Simplex Noise Help

Posted by Alex Larsen on Game Development See other posts from Game Development or by Alex Larsen
Published on 2012-10-19T19:11:59Z Indexed on 2012/10/19 23:23 UTC
Read the original article Hit count: 367

Filed under:
|
|
|

Im Making A Minecraft Like Gae In XNA C# And I Need To Generate Land With Caves

This Is The Code For Simplex I Have

    /// <summary>
    /// 1D simplex noise
    /// </summary>
    /// <param name="x"></param>
    /// <returns></returns>
    public static float Generate(float x)
    {
        int i0 = FastFloor(x);
        int i1 = i0 + 1;
        float x0 = x - i0;
        float x1 = x0 - 1.0f;

        float n0, n1;

        float t0 = 1.0f - x0 * x0;
        t0 *= t0;
        n0 = t0 * t0 * grad(perm[i0 & 0xff], x0);

        float t1 = 1.0f - x1 * x1;
        t1 *= t1;
        n1 = t1 * t1 * grad(perm[i1 & 0xff], x1);
        // The maximum value of this noise is 8*(3/4)^4 = 2.53125
        // A factor of 0.395 scales to fit exactly within [-1,1]
        return 0.395f * (n0 + n1);
    }

    /// <summary>
    /// 2D simplex noise
    /// </summary>
    /// <param name="x"></param>
    /// <param name="y"></param>
    /// <returns></returns>
    public static float Generate(float x, float y)
    {
        const float F2 = 0.366025403f; // F2 = 0.5*(sqrt(3.0)-1.0)
        const float G2 = 0.211324865f; // G2 = (3.0-Math.sqrt(3.0))/6.0

        float n0, n1, n2; // Noise contributions from the three corners

        // Skew the input space to determine which simplex cell we're in
        float s = (x + y) * F2; // Hairy factor for 2D
        float xs = x + s;
        float ys = y + s;
        int i = FastFloor(xs);
        int j = FastFloor(ys);

        float t = (float)(i + j) * G2;
        float X0 = i - t; // Unskew the cell origin back to (x,y) space
        float Y0 = j - t;
        float x0 = x - X0; // The x,y distances from the cell origin
        float y0 = y - Y0;

        // For the 2D case, the simplex shape is an equilateral triangle.
        // Determine which simplex we are in.
        int i1, j1; // Offsets for second (middle) corner of simplex in (i,j) coords
        if (x0 > y0) { i1 = 1; j1 = 0; } // lower triangle, XY order: (0,0)->(1,0)->(1,1)
        else { i1 = 0; j1 = 1; }      // upper triangle, YX order: (0,0)->(0,1)->(1,1)

        // A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
        // a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
        // c = (3-sqrt(3))/6

        float x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords
        float y1 = y0 - j1 + G2;
        float x2 = x0 - 1.0f + 2.0f * G2; // Offsets for last corner in (x,y) unskewed coords
        float y2 = y0 - 1.0f + 2.0f * G2;

        // Wrap the integer indices at 256, to avoid indexing perm[] out of bounds
        int ii = i % 256;
        int jj = j % 256;

        // Calculate the contribution from the three corners
        float t0 = 0.5f - x0 * x0 - y0 * y0;
        if (t0 < 0.0f) n0 = 0.0f;
        else
        {
            t0 *= t0;
            n0 = t0 * t0 * grad(perm[ii + perm[jj]], x0, y0);
        }

        float t1 = 0.5f - x1 * x1 - y1 * y1;
        if (t1 < 0.0f) n1 = 0.0f;
        else
        {
            t1 *= t1;
            n1 = t1 * t1 * grad(perm[ii + i1 + perm[jj + j1]], x1, y1);
        }

        float t2 = 0.5f - x2 * x2 - y2 * y2;
        if (t2 < 0.0f) n2 = 0.0f;
        else
        {
            t2 *= t2;
            n2 = t2 * t2 * grad(perm[ii + 1 + perm[jj + 1]], x2, y2);
        }

        // Add contributions from each corner to get the final noise value.
        // The result is scaled to return values in the interval [-1,1].
        return 40.0f * (n0 + n1 + n2); // TODO: The scale factor is preliminary!
    }


    public static float Generate(float x, float y, float z)
    {
        // Simple skewing factors for the 3D case
        const float F3 = 0.333333333f;
        const float G3 = 0.166666667f;

        float n0, n1, n2, n3; // Noise contributions from the four corners

        // Skew the input space to determine which simplex cell we're in
        float s = (x + y + z) * F3; // Very nice and simple skew factor for 3D
        float xs = x + s;
        float ys = y + s;
        float zs = z + s;
        int i = FastFloor(xs);
        int j = FastFloor(ys);
        int k = FastFloor(zs);

        float t = (float)(i + j + k) * G3;
        float X0 = i - t; // Unskew the cell origin back to (x,y,z) space
        float Y0 = j - t;
        float Z0 = k - t;
        float x0 = x - X0; // The x,y,z distances from the cell origin
        float y0 = y - Y0;
        float z0 = z - Z0;

        // For the 3D case, the simplex shape is a slightly irregular tetrahedron.
        // Determine which simplex we are in.
        int i1, j1, k1; // Offsets for second corner of simplex in (i,j,k) coords
        int i2, j2, k2; // Offsets for third corner of simplex in (i,j,k) coords

        /* This code would benefit from a backport from the GLSL version! */
        if (x0 >= y0)
        {
            if (y0 >= z0)
            { i1 = 1; j1 = 0; k1 = 0; i2 = 1; j2 = 1; k2 = 0; } // X Y Z order
            else if (x0 >= z0) { i1 = 1; j1 = 0; k1 = 0; i2 = 1; j2 = 0; k2 = 1; } // X Z Y order
            else { i1 = 0; j1 = 0; k1 = 1; i2 = 1; j2 = 0; k2 = 1; } // Z X Y order
        }
        else
        { // x0<y0
            if (y0 < z0) { i1 = 0; j1 = 0; k1 = 1; i2 = 0; j2 = 1; k2 = 1; } // Z Y X order
            else if (x0 < z0) { i1 = 0; j1 = 1; k1 = 0; i2 = 0; j2 = 1; k2 = 1; } // Y Z X order
            else { i1 = 0; j1 = 1; k1 = 0; i2 = 1; j2 = 1; k2 = 0; } // Y X Z order
        }

        // A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
        // a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
        // a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
        // c = 1/6.

        float x1 = x0 - i1 + G3; // Offsets for second corner in (x,y,z) coords
        float y1 = y0 - j1 + G3;
        float z1 = z0 - k1 + G3;
        float x2 = x0 - i2 + 2.0f * G3; // Offsets for third corner in (x,y,z) coords
        float y2 = y0 - j2 + 2.0f * G3;
        float z2 = z0 - k2 + 2.0f * G3;
        float x3 = x0 - 1.0f + 3.0f * G3; // Offsets for last corner in (x,y,z) coords
        float y3 = y0 - 1.0f + 3.0f * G3;
        float z3 = z0 - 1.0f + 3.0f * G3;

        // Wrap the integer indices at 256, to avoid indexing perm[] out of bounds
        int ii = i % 256;
        int jj = j % 256;
        int kk = k % 256;

        // Calculate the contribution from the four corners
        float t0 = 0.6f - x0 * x0 - y0 * y0 - z0 * z0;
        if (t0 < 0.0f) n0 = 0.0f;
        else
        {
            t0 *= t0;
            n0 = t0 * t0 * grad(perm[ii + perm[jj + perm[kk]]], x0, y0, z0);
        }

        float t1 = 0.6f - x1 * x1 - y1 * y1 - z1 * z1;
        if (t1 < 0.0f) n1 = 0.0f;
        else
        {
            t1 *= t1;
            n1 = t1 * t1 * grad(perm[ii + i1 + perm[jj + j1 + perm[kk + k1]]], x1, y1, z1);
        }

        float t2 = 0.6f - x2 * x2 - y2 * y2 - z2 * z2;
        if (t2 < 0.0f) n2 = 0.0f;
        else
        {
            t2 *= t2;
            n2 = t2 * t2 * grad(perm[ii + i2 + perm[jj + j2 + perm[kk + k2]]], x2, y2, z2);
        }

        float t3 = 0.6f - x3 * x3 - y3 * y3 - z3 * z3;
        if (t3 < 0.0f) n3 = 0.0f;
        else
        {
            t3 *= t3;
            n3 = t3 * t3 * grad(perm[ii + 1 + perm[jj + 1 + perm[kk + 1]]], x3, y3, z3);
        }

        // Add contributions from each corner to get the final noise value.
        // The result is scaled to stay just inside [-1,1]
        return 32.0f * (n0 + n1 + n2 + n3); // TODO: The scale factor is preliminary!
    }

    private static byte[] perm = new byte[512] { 151,160,137,91,90,15,
          131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
          190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
          88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
          77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
          102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
          135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
          5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
          223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
          129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
          251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
          49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
          138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180,
          151,160,137,91,90,15,
          131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
          190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
          88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
          77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
          102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
          135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
          5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
          223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
          129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
          251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
          49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
          138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180 
        };

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

    private static float grad(int hash, float x)
    {
        int h = hash & 15;
        float grad = 1.0f + (h & 7);   // Gradient value 1.0, 2.0, ..., 8.0
        if ((h & 8) != 0) grad = -grad;         // Set a random sign for the gradient
        return (grad * x);           // Multiply the gradient with the distance
    }

    private static float grad(int hash, float x, float y)
    {
        int h = hash & 7;      // Convert low 3 bits of hash code
        float u = h < 4 ? x : y;  // into 8 simple gradient directions,
        float v = h < 4 ? y : x;  // and compute the dot product with (x,y).
        return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -2.0f * v : 2.0f * v);
    }

    private static float grad(int hash, float x, float y, float z)
    {
        int h = hash & 15;     // Convert low 4 bits of hash code into 12 simple
        float u = h < 8 ? x : y; // gradient directions, and compute dot product.
        float v = h < 4 ? y : h == 12 || h == 14 ? x : z; // Fix repeats at h = 12 to 15
        return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -v : v);
    }

    private static float grad(int hash, float x, float y, float z, float t)
    {
        int h = hash & 31;      // Convert low 5 bits of hash code into 32 simple
        float u = h < 24 ? x : y; // gradient directions, and compute dot product.
        float v = h < 16 ? y : z;
        float w = h < 8 ? z : t;
        return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -v : v) + ((h & 4) != 0 ? -w : w);
    }

This Is My World Generation Code

   Block[,] BlocksInMap = new Block[1024, 256];

    public bool IsWorldGenerated = false;

    Random r = new Random();

    private void RunThread()
    {
        for (int BH = 0; BH <= 256; BH++)
        {
            for (int BW = 0; BW <= 1024; BW++)
            {
                Block b = new Block();
                if (BH >= 192)
                {

                }
                BlocksInMap[BW, BH] = b;
            }
        }

        IsWorldGenerated = true;
    }

    public void GenWorld()
    {
        new Thread(new ThreadStart(RunThread)).Start();
    }

And This Is A Example Of How I Set Blocks

Block b = new Block();
b.BlockType = = Block.BlockTypes.Air;

This Is A Example Of How I Set Models

foreach (Block b in MyWorld)
{
    switch(b.BlockType)
    {
        case Block.BlockTypes.Dirt:
            b.Model = DirtModel;
            break;
        ect.
    }
}

How Would I Use These To Generate To World (The Block Array) And If Possible Thread It More?

btw It's 1024 Wide And 256 Tall

© Game Development or respective owner

Related posts about c#

Related posts about 3d