/// <summary>
/// Clips a polygon to a plane using the Sutherland-Hodgman algorithm.
/// </summary>
/// <param name="inVertices">The input array of vertices.</param>
/// <param name="outVertices">The output array of vertices.</param>
/// <param name="distances">A buffer that stores intermediate data</param>
/// <param name="numVerts">The number of vertices to read from the arrays.</param>
/// <param name="planeX">The clip plane's X component.</param>
/// <param name="planeZ">The clip plane's Z component.</param>
/// <param name="planeD">The clip plane's D component.</param>
/// <returns>The number of vertices stored in outVertices.</returns>
internal static int ClipPolygonToPlane(Vector3[] inVertices, Vector3[] outVertices, float[] distances, int numVerts, float planeX, float planeZ, float planeD)
{
for (int i = 0; i < numVerts; i++)
{
distances[i] = planeX * inVertices[i].X + planeZ * inVertices[i].Z + planeD;
}
int m = 0;
Vector3 temp;
for (int i = 0, j = numVerts - 1; i < numVerts; j = i, i++)
{
bool inj = distances[j] >= 0;
bool ini = distances[i] >= 0;
if (inj != ini)
{
float s = distances[j] / (distances[j] - distances[i]);
Vector3.Subtract(ref inVertices[i], ref inVertices[j], out temp);
Vector3.Multiply(ref temp, s, out temp);
Vector3.Add(ref inVertices[j], ref temp, out outVertices[m]);
m++;
}
if (ini)
{
outVertices[m] = inVertices[i];
m++;
}
}
return(m);
}
public static Vector3 Subtract(Vector3 left, Vector3 right)
{
var result = MonoGameVector3.Subtract(left.MonoGameVector, right.MonoGameVector);
return(new Vector3(result));
}
