/ - -#include "Box2D/Dynamics/Joints/b2FrictionJoint.h" -#include "Box2D/Dynamics/b2Body.h" -#include "Box2D/Dynamics/b2TimeStep.h" - -// Point-to-point constraint -// Cdot = v2 - v1 -// = v2 + cross(w2, r2) - v1 - cross(w1, r1) -// J = [-I -r1_skew I r2_skew ] -// Identity used: -// w k % (rx i + ry j) = w * (-ry i + rx j) - -// Angle constraint -// Cdot = w2 - w1 -// J = [0 0 -1 0 0 1] -// K = invI1 + invI2 - -void b2FrictionJointDef::Initialize(b2Body* bA, b2Body* bB, const b2Vec2& anchor) -{ - bodyA = bA; - bodyB = bB; - localAnchorA = bodyA->GetLocalPoint(anchor); - localAnchorB = bodyB->GetLocalPoint(anchor); -} - -b2FrictionJoint::b2FrictionJoint(const b2FrictionJointDef* def) -: b2Joint(def) -{ - m_localAnchorA = def->localAnchorA; - m_localAnchorB = def->localAnchorB; - - m_linearImpulse.SetZero(); - m_angularImpulse = 0.0f; - - m_maxForce = def->maxForce; - m_maxTorque = def->maxTorque; -} - -void b2FrictionJoint::InitVelocityConstraints(const b2SolverData& data) -{ - m_indexA = m_bodyA->m_islandIndex; - m_indexB = m_bodyB->m_islandIndex; - m_localCenterA = m_bodyA->m_sweep.localCenter; - m_localCenterB = m_bodyB->m_sweep.localCenter; - m_invMassA = m_bodyA->m_invMass; - m_invMassB = m_bodyB->m_invMass; - m_invIA = m_bodyA->m_invI; - m_invIB = m_bodyB->m_invI; - - float32 aA = data.positions[m_indexA].a; - b2Vec2 vA = data.velocities[m_indexA].v; - float32 wA = data.velocities[m_indexA].w; - - float32 aB = data.positions[m_indexB].a; - b2Vec2 vB = data.velocities[m_indexB].v; - float32 wB = data.velocities[m_indexB].w; - - b2Rot qA(aA), qB(aB); - - // Compute the effective mass matrix. - m_rA = b2Mul(qA, m_localAnchorA - m_localCenterA); - m_rB = b2Mul(qB, m_localAnchorB - m_localCenterB); - - // J = [-I -r1_skew I r2_skew] - // [ 0 -1 0 1] - // r_skew = [-ry; rx] - - // Matlab - // K = [ mA+r1y^2*iA+mB+r2y^2*iB, -r1y*iA*r1x-r2y*iB*r2x, -r1y*iA-r2y*iB] - // [ -r1y*iA*r1x-r2y*iB*r2x, mA+r1x^2*iA+mB+r2x^2*iB, r1x*iA+r2x*iB] - // [ -r1y*iA-r2y*iB, r1x*iA+r2x*iB, iA+iB] - - float32 mA = m_invMassA, mB = m_invMassB; - float32 iA = m_invIA, iB = m_invIB; - - b2Mat22 K; - K.ex.x = mA + mB + iA * m_rA.y * m_rA.y + iB * m_rB.y * m_rB.y; - K.ex.y = -iA * m_rA.x * m_rA.y - iB * m_rB.x * m_rB.y; - K.ey.x = K.ex.y; - K.ey.y = mA + mB + iA * m_rA.x * m_rA.x + iB * m_rB.x * m_rB.x; - - m_linearMass = K.GetInverse(); - - m_angularMass = iA + iB; - if (m_angularMass > 0.0f) - { - m_angularMass = 1.0f / m_angularMass; - } - - if (data.step.warmStarting) - { - // Scale impulses to support a variable time step. - m_linearImpulse *= data.step.dtRatio; - m_angularImpulse *= data.step.dtRatio; - - b2Vec2 P(m_linearImpulse.x, m_linearImpulse.y); - vA -= mA * P; - wA -= iA * (b2Cross(m_rA, P) + m_angularImpulse); - vB += mB * P; - wB += iB * (b2Cross(m_rB, P) + m_angularImpulse); - } - else - { - m_linearImpulse.SetZero(); - m_angularImpulse = 0.0f; - } - - data.velocities[m_indexA].v = vA; - data.velocities[m_indexA].w = wA; - data.velocities[m_indexB].v = vB; - data.velocities[m_indexB].w = wB; -} - -void b2FrictionJoint::SolveVelocityConstraints(const b2SolverData& data) -{ - b2Vec2 vA = data.velocities[m_indexA].v; - float32 wA = data.velocities[m_indexA].w; - b2Vec2 vB = data.velocities[m_indexB].v; - float32 wB = data.velocities[m_indexB].w; - - float32 mA = m_invMassA, mB = m_invMassB; - float32 iA = m_invIA, iB = m_invIB; - - float32 h = data.step.dt; - - // Solve angular friction - { - float32 Cdot = wB - wA; - float32 impulse = -m_angularMass * Cdot; - - float32 oldImpulse = m_angularImpulse; - float32 maxImpulse = h * m_maxTorque; - m_angularImpulse = b2Clamp(m_angularImpulse + impulse, -maxImpulse, maxImpulse); - impulse = m_angularImpulse - oldImpulse; - - wA -= iA * impulse; - wB += iB * impulse; - } - - // Solve linear friction - { - b2Vec2 Cdot = vB + b2Cross(wB, m_rB) - vA - b2Cross(wA, m_rA); - - b2Vec2 impulse = -b2Mul(m_linearMass, Cdot); - b2Vec2 oldImpulse = m_linearImpulse; - m_linearImpulse += impulse; - - float32 maxImpulse = h * m_maxForce; - - if (m_linearImpulse.LengthSquared() > maxImpulse * maxImpulse) - { - m_linearImpulse.Normalize(); - m_linearImpulse *= maxImpulse; - } - - impulse = m_linearImpulse - oldImpulse; - - vA -= mA * impulse; - wA -= iA * b2Cross(m_rA, impulse); - - vB += mB * impulse; - wB += iB * b2Cross(m_rB, impulse); - } - - data.velocities[m_indexA].v = vA; - data.velocities[m_indexA].w = wA; - data.velocities[m_indexB].v = vB; - data.velocities[m_indexB].w = wB; -} - -bool b2FrictionJoint::SolvePositionConstraints(const b2SolverData& data) -{ - B2_NOT_USED(data); - - return true; -} - -b2Vec2 b2FrictionJoint::GetAnchorA() const -{ - return m_bodyA->GetWorldPoint(m_localAnchorA); -} - -b2Vec2 b2FrictionJoint::GetAnchorB() const -{ - return m_bodyB->GetWorldPoint(m_localAnchorB); -} - -b2Vec2 b2FrictionJoint::GetReactionForce(float32 inv_dt) const -{ - return inv_dt * m_linearImpulse; -} - -float32 b2FrictionJoint::GetReactionTorque(float32 inv_dt) const -{ - return inv_dt * m_angularImpulse; -} - -void b2FrictionJoint::SetMaxForce(float32 force) -{ - b2Assert(b2IsValid(force) && force >= 0.0f); - m_maxForce = force; -} - -float32 b2FrictionJoint::GetMaxForce() const -{ - return m_maxForce; -} - -void b2FrictionJoint::SetMaxTorque(float32 torque) -{ - b2Assert(b2IsValid(torque) && torque >= 0.0f); - m_maxTorque = torque; -} - -float32 b2FrictionJoint::GetMaxTorque() const -{ - return m_maxTorque; -} - -void b2FrictionJoint::Dump() -{ - int32 indexA = m_bodyA->m_islandIndex; - int32 indexB = m_bodyB->m_islandIndex; - - b2Log(" b2FrictionJointDef jd;\n"); - b2Log(" jd.bodyA = bodies[%d];\n", indexA); - b2Log(" jd.bodyB = bodies[%d];\n", indexB); - b2Log(" jd.collideConnected = bool(%d);\n", m_collideConnected); - b2Log(" jd.localAnchorA.Set(%.15lef, %.15lef);\n", m_localAnchorA.x, m_localAnchorA.y); - b2Log(" jd.localAnchorB.Set(%.15lef, %.15lef);\n", m_localAnchorB.x, m_localAnchorB.y); - b2Log(" jd.maxForce = %.15lef;\n", m_maxForce); - b2Log(" jd.maxTorque = %.15lef;\n", m_maxTorque); - b2Log(" joints[%d] = m_world->CreateJoint(&jd);\n", m_index); -} |