Exemplo n.º 1
0
 private static void add(float3 p, float3[] dest, ref int pcount)
 {
     dest[pcount++] = new float3(p);
     Debug.Assert(pcount <= 4);
 }
Exemplo n.º 2
0
        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);
        }
Exemplo n.º 3
0
 private static float DistToPt(float3 p, float4 plane)
 {
     return(p.x * plane.x + p.y * plane.y + p.z * plane.z + plane.w);
 }