/// Compute the collision manifold between two circles.
public static void CollideCircles(out Manifold manifold,
CircleShape circleA, Transform xfA,
CircleShape circleB, Transform xfB) {
throw new NotImplementedException();
//manifold.pointCount = 0;
//Vec2 pA = Utilities.Mul(xfA, circleA.m_p);
//Vec2 pB = Utilities.Mul(xfB, circleB.m_p);
//Vec2 d = pB - pA;
//float distSqr = Utilities.Dot(d, d);
//float rA = circleA.m_radius, rB = circleB.m_radius;
//float radius = rA + rB;
//if (distSqr > radius * radius)
//{
// return;
//}
//manifold.type = Manifold::e_circles;
//manifold.localPoint = circleA.m_p;
//manifold.localNormal.SetZero();
//manifold.pointCount = 1;
//manifold.points[0].localPoint = circleB.m_p;
//manifold.points[0].id.key = 0;
}
public override void Evaluate(out Manifold manifold, Transform xfA, Transform xfB){
ChainShape chain = (ChainShape)m_fixtureA.GetShape();
EdgeShape edge;
chain.GetChildEdge(out edge, m_indexA);
Collision.CollideEdgeAndCircle(out manifold, edge, xfA,
(CircleShape)m_fixtureB.GetShape(), xfB);
}
public override void PreSolve(Contact contact, Manifold oldManifold)
{
base.PreSolve(contact, oldManifold);
Fixture fixtureA = contact.FixtureA;
Fixture fixtureB = contact.FixtureB;
if (fixtureA != m_platform && fixtureA != m_character)
{
return;
}
if (fixtureB != m_platform && fixtureB != m_character)
{
return;
}
#if true
Vec2 position = m_character.GetBody().GetPosition();
if (position.Y < m_top + m_radius - 3.0f *Settings._linearSlop)
{
contact.SetEnabled(false);
}
#else
Vec2 v = m_character.GetBody().GetLinearVelocity();
if (v.Y > 0.0f)
{
contact.SetEnabled(false);
}
#endif
}
public override void PreSolve(Contact contact, Manifold oldManifold)
{
base.PreSolve(contact, oldManifold);
Fixture fixtureA = contact.FixtureA;
Fixture fixtureB = contact.FixtureB;
if (fixtureA == m_platform)
{
contact.SetTangentSpeed(5.0f);
}
if (fixtureB == m_platform)
{
contact.SetTangentSpeed(-5.0f);
}
}
/// Compute the collision manifold between an edge and a circle.
public static void CollideEdgeAndCircle(out Manifold manifold,
EdgeShape edgeA, Transform xfA,
CircleShape circleB, Transform xfB){
manifold = new Manifold();
// Compute circle in frame of edge
Vec2 Q = Utilities.MulT(xfA, Utilities.Mul(xfB, circleB.m_p));
Vec2 A = edgeA.m_vertex1, B = edgeA.m_vertex2;
Vec2 e = B - A;
// Barycentric coordinates
float u = Utilities.Dot(e, B - Q);
float v = Utilities.Dot(e, Q - A);
float radius = edgeA.m_radius + circleB.m_radius;
ContactFeature cf;
cf.indexB = 0;
cf.typeB = ContactFeature.FeatureType.e_vertex;
// Region A
if (v <= 0.0f)
{
Vec2 P = A;
Vec2 d = Q - P;
float dd = Utilities.Dot(d, d);
if (dd > radius * radius)
{
return;
}
// Is there an edge connected to A?
if (edgeA.m_hasVertex0)
{
Vec2 A1 = edgeA.m_vertex0;
Vec2 B1 = A;
Vec2 e1 = B1 - A1;
float u1 = Utilities.Dot(e1, B1 - Q);
// Is the circle in Region AB of the previous edge?
if (u1 > 0.0f)
{
return;
}
}
cf.indexA = 0;
cf.typeA = ContactFeature.FeatureType.e_vertex;
manifold.points.Clear();
manifold.points.Add(new ManifoldPoint());
manifold.type = Manifold.ManifoldType.e_circles;
manifold.localNormal.SetZero();
manifold.localPoint = P;
manifold.points[0].id.key = 0;
manifold.points[0].id.cf = cf;
manifold.points[0].localPoint = circleB.m_p;
return;
}
// Region B
if (u <= 0.0f)
{
Vec2 P = B;
Vec2 d = Q - P;
float dd = Utilities.Dot(d, d);
if (dd > radius * radius)
{
return;
}
// Is there an edge connected to B?
if (edgeA.m_hasVertex3)
{
Vec2 B2 = edgeA.m_vertex3;
Vec2 A2 = B;
Vec2 e2 = B2 - A2;
float v2 = Utilities.Dot(e2, Q - A2);
// Is the circle in Region AB of the next edge?
if (v2 > 0.0f)
{
return;
}
}
cf.indexA = 1;
cf.typeA = ContactFeature.FeatureType.e_vertex;
manifold.points.Clear();
manifold.points.Add(new ManifoldPoint());
manifold.type = Manifold.ManifoldType.e_circles;
manifold.localNormal.SetZero();
manifold.localPoint = P;
manifold.points[0].id.key = 0;
manifold.points[0].id.cf = cf;
manifold.points[0].localPoint = circleB.m_p;
return;
}
// Region AB
float den = Utilities.Dot(e, e);
Utilities.Assert(den > 0.0f);
Vec2 Pb = (1.0f / den) * (u * A + v * B);
Vec2 db = Q - Pb;
float ddb = Utilities.Dot(db, db);
if (ddb > radius * radius)
{
return;
}
Vec2 n = new Vec2(-e.Y, e.X);
if (Utilities.Dot(n, Q - A) < 0.0f)
{
n.Set(-n.X, -n.Y);
}
n.Normalize();
cf.indexA = 0;
cf.typeA = ContactFeature.FeatureType.e_face;
manifold.points.Clear();
manifold.points.Add(new ManifoldPoint());
manifold.type = Manifold.ManifoldType.e_faceA;
manifold.localNormal = n;
manifold.localPoint = A;
manifold.points[0].id.key = 0;
manifold.points[0].id.cf = cf;
manifold.points[0].localPoint = circleB.m_p;
}
/// Compute the collision manifold between a polygon and a circle.
public static void CollidePolygonAndCircle(out Manifold manifold,
PolygonShape polygonA, Transform xfA,
CircleShape circleB, Transform xfB) {
manifold = new Manifold();
manifold.points.Clear();
// Compute circle position in the frame of the polygon.
Vec2 c = Utilities.Mul(xfB, circleB.m_p);
Vec2 cLocal = Utilities.MulT(xfA, c);
// Find the min separating edge.
int normalIndex = 0;
float separation = -Single.MaxValue;
float radius = polygonA.m_radius + circleB.m_radius;
int vertexCount = polygonA.m_count;
List<Vec2> vertices = new List<Vec2>(polygonA.m_vertices);
List<Vec2> normals = new List<Vec2>(polygonA.m_normals);
for (int i = 0; i < vertexCount; ++i)
{
float s = Utilities.Dot(normals[i], cLocal - vertices[i]);
if (s > radius)
{
// Early out.
return;
}
if (s > separation)
{
separation = s;
normalIndex = i;
}
}
// Vertices that subtend the incident face.
int vertIndex1 = normalIndex;
int vertIndex2 = vertIndex1 + 1 < vertexCount ? vertIndex1 + 1 : 0;
Vec2 v1 = vertices[vertIndex1];
Vec2 v2 = vertices[vertIndex2];
// If the center is inside the polygon ...
if (separation < Single.Epsilon)
{
manifold.points.Clear();
manifold.points.Add(new ManifoldPoint());
manifold.type = Manifold.ManifoldType.e_faceA;
manifold.localNormal = normals[normalIndex];
manifold.localPoint = 0.5f * (v1 + v2);
manifold.points[0].localPoint = circleB.m_p;
manifold.points[0].id.key = 0;
return;
}
// Compute barycentric coordinates
float u1 = Utilities.Dot(cLocal - v1, v2 - v1);
float u2 = Utilities.Dot(cLocal - v2, v1 - v2);
if (u1 <= 0.0f)
{
if (Utilities.DistanceSquared(cLocal, v1) > radius * radius)
{
return;
}
manifold.points.Clear();
manifold.points.Add(new ManifoldPoint());
manifold.type = Manifold.ManifoldType.e_faceA;
manifold.localNormal = cLocal - v1;
manifold.localNormal.Normalize();
manifold.localPoint = v1;
manifold.points[0].localPoint = circleB.m_p;
manifold.points[0].id.key = 0;
}
else if (u2 <= 0.0f)
{
if (Utilities.DistanceSquared(cLocal, v2) > radius * radius)
{
return;
}
manifold.points = new List<ManifoldPoint>();
manifold.points.Add(new ManifoldPoint());
manifold.type = Manifold.ManifoldType.e_faceA;
manifold.localNormal = cLocal - v2;
manifold.localNormal.Normalize();
manifold.localPoint = v2;
manifold.points[0].localPoint = circleB.m_p;
manifold.points[0].id.key = 0;
}
else
{
Vec2 faceCenter = 0.5f * (v1 + v2);
float separation2 = Utilities.Dot(cLocal - faceCenter, normals[vertIndex1]);
if (separation2 > radius)
{
return;
}
manifold.points = new List<ManifoldPoint>();
manifold.points.Add(new ManifoldPoint());
manifold.type = Manifold.ManifoldType.e_faceA;
manifold.localNormal = normals[vertIndex1];
manifold.localPoint = faceCenter;
manifold.points[0].localPoint = circleB.m_p;
manifold.points[0].id.key = 0;
}
}
// 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
/// Compute the collision manifold between two polygons.
public static void CollidePolygons(out Manifold manifold,
PolygonShape polyA, Transform xfA,
PolygonShape polyB, Transform xfB) {
manifold = new Manifold();
float totalRadius = polyA.m_radius + polyB.m_radius;
int edgeA = 0;
float separationA = FindMaxSeparation(out edgeA, polyA, xfA, polyB, xfB);
if (separationA > totalRadius)
return;
int edgeB = 0;
float separationB = FindMaxSeparation(out edgeB, polyB, xfB, polyA, xfA);
if (separationB > totalRadius)
return;
PolygonShape poly1; // reference polygon
PolygonShape poly2; // incident polygon
Transform xf1, xf2;
int edge1; // reference edge
bool flip;
const float k_relativeTol = 0.98f;
const float k_absoluteTol = 0.001f;
if (separationB > k_relativeTol * separationA + k_absoluteTol)
{
poly1 = polyB;
poly2 = polyA;
xf1 = xfB;
xf2 = xfA;
edge1 = edgeB;
manifold.type = Manifold.ManifoldType.e_faceB;
flip = true;
}
else
{
poly1 = polyA;
poly2 = polyB;
xf1 = xfA;
xf2 = xfB;
edge1 = edgeA;
manifold.type = Manifold.ManifoldType.e_faceA;
flip = false;
}
ClipVertex[] incidentEdge = new ClipVertex[2];
FindIncidentEdge(incidentEdge, poly1, xf1, edge1, poly2, xf2);
int count1 = poly1.m_count;
Vec2[] vertices1 = poly1.m_vertices;
int iv1 = edge1;
int iv2 = edge1 + 1 < count1 ? edge1 + 1 : 0;
Vec2 v11 = vertices1[iv1];
Vec2 v12 = vertices1[iv2];
Vec2 localTangent = v12 - v11;
localTangent.Normalize();
Vec2 localNormal = Utilities.Cross(localTangent, 1.0f);
Vec2 planePoint = 0.5f * (v11 + v12);
Vec2 tangent = Utilities.Mul(xf1.q, localTangent);
Vec2 normal = Utilities.Cross(tangent, 1.0f);
v11 = Utilities.Mul(xf1, v11);
v12 = Utilities.Mul(xf1, v12);
// Face offset.
float frontOffset = Utilities.Dot(normal, v11);
// Side offsets, extended by polytope skin thickness.
float sideOffset1 = -Utilities.Dot(tangent, v11) + totalRadius;
float sideOffset2 = Utilities.Dot(tangent, v12) + totalRadius;
// Clip incident edge against extruded edge1 side edges.
ClipVertex[] clipPoints1 = new ClipVertex[2];
ClipVertex[] clipPoints2 = new ClipVertex[2];
int np;
// Clip to box side 1
np = ClipSegmentToLine(clipPoints1, incidentEdge, -tangent, sideOffset1, iv1);
if (np < 2)
return;
// Clip to negative box side 1
np = ClipSegmentToLine(clipPoints2, clipPoints1, tangent, sideOffset2, iv2);
if (np < 2)
{
return;
}
// Now clipPoints2 contains the clipped points.
manifold.localNormal = localNormal;
manifold.localPoint = planePoint;
manifold.points.Clear();
for (int i = 0; i < Settings._maxManifoldPoints; ++i)
{
float separation = Utilities.Dot(normal, clipPoints2[i].v) - frontOffset;
if (separation <= totalRadius)
{
ManifoldPoint cp = new ManifoldPoint();
cp.localPoint = Utilities.MulT(xf2, clipPoints2[i].v);
cp.id = clipPoints2[i].id;
if (flip)
{
// Swap features
ContactFeature cf = cp.id.cf;
cp.id.cf.indexA = cf.indexB;
cp.id.cf.indexB = cf.indexA;
cp.id.cf.typeA = cf.typeB;
cp.id.cf.typeB = cf.typeA;
}
manifold.points.Add(cp);
}
}
}
public void PreSolve(Contact contact, ref Manifold oldManifold)
{
}
/// Evaluate the manifold with supplied transforms. This assumes
/// modest motion from the original state. This does not change the
/// point count, impulses, etc. The radii must come from the shapes
/// that generated the manifold.
public void Initialize(Manifold manifold,
Transform xfA, float radiusA,
Transform xfB, float radiusB){
if (manifold.points.Count() == 0)
{
return;
}
switch (manifold.type)
{
case Manifold.ManifoldType.e_circles:
{
normal.Set(1.0f, 0.0f);
Vec2 pointA = Utilities.Mul(xfA, manifold.localPoint);
Vec2 pointB = Utilities.Mul(xfB, manifold.points[0].localPoint);
if (Utilities.DistanceSquared(pointA, pointB) > Single.Epsilon * Single.Epsilon)
{
normal = pointB - pointA;
normal.Normalize();
}
Vec2 cA = pointA + radiusA * normal;
Vec2 cB = pointB - radiusB * normal;
points[0] = 0.5f * (cA + cB);
}
break;
case Manifold.ManifoldType.e_faceA:
{
normal = Utilities.Mul(xfA.q, manifold.localNormal);
Vec2 planePoint = Utilities.Mul(xfA, manifold.localPoint);
points.Clear();
for (int i = 0; i < manifold.points.Count(); ++i)
{
Vec2 clipPoint = Utilities.Mul(xfB, manifold.points[i].localPoint);
Vec2 cA = clipPoint + (radiusA - Utilities.Dot(clipPoint - planePoint, normal)) * normal;
Vec2 cB = clipPoint - radiusB * normal;
points.Add(0.5f * (cA + cB));
}
}
break;
case Manifold.ManifoldType.e_faceB:
{
normal = Utilities.Mul(xfB.q, manifold.localNormal);
Vec2 planePoint = Utilities.Mul(xfB, manifold.localPoint);
points.Clear();
for (int i = 0; i < manifold.points.Count(); ++i)
{
Vec2 clipPoint = Utilities.Mul(xfA, manifold.points[i].localPoint);
Vec2 cB = clipPoint + (radiusB - Utilities.Dot(clipPoint - planePoint, normal)) * normal;
Vec2 cA = clipPoint - radiusA * normal;
points.Add(0.5f * (cA + cB));
}
// Ensure normal points from A to B.
normal = -normal;
}
break;
}
}
/// Evaluate this contact with your own manifold and transforms. public abstract void Evaluate(out Manifold manifold, Transform xfA, Transform xfB); //manifold was pointer
public virtual void PreSolve(Contact contact, Manifold oldManifold) {
Manifold manifold = contact.GetManifold();
if (manifold.points.Count() == 0)
{
return;
}
Fixture fixtureA = contact.FixtureA;
Fixture fixtureB = contact.FixtureB;
PointState[] state1 = new PointState[Settings._maxManifoldPoints];
PointState[] state2 = new PointState[Settings._maxManifoldPoints];
Collision.GetPointStates(state1, state2, oldManifold, manifold);
WorldManifold worldManifold;
contact.GetWorldManifold(out worldManifold);
for (int i = 0; i < manifold.points.Count() && m_pointCount < Program.k_maxContactPoints; ++i)
{
ContactPoint cp = m_points[m_pointCount];
cp.fixtureA = fixtureA;
cp.fixtureB = fixtureB;
cp.position = worldManifold.points[i];
cp.normal = worldManifold.normal;
cp.state = state2[i];
cp.normalImpulse = manifold.points[i].normalImpulse;
cp.tangentImpulse = manifold.points[i].tangentImpulse;
++m_pointCount;
}
}
public void InitializeVelocityConstraints()
{
for (int i = 0; i < m_contacts.Count(); ++i)
{
ContactVelocityConstraint vc = m_velocityConstraints[i];
ContactPositionConstraint pc = m_positionConstraints[i];
float radiusA = pc.radiusA;
float radiusB = pc.radiusB;
Manifold manifold = m_contacts[vc.contactIndex].GetManifold();
int indexA = vc.indexA;
int indexB = vc.indexB;
float mA = vc.invMassA;
float mB = vc.invMassB;
float iA = vc.invIA;
float iB = vc.invIB;
Vec2 localCenterA = pc.localCenterA;
Vec2 localCenterB = pc.localCenterB;
Vec2 cA = m_positions[indexA].c;
float aA = m_positions[indexA].a;
Vec2 vA = m_velocities[indexA].v;
float wA = m_velocities[indexA].w;
Vec2 cB = m_positions[indexB].c;
float aB = m_positions[indexB].a;
Vec2 vB = m_velocities[indexB].v;
float wB = m_velocities[indexB].w;
Utilities.Assert(manifold.points.Count() > 0);
Transform xfA = new Transform();
Transform xfB = new Transform();
xfA.q.Set(aA);
xfB.q.Set(aB);
xfA.p = cA - Utilities.Mul(xfA.q, localCenterA);
xfB.p = cB - Utilities.Mul(xfB.q, localCenterB);
WorldManifold worldManifold = new WorldManifold();
worldManifold.Initialize(manifold, xfA, radiusA, xfB, radiusB);
vc.normal = worldManifold.normal;
int pointCount = vc.points.Count;
for (int j = 0; j < pointCount; ++j)
{
VelocityConstraintPoint vcp = vc.points[j];
vcp.rA = worldManifold.points[j] - cA;
vcp.rB = worldManifold.points[j] - cB;
float rnA = Utilities.Cross(vcp.rA, vc.normal);
float rnB = Utilities.Cross(vcp.rB, vc.normal);
float kNormal = mA + mB + iA * rnA * rnA + iB * rnB * rnB;
vcp.normalMass = kNormal > 0.0f ? 1.0f / kNormal : 0.0f;
Vec2 tangent = Utilities.Cross(vc.normal, 1.0f);
float rtA = Utilities.Cross(vcp.rA, tangent);
float rtB = Utilities.Cross(vcp.rB, tangent);
float kTangent = mA + mB + iA * rtA * rtA + iB * rtB * rtB;
vcp.tangentMass = kTangent > 0.0f ? 1.0f / kTangent : 0.0f;
// Setup a velocity bias for restitution.
vcp.velocityBias = 0.0f;
float vRel = Utilities.Dot(vc.normal, vB + Utilities.Cross(wB, vcp.rB) - vA - Utilities.Cross(wA, vcp.rA));
if (vRel < -Settings._velocityThreshold)
{
vcp.velocityBias = -vc.restitution * vRel;
}
}
// If we have two points, then prepare the block solver.
if (vc.points.Count() == 2)
{
VelocityConstraintPoint vcp1 = vc.points[0];
VelocityConstraintPoint vcp2 = vc.points[1];
float rn1A = Utilities.Cross(vcp1.rA, vc.normal);
float rn1B = Utilities.Cross(vcp1.rB, vc.normal);
float rn2A = Utilities.Cross(vcp2.rA, vc.normal);
float rn2B = Utilities.Cross(vcp2.rB, vc.normal);
float k11 = mA + mB + iA * rn1A * rn1A + iB * rn1B * rn1B;
float k22 = mA + mB + iA * rn2A * rn2A + iB * rn2B * rn2B;
float k12 = mA + mB + iA * rn1A * rn2A + iB * rn1B * rn2B;
// Ensure a reasonable condition number.
const float k_maxConditionNumber = 1000.0f;
if (k11 * k11 < k_maxConditionNumber * (k11 * k22 - k12 * k12))
{
// K is safe to invert.
vc.K.ex.Set(k11, k12);
vc.K.ey.Set(k12, k22);
vc.normalMass = vc.K.GetInverse();
}
else
{
// The constraints are redundant, just use one.
// TODO_ERIN use deepest?
vc.points.Clear();
vc.points.Add(new VelocityConstraintPoint());
}
}
}
}
public ContactSolver(ContactSolverDef def)
{
m_step = def.step;
m_positionConstraints = new List <ContactPositionConstraint>();
m_velocityConstraints = new List <ContactVelocityConstraint>();
m_positions = def.positions;
m_velocities = def.velocities;
m_contacts = def.contacts;
// Initialize position independent portions of the constraints.
for (int i = 0; i < def.contacts.Count(); ++i)
{
Contact contact = m_contacts[i];
Fixture fixtureA = contact.m_fixtureA;
Fixture fixtureB = contact.m_fixtureB;
Shape shapeA = fixtureA.GetShape();
Shape shapeB = fixtureB.GetShape();
float radiusA = shapeA.m_radius;
float radiusB = shapeB.m_radius;
Body bodyA = fixtureA.GetBody();
Body bodyB = fixtureB.GetBody();
Manifold manifold = contact.GetManifold();
int pointCount = manifold.points.Count();
Utilities.Assert(pointCount > 0);
ContactVelocityConstraint vc = new ContactVelocityConstraint();
vc.friction = contact.m_friction;
vc.restitution = contact.m_restitution;
vc.tangentSpeed = contact.m_tangentSpeed;
vc.indexA = bodyA.m_islandIndex;
vc.indexB = bodyB.m_islandIndex;
vc.invMassA = bodyA.m_invMass;
vc.invMassB = bodyB.m_invMass;
vc.invIA = bodyA.m_invI;
vc.invIB = bodyB.m_invI;
vc.contactIndex = i;
//vc.points.Count() = pointCount;
vc.K.SetZero();
vc.normalMass.SetZero();
ContactPositionConstraint pc = new ContactPositionConstraint();
pc.indexA = bodyA.m_islandIndex;
pc.indexB = bodyB.m_islandIndex;
pc.invMassA = bodyA.m_invMass;
pc.invMassB = bodyB.m_invMass;
pc.localCenterA = bodyA.m_sweep.localCenter;
pc.localCenterB = bodyB.m_sweep.localCenter;
pc.invIA = bodyA.m_invI;
pc.invIB = bodyB.m_invI;
pc.localNormal = manifold.localNormal;
pc.localPoint = manifold.localPoint;
pc.pointCount = pointCount;
pc.radiusA = radiusA;
pc.radiusB = radiusB;
pc.type = manifold.type;
for (int j = 0; j < pointCount; ++j)
{
ManifoldPoint cp = manifold.points[j];
VelocityConstraintPoint vcp = new VelocityConstraintPoint();
if (m_step.warmStarting)
{
vcp.normalImpulse = m_step.dtRatio * cp.normalImpulse;
vcp.tangentImpulse = m_step.dtRatio * cp.tangentImpulse;
}
else
{
vcp.normalImpulse = 0.0f;
vcp.tangentImpulse = 0.0f;
}
vcp.rA.SetZero();
vcp.rB.SetZero();
vcp.normalMass = 0.0f;
vcp.tangentMass = 0.0f;
vcp.velocityBias = 0.0f;
vc.points.Add(vcp);
pc.localPoints[j] = cp.localPoint;
}
m_velocityConstraints.Add(vc);
m_positionConstraints.Add(pc);
}
}
public override void Evaluate(out Manifold manifold, Transform xfA, Transform xfB)
{
Collision.CollidePolygonAndCircle(out manifold,
(PolygonShape)m_fixtureA.GetShape(), xfA,
(CircleShape)m_fixtureB.GetShape(), xfB);
}
/// Compute the collision manifold between an edge and a circle.
public static void CollideEdgeAndPolygon(out Manifold manifold,
EdgeShape edgeA, Transform xfA,
PolygonShape polygonB, Transform xfB) {
EPCollider collider = new EPCollider();
collider.Collide(out manifold, edgeA, xfA, polygonB, xfB);
}
/// Compute the point states given two manifolds. The states pertain to the transition from manifold1
/// to manifold2. So state1 is either persist or remove while state2 is either add or persist.
public static void GetPointStates(PointState[/*Settings._maxManifoldPoints*/] state1, PointState[/*Settings._maxManifoldPoints*/] state2,
Manifold manifold1, Manifold manifold2) {
throw new NotImplementedException();
//for (int i = 0; i < Settings._maxManifoldPoints; ++i)
//{
// state1[i] = _nullState;
// state2[i] = _nullState;
//}
//// Detect persists and removes.
//for (int i = 0; i < manifold1.pointCount; ++i)
//{
// ContactID id = manifold1.points[i].id;
// state1[i] = _removeState;
// for (int j = 0; j < manifold2.pointCount; ++j)
// {
// if (manifold2.points[j].id.key == id.key)
// {
// state1[i] = _persistState;
// break;
// }
// }
//}
//// Detect persists and adds.
//for (int i = 0; i < manifold2.pointCount; ++i)
//{
// ContactID id = manifold2.points[i].id;
// state2[i] = _addState;
// for (int j = 0; j < manifold1.pointCount; ++j)
// {
// if (manifold1.points[j].id.key == id.key)
// {
// state2[i] = _persistState;
// break;
// }
// }
//}
}
protected Contact(Fixture fA, int indexA, Fixture fB, int indexB) {
m_flags = ContactFlags.e_enabledFlag;
m_fixtureA = fA;
m_fixtureB = fB;
m_indexA = indexA;
m_indexB = indexB;
m_manifold = new Manifold();
m_manifold.points.Clear();
m_nodeA.contact = null;
m_nodeA.other = null;
m_nodeB.contact = null;
m_nodeB.other = null;
m_toiCount = 0;
m_friction = MixFriction(m_fixtureA.m_friction, m_fixtureB.m_friction);
m_restitution = MixRestitution(m_fixtureA.m_restitution, m_fixtureB.m_restitution);
m_tangentSpeed = 0.0f;
}
// Algorithm:
// 1. Classify v1 and v2
// 2. Classify polygon centroid as front or back
// 3. Flip normal if necessary
// 4. Initialize normal range to [-pi, pi] about face normal
// 5. Adjust normal range according to adjacent edges
// 6. Visit each separating axes, only accept axes within the range
// 7. Return if _any_ axis indicates separation
// 8. Clip
public void Collide(out Manifold manifold, EdgeShape edgeA, Transform xfA, PolygonShape polygonB, Transform xfB){
manifold = new Manifold();
m_xf = Utilities.MulT(xfA, xfB);
m_centroidB = Utilities.Mul(m_xf, polygonB.m_centroid);
m_v0 = edgeA.m_vertex0;
m_v1 = edgeA.m_vertex1;
m_v2 = edgeA.m_vertex2;
m_v3 = edgeA.m_vertex3;
bool hasVertex0 = edgeA.m_hasVertex0;
bool hasVertex3 = edgeA.m_hasVertex3;
Vec2 edge1 = m_v2 - m_v1;
edge1.Normalize();
m_normal1.Set(edge1.Y, -edge1.X);
float offset1 = Utilities.Dot(m_normal1, m_centroidB - m_v1);
float offset0 = 0.0f, offset2 = 0.0f;
bool convex1 = false, convex2 = false;
// Is there a preceding edge?
if (hasVertex0)
{
Vec2 edge0 = m_v1 - m_v0;
edge0.Normalize();
m_normal0.Set(edge0.Y, -edge0.X);
convex1 = Utilities.Cross(edge0, edge1) >= 0.0f;
offset0 = Utilities.Dot(m_normal0, m_centroidB - m_v0);
}
// Is there a following edge?
if (hasVertex3)
{
Vec2 edge2 = m_v3 - m_v2;
edge2.Normalize();
m_normal2.Set(edge2.Y, -edge2.X);
convex2 = Utilities.Cross(edge1, edge2) > 0.0f;
offset2 = Utilities.Dot(m_normal2, m_centroidB - m_v2);
}
// Determine front or back collision. Determine collision normal limits.
if (hasVertex0 && hasVertex3)
{
if (convex1 && convex2)
{
m_front = offset0 >= 0.0f || offset1 >= 0.0f || offset2 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal0;
m_upperLimit = m_normal2;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = -m_normal1;
}
}
else if (convex1)
{
m_front = offset0 >= 0.0f || (offset1 >= 0.0f && offset2 >= 0.0f);
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal0;
m_upperLimit = m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal2;
m_upperLimit = -m_normal1;
}
}
else if (convex2)
{
m_front = offset2 >= 0.0f || (offset0 >= 0.0f && offset1 >= 0.0f);
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = m_normal2;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = -m_normal0;
}
}
else
{
m_front = offset0 >= 0.0f && offset1 >= 0.0f && offset2 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal2;
m_upperLimit = -m_normal0;
}
}
}
else if (hasVertex0)
{
if (convex1)
{
m_front = offset0 >= 0.0f || offset1 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal0;
m_upperLimit = -m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = -m_normal1;
}
}
else
{
m_front = offset0 >= 0.0f && offset1 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = -m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = -m_normal0;
}
}
}
else if (hasVertex3)
{
if (convex2)
{
m_front = offset1 >= 0.0f || offset2 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = m_normal2;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = m_normal1;
}
}
else
{
m_front = offset1 >= 0.0f && offset2 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = -m_normal2;
m_upperLimit = m_normal1;
}
}
}
else
{
m_front = offset1 >= 0.0f;
if (m_front)
{
m_normal = m_normal1;
m_lowerLimit = -m_normal1;
m_upperLimit = -m_normal1;
}
else
{
m_normal = -m_normal1;
m_lowerLimit = m_normal1;
m_upperLimit = m_normal1;
}
}
// Get polygonB in frameA
m_polygonB.count = polygonB.m_count;
for (int i = 0; i < polygonB.m_count; ++i)
{
m_polygonB.vertices[i] = Utilities.Mul(m_xf, polygonB.m_vertices[i]);
m_polygonB.normals[i] = Utilities.Mul(m_xf.q, polygonB.m_normals[i]);
}
m_radius = 2.0f * Settings._polygonRadius;
manifold.points.Clear();
EPAxis edgeAxis = ComputeEdgeSeparation();
// If no valid normal can be found than this edge should not collide.
if (edgeAxis.type == EPAxisType.e_unknown)
{
return;
}
if (edgeAxis.separation > m_radius)
{
return;
}
EPAxis polygonAxis = ComputePolygonSeparation();
if (polygonAxis.type != EPAxisType.e_unknown && polygonAxis.separation > m_radius)
{
return;
}
// Use hysteresis for jitter reduction.
const float k_relativeTol = 0.98f;
const float k_absoluteTol = 0.001f;
EPAxis primaryAxis;
if (polygonAxis.type == EPAxisType.e_unknown)
{
primaryAxis = edgeAxis;
}
else if (polygonAxis.separation > k_relativeTol * edgeAxis.separation + k_absoluteTol)
{
primaryAxis = polygonAxis;
}
else
{
primaryAxis = edgeAxis;
}
ClipVertex[] ie = new ClipVertex[2];
ReferenceFace rf = new ReferenceFace();
if (primaryAxis.type == EPAxisType.e_edgeA)
{
manifold.type = Manifold.ManifoldType.e_faceA;
// Search for the polygon normal that is most anti-parallel to the edge normal.
int bestIndex = 0;
float bestValue = Utilities.Dot(m_normal, m_polygonB.normals[0]);
for (int i = 1; i < m_polygonB.count; ++i)
{
float value = Utilities.Dot(m_normal, m_polygonB.normals[i]);
if (value < bestValue)
{
bestValue = value;
bestIndex = i;
}
}
int i1 = bestIndex;
int i2 = i1 + 1 < m_polygonB.count ? i1 + 1 : 0;
ie[0].v = m_polygonB.vertices[i1];
ie[0].id.cf.indexA = 0;
ie[0].id.cf.indexB = (byte)i1;
ie[0].id.cf.typeA = ContactFeature.FeatureType.e_face;
ie[0].id.cf.typeB = ContactFeature.FeatureType.e_vertex;
ie[1].v = m_polygonB.vertices[i2];
ie[1].id.cf.indexA = 0;
ie[1].id.cf.indexB = (byte)i2;
ie[1].id.cf.typeA = ContactFeature.FeatureType.e_face;
ie[1].id.cf.typeB = ContactFeature.FeatureType.e_vertex;
if (m_front)
{
rf.i1 = 0;
rf.i2 = 1;
rf.v1 = m_v1;
rf.v2 = m_v2;
rf.normal = m_normal1;
}
else
{
rf.i1 = 1;
rf.i2 = 0;
rf.v1 = m_v2;
rf.v2 = m_v1;
rf.normal = -m_normal1;
}
}
else
{
manifold.type = Manifold.ManifoldType.e_faceB;
ie[0].v = m_v1;
ie[0].id.cf.indexA = 0;
ie[0].id.cf.indexB = (byte)primaryAxis.index;
ie[0].id.cf.typeA = ContactFeature.FeatureType.e_vertex;
ie[0].id.cf.typeB = ContactFeature.FeatureType.e_face;
ie[1].v = m_v2;
ie[1].id.cf.indexA = 0;
ie[1].id.cf.indexB = (byte)primaryAxis.index;
ie[1].id.cf.typeA = ContactFeature.FeatureType.e_vertex;
ie[1].id.cf.typeB = ContactFeature.FeatureType.e_face;
rf.i1 = primaryAxis.index;
rf.i2 = rf.i1 + 1 < m_polygonB.count ? rf.i1 + 1 : 0;
rf.v1 = m_polygonB.vertices[rf.i1];
rf.v2 = m_polygonB.vertices[rf.i2];
rf.normal = m_polygonB.normals[rf.i1];
}
rf.sideNormal1.Set(rf.normal.Y, -rf.normal.X);
rf.sideNormal2 = -rf.sideNormal1;
rf.sideOffset1 = Utilities.Dot(rf.sideNormal1, rf.v1);
rf.sideOffset2 = Utilities.Dot(rf.sideNormal2, rf.v2);
// Clip incident edge against extruded edge1 side edges.
ClipVertex[] clipPoints1 = new ClipVertex[2];
ClipVertex[] clipPoints2 = new ClipVertex[2];
int np;
// Clip to box side 1
np = Collision.ClipSegmentToLine(clipPoints1, ie, rf.sideNormal1, rf.sideOffset1, rf.i1);
if (np < Settings._maxManifoldPoints)
{
return;
}
// Clip to negative box side 1
np = Collision.ClipSegmentToLine(clipPoints2, clipPoints1, rf.sideNormal2, rf.sideOffset2, rf.i2);
if (np < Settings._maxManifoldPoints)
{
return;
}
// Now clipPoints2 contains the clipped points.
if (primaryAxis.type == EPAxisType.e_edgeA)
{
manifold.localNormal = rf.normal;
manifold.localPoint = rf.v1;
}
else
{
manifold.localNormal = polygonB.m_normals[rf.i1];
manifold.localPoint = polygonB.m_vertices[rf.i1];
}
manifold.points.Clear();
for (int i = 0; i < Settings._maxManifoldPoints; ++i)
{
float separation;
separation = Utilities.Dot(rf.normal, clipPoints2[i].v - rf.v1);
if (separation <= m_radius)
{
ManifoldPoint cp = new ManifoldPoint();
if (primaryAxis.type == EPAxisType.e_edgeA)
{
cp.localPoint = Utilities.MulT(m_xf, clipPoints2[i].v);
cp.id = clipPoints2[i].id;
}
else
{
cp.localPoint = clipPoints2[i].v;
cp.id.cf.typeA = clipPoints2[i].id.cf.typeB;
cp.id.cf.typeB = clipPoints2[i].id.cf.typeA;
cp.id.cf.indexA = clipPoints2[i].id.cf.indexB;
cp.id.cf.indexB = clipPoints2[i].id.cf.indexA;
}
manifold.points.Add(cp);
}
}
}
public override void Evaluate(out Manifold manifold, Transform xfA, Transform xfB) {
Collision.CollideEdgeAndCircle(out manifold,
(EdgeShape)m_fixtureA.GetShape(), xfA,
(CircleShape)m_fixtureB.GetShape(), xfB);
}
/// This is called after a contact is updated. This allows you to inspect a
/// contact before it goes to the solver. If you are careful, you can modify the
/// contact manifold (e.g. disable contact).
/// A copy of the old manifold is provided so that you can detect changes.
/// Note: this is called only for awake bodies.
/// Note: this is called even when the number of contact points is zero.
/// Note: this is not called for sensors.
/// Note: if you set the number of contact points to zero, you will not
/// get an EndContact callback. However, you may get a BeginContact callback
/// the next step.
public virtual void PreSolve(Contact contact, Manifold oldManifold)
{
}
public override void Evaluate(out Manifold manifold, Transform xfA, Transform xfB) {
Collision.CollidePolygons( out manifold,
(PolygonShape)m_fixtureA.GetShape(), xfA,
(PolygonShape)m_fixtureB.GetShape(), xfB);
}
