/// <summary>
/// Gets the shortest collision distance in the Y direction for this entity.
/// </summary>
/// <param name="chunk">The current chunk.</param>
/// <param name="rayDir">The ray direction.</param>
/// <returns></returns>
private float GetShortestCollisionDistanceY( Chunk chunk, ref Vector3 rayDir )
{
// create our rays
Ray ray0 = new Ray( new Vector3( Position.X + Size.X * 0.5f, Position.Y + rayDir.Y * Size.Y * 0.5f, Position.Z + Size.Z * 0.5f ), rayDir );
Ray ray1 = new Ray( new Vector3( Position.X + Size.X * 0.5f, Position.Y + rayDir.Y * Size.Y * 0.5f, Position.Z - Size.Z * 0.5f ), rayDir );
Ray ray2 = new Ray( new Vector3( Position.X - Size.X * 0.5f, Position.Y + rayDir.Y * Size.Y * 0.5f, Position.Z + Size.Z * 0.5f ), rayDir );
Ray ray3 = new Ray( new Vector3( Position.X - Size.X * 0.5f, Position.Y + rayDir.Y * Size.Y * 0.5f, Position.Z - Size.Z * 0.5f ), rayDir );
// get each collision distance
List<float> intersections = new List<float>();
chunk.GetIntersectionDistances( ray0, ref intersections );
float dist0 = GetMinimumFromList( intersections );
chunk.GetIntersectionDistances( ray1, ref intersections );
float dist1 = GetMinimumFromList( intersections );
chunk.GetIntersectionDistances( ray2, ref intersections );
float dist2 = GetMinimumFromList( intersections );
chunk.GetIntersectionDistances( ray3, ref intersections );
float dist3 = GetMinimumFromList( intersections );
// now return the absolute minimum
return Math.Min( Math.Min( dist0, dist1 ), Math.Min( dist2, dist3 ) );
}
/// <summary>
/// Gets the shortest collision distance in the XZ plane for this entity.
/// </summary>
/// <param name="chunk">The current chunk.</param>
/// <param name="rayDir">The direction of the ray.</param>
/// <param name="offs">The position offset.</param>
/// <returns></returns>
private float GetShortestCollisionDistanceXZ( Chunk chunk, Vector3 rayDir, Vector3 offs )
{
// loop helpers
float startY = -Size.Y * 0.5f;
float endY = Size.Y * 0.5f;
int countY = (int)Math.Ceiling( Size.Y ) + 1;
float yStep = Math.Abs( endY - startY ) / (float)( countY - 1 );
// create the ray
Ray ray = new Ray();
ray.Position.X = Position.X + offs.X;
ray.Position.Z = Position.Z + offs.Z;
ray.Direction = rayDir;
// get the nearest collision distance
List<float> intersections = new List<float>();
float dist = float.MaxValue;
for ( float y = startY; y <= endY; y += yStep )
{
ray.Position.Y = Position.Y + offs.Y + y;
chunk.GetIntersectionDistances( ray, ref intersections );
dist = Math.Min( dist, GetMinimumFromList( intersections ) );
}
return dist;
}