/// <seealso cref="Silver.Weight.Raw.Collide.Collider.Collide(Silver.Weight.Raw.Contact[], Silver.Weight.Raw.Body, Silver.Weight.Raw.Body)">
/// </seealso>
public virtual int Collide(Contact[] contacts, Body bodyA, Body bodyB)
{
int numContacts = 0;
Line line = (Line) bodyA.Shape;
Box box = (Box) bodyB.Shape;
Vector2f lineVec = new Vector2f(line.DX, line.DY);
lineVec.Normalise();
Vector2f axis = new Vector2f(- line.DY, line.DX);
axis.Normalise();
Vector2f res = new Vector2f();
line.Start.ProjectOntoUnit(axis, res);
float linePos = GetProp(res, axis);
Vector2f c = MathUtil.Sub(bodyB.GetPosition(), bodyA.GetPosition());
c.ProjectOntoUnit(axis, res);
float centre = GetProp(res, axis);
Vector2f[] pts = box.GetPoints(bodyB.GetPosition(), bodyB.Rotation);
float[] tangent = new float[4];
float[] proj = new float[4];
int outOfRange = 0;
for (int i = 0; i < 4; i++)
{
pts[i].Sub(bodyA.GetPosition());
pts[i].ProjectOntoUnit(axis, res);
tangent[i] = GetProp(res, axis);
pts[i].ProjectOntoUnit(lineVec, res);
proj[i] = GetProp(res, new Vector2f(line.DX, line.DY));
if ((proj[i] >= 1) || (proj[i] <= 0))
{
outOfRange++;
}
}
if (outOfRange == 4)
{
return 0;
}
Vector2f normal = new Vector2f(axis);
if (centre < linePos)
{
if (!line.BlocksInnerEdge)
{
return 0;
}
normal.Scale(- 1);
for (int i = 0; i < 4; i++)
{
if (tangent[i] > linePos)
{
if (proj[i] < 0)
{
Vector2f onAxis = new Vector2f();
Line leftLine = new Line(GetPt(pts, i - 1), pts[i]);
Line rightLine = new Line(GetPt(pts, i + 1), pts[i]);
leftLine.getClosestPoint(line.Start, res);
res.ProjectOntoUnit(axis, onAxis);
float left = GetProp(onAxis, axis);
rightLine.getClosestPoint(line.Start, res);
res.ProjectOntoUnit(axis, onAxis);
float right = GetProp(onAxis, axis);
if ((left > 0) && (right > 0))
{
Vector2f pos = new Vector2f(bodyA.GetPosition());
pos.Add(line.Start);
ResolveEndPointCollision(pos, bodyA, bodyB, normal, leftLine, rightLine, contacts[numContacts], i);
numContacts++;
}
}
else if (proj[i] > 1)
{
Vector2f onAxis = new Vector2f();
Line leftLine = new Line(GetPt(pts, i - 1), pts[i]);
Line rightLine = new Line(GetPt(pts, i + 1), pts[i]);
leftLine.getClosestPoint(line.End, res);
res.ProjectOntoUnit(axis, onAxis);
float left = GetProp(onAxis, axis);
rightLine.getClosestPoint(line.End, res);
res.ProjectOntoUnit(axis, onAxis);
float right = GetProp(onAxis, axis);
if ((left > 0) && (right > 0))
{
Vector2f pos = new Vector2f(bodyA.GetPosition());
pos.Add(line.End);
ResolveEndPointCollision(pos, bodyA, bodyB, normal, leftLine, rightLine, contacts[numContacts], i);
numContacts++;
}
}
else
{
pts[i].ProjectOntoUnit(lineVec, res);
res.Add(bodyA.GetPosition());
contacts[numContacts].Separation = - (tangent[i] - linePos);
contacts[numContacts].Position = new Vector2f(res);
contacts[numContacts].Normal = normal;
contacts[numContacts].Feature = new FeaturePair(i);
numContacts++;
}
}
}
}
else
{
if (!line.BlocksOuterEdge)
{
return 0;
}
for (int i = 0; i < 4; i++)
{
if (tangent[i] < linePos)
{
if (proj[i] < 0)
{
Vector2f onAxis = new Vector2f();
Line leftLine = new Line(GetPt(pts, i - 1), pts[i]);
Line rightLine = new Line(GetPt(pts, i + 1), pts[i]);
leftLine.getClosestPoint(line.Start, res);
res.ProjectOntoUnit(axis, onAxis);
float left = GetProp(onAxis, axis);
rightLine.getClosestPoint(line.Start, res);
res.ProjectOntoUnit(axis, onAxis);
float right = GetProp(onAxis, axis);
if ((left < 0) && (right < 0))
{
Vector2f pos = new Vector2f(bodyA.GetPosition());
pos.Add(line.Start);
ResolveEndPointCollision(pos, bodyA, bodyB, normal, leftLine, rightLine, contacts[numContacts], i);
numContacts++;
}
}
else if (proj[i] > 1)
{
Vector2f onAxis = new Vector2f();
Line leftLine = new Line(GetPt(pts, i - 1), pts[i]);
Line rightLine = new Line(GetPt(pts, i + 1), pts[i]);
leftLine.getClosestPoint(line.End, res);
res.ProjectOntoUnit(axis, onAxis);
float left = GetProp(onAxis, axis);
rightLine.getClosestPoint(line.End, res);
res.ProjectOntoUnit(axis, onAxis);
float right = GetProp(onAxis, axis);
if ((left < 0) && (right < 0))
{
Vector2f pos = new Vector2f(bodyA.GetPosition());
pos.Add(line.End);
ResolveEndPointCollision(pos, bodyA, bodyB, normal, leftLine, rightLine, contacts[numContacts], i);
numContacts++;
}
}
else
{
pts[i].ProjectOntoUnit(lineVec, res);
res.Add(bodyA.GetPosition());
contacts[numContacts].Separation = - (linePos - tangent[i]);
contacts[numContacts].Position = new Vector2f(res);
contacts[numContacts].Normal = normal;
contacts[numContacts].Feature = new FeaturePair();
numContacts++;
}
}
}
}
if (numContacts > 2)
{
throw new System.SystemException("LineBoxCollision: > 2 contacts");
}
return numContacts;
}