// Split this Face with given Plane
public bool Split(Plane inPlane, out CSGFace outFront, out CSGFace outBack)
{
outFront = new CSGFace();
outBack = new CSGFace();
float[] distance = new float[vertices.Length + 1];
EPlaneSide[] side = new EPlaneSide[vertices.Length + 1];
for (int i = 0; i < vertices.Length; ++i)
{
distance[i] = inPlane.GetDistanceToPoint(vertices[i]);
side[i] = Side(inPlane, vertices[i]);
}
distance[vertices.Length] = distance[0];
side[vertices.Length] = side[0];
for (int i = 0; i < vertices.Length; ++i)
{
// if we lie on plane, add them to both
if (side[i] == EPlaneSide.Side_Planar)
{
outFront.AddVertex(vertices[i], uv[i]);
outBack.AddVertex(vertices[i], uv[i]);
// nothing todo with this vertex
continue;
}
// if we are on the front, add it to front face
if (side[i] == EPlaneSide.Side_Front)
{
outFront.AddVertex(vertices[i], uv[i]);
}
// if we are on the back, add it to the back side
else if (side[i] == EPlaneSide.Side_Back)
{
outBack.AddVertex(vertices[i], uv[i]);
}
// check if the next vertex is planar or on the same side, then we do not split
if (side[i + 1] == EPlaneSide.Side_Planar || side[i] == side[i + 1])
{
continue;
}
// create split point
Vector3 nextVector = vertices[(i + 1) % vertices.Length];
Vector2 nextUV = uv[(i + 1) % uv.Length];
Vector3 newVector, newUV;
// if we were on the front
if (side[i] == EPlaneSide.Side_Front)
{
float t = distance[i] / (distance[i] - distance[i + 1]);
newVector = vertices[i] + t * (nextVector - vertices[i]);
newUV = uv[i] + t * (nextUV - uv[i]);
}
else // back side...
{
float t = distance[i + 1] / (distance[i + 1] - distance[i]);
newVector = nextVector + t * (vertices[i] - nextVector);
newUV = nextUV + t * (uv[i] - nextUV);
}
// split points are added
// add to front
outFront.AddVertex(newVector, newUV);
// add to back
outBack.AddVertex(newVector, newUV);
}
// Debugging checks
if (outFront.vertices.Length < 3 || outBack.vertices.Length < 3)
{
Debug.Log("Degenerate Faces");
}
// todo...
outFront.material = material;
//
outBack.material = material;
return(true);
}
public bool Merge(CSGFace inOther, out CSGFace outFace)
{
outFace = null;
// do not share same material
if (material != inOther.material || vertices.Length < 1)
{
return(false);
}
Vector3 p1, p2;
Vector3 p3, p4;
int i = 0, j = 0;
// just to fix compiler error
p1 = vertices[0];
p2 = vertices[1 % vertices.Length];
// check if we share an edge
for (i = 0; i < vertices.Length; ++i)
{
// get edge
p1 = vertices[i];
p2 = vertices[(i + 1) % vertices.Length];
// go through all edges of other face
for (j = 0; j < inOther.vertices.Length; ++j)
{
// get other edge
p3 = inOther.vertices[j];
p4 = inOther.vertices[(j + 1) % inOther.vertices.Length];
// check if we are sharing an edge
if (p1.Equals(p4) && p2.Equals(p3))
{
break;
}
}
// found edge
if (j < inOther.vertices.Length)
{
break;
}
}
// no edge found
if (i == vertices.Length)
{
return(false);
}
// ...
Vector3 back = vertices[(i + vertices.Length - 1) % vertices.Length];
Vector3 delta = p1 - back;
Vector3 normal = Vector3.Cross(GetPlane().normal, delta);
normal.Normalize();
back = inOther.vertices[(j + 2) % inOther.vertices.Length];
delta = back - p1;
float dot = Vector3.Dot(delta, normal);
// not a convex polygon
if (dot > GlobalSettings.Epsilonf)
{
return(false);
}
// if they are co linear
bool keep1 = (dot < -GlobalSettings.Epsilonf);
// ...
back = vertices[(i + 2) % vertices.Length];
delta = back - p2;
normal = Vector3.Cross(GetPlane().normal, delta);
normal.Normalize();
back = inOther.vertices[(j + inOther.vertices.Length - 1) % inOther.vertices.Length];
delta = back - p2;
dot = Vector3.Dot(delta, normal);
// not convex
if (dot > GlobalSettings.Epsilonf)
{
return(false);
}
bool keep2 = (dot < -GlobalSettings.Epsilonf);
bool keep = false;
// create out face
outFace = new CSGFace();
outFace.flags = flags;
outFace.material = material;
// copy vertices from this
for (int k = (i + 1) % vertices.Length; k != i; k = (k + 1) % vertices.Length)
{
if (!keep && k == (i + 1) % vertices.Length && !keep2)
{
continue;
}
// copy vector
outFace.AddVertex(vertices[k], uv[k]);
}
// copy vertices from other
for (int k = (j + 1) % inOther.vertices.Length; k != j; k = (k + 1) % inOther.vertices.Length)
{
if (!keep && k == (j + 1) % inOther.vertices.Length && !keep1)
{
continue;
}
outFace.AddVertex(inOther.vertices[k], inOther.uv[k]);
}
return(true);
}
