Version of Improved Noise keeps returning 0

I'm trying to implement Improved Noise in my XNA game, but my Improved Noise function keeps returning 0.0f. It's the exact same code as Ken Perlin's (http://mrl.nyu.edu/~perlin/noise/), just ported to C#.

I've tried rewriting the class and even copy and pasting directly from the site (and then porting to C#, of course), but it just won't output any value but 0.

Here's the code that I'm using:

public class PerlinNoise 
    { 
        private int[] permutations = new int[512]; 

    private Random random; 

    public PerlinNoise() 
        : this(Environment.TickCount) 
    { } 

    public PerlinNoise(int seed) 
    { 
        random = new Random(seed); 

        for (int i = 0; i < 256; i++) 
        { 
            permutations[i] = i; 
        } 

        for (int i = 0; i < 256; i++) 
        { 
            int k = random.Next(256 - i) + i; 

            int l = permutations[i]; 

            permutations[i] = permutations[k]; 
            permutations[k] = l; 
            permutations[i + 256] = permutations[i]; 
        } 
    } 

    private int fastfloor(float x) 
    { 
        return x > 0 ? (int)x : (int)x - 1; 
    } 

    private float fade(float t) 
    { 
        return t * t * t * (t * (t * 6 - 15) + 10); 
    } 

    private float lerp(float t, float a, float b) 
    { 
        return a + t * (b - a); 
    } 

    public float grad(int hash, float x, float y, float z) 
    { 
        int h = hash & 15; 

        float u = h < 8 ? x : y, 
            v = h < 4 ? y : h == 12 || h == 14 ? x : z; 

        return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v); 
    } 

    public float noise3d(float x, float y, float z) 
    { 
        int X = fastfloor(x) & 0xff, 
            Y = fastfloor(y) & 0xff, 
            Z = fastfloor(z) & 0xff; 

        x -= fastfloor(x); 
        y -= fastfloor(y); 
        z -= fastfloor(z); 

        float u = fade(x); 
        float v = fade(y); 
        float w = fade(z); 

        int A = permutations[X] + Y, AA = permutations[A] + Z, AB = permutations[A + 1] + Z, 
            B = permutations[X + 1] + Y, BA = permutations[B] + Z, BB = permutations[B + 1] + Z; 

        return lerp(w, lerp(v, lerp(u, grad(permutations[AA], x, y, z), 
                                 grad(permutations[BA], x - 1, y, z)), 
     开发者_Go百科                    lerp(u, grad(permutations[AB], x, y - 1, z), 
                                 grad(permutations[BB], x - 1, y - 1, z))), 

                         lerp(v, lerp(u, grad(permutations[AA + 1], x, y, z - 1), 
                                 grad(permutations[BA + 1], x - 1, y, z - 1)), 
                         lerp(u, grad(permutations[AB + 1], x, y - 1, z - 1), 
                                 grad(permutations[BB + 1], x - 1, y - 1, z - 1)))); 
    } 

    public float noise2d(float x, float y) 
    { 
        return noise3d(x, y, 0f); 
    } 
} `

To test it, I simply did:

string[] args = Console.ReadLine().Split(' '); 

PerlinNoise noise = new PerlinNoise(); 

int x = args[0]; 
int y = args[1]; 
int z = args[2]; 

Console.WriteLine(noise.noise3d(x, y, z));

And as I said above, it'll always output 0.

It seems to output 0.0f if all arguments are integral numbers. Change your testing code to

var input = Console.ReadLine()
                    .Split(' ')
                    .Select(s => float.Parse(s,
                        System.Globalization.CultureInfo.InvariantCulture))
                    .ToArray();

and try to enter, for example, 4234.2123 3123.12312 423.2434.

I'm not quite sure if it is desired behavior, but

        x -= Math.Floor(x);                                // FIND RELATIVE X,Y,Z
        y -= Math.Floor(y);                                // OF POINT IN CUBE.
        z -= Math.Floor(z);

will always make x, y & z = 0 if they are integral numbers; fade(0.0f) is also always zero.

Multiply your inputs by (1 / MAX_VALUE) in your input case, just multiply by 1 / 256 or so, and never give it anything larger than that. When used in your game, multiply the input by (1 / MAXIMUM_CHOORD_VALUE).