Exemplo n.º 1
0
        private static CollisionShape ExtractCapsule(SubMesh subMesh)
        {
            // Find the two triangles that are farthest apart.  The
            // distance between them is the distance betwen
            // bottomCenter and topCenter, plus twice the capRadius.
            // The centers of these two triangles define a line which
            // contains the capsule segment.  Finally, find the
            // triangle whose center is furthest from the centers of
            // those two triangles, and determine the distance from
            // the center of that triangle to the line.  That distance
            // is the capRadius.  Move from the original two triangles
            // toward each other capRadius distance and that
            // determines the bottomCenter and topCenter
            int[] farthest = new int[2] {
                -1, -1
            };
            float farthestDistanceSquared = 0.0f;

            MeshTriangle[] triangles = ExtractSubmeshTriangles(subMesh);
            int            count     = triangles.Length;

            for (int i = 0; i < count; i++)
            {
                MeshTriangle t = triangles[i];
                Vector3      c = t.Center();
                for (int j = 0; j < count; j++)
                {
                    float d = (c - triangles[j].Center()).LengthSquared;
                    if (farthestDistanceSquared < d)
                    {
                        farthest[0]             = i;
                        farthest[1]             = j;
                        farthestDistanceSquared = d;
                    }
                }
            }
            Vector3 bottom            = triangles[farthest[0]].Center();
            Vector3 top               = triangles[farthest[1]].Center();
            float   bottomTopDistance = (float)Math.Sqrt(farthestDistanceSquared);
            float   capRadiusSquared  = 0f;

            for (int i = 0; i < count; i++)
            {
                MeshTriangle t = triangles[i];
                Vector3      c = t.Center();
                float        d = Primitives.SqDistPointSegment(bottom, top, c);
                if (capRadiusSquared < d)
                {
                    capRadiusSquared = d;
                }
            }
            float   capRadius     = (float)Math.Sqrt(capRadiusSquared);
            Vector3 unitBottomTop = (top - bottom) / bottomTopDistance;

            return(new CollisionCapsule(bottom + (unitBottomTop * capRadius),
                                        top - (unitBottomTop * capRadius),
                                        capRadius));
        }