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-/*
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-* Copyright (c) 2006-2011 Erin Catto http://www.box2d.org
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-*
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-* This software is provided 'as-is', without any express or implied
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-* warranty. In no event will the authors be held liable for any damages
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-* arising from the use of this software.
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-* Permission is granted to anyone to use this software for any purpose,
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-* including commercial applications, and to alter it and redistribute it
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-* freely, subject to the following restrictions:
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-* 1. The origin of this software must not be misrepresented; you must not
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-* claim that you wrote the original software. If you use this software
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-* in a product, an acknowledgment in the product documentation would be
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-* appreciated but is not required.
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-* 2. Altered source versions must be plainly marked as such, and must not be
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-* misrepresented as being the original software.
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-* 3. This notice may not be removed or altered from any source distribution.
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-*/
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-
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-#include "Box2D/Dynamics/Joints/b2PrismaticJoint.h"
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-#include "Box2D/Dynamics/b2Body.h"
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-#include "Box2D/Dynamics/b2TimeStep.h"
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-
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-// Linear constraint (point-to-line)
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-// d = p2 - p1 = x2 + r2 - x1 - r1
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-// C = dot(perp, d)
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-// Cdot = dot(d, cross(w1, perp)) + dot(perp, v2 + cross(w2, r2) - v1 - cross(w1, r1))
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-// = -dot(perp, v1) - dot(cross(d + r1, perp), w1) + dot(perp, v2) + dot(cross(r2, perp), v2)
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-// J = [-perp, -cross(d + r1, perp), perp, cross(r2,perp)]
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-//
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-// Angular constraint
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-// C = a2 - a1 + a_initial
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-// Cdot = w2 - w1
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-// J = [0 0 -1 0 0 1]
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-//
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-// K = J * invM * JT
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-//
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-// J = [-a -s1 a s2]
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-// [0 -1 0 1]
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-// a = perp
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-// s1 = cross(d + r1, a) = cross(p2 - x1, a)
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-// s2 = cross(r2, a) = cross(p2 - x2, a)
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-
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-
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-// Motor/Limit linear constraint
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-// C = dot(ax1, d)
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-// Cdot = = -dot(ax1, v1) - dot(cross(d + r1, ax1), w1) + dot(ax1, v2) + dot(cross(r2, ax1), v2)
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-// J = [-ax1 -cross(d+r1,ax1) ax1 cross(r2,ax1)]
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-
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-// Block Solver
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-// We develop a block solver that includes the joint limit. This makes the limit stiff (inelastic) even
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-// when the mass has poor distribution (leading to large torques about the joint anchor points).
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-//
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-// The Jacobian has 3 rows:
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-// J = [-uT -s1 uT s2] // linear
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-// [0 -1 0 1] // angular
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-// [-vT -a1 vT a2] // limit
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-//
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-// u = perp
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-// v = axis
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-// s1 = cross(d + r1, u), s2 = cross(r2, u)
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-// a1 = cross(d + r1, v), a2 = cross(r2, v)
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-
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-// M * (v2 - v1) = JT * df
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-// J * v2 = bias
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-//
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-// v2 = v1 + invM * JT * df
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-// J * (v1 + invM * JT * df) = bias
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-// K * df = bias - J * v1 = -Cdot
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-// K = J * invM * JT
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-// Cdot = J * v1 - bias
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-//
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-// Now solve for f2.
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-// df = f2 - f1
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-// K * (f2 - f1) = -Cdot
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-// f2 = invK * (-Cdot) + f1
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-//
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-// Clamp accumulated limit impulse.
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-// lower: f2(3) = max(f2(3), 0)
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-// upper: f2(3) = min(f2(3), 0)
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-//
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-// Solve for correct f2(1:2)
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-// K(1:2, 1:2) * f2(1:2) = -Cdot(1:2) - K(1:2,3) * f2(3) + K(1:2,1:3) * f1
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-// = -Cdot(1:2) - K(1:2,3) * f2(3) + K(1:2,1:2) * f1(1:2) + K(1:2,3) * f1(3)
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-// 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)
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-// f2(1:2) = invK(1:2,1:2) * (-Cdot(1:2) - K(1:2,3) * (f2(3) - f1(3))) + f1(1:2)
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-//
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-// Now compute impulse to be applied:
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-// df = f2 - f1
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-
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-void b2PrismaticJointDef::Initialize(b2Body* bA, b2Body* bB, const b2Vec2& anchor, const b2Vec2& axis)
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-{
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- bodyA = bA;
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- bodyB = bB;
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- localAnchorA = bodyA->GetLocalPoint(anchor);
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- localAnchorB = bodyB->GetLocalPoint(anchor);
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- localAxisA = bodyA->GetLocalVector(axis);
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- referenceAngle = bodyB->GetAngle() - bodyA->GetAngle();
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-}
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-
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-b2PrismaticJoint::b2PrismaticJoint(const b2PrismaticJointDef* def)
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-: b2Joint(def)
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-{
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- m_localAnchorA = def->localAnchorA;
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- m_localAnchorB = def->localAnchorB;
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- m_localXAxisA = def->localAxisA;
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- m_localXAxisA.Normalize();
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- m_localYAxisA = b2Cross(1.0f, m_localXAxisA);
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- m_referenceAngle = def->referenceAngle;
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-
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- m_impulse.SetZero();
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- m_motorMass = 0.0f;
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- m_motorImpulse = 0.0f;
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-
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- m_lowerTranslation = def->lowerTranslation;
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- m_upperTranslation = def->upperTranslation;
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- m_maxMotorForce = def->maxMotorForce;
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- m_motorSpeed = def->motorSpeed;
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- m_enableLimit = def->enableLimit;
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- m_enableMotor = def->enableMotor;
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- m_limitState = e_inactiveLimit;
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-
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- m_axis.SetZero();
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- m_perp.SetZero();
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-}
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-
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-void b2PrismaticJoint::InitVelocityConstraints(const b2SolverData& data)
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-{
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- m_indexA = m_bodyA->m_islandIndex;
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- m_indexB = m_bodyB->m_islandIndex;
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- m_localCenterA = m_bodyA->m_sweep.localCenter;
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- m_localCenterB = m_bodyB->m_sweep.localCenter;
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- m_invMassA = m_bodyA->m_invMass;
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- m_invMassB = m_bodyB->m_invMass;
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- m_invIA = m_bodyA->m_invI;
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- m_invIB = m_bodyB->m_invI;
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-
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- b2Vec2 cA = data.positions[m_indexA].c;
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- float32 aA = data.positions[m_indexA].a;
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- b2Vec2 vA = data.velocities[m_indexA].v;
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- float32 wA = data.velocities[m_indexA].w;
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-
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- b2Vec2 cB = data.positions[m_indexB].c;
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- float32 aB = data.positions[m_indexB].a;
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- b2Vec2 vB = data.velocities[m_indexB].v;
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- float32 wB = data.velocities[m_indexB].w;
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-
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- b2Rot qA(aA), qB(aB);
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-
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- // Compute the effective masses.
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- b2Vec2 rA = b2Mul(qA, m_localAnchorA - m_localCenterA);
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- b2Vec2 rB = b2Mul(qB, m_localAnchorB - m_localCenterB);
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- b2Vec2 d = (cB - cA) + rB - rA;
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-
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- float32 mA = m_invMassA, mB = m_invMassB;
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- float32 iA = m_invIA, iB = m_invIB;
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-
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- // Compute motor Jacobian and effective mass.
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- {
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- m_axis = b2Mul(qA, m_localXAxisA);
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- m_a1 = b2Cross(d + rA, m_axis);
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- m_a2 = b2Cross(rB, m_axis);
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-
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- m_motorMass = mA + mB + iA * m_a1 * m_a1 + iB * m_a2 * m_a2;
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- if (m_motorMass > 0.0f)
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- {
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- m_motorMass = 1.0f / m_motorMass;
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- }
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- }
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-
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- // Prismatic constraint.
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- {
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- m_perp = b2Mul(qA, m_localYAxisA);
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-
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- m_s1 = b2Cross(d + rA, m_perp);
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- m_s2 = b2Cross(rB, m_perp);
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-
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- float32 k11 = mA + mB + iA * m_s1 * m_s1 + iB * m_s2 * m_s2;
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- float32 k12 = iA * m_s1 + iB * m_s2;
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- float32 k13 = iA * m_s1 * m_a1 + iB * m_s2 * m_a2;
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- float32 k22 = iA + iB;
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- if (k22 == 0.0f)
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- {
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- // For bodies with fixed rotation.
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- k22 = 1.0f;
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- }
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- float32 k23 = iA * m_a1 + iB * m_a2;
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- float32 k33 = mA + mB + iA * m_a1 * m_a1 + iB * m_a2 * m_a2;
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-
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- m_K.ex.Set(k11, k12, k13);
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- m_K.ey.Set(k12, k22, k23);
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- m_K.ez.Set(k13, k23, k33);
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- }
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-
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- // Compute motor and limit terms.
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- if (m_enableLimit)
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- {
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- float32 jointTranslation = b2Dot(m_axis, d);
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- if (b2Abs(m_upperTranslation - m_lowerTranslation) < 2.0f * b2_linearSlop)
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- {
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- m_limitState = e_equalLimits;
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- }
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- else if (jointTranslation <= m_lowerTranslation)
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- {
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- if (m_limitState != e_atLowerLimit)
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- {
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- m_limitState = e_atLowerLimit;
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- m_impulse.z = 0.0f;
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- }
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- }
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- else if (jointTranslation >= m_upperTranslation)
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- {
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- if (m_limitState != e_atUpperLimit)
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- {
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- m_limitState = e_atUpperLimit;
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- m_impulse.z = 0.0f;
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- }
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- }
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- else
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- {
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- m_limitState = e_inactiveLimit;
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- m_impulse.z = 0.0f;
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- }
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- }
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- else
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- {
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- m_limitState = e_inactiveLimit;
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- m_impulse.z = 0.0f;
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- }
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-
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- if (m_enableMotor == false)
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- {
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- m_motorImpulse = 0.0f;
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- }
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-
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- if (data.step.warmStarting)
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- {
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- // Account for variable time step.
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- m_impulse *= data.step.dtRatio;
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- m_motorImpulse *= data.step.dtRatio;
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-
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- b2Vec2 P = m_impulse.x * m_perp + (m_motorImpulse + m_impulse.z) * m_axis;
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- float32 LA = m_impulse.x * m_s1 + m_impulse.y + (m_motorImpulse + m_impulse.z) * m_a1;
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- float32 LB = m_impulse.x * m_s2 + m_impulse.y + (m_motorImpulse + m_impulse.z) * m_a2;
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-
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- vA -= mA * P;
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- wA -= iA * LA;
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-
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- vB += mB * P;
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- wB += iB * LB;
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- }
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- else
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- {
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- m_impulse.SetZero();
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- m_motorImpulse = 0.0f;
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- }
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-
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- data.velocities[m_indexA].v = vA;
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- data.velocities[m_indexA].w = wA;
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- data.velocities[m_indexB].v = vB;
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- data.velocities[m_indexB].w = wB;
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-}
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-
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-void b2PrismaticJoint::SolveVelocityConstraints(const b2SolverData& data)
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-{
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- b2Vec2 vA = data.velocities[m_indexA].v;
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- float32 wA = data.velocities[m_indexA].w;
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- b2Vec2 vB = data.velocities[m_indexB].v;
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- float32 wB = data.velocities[m_indexB].w;
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-
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- float32 mA = m_invMassA, mB = m_invMassB;
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- float32 iA = m_invIA, iB = m_invIB;
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-
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- // Solve linear motor constraint.
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- if (m_enableMotor && m_limitState != e_equalLimits)
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- {
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- float32 Cdot = b2Dot(m_axis, vB - vA) + m_a2 * wB - m_a1 * wA;
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- float32 impulse = m_motorMass * (m_motorSpeed - Cdot);
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- float32 oldImpulse = m_motorImpulse;
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- float32 maxImpulse = data.step.dt * m_maxMotorForce;
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- m_motorImpulse = b2Clamp(m_motorImpulse + impulse, -maxImpulse, maxImpulse);
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- impulse = m_motorImpulse - oldImpulse;
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-
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- b2Vec2 P = impulse * m_axis;
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- float32 LA = impulse * m_a1;
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- float32 LB = impulse * m_a2;
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-
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- vA -= mA * P;
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- wA -= iA * LA;
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-
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- vB += mB * P;
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- wB += iB * LB;
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- }
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-
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- b2Vec2 Cdot1;
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- Cdot1.x = b2Dot(m_perp, vB - vA) + m_s2 * wB - m_s1 * wA;
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- Cdot1.y = wB - wA;
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-
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- if (m_enableLimit && m_limitState != e_inactiveLimit)
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- {
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- // Solve prismatic and limit constraint in block form.
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- float32 Cdot2;
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- Cdot2 = b2Dot(m_axis, vB - vA) + m_a2 * wB - m_a1 * wA;
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- b2Vec3 Cdot(Cdot1.x, Cdot1.y, Cdot2);
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-
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- b2Vec3 f1 = m_impulse;
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- b2Vec3 df = m_K.Solve33(-Cdot);
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- m_impulse += df;
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-
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- if (m_limitState == e_atLowerLimit)
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- {
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- m_impulse.z = b2Max(m_impulse.z, 0.0f);
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- }
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- else if (m_limitState == e_atUpperLimit)
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- {
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- m_impulse.z = b2Min(m_impulse.z, 0.0f);
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- }
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-
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- // f2(1:2) = invK(1:2,1:2) * (-Cdot(1:2) - K(1:2,3) * (f2(3) - f1(3))) + f1(1:2)
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- b2Vec2 b = -Cdot1 - (m_impulse.z - f1.z) * b2Vec2(m_K.ez.x, m_K.ez.y);
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- b2Vec2 f2r = m_K.Solve22(b) + b2Vec2(f1.x, f1.y);
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- m_impulse.x = f2r.x;
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- m_impulse.y = f2r.y;
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-
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- df = m_impulse - f1;
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-
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- b2Vec2 P = df.x * m_perp + df.z * m_axis;
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- float32 LA = df.x * m_s1 + df.y + df.z * m_a1;
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- float32 LB = df.x * m_s2 + df.y + df.z * m_a2;
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-
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- vA -= mA * P;
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- wA -= iA * LA;
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-
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- vB += mB * P;
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- wB += iB * LB;
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- }
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- else
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- {
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- // Limit is inactive, just solve the prismatic constraint in block form.
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- b2Vec2 df = m_K.Solve22(-Cdot1);
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- m_impulse.x += df.x;
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- m_impulse.y += df.y;
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-
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- b2Vec2 P = df.x * m_perp;
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- float32 LA = df.x * m_s1 + df.y;
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- float32 LB = df.x * m_s2 + df.y;
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-
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- vA -= mA * P;
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- wA -= iA * LA;
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-
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- vB += mB * P;
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- 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);
|
|
|
-}
|