public static PlaneTriResult planeTriIntersection(float4 plane, FaceTri triangle, float epsilon, ref float3[] front, out int fcount, ref float3[] back, out int bcount)
{
fcount = 0;
bcount = 0;
// get the three vertices of the triangle.
float3 p1 = triangle.P1;
float3 p2 = triangle.P2;
float3 p3 = triangle.P3;
PlaneTriResult r1 = getSidePlane(p1, plane, epsilon); // compute the side of the plane each vertex is on
PlaneTriResult r2 = getSidePlane(p2, plane, epsilon);
PlaneTriResult r3 = getSidePlane(p3, plane, epsilon);
if (r1 == r2 && r1 == r3) // if all three vertices are on the same side of the plane.
{
if (r1 == PlaneTriResult.PTR_FRONT) // if all three are in front of the plane, then copy to the 'front' output triangle.
{
add(p1, front, ref fcount);
add(p2, front, ref fcount);
add(p3, front, ref fcount);
}
else
{
add(p1, back, ref bcount); // if all three are in 'back' then copy to the 'back' output triangle.
add(p2, back, ref bcount);
add(p3, back, ref bcount);
}
return(r1); // if all three points are on the same side of the plane return result
}
// ok.. we need to split the triangle at the plane.
// First test ray segment P1 to P2
if (r1 == r2) // if these are both on the same side...
{
if (r1 == PlaneTriResult.PTR_FRONT)
{
add(p1, front, ref fcount);
add(p2, front, ref fcount);
}
else
{
add(p1, back, ref bcount);
add(p2, back, ref bcount);
}
}
else
{
float3 split = new float3();
intersect(p1, p2, split, plane);
if (r1 == PlaneTriResult.PTR_FRONT)
{
add(p1, front, ref fcount);
add(split, front, ref fcount);
add(split, back, ref bcount);
add(p2, back, ref bcount);
}
else
{
add(p1, back, ref bcount);
add(split, back, ref bcount);
add(split, front, ref fcount);
add(p2, front, ref fcount);
}
}
// Next test ray segment P2 to P3
if (r2 == r3) // if these are both on the same side...
{
if (r3 == PlaneTriResult.PTR_FRONT)
{
add(p3, front, ref fcount);
}
else
{
add(p3, back, ref bcount);
}
}
else
{
float3 split = new float3(); // split the point
intersect(p2, p3, split, plane);
if (r3 == PlaneTriResult.PTR_FRONT)
{
add(split, front, ref fcount);
add(split, back, ref bcount);
add(p3, front, ref fcount);
}
else
{
add(split, front, ref fcount);
add(split, back, ref bcount);
add(p3, back, ref bcount);
}
}
// Next test ray segment P3 to P1
if (r3 != r1) // if these are both on the same side...
{
float3 split = new float3(); // split the point
intersect(p3, p1, split, plane);
if (r1 == PlaneTriResult.PTR_FRONT)
{
add(split, front, ref fcount);
add(split, back, ref bcount);
}
else
{
add(split, front, ref fcount);
add(split, back, ref bcount);
}
}
return(PlaneTriResult.PTR_SPLIT);
}
public static void calcConvexDecomposition(List <float3> vertices, List <int> indices, ConvexDecompositionCallback callback, float masterVolume, int depth,
int maxDepth, float concavePercent, float mergePercent)
{
float4 plane = new float4();
bool split = false;
if (depth < maxDepth)
{
float volume = 0f;
float c = Concavity.computeConcavity(vertices, indices, ref plane, ref volume);
if (depth == 0)
{
masterVolume = volume;
}
float percent = (c * 100.0f) / masterVolume;
if (percent > concavePercent) // if great than 5% of the total volume is concave, go ahead and keep splitting.
{
split = true;
}
}
if (depth >= maxDepth || !split)
{
HullResult result = new HullResult();
HullDesc desc = new HullDesc();
desc.SetHullFlag(HullFlag.QF_TRIANGLES);
desc.Vertices = vertices;
HullError ret = HullUtils.CreateConvexHull(desc, ref result);
if (ret == HullError.QE_OK)
{
ConvexResult r = new ConvexResult(result.OutputVertices, result.Indices);
callback(r);
}
return;
}
List <int> ifront = new List <int>();
List <int> iback = new List <int>();
VertexPool vfront = new VertexPool();
VertexPool vback = new VertexPool();
// ok..now we are going to 'split' all of the input triangles against this plane!
for (int i = 0; i < indices.Count / 3; i++)
{
int i1 = indices[i * 3 + 0];
int i2 = indices[i * 3 + 1];
int i3 = indices[i * 3 + 2];
FaceTri t = new FaceTri(vertices, i1, i2, i3);
float3[] front = new float3[4];
float3[] back = new float3[4];
int fcount = 0;
int bcount = 0;
PlaneTriResult result = PlaneTri.planeTriIntersection(plane, t, 0.00001f, ref front, out fcount, ref back, out bcount);
if (fcount > 4 || bcount > 4)
{
result = PlaneTri.planeTriIntersection(plane, t, 0.00001f, ref front, out fcount, ref back, out bcount);
}
switch (result)
{
case PlaneTriResult.PTR_FRONT:
Debug.Assert(fcount == 3);
addTri(vfront, ifront, front[0], front[1], front[2]);
break;
case PlaneTriResult.PTR_BACK:
Debug.Assert(bcount == 3);
addTri(vback, iback, back[0], back[1], back[2]);
break;
case PlaneTriResult.PTR_SPLIT:
Debug.Assert(fcount >= 3 && fcount <= 4);
Debug.Assert(bcount >= 3 && bcount <= 4);
addTri(vfront, ifront, front[0], front[1], front[2]);
addTri(vback, iback, back[0], back[1], back[2]);
if (fcount == 4)
{
addTri(vfront, ifront, front[0], front[2], front[3]);
}
if (bcount == 4)
{
addTri(vback, iback, back[0], back[2], back[3]);
}
break;
}
}
// ok... here we recursively call
if (ifront.Count > 0)
{
int vcount = vfront.GetSize();
List <float3> vertices2 = vfront.GetVertices();
for (int i = 0; i < vertices2.Count; i++)
{
vertices2[i] = new float3(vertices2[i]);
}
int tcount = ifront.Count / 3;
calcConvexDecomposition(vertices2, ifront, callback, masterVolume, depth + 1, maxDepth, concavePercent, mergePercent);
}
ifront.Clear();
vfront.Clear();
if (iback.Count > 0)
{
int vcount = vback.GetSize();
List <float3> vertices2 = vback.GetVertices();
int tcount = iback.Count / 3;
calcConvexDecomposition(vertices2, iback, callback, masterVolume, depth + 1, maxDepth, concavePercent, mergePercent);
}
iback.Clear();
vback.Clear();
}