/// <summary>
/// Creates a perspective matrix
/// </summary>
/// <param name="fov">Field of view</param>
/// <param name="aspect">Aspect ratio</param>
/// <param name="n">Near plane</param>
/// <param name="f">Far plane</param>
/// <returns></returns>
protected static Matrix PerspectiveMatrix(float fov, float aspect, float n, float f)
{
fov = MathF.Radians(fov);
var a = (f + n) / (f - n);
var b = (2 * n * f) / (f - n);
var yScale = MathF.Cot(fov / 2);
var xScale = yScale / aspect;
var m = new Matrix(new[]
{
new[] { xScale, 0f, 0f, 0f },
new[] { 0f, yScale, 0f, 0f },
new[] { 0f, 0f, a, 1f },
new[] { 0f, 0f, b, 0f }
});
return(m);
}
