The other day I converted a formula I found on Wikipedia into XNA C# code, basically I wanted to turn the 360 degree direction of a controller stick into a pure colour hue.

It’s a bit of a weird formula but it works a treat.

public static Color ColourFromAngle(float angle)
{
    float a = angle / 60.0f;
    int h1 = (int)a;
    int h = h1 % 6;
    float f = a - (float)h1;
    float p = 0;
    float q = 1.0f - f;
    float t = 1 - (1 - f);

    switch (h1)
    {
        case 0: return new Color(new Vector3(1, t, p));
        case 1: return new Color(new Vector3(q, 1, p));
        case 2: return new Color(new Vector3(p, 1, t));
        case 3: return new Color(new Vector3(p, q, 1));
        case 4: return new Color(new Vector3(t, p, 1));
        case 5: return new Color(new Vector3(1, p, q));
    }
    return Color.Red;
}