public Triangle[] ClipBy(Plane inPlane)
{
Vector3 ptOnPlane = -inPlane.normal * inPlane.distance;
float dot0 = Vector3.Dot(p0.vertex - ptOnPlane, inPlane.normal);
float dot1 = Vector3.Dot(p1.vertex - ptOnPlane, inPlane.normal);
float dot2 = Vector3.Dot(p2.vertex - ptOnPlane, inPlane.normal);
int dr0 = MUtils.Approximately(dot0, 0f) ? 0 : (dot0 < 0f ? -1 : 1);
int dr1 = MUtils.Approximately(dot1, 0f) ? 0 : (dot1 < 0f ? -1 : 1);
int dr2 = MUtils.Approximately(dot2, 0f) ? 0 : (dot2 < 0f ? -1 : 1);
if (dr0 > 0 && dr1 > 0 && dr2 > 0)
{
return(null);
}
if (dr0 < 0 && dr1 < 0 && dr2 < 0)
{
return new Triangle[] { this }
}
;
// one edge lay on the plane
System.Func <int, int, int, bool> check = delegate(int kr0, int kr1, int kr2)
{
if (kr0 == 0 && kr1 == 0)
{
return(kr2 <= 0);
}
return(false);
};
if (check(dr0, dr1, dr2) || check(dr0, dr2, dr1) ||
check(dr1, dr0, dr2) || check(dr1, dr2, dr0) ||
check(dr2, dr0, dr1) || check(dr2, dr1, dr0))
{
return(new Triangle[] { this });
}
List <Triangle> tris = new List <Triangle>();
Func <int, int, int, Vertex, Vertex, Vertex, bool> clip = delegate(int kr0, int kr1, int kr2, Vertex pt0, Vertex pt1, Vertex pt2)
{
if (kr0 > 0) // p0 at positive side
{
float enter;
if (kr1 < 0 && kr2 < 0) // other two on nagetive plane
{
var r = new Ray(pt0.vertex, pt1.vertex - pt0.vertex);
inPlane.Raycast(r, out enter);
var t0 = r.GetPoint(enter);
Vertex tt0 = new Vertex();
tt0.vertex = t0;
tt0.uv = pt0.uv + (pt1.uv - pt0.uv) * enter;
tt0.uv2 = pt0.uv2 + (pt1.uv2 - pt0.uv2) * enter;
tt0.uv3 = pt0.uv3 + (pt1.uv3 - pt0.uv3) * enter;
tt0.uv4 = pt0.uv4 + (pt1.uv4 - pt0.uv4) * enter;
r = new Ray(pt0.vertex, pt2.vertex - pt0.vertex);
inPlane.Raycast(r, out enter);
var t1 = r.GetPoint(enter);
Vertex tt1 = new Vertex();
tt1.vertex = t1;
tt1.uv = pt0.uv + (pt2.uv - pt0.uv) * enter;
tt1.uv2 = pt0.uv2 + (pt2.uv2 - pt0.uv2) * enter;
tt1.uv3 = pt0.uv3 + (pt2.uv3 - pt0.uv3) * enter;
tt1.uv4 = pt0.uv4 + (pt2.uv4 - pt0.uv4) * enter;
tris.Add(new Triangle(tt0, pt1, pt2));
tris.Add(new Triangle(tt0, pt2, tt1));
}
else if (kr1 > 0 && kr2 < 0) // p1 at positive side. p2 at nagetive side
{
var r = new Ray(pt0.vertex, pt2.vertex - pt0.vertex);
inPlane.Raycast(r, out enter);
var t0 = r.GetPoint(enter);
Vertex tt0 = new Vertex();
tt0.vertex = t0;
tt0.uv = pt0.uv + (pt2.uv - pt0.uv) * enter;
tt0.uv2 = pt0.uv2 + (pt2.uv2 - pt0.uv2) * enter;
tt0.uv3 = pt0.uv3 + (pt2.uv3 - pt0.uv3) * enter;
tt0.uv4 = pt0.uv4 + (pt2.uv4 - pt0.uv4) * enter;
r = new Ray(pt1.vertex, pt2.vertex - pt1.vertex);
inPlane.Raycast(r, out enter);
var t1 = r.GetPoint(enter);
Vertex tt1 = new Vertex();
tt1.vertex = t1;
tt1.uv = pt1.uv + (pt2.uv - pt1.uv) * enter;
tt1.uv2 = pt1.uv2 + (pt2.uv2 - pt1.uv2) * enter;
tt1.uv3 = pt1.uv3 + (pt2.uv3 - pt1.uv3) * enter;
tt1.uv4 = pt1.uv4 + (pt2.uv4 - pt1.uv4) * enter;
tris.Add(new Triangle(tt0, pt2, tt1));
}
else if (kr1 < 0 && kr2 > 0) // p2 at positive side, p1 at nagetive side,
{
var r = new Ray(pt0.vertex, pt1.vertex - pt0.vertex);
inPlane.Raycast(r, out enter);
var t0 = r.GetPoint(enter);
Vertex tt0 = new Vertex();
tt0.vertex = t0;
tt0.uv = pt0.uv + (pt1.uv - pt0.uv) * enter;
tt0.uv2 = pt0.uv2 + (pt1.uv2 - pt0.uv2) * enter;
tt0.uv3 = pt0.uv3 + (pt1.uv3 - pt0.uv3) * enter;
tt0.uv4 = pt0.uv4 + (pt1.uv4 - pt0.uv4) * enter;
r = new Ray(pt2.vertex, pt1.vertex - pt2.vertex);
inPlane.Raycast(r, out enter);
var t1 = r.GetPoint(enter);
Vertex tt1 = new Vertex();
tt1.vertex = t1;
tt1.uv = pt2.uv + (pt2.uv - pt1.uv) * enter;
tt1.uv2 = pt2.uv2 + (pt2.uv2 - pt1.uv2) * enter;
tt1.uv3 = pt2.uv3 + (pt2.uv3 - pt1.uv3) * enter;
tt1.uv4 = pt2.uv4 + (pt2.uv4 - pt1.uv4) * enter;
tris.Add(new Triangle(tt0, pt1, tt1));
}
return(true);
}
return(false);
};
bool clipped = clip(dr0, dr1, dr2, p0, p1, p2);
clipped = clipped || clip(dr1, dr2, dr0, p1, p2, p0);
clipped = clipped || clip(dr2, dr0, dr1, p2, p0, p1);
return(tris.ToArray());
}
}
public Triangle(Vertex inP0, Vertex inP1, Vertex inP2)
{
p0 = inP0;
p1 = inP1;
p2 = inP2;
}