@Override
public boolean solvePositionConstraints(final org.jbox2d.dynamics.SolverData data) {
final Rot qA = pool.popRot();
final Rot qB = pool.popRot();
Vec2 cA = data.positions[m_indexA].c;
float aA = data.positions[m_indexA].a;
Vec2 cB = data.positions[m_indexB].c;
float aB = data.positions[m_indexB].a;
qA.set(aA);
qB.set(aB);
float angularError = 0.0f;
float positionError = 0.0f;
boolean fixedRotation = (m_invIA + m_invIB == 0.0f);
// Solve angular limit constraint.
if (m_enableLimit && m_limitState != LimitState.INACTIVE && fixedRotation == false) {
float angle = aB - aA - m_referenceAngle;
float limitImpulse = 0.0f;
if (m_limitState == LimitState.EQUAL) {
// Prevent large angular corrections
float C =
MathUtils.clamp(
angle - m_lowerAngle,
-Settings.maxAngularCorrection,
Settings.maxAngularCorrection);
limitImpulse = -m_motorMass * C;
angularError = MathUtils.abs(C);
} else if (m_limitState == LimitState.AT_LOWER) {
float C = angle - m_lowerAngle;
angularError = -C;
// Prevent large angular corrections and allow some slop.
C = MathUtils.clamp(C + Settings.angularSlop, -Settings.maxAngularCorrection, 0.0f);
limitImpulse = -m_motorMass * C;
} else if (m_limitState == LimitState.AT_UPPER) {
float C = angle - m_upperAngle;
angularError = C;
// Prevent large angular corrections and allow some slop.
C = MathUtils.clamp(C - Settings.angularSlop, 0.0f, Settings.maxAngularCorrection);
limitImpulse = -m_motorMass * C;
}
aA -= m_invIA * limitImpulse;
aB += m_invIB * limitImpulse;
}
// Solve point-to-point constraint.
{
qA.set(aA);
qB.set(aB);
final Vec2 rA = pool.popVec2();
final Vec2 rB = pool.popVec2();
final Vec2 C = pool.popVec2();
final Vec2 impulse = pool.popVec2();
Rot.mulToOutUnsafe(qA, C.set(m_localAnchorA).subLocal(m_localCenterA), rA);
Rot.mulToOutUnsafe(qB, C.set(m_localAnchorB).subLocal(m_localCenterB), rB);
C.set(cB).addLocal(rB).subLocal(cA).subLocal(rA);
positionError = C.length();
float mA = m_invMassA, mB = m_invMassB;
float iA = m_invIA, iB = m_invIB;
final org.jbox2d.common.Mat22 K = pool.popMat22();
K.ex.x = mA + mB + iA * rA.y * rA.y + iB * rB.y * rB.y;
K.ex.y = -iA * rA.x * rA.y - iB * rB.x * rB.y;
K.ey.x = K.ex.y;
K.ey.y = mA + mB + iA * rA.x * rA.x + iB * rB.x * rB.x;
K.solveToOut(C, impulse);
impulse.negateLocal();
cA.x -= mA * impulse.x;
cA.y -= mA * impulse.y;
aA -= iA * Vec2.cross(rA, impulse);
cB.x += mB * impulse.x;
cB.y += mB * impulse.y;
aB += iB * Vec2.cross(rB, impulse);
pool.pushVec2(4);
pool.pushMat22(1);
}
// data.positions[m_indexA].c.set(cA);
data.positions[m_indexA].a = aA;
// data.positions[m_indexB].c.set(cB);
data.positions[m_indexB].a = aB;
pool.pushRot(2);
return positionError <= Settings.linearSlop && angularError <= Settings.angularSlop;
}
/**
* Compute the collision manifold between two polygons.
*
* @param manifold
* @param polygon1
* @param xf1
* @param polygon2
* @param xf2
*/
public final void collidePolygons(
Manifold manifold,
final PolygonShape polyA,
final Transform xfA,
final PolygonShape polyB,
final Transform xfB) {
// Find edge normal of max separation on A - return if separating axis is found
// Find edge normal of max separation on B - return if separation axis is found
// Choose reference edge as min(minA, minB)
// Find incident edge
// Clip
// The normal points from 1 to 2
manifold.pointCount = 0;
float totalRadius = polyA.m_radius + polyB.m_radius;
findMaxSeparation(results1, polyA, xfA, polyB, xfB);
if (results1.separation > totalRadius) {
return;
}
findMaxSeparation(results2, polyB, xfB, polyA, xfA);
if (results2.separation > totalRadius) {
return;
}
final PolygonShape poly1; // reference polygon
final PolygonShape poly2; // incident polygon
Transform xf1, xf2;
int edge1; // reference edge
int flip;
final float k_relativeTol = 0.98f;
final float k_absoluteTol = 0.001f;
if (results2.separation > k_relativeTol * results1.separation + k_absoluteTol) {
poly1 = polyB;
poly2 = polyA;
xf1 = xfB;
xf2 = xfA;
edge1 = results2.edgeIndex;
manifold.type = ManifoldType.FACE_B;
flip = 1;
} else {
poly1 = polyA;
poly2 = polyB;
xf1 = xfA;
xf2 = xfB;
edge1 = results1.edgeIndex;
manifold.type = ManifoldType.FACE_A;
flip = 0;
}
findIncidentEdge(incidentEdge, poly1, xf1, edge1, poly2, xf2);
int count1 = poly1.m_vertexCount;
final Vec2[] vertices1 = poly1.m_vertices;
v11.set(vertices1[edge1]);
v12.set(edge1 + 1 < count1 ? vertices1[edge1 + 1] : vertices1[0]);
localTangent.set(v12).subLocal(v11);
localTangent.normalize();
Vec2.crossToOut(localTangent, 1f, localNormal); // Vec2 localNormal = Cross(dv,
// 1.0f);
planePoint.set(v11).addLocal(v12).mulLocal(.5f); // Vec2 planePoint = 0.5f * (v11
// + v12);
Mat22.mulToOut(xf1.R, localTangent, tangent); // Vec2 sideNormal = Mul(xf1.R, v12
// - v11);
Vec2.crossToOut(tangent, 1f, normal); // Vec2 frontNormal = Cross(sideNormal,
// 1.0f);
Transform.mulToOut(xf1, v11, v11);
Transform.mulToOut(xf1, v12, v12);
// v11 = Mul(xf1, v11);
// v12 = Mul(xf1, v12);
// Face offset
float frontOffset = Vec2.dot(normal, v11);
// Side offsets, extended by polytope skin thickness.
float sideOffset1 = -Vec2.dot(tangent, v11) + totalRadius;
float sideOffset2 = Vec2.dot(tangent, v12) + totalRadius;
// Clip incident edge against extruded edge1 side edges.
// ClipVertex clipPoints1[2];
// ClipVertex clipPoints2[2];
int np;
// Clip to box side 1
// np = ClipSegmentToLine(clipPoints1, incidentEdge, -sideNormal, sideOffset1);
tangent.negateLocal();
np = clipSegmentToLine(clipPoints1, incidentEdge, tangent, sideOffset1);
tangent.negateLocal();
if (np < 2) {
return;
}
// Clip to negative box side 1
np = clipSegmentToLine(clipPoints2, clipPoints1, tangent, sideOffset2);
if (np < 2) {
return;
}
// Now clipPoints2 contains the clipped points.
manifold.localNormal.set(localNormal);
manifold.localPoint.set(planePoint);
int pointCount = 0;
for (int i = 0; i < Settings.maxManifoldPoints; ++i) {
float separation = Vec2.dot(normal, clipPoints2[i].v) - frontOffset;
if (separation <= totalRadius) {
ManifoldPoint cp = manifold.points[pointCount];
Transform.mulTransToOut(xf2, clipPoints2[i].v, cp.localPoint);
// cp.m_localPoint = MulT(xf2, clipPoints2[i].v);
cp.id.set(clipPoints2[i].id);
cp.id.features.flip = flip;
++pointCount;
}
}
manifold.pointCount = pointCount;
}
@Override
public void solveVelocityConstraints(final org.jbox2d.dynamics.SolverData data) {
Vec2 vA = data.velocities[m_indexA].v;
float wA = data.velocities[m_indexA].w;
Vec2 vB = data.velocities[m_indexB].v;
float wB = data.velocities[m_indexB].w;
float mA = m_invMassA, mB = m_invMassB;
float iA = m_invIA, iB = m_invIB;
boolean fixedRotation = (iA + iB == 0.0f);
// Solve motor constraint.
if (m_enableMotor && m_limitState != LimitState.EQUAL && fixedRotation == false) {
float Cdot = wB - wA - m_motorSpeed;
float impulse = -m_motorMass * Cdot;
float oldImpulse = m_motorImpulse;
float maxImpulse = data.step.dt * m_maxMotorTorque;
m_motorImpulse = MathUtils.clamp(m_motorImpulse + impulse, -maxImpulse, maxImpulse);
impulse = m_motorImpulse - oldImpulse;
wA -= iA * impulse;
wB += iB * impulse;
}
final Vec2 temp = pool.popVec2();
// Solve limit constraint.
if (m_enableLimit && m_limitState != LimitState.INACTIVE && fixedRotation == false) {
final Vec2 Cdot1 = pool.popVec2();
final Vec3 Cdot = pool.popVec3();
// Solve point-to-point constraint
Vec2.crossToOutUnsafe(wA, m_rA, temp);
Vec2.crossToOutUnsafe(wB, m_rB, Cdot1);
Cdot1.addLocal(vB).subLocal(vA).subLocal(temp);
float Cdot2 = wB - wA;
Cdot.set(Cdot1.x, Cdot1.y, Cdot2);
Vec3 impulse = pool.popVec3();
m_mass.solve33ToOut(Cdot, impulse);
impulse.negateLocal();
if (m_limitState == LimitState.EQUAL) {
m_impulse.addLocal(impulse);
} else if (m_limitState == LimitState.AT_LOWER) {
float newImpulse = m_impulse.z + impulse.z;
if (newImpulse < 0.0f) {
final Vec2 rhs = pool.popVec2();
rhs.set(m_mass.ez.x, m_mass.ez.y).mulLocal(m_impulse.z).subLocal(Cdot1);
m_mass.solve22ToOut(rhs, temp);
impulse.x = temp.x;
impulse.y = temp.y;
impulse.z = -m_impulse.z;
m_impulse.x += temp.x;
m_impulse.y += temp.y;
m_impulse.z = 0.0f;
pool.pushVec2(1);
} else {
m_impulse.addLocal(impulse);
}
} else if (m_limitState == LimitState.AT_UPPER) {
float newImpulse = m_impulse.z + impulse.z;
if (newImpulse > 0.0f) {
final Vec2 rhs = pool.popVec2();
rhs.set(m_mass.ez.x, m_mass.ez.y).mulLocal(m_impulse.z).subLocal(Cdot1);
m_mass.solve22ToOut(rhs, temp);
impulse.x = temp.x;
impulse.y = temp.y;
impulse.z = -m_impulse.z;
m_impulse.x += temp.x;
m_impulse.y += temp.y;
m_impulse.z = 0.0f;
pool.pushVec2(1);
} else {
m_impulse.addLocal(impulse);
}
}
final Vec2 P = pool.popVec2();
P.set(impulse.x, impulse.y);
vA.x -= mA * P.x;
vA.y -= mA * P.y;
wA -= iA * (Vec2.cross(m_rA, P) + impulse.z);
vB.x += mB * P.x;
vB.y += mB * P.y;
wB += iB * (Vec2.cross(m_rB, P) + impulse.z);
pool.pushVec2(2);
pool.pushVec3(2);
} else {
// Solve point-to-point constraint
Vec2 Cdot = pool.popVec2();
Vec2 impulse = pool.popVec2();
Vec2.crossToOutUnsafe(wA, m_rA, temp);
Vec2.crossToOutUnsafe(wB, m_rB, Cdot);
Cdot.addLocal(vB).subLocal(vA).subLocal(temp);
m_mass.solve22ToOut(Cdot.negateLocal(), impulse); // just leave negated
m_impulse.x += impulse.x;
m_impulse.y += impulse.y;
vA.x -= mA * impulse.x;
vA.y -= mA * impulse.y;
wA -= iA * Vec2.cross(m_rA, impulse);
vB.x += mB * impulse.x;
vB.y += mB * impulse.y;
wB += iB * Vec2.cross(m_rB, impulse);
pool.pushVec2(2);
}
// data.velocities[m_indexA].v.set(vA);
data.velocities[m_indexA].w = wA;
// data.velocities[m_indexB].v.set(vB);
data.velocities[m_indexB].w = wB;
pool.pushVec2(1);
}