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Diffstat (limited to 'Source/3rdParty/Box2D/Dynamics/Joints/b2PrismaticJoint.cpp')
| -rw-r--r-- | Source/3rdParty/Box2D/Dynamics/Joints/b2PrismaticJoint.cpp | 642 |
1 files changed, 0 insertions, 642 deletions
diff --git a/Source/3rdParty/Box2D/Dynamics/Joints/b2PrismaticJoint.cpp b/Source/3rdParty/Box2D/Dynamics/Joints/b2PrismaticJoint.cpp deleted file mode 100644 index 5da19b6..0000000 --- a/Source/3rdParty/Box2D/Dynamics/Joints/b2PrismaticJoint.cpp +++ /dev/null @@ -1,642 +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/b2PrismaticJoint.h" -#include "Box2D/Dynamics/b2Body.h" -#include "Box2D/Dynamics/b2TimeStep.h" - -// Linear constraint (point-to-line) -// d = p2 - p1 = x2 + r2 - x1 - r1 -// C = dot(perp, d) -// Cdot = dot(d, cross(w1, perp)) + dot(perp, v2 + cross(w2, r2) - v1 - cross(w1, r1)) -// = -dot(perp, v1) - dot(cross(d + r1, perp), w1) + dot(perp, v2) + dot(cross(r2, perp), v2) -// J = [-perp, -cross(d + r1, perp), perp, cross(r2,perp)] -// -// Angular constraint -// C = a2 - a1 + a_initial -// Cdot = w2 - w1 -// J = [0 0 -1 0 0 1] -// -// K = J * invM * JT -// -// J = [-a -s1 a s2] -// [0 -1 0 1] -// a = perp -// s1 = cross(d + r1, a) = cross(p2 - x1, a) -// s2 = cross(r2, a) = cross(p2 - x2, a) - - -// Motor/Limit linear constraint -// C = dot(ax1, d) -// Cdot = = -dot(ax1, v1) - dot(cross(d + r1, ax1), w1) + dot(ax1, v2) + dot(cross(r2, ax1), v2) -// J = [-ax1 -cross(d+r1,ax1) ax1 cross(r2,ax1)] - -// Block Solver -// We develop a block solver that includes the joint limit. This makes the limit stiff (inelastic) even -// when the mass has poor distribution (leading to large torques about the joint anchor points). -// -// The Jacobian has 3 rows: -// J = [-uT -s1 uT s2] // linear -// [0 -1 0 1] // angular -// [-vT -a1 vT a2] // limit -// -// u = perp -// v = axis -// s1 = cross(d + r1, u), s2 = cross(r2, u) -// a1 = cross(d + r1, v), a2 = cross(r2, v) - -// M * (v2 - v1) = JT * df -// J * v2 = bias -// -// v2 = v1 + invM * JT * df -// J * (v1 + invM * JT * df) = bias -// K * df = bias - J * v1 = -Cdot -// K = J * invM * JT -// Cdot = J * v1 - bias -// -// Now solve for f2. -// df = f2 - f1 -// K * (f2 - f1) = -Cdot -// f2 = invK * (-Cdot) + f1 -// -// Clamp accumulated limit impulse. -// lower: f2(3) = max(f2(3), 0) -// upper: f2(3) = min(f2(3), 0) -// -// Solve for correct f2(1:2) -// K(1:2, 1:2) * f2(1:2) = -Cdot(1:2) - K(1:2,3) * f2(3) + K(1:2,1:3) * f1 -// = -Cdot(1:2) - K(1:2,3) * f2(3) + K(1:2,1:2) * f1(1:2) + K(1:2,3) * f1(3) -// K(1:2, 1:2) * f2(1:2) = -Cdot(1:2) - K(1:2,3) * (f2(3) - f1(3)) + K(1:2,1:2) * f1(1:2) -// f2(1:2) = invK(1:2,1:2) * (-Cdot(1:2) - K(1:2,3) * (f2(3) - f1(3))) + f1(1:2) -// -// Now compute impulse to be applied: -// df = f2 - f1 - -void b2PrismaticJointDef::Initialize(b2Body* bA, b2Body* bB, const b2Vec2& anchor, const b2Vec2& axis) -{ - bodyA = bA; - bodyB = bB; - localAnchorA = bodyA->GetLocalPoint(anchor); - localAnchorB = bodyB->GetLocalPoint(anchor); - localAxisA = bodyA->GetLocalVector(axis); - referenceAngle = bodyB->GetAngle() - bodyA->GetAngle(); -} - -b2PrismaticJoint::b2PrismaticJoint(const b2PrismaticJointDef* def) -: b2Joint(def) -{ - m_localAnchorA = def->localAnchorA; - m_localAnchorB = def->localAnchorB; - m_localXAxisA = def->localAxisA; - m_localXAxisA.Normalize(); - m_localYAxisA = b2Cross(1.0f, m_localXAxisA); - m_referenceAngle = def->referenceAngle; - - m_impulse.SetZero(); - m_motorMass = 0.0f; - m_motorImpulse = 0.0f; - - m_lowerTranslation = def->lowerTranslation; - m_upperTranslation = def->upperTranslation; - m_maxMotorForce = def->maxMotorForce; - m_motorSpeed = def->motorSpeed; - m_enableLimit = def->enableLimit; - m_enableMotor = def->enableMotor; - m_limitState = e_inactiveLimit; - - m_axis.SetZero(); - m_perp.SetZero(); -} - -void b2PrismaticJoint::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; - - b2Vec2 cA = data.positions[m_indexA].c; - float32 aA = data.positions[m_indexA].a; - b2Vec2 vA = data.velocities[m_indexA].v; - float32 wA = data.velocities[m_indexA].w; - - b2Vec2 cB = data.positions[m_indexB].c; - 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 masses. - b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA); - b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB); - b2Vec2 d = (cB - cA) + rB - rA; - - float32 mA = m_invMassA, mB = m_invMassB; - float32 iA = m_invIA, iB = m_invIB; - - // Compute motor Jacobian and effective mass. - { - m_axis = b2Mul(qA, m_localXAxisA); - m_a1 = b2Cross(d + rA, m_axis); - m_a2 = b2Cross(rB, m_axis); - - m_motorMass = mA + mB + iA * m_a1 * m_a1 + iB * m_a2 * m_a2; - if (m_motorMass > 0.0f) - { - m_motorMass = 1.0f / m_motorMass; - } - } - - // Prismatic constraint. - { - m_perp = b2Mul(qA, m_localYAxisA); - - m_s1 = b2Cross(d + rA, m_perp); - m_s2 = b2Cross(rB, m_perp); - - float32 k11 = mA + mB + iA * m_s1 * m_s1 + iB * m_s2 * m_s2; - float32 k12 = iA * m_s1 + iB * m_s2; - float32 k13 = iA * m_s1 * m_a1 + iB * m_s2 * m_a2; - float32 k22 = iA + iB; - if (k22 == 0.0f) - { - // For bodies with fixed rotation. - k22 = 1.0f; - } - float32 k23 = iA * m_a1 + iB * m_a2; - float32 k33 = mA + mB + iA * m_a1 * m_a1 + iB * m_a2 * m_a2; - - m_K.ex.Set(k11, k12, k13); - m_K.ey.Set(k12, k22, k23); - m_K.ez.Set(k13, k23, k33); - } - - // Compute motor and limit terms. - if (m_enableLimit) - { - float32 jointTranslation = b2Dot(m_axis, d); - if (b2Abs(m_upperTranslation - m_lowerTranslation) < 2.0f * b2_linearSlop) - { - m_limitState = e_equalLimits; - } - else if (jointTranslation <= m_lowerTranslation) - { - if (m_limitState != e_atLowerLimit) - { - m_limitState = e_atLowerLimit; - m_impulse.z = 0.0f; - } - } - else if (jointTranslation >= m_upperTranslation) - { - if (m_limitState != e_atUpperLimit) - { - m_limitState = e_atUpperLimit; - m_impulse.z = 0.0f; - } - } - else - { - m_limitState = e_inactiveLimit; - m_impulse.z = 0.0f; - } - } - else - { - m_limitState = e_inactiveLimit; - m_impulse.z = 0.0f; - } - - if (m_enableMotor == false) - { - m_motorImpulse = 0.0f; - } - - if (data.step.warmStarting) - { - // Account for variable time step. - m_impulse *= data.step.dtRatio; - m_motorImpulse *= data.step.dtRatio; - - b2Vec2 P = m_impulse.x * m_perp + (m_motorImpulse + m_impulse.z) * m_axis; - float32 LA = m_impulse.x * m_s1 + m_impulse.y + (m_motorImpulse + m_impulse.z) * m_a1; - float32 LB = m_impulse.x * m_s2 + m_impulse.y + (m_motorImpulse + m_impulse.z) * m_a2; - - vA -= mA * P; - wA -= iA * LA; - - vB += mB * P; - wB += iB * LB; - } - else - { - m_impulse.SetZero(); - m_motorImpulse = 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 b2PrismaticJoint::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; - - // Solve linear motor constraint. - if (m_enableMotor && m_limitState != e_equalLimits) - { - float32 Cdot = b2Dot(m_axis, vB - vA) + m_a2 * wB - m_a1 * wA; - float32 impulse = m_motorMass * (m_motorSpeed - Cdot); - float32 oldImpulse = m_motorImpulse; - float32 maxImpulse = data.step.dt * m_maxMotorForce; - m_motorImpulse = b2Clamp(m_motorImpulse + impulse, -maxImpulse, maxImpulse); - impulse = m_motorImpulse - oldImpulse; - - b2Vec2 P = impulse * m_axis; - float32 LA = impulse * m_a1; - float32 LB = impulse * m_a2; - - vA -= mA * P; - wA -= iA * LA; - - vB += mB * P; - wB += iB * LB; - } - - b2Vec2 Cdot1; - Cdot1.x = b2Dot(m_perp, vB - vA) + m_s2 * wB - m_s1 * wA; - Cdot1.y = wB - wA; - - if (m_enableLimit && m_limitState != e_inactiveLimit) - { - // Solve prismatic and limit constraint in block form. - float32 Cdot2; - Cdot2 = b2Dot(m_axis, vB - vA) + m_a2 * wB - m_a1 * wA; - b2Vec3 Cdot(Cdot1.x, Cdot1.y, Cdot2); - - b2Vec3 f1 = m_impulse; - b2Vec3 df = m_K.Solve33(-Cdot); - m_impulse += df; - - if (m_limitState == e_atLowerLimit) - { - m_impulse.z = b2Max(m_impulse.z, 0.0f); - } - else if (m_limitState == e_atUpperLimit) - { - m_impulse.z = b2Min(m_impulse.z, 0.0f); - } - - // f2(1:2) = invK(1:2,1:2) * (-Cdot(1:2) - K(1:2,3) * (f2(3) - f1(3))) + f1(1:2) - b2Vec2 b = -Cdot1 - (m_impulse.z - f1.z) * b2Vec2(m_K.ez.x, m_K.ez.y); - b2Vec2 f2r = m_K.Solve22(b) + b2Vec2(f1.x, f1.y); - m_impulse.x = f2r.x; - m_impulse.y = f2r.y; - - df = m_impulse - f1; - - b2Vec2 P = df.x * m_perp + df.z * m_axis; - float32 LA = df.x * m_s1 + df.y + df.z * m_a1; - float32 LB = df.x * m_s2 + df.y + df.z * m_a2; - - vA -= mA * P; - wA -= iA * LA; - - vB += mB * P; - wB += iB * LB; - } - else - { - // Limit is inactive, just solve the prismatic constraint in block form. - b2Vec2 df = m_K.Solve22(-Cdot1); - m_impulse.x += df.x; - m_impulse.y += df.y; - - b2Vec2 P = df.x * m_perp; - float32 LA = df.x * m_s1 + df.y; - float32 LB = df.x * m_s2 + df.y; - - vA -= mA * P; - wA -= iA * LA; - - vB += mB * P; - wB += iB * LB; - } - - data.velocities[m_indexA].v = vA; - data.velocities[m_indexA].w = wA; - data.velocities[m_indexB].v = vB; - data.velocities[m_indexB].w = wB; -} - -// A velocity based solver computes reaction forces(impulses) using the velocity constraint solver.Under this context, -// the position solver is not there to resolve forces.It is only there to cope with integration error. -// -// Therefore, the pseudo impulses in the position solver do not have any physical meaning.Thus it is okay if they suck. -// -// We could take the active state from the velocity solver.However, the joint might push past the limit when the velocity -// solver indicates the limit is inactive. -bool b2PrismaticJoint::SolvePositionConstraints(const b2SolverData& data) -{ - b2Vec2 cA = data.positions[m_indexA].c; - float32 aA = data.positions[m_indexA].a; - b2Vec2 cB = data.positions[m_indexB].c; - float32 aB = data.positions[m_indexB].a; - - b2Rot qA(aA), qB(aB); - - float32 mA = m_invMassA, mB = m_invMassB; - float32 iA = m_invIA, iB = m_invIB; - - // Compute fresh Jacobians - b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA); - b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB); - b2Vec2 d = cB + rB - cA - rA; - - b2Vec2 axis = b2Mul(qA, m_localXAxisA); - float32 a1 = b2Cross(d + rA, axis); - float32 a2 = b2Cross(rB, axis); - b2Vec2 perp = b2Mul(qA, m_localYAxisA); - - float32 s1 = b2Cross(d + rA, perp); - float32 s2 = b2Cross(rB, perp); - - b2Vec3 impulse; - b2Vec2 C1; - C1.x = b2Dot(perp, d); - C1.y = aB - aA - m_referenceAngle; - - float32 linearError = b2Abs(C1.x); - float32 angularError = b2Abs(C1.y); - - bool active = false; - float32 C2 = 0.0f; - if (m_enableLimit) - { - float32 translation = b2Dot(axis, d); - if (b2Abs(m_upperTranslation - m_lowerTranslation) < 2.0f * b2_linearSlop) - { - // Prevent large angular corrections - C2 = b2Clamp(translation, -b2_maxLinearCorrection, b2_maxLinearCorrection); - linearError = b2Max(linearError, b2Abs(translation)); - active = true; - } - else if (translation <= m_lowerTranslation) - { - // Prevent large linear corrections and allow some slop. - C2 = b2Clamp(translation - m_lowerTranslation + b2_linearSlop, -b2_maxLinearCorrection, 0.0f); - linearError = b2Max(linearError, m_lowerTranslation - translation); - active = true; - } - else if (translation >= m_upperTranslation) - { - // Prevent large linear corrections and allow some slop. - C2 = b2Clamp(translation - m_upperTranslation - b2_linearSlop, 0.0f, b2_maxLinearCorrection); - linearError = b2Max(linearError, translation - m_upperTranslation); - active = true; - } - } - - if (active) - { - float32 k11 = mA + mB + iA * s1 * s1 + iB * s2 * s2; - float32 k12 = iA * s1 + iB * s2; - float32 k13 = iA * s1 * a1 + iB * s2 * a2; - float32 k22 = iA + iB; - if (k22 == 0.0f) - { - // For fixed rotation - k22 = 1.0f; - } - float32 k23 = iA * a1 + iB * a2; - float32 k33 = mA + mB + iA * a1 * a1 + iB * a2 * a2; - - b2Mat33 K; - K.ex.Set(k11, k12, k13); - K.ey.Set(k12, k22, k23); - K.ez.Set(k13, k23, k33); - - b2Vec3 C; - C.x = C1.x; - C.y = C1.y; - C.z = C2; - - impulse = K.Solve33(-C); - } - else - { - float32 k11 = mA + mB + iA * s1 * s1 + iB * s2 * s2; - float32 k12 = iA * s1 + iB * s2; - float32 k22 = iA + iB; - if (k22 == 0.0f) - { - k22 = 1.0f; - } - - b2Mat22 K; - K.ex.Set(k11, k12); - K.ey.Set(k12, k22); - - b2Vec2 impulse1 = K.Solve(-C1); - impulse.x = impulse1.x; - impulse.y = impulse1.y; - impulse.z = 0.0f; - } - - b2Vec2 P = impulse.x * perp + impulse.z * axis; - float32 LA = impulse.x * s1 + impulse.y + impulse.z * a1; - float32 LB = impulse.x * s2 + impulse.y + impulse.z * a2; - - cA -= mA * P; - aA -= iA * LA; - cB += mB * P; - aB += iB * LB; - - data.positions[m_indexA].c = cA; - data.positions[m_indexA].a = aA; - data.positions[m_indexB].c = cB; - data.positions[m_indexB].a = aB; - - return linearError <= b2_linearSlop && angularError <= b2_angularSlop; -} - -b2Vec2 b2PrismaticJoint::GetAnchorA() const -{ - return m_bodyA->GetWorldPoint(m_localAnchorA); -} - -b2Vec2 b2PrismaticJoint::GetAnchorB() const -{ - return m_bodyB->GetWorldPoint(m_localAnchorB); -} - -b2Vec2 b2PrismaticJoint::GetReactionForce(float32 inv_dt) const -{ - return inv_dt * (m_impulse.x * m_perp + (m_motorImpulse + m_impulse.z) * m_axis); -} - -float32 b2PrismaticJoint::GetReactionTorque(float32 inv_dt) const -{ - return inv_dt * m_impulse.y; -} - -float32 b2PrismaticJoint::GetJointTranslation() const -{ - b2Vec2 pA = m_bodyA->GetWorldPoint(m_localAnchorA); - b2Vec2 pB = m_bodyB->GetWorldPoint(m_localAnchorB); - b2Vec2 d = pB - pA; - b2Vec2 axis = m_bodyA->GetWorldVector(m_localXAxisA); - - float32 translation = b2Dot(d, axis); - return translation; -} - -float32 b2PrismaticJoint::GetJointSpeed() const -{ - b2Body* bA = m_bodyA; - b2Body* bB = m_bodyB; - - b2Vec2 rA = b2Mul(bA->m_xf.q, m_localAnchorA - bA->m_sweep.localCenter); - b2Vec2 rB = b2Mul(bB->m_xf.q, m_localAnchorB - bB->m_sweep.localCenter); - b2Vec2 p1 = bA->m_sweep.c + rA; - b2Vec2 p2 = bB->m_sweep.c + rB; - b2Vec2 d = p2 - p1; - b2Vec2 axis = b2Mul(bA->m_xf.q, m_localXAxisA); - - b2Vec2 vA = bA->m_linearVelocity; - b2Vec2 vB = bB->m_linearVelocity; - float32 wA = bA->m_angularVelocity; - float32 wB = bB->m_angularVelocity; - - float32 speed = b2Dot(d, b2Cross(wA, axis)) + b2Dot(axis, vB + b2Cross(wB, rB) - vA - b2Cross(wA, rA)); - return speed; -} - -bool b2PrismaticJoint::IsLimitEnabled() const -{ - return m_enableLimit; -} - -void b2PrismaticJoint::EnableLimit(bool flag) -{ - if (flag != m_enableLimit) - { - m_bodyA->SetAwake(true); - m_bodyB->SetAwake(true); - m_enableLimit = flag; - m_impulse.z = 0.0f; - } -} - -float32 b2PrismaticJoint::GetLowerLimit() const -{ - return m_lowerTranslation; -} - -float32 b2PrismaticJoint::GetUpperLimit() const -{ - return m_upperTranslation; -} - -void b2PrismaticJoint::SetLimits(float32 lower, float32 upper) -{ - b2Assert(lower <= upper); - if (lower != m_lowerTranslation || upper != m_upperTranslation) - { - m_bodyA->SetAwake(true); - m_bodyB->SetAwake(true); - m_lowerTranslation = lower; - m_upperTranslation = upper; - m_impulse.z = 0.0f; - } -} - -bool b2PrismaticJoint::IsMotorEnabled() const -{ - return m_enableMotor; -} - -void b2PrismaticJoint::EnableMotor(bool flag) -{ - if (flag != m_enableMotor) - { - m_bodyA->SetAwake(true); - m_bodyB->SetAwake(true); - m_enableMotor = flag; - } -} - -void b2PrismaticJoint::SetMotorSpeed(float32 speed) -{ - if (speed != m_motorSpeed) - { - m_bodyA->SetAwake(true); - m_bodyB->SetAwake(true); - m_motorSpeed = speed; - } -} - -void b2PrismaticJoint::SetMaxMotorForce(float32 force) -{ - if (force != m_maxMotorForce) - { - m_bodyA->SetAwake(true); - m_bodyB->SetAwake(true); - m_maxMotorForce = force; - } -} - -float32 b2PrismaticJoint::GetMotorForce(float32 inv_dt) const -{ - return inv_dt * m_motorImpulse; -} - -void b2PrismaticJoint::Dump() -{ - int32 indexA = m_bodyA->m_islandIndex; - int32 indexB = m_bodyB->m_islandIndex; - - b2Log(" b2PrismaticJointDef 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.localAxisA.Set(%.15lef, %.15lef);\n", m_localXAxisA.x, m_localXAxisA.y); - b2Log(" jd.referenceAngle = %.15lef;\n", m_referenceAngle); - b2Log(" jd.enableLimit = bool(%d);\n", m_enableLimit); - b2Log(" jd.lowerTranslation = %.15lef;\n", m_lowerTranslation); - b2Log(" jd.upperTranslation = %.15lef;\n", m_upperTranslation); - b2Log(" jd.enableMotor = bool(%d);\n", m_enableMotor); - b2Log(" jd.motorSpeed = %.15lef;\n", m_motorSpeed); - b2Log(" jd.maxMotorForce = %.15lef;\n", m_maxMotorForce); - b2Log(" joints[%d] = m_world->CreateJoint(&jd);\n", m_index); -} |