public static Vector2 Transform2d(this Matrix44 matrix, Vector2 from)
{
var transformed = new Vector2();
transformed.X = from.X * matrix.M00 +
//from.Y * matrix.M10 +
from.Y * matrix.M20
//+
//matrix.M30
;
transformed.Y = from.X * matrix.M02 +
//from.Y * matrix.M12 +
from.Y * matrix.M22
//+
//matrix.M32
;
return(transformed);
}
/// <summary>
/// makes a donut thing...
/// </summary>
/// <param name="inner"></param>
/// <param name="outer"></param>
/// <param name="N"></param>
/// <returns></returns>
public Vector2[] Torus(float inner, float outer, int N = 100)
{
List <Vector2> list = new List <Vector2>();
List <Vector2> listb = new List <Vector2>();
const double twopi = Math.PI * 2f;
var pos = 0f;
Vector2 item;
do
{
item = new Vector2((float)Math.Cos(twopi * pos / N), (float)-Math.Sin(twopi * pos / N)) * inner;
list.Add(item);
item = new Vector2((float)Math.Cos(twopi * pos / N), (float)-Math.Sin(twopi * pos / N)) * outer;
listb.Add(item);
pos++;
} while (pos < N);
return(list.Concat(listb).ToArray());
}
