public void SetAsBox(float hx, float hy, Vec2 center, float angle)
{
VertexCount = 4;
Vertices[0].Set(-hx, -hy);
Vertices[1].Set(hx, -hy);
Vertices[2].Set(hx, hy);
Vertices[3].Set(-hx, hy);
Normals[0].Set(0.0f, -1.0f);
Normals[1].Set(1.0f, 0.0f);
Normals[2].Set(0.0f, 1.0f);
Normals[3].Set(-1.0f, 0.0f);
Centroid = center;
Transform xf = new Transform();
xf.Position = center;
xf.R.Set(angle);
// Transform vertices and normals.
for (int i = 0; i < VertexCount; ++i)
{
Vertices[i] = Math.Mul(xf, Vertices[i]);
Normals[i] = Math.Mul(xf.R, Normals[i]);
}
}
public override bool TestPoint(Transform transform, Vec2 p)
{
Vec2 center = transform.Position + Math.Mul(transform.R, _p);
Vec2 d = p - center;
return(Vec2.Dot(d, d) <= _radius * _radius);
}
private void DrawShape(Fixture fixture, Transform xf, Color color)
{
Color coreColor = new Color(0.9f, 0.6f, 0.6f);
switch (fixture.GetType())
{
case ShapeType.CircleShape:
{
CircleShape circle = (CircleShape)fixture.GetShape();
Vec2 center = Math.Mul(xf, circle._p);
float radius = circle._radius;
Vec2 axis = xf.R.Col1;
_debugDraw.DrawSolidCircle(center, radius, axis, color);
}
break;
case ShapeType.PolygonShape:
{
PolygonShape poly = (PolygonShape)fixture.GetShape();
int vertexCount = poly.VertexCount;
Box2DXDebug.Assert(vertexCount <= Settings.MaxPolygonVertices);
Vec2[] vertices = new Vec2[Settings.MaxPolygonVertices];
for (int i = 0; i < vertexCount; ++i)
{
vertices[i] = Math.Mul(xf, poly.Vertices[i]);
}
_debugDraw.DrawSolidPolygon(vertices, vertexCount, color);
}
break;
}
}
internal Body(BodyDef bd, World world)
{
_flags = 0;
if (bd.IsBullet)
{
_flags |= BodyFlags.Bullet;
}
if (bd.FixedRotation)
{
_flags |= BodyFlags.FixedRotation;
}
if (bd.AllowSleep)
{
_flags |= BodyFlags.AllowSleep;
}
if (bd.IsSleeping)
{
_flags |= BodyFlags.Sleep;
}
_world = world;
_xf.Position = bd.Position;
_xf.R.Set(bd.Angle);
_sweep.LocalCenter.SetZero();
_sweep.T0 = 1.0f;
_sweep.A0 = _sweep.A = bd.Angle;
_sweep.C0 = _sweep.C = Math.Mul(_xf, _sweep.LocalCenter);
_jointList = null;
_contactList = null;
_prev = null;
_next = null;
_linearVelocity = bd.LinearVelocity;
_angularVelocity = bd.AngularVelocity;
_linearDamping = bd.LinearDamping;
_angularDamping = bd.AngularDamping;
_force.Set(0.0f, 0.0f);
_torque = 0.0f;
_sleepTime = 0.0f;
_mass = 0;
_invMass = 0.0f;
_I = 0.0f;
_invI = 0.0f;
_type = BodyType.Static;
_userData = bd.UserData;
_fixtureList = null;
_fixtureCount = 0;
}
public override void ComputeAABB(out AABB aabb, ref Transform transform)
{
aabb = new AABB();
Vec2 p = transform.Position + Math.Mul(transform.R, _p);
aabb.LowerBound.Set(p.X - _radius, p.Y - _radius);
aabb.UpperBound.Set(p.X + _radius, p.Y + _radius);
}
/// Set the mass properties to override the mass properties of the fixtures.
/// Note that this changes the center of mass position. You can make the body
/// static by using zero mass.
/// Note that creating or destroying fixtures can also alter the mass.
/// @warning The supplied rotational inertia is assumed to be relative to the center of mass.
/// @param massData the mass properties.
// TODO ERIN adjust linear velocity and torque to account for movement of center.
public void SetMassData(MassData massData)
{
Box2DXDebug.Assert(_world.IsLocked() == false);
if (_world.IsLocked() == true)
{
return;
}
_invMass = 0.0f;
_I = 0.0f;
_invI = 0.0f;
_mass = massData.Mass;
if (_mass > 0.0f)
{
_invMass = 1.0f / _mass;
}
if (massData.I > 0.0f && (_flags & BodyFlags.FixedRotation) == 0)
{
_I = massData.I - _mass * Vec2.Dot(massData.Center, massData.Center);
_invI = 1.0f / _I;
}
// Move center of mass.
Vec2 oldCenter = _sweep.C;
_sweep.LocalCenter = massData.Center;
_sweep.C0 = _sweep.C = Math.Mul(_xf, _sweep.LocalCenter);
// Update center of mass velocity.
_linearVelocity += Vec2.Cross(_angularVelocity, _sweep.C - oldCenter);
BodyType oldType = _type;
if (_invMass == 0.0f && _invI == 0.0f)
{
_type = BodyType.Static;
}
else
{
_type = BodyType.Dynamic;
}
// If the body type changed, we need to flag contacts for filtering.
if (oldType != _type)
{
for (ContactEdge ce = _contactList; ce != null; ce = ce.Next)
{
ce.Contact.FlagForFiltering();
}
}
}
//TODO: uncomment
//public void Rebalance(int iterations)
//{
// if (_root == NullNode)
// {
// return;
// }
// for (int i = 0; i < iterations; ++i)
// {
// int node = _root;
// uint bit = 0;
// while (_nodes[node].IsLeaf() == false)
// {
// int children = _nodes[node].Child1;
// node = children[(_path >> bit) & 1];
// bit = (bit + 1) & (8 * sizeof(uint) - 1);
// }
// ++_path;
// RemoveLeaf(node);
// InsertLeaf(node);
// }
//}
// Compute the height of a sub-tree.
public int ComputeHeight(int nodeId)
{
if (nodeId == NullNode)
{
return(0);
}
Box2DXDebug.Assert(0 <= nodeId && nodeId < _nodeCapacity);
DynamicTreeNode node = _nodes[nodeId];
int height1 = ComputeHeight(node.Child1);
int height2 = ComputeHeight(node.Child2);
return(1 + Math.Max(height1, height2));
}
internal void SynchronizeFixtures()
{
Transform xf1 = new Transform();
xf1.R.Set(_sweep.A0);
xf1.Position = _sweep.C0 - Math.Mul(xf1.R, _sweep.LocalCenter);
BroadPhase broadPhase = _world._contactManager._broadPhase;
for (Fixture f = _fixtureList; f != null; f = f._next)
{
f.Synchronize(broadPhase, xf1, _xf);
}
}
public override void Step(Settings settings)
{
base.Step(settings);
DistanceInput input = new DistanceInput();
input.TransformA = _transformA;
input.TransformB = _transformB;
input.UseRadii = true;
SimplexCache cache = new SimplexCache();
cache.Count = 0;
DistanceOutput output;
Collision.Distance(out output, ref cache, ref input, _polygonA, _polygonB);
StringBuilder strBld = new StringBuilder();
strBld.AppendFormat("distance = {0}", new object[] { output.Distance });
OpenGLDebugDraw.DrawString(5, _textLine, strBld.ToString());
_textLine += 15;
strBld = new StringBuilder();
strBld.AppendFormat("iterations = {0}", new object[] { output.Iterations });
OpenGLDebugDraw.DrawString(5, _textLine, strBld.ToString());
_textLine += 15;
{
Color color = new Color(0.9f, 0.9f, 0.9f);
int i;
for (i = 0; i < _polygonA.VertexCount; ++i)
{
_dv[i] = Math.Mul(_transformA, _polygonA.Vertices[i]);
}
_debugDraw.DrawPolygon(_dv, _polygonA.VertexCount, color);
for (i = 0; i < _polygonB.VertexCount; ++i)
{
_dv[i] = Math.Mul(_transformB, _polygonB.Vertices[i]);
}
_debugDraw.DrawPolygon(_dv, _polygonB.VertexCount, color);
}
Vec2 x1 = output.PointA;
Vec2 x2 = output.PointB;
OpenGLDebugDraw.DrawPoint(x1, 4.0f, new Color(1, 0, 0));
OpenGLDebugDraw.DrawSegment(x1, x2, new Color(1, 1, 0));
OpenGLDebugDraw.DrawPoint(x2, 4.0f, new Color(1, 0, 0));
}
public override bool TestPoint(Transform xf, Vec2 p)
{
Vec2 pLocal = Math.MulT(xf.R, p - xf.Position);
for (int i = 0; i < VertexCount; ++i)
{
float dot = Vec2.Dot(Normals[i], pLocal - Vertices[i]);
if (dot > 0.0f)
{
return(false);
}
}
return(true);
}
public override void ComputeAABB(out AABB aabb, ref Transform xf)
{
Vec2 lower = Math.Mul(xf, Vertices[0]);
Vec2 upper = lower;
for (int i = 1; i < VertexCount; ++i)
{
Vec2 v = Math.Mul(xf, Vertices[i]);
lower = Math.Min(lower, v);
upper = Math.Max(upper, v);
}
Vec2 r = new Vec2(_radius, _radius);
aabb.LowerBound = lower - r;
aabb.UpperBound = upper + r;
}
public override void Step(TimeStep step)
{
//B2_NOT_USED(step);
if (InvSqr)
{
for (ControllerEdge i = _bodyList; i != null; i = i.nextBody)
{
Body body1 = i.body;
for (ControllerEdge j = _bodyList; j != i; j = j.nextBody)
{
Body body2 = j.body;
Vector2 d = body2.GetWorldCenter() - body1.GetWorldCenter();
float r2 = d.LengthSquared;
if (r2 < Settings.FLT_EPSILON)
{
continue;
}
Vector2 f = G / r2 / Math.Sqrt(r2) * body1.GetMass() * body2.GetMass() * d;
body1.ApplyForce(f, body1.GetWorldCenter());
body2.ApplyForce(-1.0f * f, body2.GetWorldCenter());
}
}
}
else
{
for (ControllerEdge i = _bodyList; i != null; i = i.nextBody)
{
Body body1 = i.body;
for (ControllerEdge j = _bodyList; j != i; j = j.nextBody)
{
Body body2 = j.body;
Vector2 d = body2.GetWorldCenter() - body1.GetWorldCenter();
float r2 = d.LengthSquared;
if (r2 < Settings.FLT_EPSILON)
{
continue;
}
Vector2 f = G / r2 * body1.GetMass() * body2.GetMass() * d;
body1.ApplyForce(f, body1.GetWorldCenter());
body2.ApplyForce(-1.0f * f, body2.GetWorldCenter());
}
}
}
}
// Collision Detection in Interactive 3D Environments by Gino van den Bergen
// From Section 3.1.2
// x = s + a * r
// norm(x) = radius
public override void RayCast(out RayCastOutput output, ref RayCastInput input, Transform transform)
{
output = new RayCastOutput();
Vec2 position = transform.Position + Math.Mul(transform.R, _p);
Vec2 s = input.P1 - position;
float b = Vec2.Dot(s, s) - _radius * _radius;
// Solve quadratic equation.
Vec2 r = input.P2 - input.P1;
float c = Vec2.Dot(s, r);
float rr = Vec2.Dot(r, r);
float sigma = c * c - rr * b;
// Check for negative discriminant and short segment.
if (sigma < 0.0f || rr < Settings.FLT_EPSILON)
{
output.Hit = false;
return;
}
// Find the point of intersection of the line with the circle.
float a = -(c + Math.Sqrt(sigma));
// Is the intersection point on the segment?
if (0.0f <= a && a <= input.MaxFraction * rr)
{
a /= rr;
output.Hit = true;
output.Fraction = a;
output.Normal = s + a * r;
output.Normal.Normalize();
return;
}
output.Hit = false;
return;
}
public void SetTransform(Vec2 position, float angle)
{
Box2DXDebug.Assert(_world.IsLocked() == false);
if (_world.IsLocked() == true)
{
return;
}
_xf.R.Set(angle);
_xf.Position = position;
_sweep.C0 = _sweep.C = Math.Mul(_xf, _sweep.LocalCenter);
_sweep.A0 = _sweep.A = angle;
BroadPhase broadPhase = _world._contactManager._broadPhase;
for (Fixture f = _fixtureList; f != null; f = f._next)
{
f.Synchronize(broadPhase, _xf, _xf);
}
_world._contactManager.FindNewContacts();
}
/// <summary>
/// Create a joint to constrain bodies together. No reference to the definition
/// is retained. This may cause the connected bodies to cease colliding.
/// @warning This function is locked during callbacks.
/// </summary>
/// <param name="def"></param>
/// <returns></returns>
public Joint CreateJoint(JointDef def)
{
Box2DXDebug.Assert(IsLocked() == false);
if (IsLocked())
{
return(null);
}
Joint j = Joint.Create(def);
// Connect to the world list.
j._prev = null;
j._next = _jointList;
if (_jointList != null)
{
_jointList._prev = j;
}
_jointList = j;
++_jointCount;
// Connect to the bodies' doubly linked lists.
j._edgeA.Joint = j;
j._edgeA.Other = j._bodyB;
j._edgeA.Prev = null;
j._edgeA.Next = j._bodyA._jointList;
if (j._bodyA._jointList != null)
{
j._bodyA._jointList.Prev = j._edgeA;
}
j._bodyA._jointList = j._edgeA;
j._edgeB.Joint = j;
j._edgeB.Other = j._bodyA;
j._edgeB.Prev = null;
j._edgeB.Next = j._bodyB._jointList;
if (j._bodyB._jointList != null)
{
j._bodyB._jointList.Prev = j._edgeB;
}
j._bodyB._jointList = j._edgeB;
Body bodyA = def.Body1;
Body bodyB = def.Body2;
bool staticA = bodyA.IsStatic();
bool staticB = bodyB.IsStatic();
// If the joint prevents collisions, then flag any contacts for filtering.
if (def.CollideConnected == false && (staticA == false || staticB == false))
{
// Ensure we iterate over contacts on a dynamic body (usually have less contacts
// than a static body). Ideally we will have a contact count on both bodies.
if (staticB)
{
Math.Swap(ref bodyA, ref bodyB);
}
ContactEdge edge = bodyB.GetContactList();
while (edge != null)
{
if (edge.Other == bodyA)
{
// Flag the contact for filtering at the next time step (where either
// body is awake).
edge.Contact.FlagForFiltering();
}
edge = edge.Next;
}
}
// Note: creating a joint doesn't wake the bodies.
return(j);
}
public override void RayCast(out RayCastOutput output, ref RayCastInput input, Transform xf)
{
output = new RayCastOutput();
float lower = 0.0f, upper = input.MaxFraction;
// Put the ray into the polygon's frame of reference.
Vec2 p1 = Math.MulT(xf.R, input.P1 - xf.Position);
Vec2 p2 = Math.MulT(xf.R, input.P2 - xf.Position);
Vec2 d = p2 - p1;
int index = -1;
output.Hit = false;
for (int i = 0; i < VertexCount; ++i)
{
// p = p1 + a * d
// dot(normal, p - v) = 0
// dot(normal, p1 - v) + a * dot(normal, d) = 0
float numerator = Vec2.Dot(Normals[i], Vertices[i] - p1);
float denominator = Vec2.Dot(Normals[i], d);
if (denominator == 0.0f)
{
if (numerator < 0.0f)
{
return;
}
}
else
{
// Note: we want this predicate without division:
// lower < numerator / denominator, where denominator < 0
// Since denominator < 0, we have to flip the inequality:
// lower < numerator / denominator <==> denominator * lower > numerator.
if (denominator < 0.0f && numerator < lower * denominator)
{
// Increase lower.
// The segment enters this half-space.
lower = numerator / denominator;
index = i;
}
else if (denominator > 0.0f && numerator < upper * denominator)
{
// Decrease upper.
// The segment exits this half-space.
upper = numerator / denominator;
}
}
if (upper < lower)
{
return;
}
}
Box2DXDebug.Assert(0.0f <= lower && lower <= input.MaxFraction);
if (index >= 0)
{
output.Hit = true;
output.Fraction = lower;
output.Normal = Math.Mul(xf.R, Normals[index]);
return;
}
}
public void InsertLeaf(int leaf)
{
++_insertionCount;
if (_root == NullNode)
{
_root = leaf;
_nodes[_root].Parent = NullNode;
return;
}
// Find the best sibling for this node.
Vec2 center = _nodes[leaf].Aabb.GetCenter();
int sibling = _root;
if (_nodes[sibling].IsLeaf() == false)
{
do
{
int child1 = _nodes[sibling].Child1;
int child2 = _nodes[sibling].Child2;
Vec2 delta1 = Math.Abs(_nodes[child1].Aabb.GetCenter() - center);
Vec2 delta2 = Math.Abs(_nodes[child2].Aabb.GetCenter() - center);
float norm1 = delta1.X + delta1.Y;
float norm2 = delta2.X + delta2.Y;
if (norm1 < norm2)
{
sibling = child1;
}
else
{
sibling = child2;
}
}while (_nodes[sibling].IsLeaf() == false);
}
// Create a parent for the siblings.
int node1 = _nodes[sibling].Parent;
int node2 = AllocateNode();
_nodes[node2].Parent = node1;
_nodes[node2].UserData = null;
_nodes[node2].Aabb.Combine(_nodes[leaf].Aabb, _nodes[sibling].Aabb);
if (node1 != NullNode)
{
if (_nodes[_nodes[sibling].Parent].Child1 == sibling)
{
_nodes[node1].Child1 = node2;
}
else
{
_nodes[node1].Child2 = node2;
}
_nodes[node2].Child1 = sibling;
_nodes[node2].Child2 = leaf;
_nodes[sibling].Parent = node2;
_nodes[leaf].Parent = node2;
do
{
if (_nodes[node1].Aabb.Contains(_nodes[node2].Aabb))
{
break;
}
_nodes[node1].Aabb.Combine(_nodes[_nodes[node1].Child1].Aabb, _nodes[_nodes[node1].Child2].Aabb);
node2 = node1;
node1 = _nodes[node1].Parent;
}while (node1 != NullNode);
}
else
{
_nodes[node2].Child1 = sibling;
_nodes[node2].Child2 = leaf;
_nodes[sibling].Parent = node2;
_nodes[leaf].Parent = node2;
_root = node2;
}
}
internal void SynchronizeTransform()
{
_xf.R.Set(_sweep.A);
_xf.Position = _sweep.C - Math.Mul(_xf.R, _sweep.LocalCenter);
}
/// Ray-cast against the proxies in the tree. This relies on the callback
/// to perform a exact ray-cast in the case were the proxy contains a shape.
/// The callback also performs the any collision filtering. This has performance
/// roughly equal to k * log(n), where k is the number of collisions and n is the
/// number of proxies in the tree.
/// @param input the ray-cast input data. The ray extends from p1 to p1 + maxFraction * (p2 - p1).
/// @param callback a callback class that is called for each proxy that is hit by the ray.
public void RayCast(IRayCastEnabled callback, RayCastInput input)
{
Vec2 p1 = input.P1;
Vec2 p2 = input.P2;
Vec2 r = p2 - p1;
Box2DXDebug.Assert(r.LengthSquared() > 0.0f);
r.Normalize();
// v is perpendicular to the segment.
Vec2 v = Vec2.Cross(1.0f, r);
Vec2 abs_v = Math.Abs(v);
// Separating axis for segment (Gino, p80).
// |dot(v, p1 - c)| > dot(|v|, h)
float maxFraction = input.MaxFraction;
// Build a bounding box for the segment.
AABB segmentAABB = new AABB();
{
Vec2 t = p1 + maxFraction * (p2 - p1);
segmentAABB.LowerBound = Math.Min(p1, t);
segmentAABB.UpperBound = Math.Max(p1, t);
}
const int k_stackSize = 128;
int[] stack = new int[k_stackSize];
int count = 0;
stack[count++] = _root;
while (count > 0)
{
int nodeId = stack[--count];
if (nodeId == NullNode)
{
continue;
}
DynamicTreeNode node = _nodes[nodeId];
if (Collision.TestOverlap(node.Aabb, segmentAABB) == false)
{
continue;
}
// Separating axis for segment (Gino, p80).
// |dot(v, p1 - c)| > dot(|v|, h)
Vec2 c = node.Aabb.GetCenter();
Vec2 h = node.Aabb.GetExtents();
float separation = Math.Abs(Vec2.Dot(v, p1 - c)) - Vec2.Dot(abs_v, h);
if (separation > 0.0f)
{
continue;
}
if (node.IsLeaf())
{
RayCastInput subInput = new RayCastInput();
subInput.P1 = input.P1;
subInput.P2 = input.P2;
subInput.MaxFraction = maxFraction;
maxFraction = callback.RayCastCallback(subInput, nodeId);
if (maxFraction == 0.0f)
{
return;
}
// Update segment bounding box.
{
Vec2 t = p1 + maxFraction * (p2 - p1);
segmentAABB.LowerBound = Math.Min(p1, t);
segmentAABB.UpperBound = Math.Max(p1, t);
}
}
else
{
Box2DXDebug.Assert(count + 1 < k_stackSize);
stack[count++] = node.Child1;
stack[count++] = node.Child2;
}
}
}
/// This resets the mass properties to the sum of the mass properties of the fixtures.
/// This normally does not need to be called unless you called SetMassData to override
/// the mass and you later want to reset the mass.
public void ResetMass()
{
// Compute mass data from shapes. Each shape has its own density.
_mass = 0.0f;
_invMass = 0.0f;
_I = 0.0f;
_invI = 0.0f;
Vec2 center = Vec2.Zero;
for (Fixture f = _fixtureList; f != null; f = f._next)
{
MassData massData = f.GetMassData();
_mass += massData.Mass;
center += massData.Mass * massData.Center;
_I += massData.I;
}
// Compute center of mass.
if (_mass > 0.0f)
{
_invMass = 1.0f / _mass;
center *= _invMass;
}
if (_I > 0.0f && (_flags & BodyFlags.FixedRotation) == 0)
{
// Center the inertia about the center of mass.
_I -= _mass * Vec2.Dot(center, center);
Box2DXDebug.Assert(_I > 0.0f);
_invI = 1.0f / _I;
}
else
{
_I = 0.0f;
_invI = 0.0f;
}
// Move center of mass.
Vec2 oldCenter = _sweep.C;
_sweep.LocalCenter = center;
_sweep.C0 = _sweep.C = Math.Mul(_xf, _sweep.LocalCenter);
// Update center of mass velocity.
_linearVelocity += Vec2.Cross(_angularVelocity, _sweep.C - oldCenter);
// Determine the new body type.
BodyType oldType = _type;
if (_invMass == 0.0f && _invI == 0.0f)
{
_type = BodyType.Static;
}
else
{
_type = BodyType.Dynamic;
}
// If the body type changed, we need to flag contacts for filtering.
if (oldType != _type)
{
for (ContactEdge ce = _contactList; ce != null; ce = ce.Next)
{
ce.Contact.FlagForFiltering();
}
}
}
// Find TOI contacts and solve them.
private void SolveTOI(TimeStep step)
{
// Reserve an island and a queue for TOI island solution.
Island island = new Island(_bodyCount,
Settings.MaxTOIContactsPerIsland,
Settings.MaxTOIJointsPerIsland,
_contactManager._contactListener);
//Simple one pass queue
//Relies on the fact that we're only making one pass
//through and each body can only be pushed/popped once.
//To push:
// queue[queueStart+queueSize++] = newElement;
//To pop:
// poppedElement = queue[queueStart++];
// --queueSize;
int queueCapacity = _bodyCount;
Body[] queue = new Body[queueCapacity];
for (Body b = _bodyList; b != null; b = b._next)
{
b._flags &= ~Body.BodyFlags.Island;
b._sweep.T0 = 0.0f;
}
for (Contact c = _contactManager._contactList; c != null; c = c.Next)
{
// Invalidate TOI
c.Flags &= ~(ContactFlag.ToiFlag | ContactFlag.IslandFlag);
}
for (Joint j = _jointList; j != null; j = j._next)
{
j._islandFlag = false;
}
// Find TOI events and solve them.
for (; ;)
{
// Find the first TOI.
Contact minContact = null;
float minTOI = 1.0f;
for (Contact c = _contactManager._contactList; c != null; c = c.Next)
{
// Can this contact generate a solid TOI contact?
if (c.IsSolid() == false || c.IsContinuous() == false)
{
continue;
}
// TODO_ERIN keep a counter on the contact, only respond to M TOIs per contact.
float toi = 1.0f;
if ((c.Flags & ContactFlag.ToiFlag) != 0)
{
// This contact has a valid cached TOI.
toi = c.Toi;
}
else
{
// Compute the TOI for this contact.
Fixture s1 = c.GetFixtureA();
Fixture s2 = c.GetFixtureB();
Body b1 = s1.GetBody();
Body b2 = s2.GetBody();
if ((b1.IsStatic() || b1.IsSleeping()) && (b2.IsStatic() || b2.IsSleeping()))
{
continue;
}
// Put the sweeps onto the same time interval.
float t0 = b1._sweep.T0;
if (b1._sweep.T0 < b2._sweep.T0)
{
t0 = b2._sweep.T0;
b1._sweep.Advance(t0);
}
else if (b2._sweep.T0 < b1._sweep.T0)
{
t0 = b1._sweep.T0;
b2._sweep.Advance(t0);
}
Box2DXDebug.Assert(t0 < 1.0f);
// Compute the time of impact.
toi = c.ComputeTOI(b1._sweep, b2._sweep);
Box2DXDebug.Assert(0.0f <= toi && toi <= 1.0f);
// If the TOI is in range ...
if (0.0f < toi && toi < 1.0f)
{
// Interpolate on the actual range.
toi = Math.Min((1.0f - toi) * t0 + toi, 1.0f);
}
c.Toi = toi;
c.Flags |= ContactFlag.ToiFlag;
}
if (Settings.FLT_EPSILON < toi && toi < minTOI)
{
// This is the minimum TOI found so far.
minContact = c;
minTOI = toi;
}
}
if (minContact == null || 1.0f - 100.0f * Settings.FLT_EPSILON < minTOI)
{
// No more TOI events. Done!
break;
}
// Advance the bodies to the TOI.
Fixture f1 = minContact.GetFixtureA();
Fixture f2 = minContact.GetFixtureB();
Body b3 = f1.GetBody();
Body b4 = f2.GetBody();
Sweep backup1 = b3._sweep;
Sweep backup2 = b4._sweep;
b3.Advance(minTOI);
b4.Advance(minTOI);
// The TOI contact likely has some new contact points.
minContact.Update(_contactManager._contactListener);
minContact.Flags &= ~ContactFlag.ToiFlag;
// Is the contact solid?
if (minContact.IsSolid() == false)
{
// Restore the sweeps.
b3._sweep = backup1;
b4._sweep = backup2;
b3.SynchronizeTransform();
b4.SynchronizeTransform();
continue;
}
// Did numerical issues prevent a contact point from being generated?
if (minContact.IsTouching() == false)
{
// Give up on this TOI.
continue;
}
// Build the TOI island. We need a dynamic seed.
Body seed = b3;
if (seed.IsStatic())
{
seed = b4;
}
// Reset island and queue.
island.Clear();
int queueStart = 0; // starting index for queue
int queueSize = 0; // elements in queue
queue[queueStart + queueSize++] = seed;
seed._flags |= Body.BodyFlags.Island;
// Perform a breadth first search (BFS) on the contact/joint graph.
while (queueSize > 0)
{
// Grab the next body off the stack and add it to the island.
Body b = queue[queueStart++];
--queueSize;
island.Add(ref b);
// Make sure the body is awake.
b._flags &= ~Body.BodyFlags.Sleep;
// To keep islands as small as possible, we don't
// propagate islands across static bodies.
if (b.IsStatic())
{
continue;
}
// Search all contacts connected to this body.
for (ContactEdge cEdge = b._contactList; cEdge != null; cEdge = cEdge.Next)
{
// Does the TOI island still have space for contacts?
if (island.ContactCount == island.ContactCapacity)
{
break;
}
// Has this contact already been added to an island? Skip slow or non-solid contacts.
if ((cEdge.Contact.Flags & ContactFlag.IslandFlag) != 0)
{
continue;
}
// Is this contact touching? For performance we are not updating this contact.
if (cEdge.Contact.IsSolid() == false || cEdge.Contact.IsTouching() == false)
{
continue;
}
island.Add(ref cEdge.Contact);
cEdge.Contact.Flags |= ContactFlag.IslandFlag;
// Update other body.
Body other = cEdge.Other;
// Was the other body already added to this island?
if ((other._flags & Body.BodyFlags.Island) != 0)
{
continue;
}
// March forward, this can do no harm since this is the min TOI.
if (other.IsStatic() == false)
{
other.Advance(minTOI);
other.WakeUp();
}
Box2DXDebug.Assert(queueStart + queueSize < queueCapacity);
queue[queueStart + queueSize] = other;
++queueSize;
other._flags |= Body.BodyFlags.Island;
}
for (JointEdge jEdge = b._jointList; jEdge != null; jEdge = jEdge.Next)
{
if (island.JointCount == island.JointCapacity)
{
continue;
}
if (jEdge.Joint._islandFlag == true)
{
continue;
}
island.Add(jEdge.Joint);
jEdge.Joint._islandFlag = true;
Body other = jEdge.Other;
if ((other._flags & Body.BodyFlags.Island) != 0)
{
continue;
}
if (!other.IsStatic())
{
other.Advance(minTOI);
other.WakeUp();
}
Box2DXDebug.Assert(queueStart + queueSize < queueCapacity);
queue[queueStart + queueSize] = other;
++queueSize;
other._flags |= Body.BodyFlags.Island;
}
}
TimeStep subStep;
subStep.WarmStarting = false;
subStep.Dt = (1.0f - minTOI) * step.Dt;
subStep.Inv_Dt = 1.0f / subStep.Dt;
subStep.DtRatio = 0.0f;
subStep.VelocityIterations = step.VelocityIterations;
subStep.PositionIterations = step.PositionIterations;
island.SolveTOI(ref subStep);
// Post solve cleanup.
for (int i = 0; i < island.BodyCount; ++i)
{
// Allow bodies to participate in future TOI islands.
Body b = island.Bodies[i];
b._flags &= ~Body.BodyFlags.Island;
if ((b._flags & Body.BodyFlags.Sleep) != 0)
{
continue;
}
if (b.IsStatic())
{
continue;
}
b.SynchronizeFixtures();
// Invalidate all contact TOIs associated with this body. Some of these
// may not be in the island because they were not touching.
for (ContactEdge ce = b._contactList; ce != null; ce = ce.Next)
{
ce.Contact.Flags &= ~ContactFlag.ToiFlag;
}
}
for (int i = 0; i < island.ContactCount; ++i)
{
// Allow contacts to participate in future TOI islands.
Contact c = island.Contacts[i];
c.Flags &= ~(ContactFlag.ToiFlag | ContactFlag.IslandFlag);
}
for (int i = 0; i < island.JointCount; ++i)
{
// Allow joints to participate in future TOI islands.
Joint j = island.Joints[i];
j._islandFlag = false;
}
// Commit fixture proxy movements to the broad-phase so that new contacts are created.
// Also, some contacts can be destroyed.
_contactManager.FindNewContacts();
}
queue = null;
}
