public PolyNode GetRightestConnection(PolyNode incoming)
{
if (NConnected == 0)
{
Debug.Assert(false); // This means the connection graph is inconsistent
}
if (NConnected == 1)
{
//b2Assert(false);
// Because of the possibility of collapsing nearby points,
// we may end up with "spider legs" dangling off of a region.
// The correct behavior here is to turn around.
return(incoming);
}
FVector2 inDir = Position - incoming.Position;
float inLength = inDir.Length();
inDir.Normalize();
Debug.Assert(inLength > Box2D.Settings.b2_epsilon);
PolyNode result = null;
for (int i = 0; i < NConnected; ++i)
{
if (Connected[i] == incoming)
{
continue;
}
FVector2 testDir = Connected[i].Position - Position;
float testLengthSqr = testDir.LengthSquared();
testDir.Normalize();
Debug.Assert(testLengthSqr >= Box2D.Settings.b2_epsilon * Box2D.Settings.b2_epsilon);
float myCos = FVector2.Dot(inDir, testDir);
float mySin = MathUtils.Cross(inDir, testDir);
if (result != null)
{
FVector2 resultDir = result.Position - Position;
resultDir.Normalize();
float resCos = FVector2.Dot(inDir, resultDir);
float resSin = MathUtils.Cross(inDir, resultDir);
if (IsRighter(mySin, myCos, resSin, resCos))
{
result = Connected[i];
}
}
else
{
result = Connected[i];
}
}
Debug.Assert(result != null);
return(result);
}
private static bool SanityCheck(Vertices vertices)
{
if (vertices.Count < 3)
{
return(false);
}
if (vertices.GetArea() < 0.00001f)
{
return(false);
}
for (int i = 0; i < vertices.Count; ++i)
{
int i1 = i;
int i2 = i + 1 < vertices.Count ? i + 1 : 0;
FVector2 edge = vertices[i2] - vertices[i1];
if (edge.LengthSquared() < Box2D.Settings.b2_epsilon * Box2D.Settings.b2_epsilon)
{
return(false);
}
}
for (int i = 0; i < vertices.Count; ++i)
{
int i1 = i;
int i2 = i + 1 < vertices.Count ? i + 1 : 0;
FVector2 edge = vertices[i2] - vertices[i1];
for (int j = 0; j < vertices.Count; ++j)
{
// Don't check vertices on the current edge.
if (j == i1 || j == i2)
{
continue;
}
FVector2 r = vertices[j] - vertices[i1];
// Your polygon is non-convex (it has an indentation) or
// has colinear edges.
float s = edge.X * r.Y - edge.Y * r.X;
if (s < 0.0f)
{
return(false);
}
}
}
return(true);
}