ShaderHelpers.cs

public static class ShaderHelpers
{
    private static readonly Vector3 m_normal_xxx = new Vector3(1f, 1f, 1f);
    private static readonly Vector3 m_normal_xyy = new Vector3(1f, -1f, -1f);
    private static readonly Vector3 m_normal_yxy = new Vector3(-1f, 1f, -1f);
    private static readonly Vector3 m_normal_yyx = new Vector3(-1f, -1f, 1f);

    public static float Clamp(float value, float x, float y) {
        if (x > y) {
            var z = x;

            x = y;
            y = z;
        }

        if (value < x) {
            return x;
        }
        else if (value > y) {
            return y;
        }
        else {
            return value;
        }
    }
    /// <remarks>
    /// http://iquilezles.org/www/articles/normalsSDF/normalsSDF.htm
    /// </remarks>
    public static Vector3 GetNormal(in Vector3 position, Func<Vector3, float> signedDistanceFunction, float epsilon = 0.0001f) {
        var xxx = m_normal_xxx;
        var xyy = m_normal_xyy;
        var yxy = m_normal_yxy;
        var yyx = m_normal_yyx;

        return Vector3.Normalize(
              (xxx * signedDistanceFunction(position + (xxx * epsilon)))
            + (xyy * signedDistanceFunction(position + (xyy * epsilon)))
            + (yxy * signedDistanceFunction(position + (yxy * epsilon)))
            + (yyx * signedDistanceFunction(position + (yyx * epsilon)))
        );
    }
    /// <remarks>
    /// https://thebookofshaders.com/glossary/?search=mix
    /// </remarks>
    public static float Mix(float x, float y, float i) => ((x * (1.0f - i)) + (y * i));
    /// <remarks>
    /// https://www.iquilezles.org/www/articles/distfunctions/distfunctions.htm
    /// </remarks>
    public static float SmoothIntersection(float x, float y, float i) {
        var h = Clamp((0.5f - ((0.5f * (y - x)) / i)), 0.0f, 1.0f);

        return (Mix(x, y, h) + ((i * h) * (1.0f - h)));
    }
    /// <remarks>
    /// https://www.iquilezles.org/www/articles/distfunctions/distfunctions.htm
    /// </remarks>
    public static float SmoothSubtraction(float x, float y, float i) {
        var h = Clamp((0.5f - ((0.5f * (y + x)) / i)), 0.0f, 1.0f);

        return (Mix(-x, y, h) + ((i * h) * (1.0f - h)));
    }
    /// <remarks>
    /// https://www.iquilezles.org/www/articles/distfunctions/distfunctions.htm
    /// </remarks>
    public static float SmoothUnion(float x, float y, float i) {
        var h = Clamp((0.5f + ((0.5f * (y - x)) / i)), 0.0f, 1.0f);

        return (Mix(x, y, h) - ((i * h) * (1.0f - h)));
    }
}

static void MakeCheckerboard(int size = 20, bool prettify = true, ConsoleColor primaryColor = ConsoleColor.Black, ConsoleColor secondaryColor = ConsoleColor.White) {
    var originalConsoleBackgroundColor = Console.BackgroundColor;
    var originalConsoleForegroundColor = Console.ForegroundColor;

    Console.BackgroundColor = secondaryColor;
    Console.ForegroundColor = primaryColor;

    for (var x = 0; (x < size); ++x)
    for (var y = 0; (y < (size >> Convert.ToInt32(prettify))); ++y) {
        Console.SetCursorPosition(x, y);
        Console.Write((!IsOdd(x) ^ IsOdd(y)) ? '█' : ' ');
    }

    Console.BackgroundColor = originalConsoleBackgroundColor;
    Console.ForegroundColor = originalConsoleForegroundColor;
}