314 lines
12 KiB
HLSL
314 lines
12 KiB
HLSL
#ifndef GENA_NOISE_GENERATOR
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#define GENA_NOISE_GENERATOR
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#include "../Includes/Common.cginc"
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//-----------------------------------------------------------------------------
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// NOISE GENERATOR
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//-----------------------------------------------------------------------------
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int perm[] = {
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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,
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190, 6, 148, 247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32, 57, 177, 33,
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88, 237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175, 74, 165, 71, 134, 139, 48, 27, 166,
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77, 146, 158, 231, 83, 111, 229, 122, 60, 211, 133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244,
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102, 143, 54, 65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169, 200, 196,
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135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64, 52, 217, 226, 250, 124, 123,
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5, 202, 38, 147, 118, 126, 255, 82, 85, 212, 207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42,
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223, 183, 170, 213, 119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9,
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129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185, 112, 104, 218, 246, 97, 228,
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251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241, 81, 51, 145, 235, 249, 14, 239, 107,
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49, 192, 214, 31, 181, 199, 106, 157, 184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254,
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138, 236, 205, 93, 222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180,
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151, 160, 137, 91, 90, 15,
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131, 13, 201, 95, 96, 53, 194, 233, 7, 225, 140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23,
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190, 6, 148, 247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32, 57, 177, 33,
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88, 237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175, 74, 165, 71, 134, 139, 48, 27, 166,
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77, 146, 158, 231, 83, 111, 229, 122, 60, 211, 133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244,
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102, 143, 54, 65, 25, 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169, 200, 196,
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135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64, 52, 217, 226, 250, 124, 123,
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5, 202, 38, 147, 118, 126, 255, 82, 85, 212, 207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42,
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223, 183, 170, 213, 119, 248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9,
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129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185, 112, 104, 218, 246, 97, 228,
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251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241, 81, 51, 145, 235, 249, 14, 239, 107,
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49, 192, 214, 31, 181, 199, 106, 157, 184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254,
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138, 236, 205, 93, 222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180
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};
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int NoiseGenerator_FastFloor(float x)
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{
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return (x > 0) ? ((int)x) : (((int)x) - 1);
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}
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int NoiseGenerator_Mod(int x, int m)
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{
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int a = x % m;
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return a < 0 ? a + m : a;
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}
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float NoiseGenerator_Grad(int hash, float x)
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{
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int h = hash & 15;
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float grad = 1.0f + (h & 7); // Gradient value 1.0, 2.0, ..., 8.0
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if ((h & 8) != 0) grad = -grad; // Set a random sign for the gradient
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return (grad * x); // Multiply the gradient with the distance
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}
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float NoiseGenerator_Grad(int hash, float x, float y)
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{
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int h = hash & 7; // Convert low 3 bits of hash code
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float u = h < 4 ? x : y; // into 8 simple gradient directions,
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float v = h < 4 ? y : x; // and compute the dot product with (x,y).
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return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -2.0f * v : 2.0f * v);
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}
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float NoiseGenerator_Grad(int hash, float x, float y, float z)
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{
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int h = hash & 15; // Convert low 4 bits of hash code into 12 simple
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float u = h < 8 ? x : y; // gradient directions, and compute dot product.
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float v = h < 4 ? y : h == 12 || h == 14 ? x : z; // Fix repeats at h = 12 to 15
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return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -v : v);
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}
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float NoiseGenerator_Grad(int hash, float x, float y, float z, float t)
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{
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int h = hash & 31; // Convert low 5 bits of hash code into 32 simple
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float u = h < 24 ? x : y; // gradient directions, and compute dot product.
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float v = h < 16 ? y : z;
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float w = h < 8 ? z : t;
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return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -v : v) + ((h & 4) != 0 ? -w : w);
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}
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float NoiseGenerator_Generate(float x)
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{
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int i0 = NoiseGenerator_FastFloor(x);
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int i1 = i0 + 1;
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float x0 = x - i0;
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float x1 = x0 - 1.0f;
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float n0, n1;
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float t0 = 1.0f - x0 * x0;
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t0 *= t0;
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n0 = t0 * t0 * NoiseGenerator_Grad(perm[i0 & 0xff], x0);
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float t1 = 1.0f - x1 * x1;
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t1 *= t1;
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n1 = t1 * t1 * NoiseGenerator_Grad(perm[i1 & 0xff], x1);
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// The maximum value of this noise is 8*(3/4)^4 = 2.53125
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// A factor of 0.395 scales to fit exactly within [-1,1]
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return 0.395f * (n0 + n1);
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}
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float NoiseGenerator_Generate(float x, float y)
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{
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const float F2 = 0.366025403f; // F2 = 0.5*(sqrt(3.0)-1.0)
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const float G2 = 0.211324865f; // G2 = (3.0-Math.sqrt(3.0))/6.0
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float n0, n1, n2; // Noise contributions from the three corners
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// Skew the input space to determine which simplex cell we're in
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float s = (x + y) * F2; // Hairy factor for 2D
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float xs = x + s;
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float ys = y + s;
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int i = NoiseGenerator_FastFloor(xs);
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int j = NoiseGenerator_FastFloor(ys);
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float t = (float)(i + j) * G2;
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float X0 = i - t; // Unskew the cell origin back to (x,y) space
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float Y0 = j - t;
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float x0 = x - X0; // The x,y distances from the cell origin
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float y0 = y - Y0;
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// For the 2D case, the simplex shape is an equilateral triangle.
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// Determine which simplex we are in.
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int i1, j1; // Offsets for second (middle) corner of simplex in (i,j) coords
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if (x0 > y0)
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{
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i1 = 1;
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j1 = 0;
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} // lower triangle, XY order: (0,0)->(1,0)->(1,1)
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else
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{
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i1 = 0;
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j1 = 1;
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} // upper triangle, YX order: (0,0)->(0,1)->(1,1)
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// A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
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// a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
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// c = (3-sqrt(3))/6
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float x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords
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float y1 = y0 - j1 + G2;
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float x2 = x0 - 1.0f + 2.0f * G2; // Offsets for last corner in (x,y) unskewed coords
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float y2 = y0 - 1.0f + 2.0f * G2;
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// Wrap the integer indices at 256, to avoid indexing perm[] out of bounds
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int ii = (int)mod((float)i, (float)256);
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int jj = (int)mod((float)j, (float)256);
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// Calculate the contribution from the three corners
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float t0 = 0.5f - x0 * x0 - y0 * y0;
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if (t0 < 0.0f) n0 = 0.0f;
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else
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{
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t0 *= t0;
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n0 = t0 * t0 * NoiseGenerator_Grad(perm[ii + perm[jj]], x0, y0);
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}
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float t1 = 0.5f - x1 * x1 - y1 * y1;
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if (t1 < 0.0f) n1 = 0.0f;
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else
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{
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t1 *= t1;
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n1 = t1 * t1 * NoiseGenerator_Grad(perm[ii + i1 + perm[jj + j1]], x1, y1);
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}
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float t2 = 0.5f - x2 * x2 - y2 * y2;
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if (t2 < 0.0f) n2 = 0.0f;
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else
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{
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t2 *= t2;
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n2 = t2 * t2 * NoiseGenerator_Grad(perm[ii + 1 + perm[jj + 1]], x2, y2);
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}
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// Add contributions from each corner to get the final noise value.
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// The result is scaled to return values in the interval [-1,1].
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return 40.0f * (n0 + n1 + n2); // TODO: The scale factor is preliminary!
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}
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float NoiseGenerator_Generate(float x, float y, float z)
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{
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// Simple skewing factors for the 3D case
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const float F3 = 0.333333333f;
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const float G3 = 0.166666667f;
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float n0, n1, n2, n3; // Noise contributions from the four corners
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// Skew the input space to determine which simplex cell we're in
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float s = (x + y + z) * F3; // Very nice and simple skew factor for 3D
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float xs = x + s;
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float ys = y + s;
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float zs = z + s;
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int i = NoiseGenerator_FastFloor(xs);
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int j = NoiseGenerator_FastFloor(ys);
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int k = NoiseGenerator_FastFloor(zs);
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float t = (float)(i + j + k) * G3;
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float X0 = i - t; // Unskew the cell origin back to (x,y,z) space
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float Y0 = j - t;
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float Z0 = k - t;
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float x0 = x - X0; // The x,y,z distances from the cell origin
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float y0 = y - Y0;
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float z0 = z - Z0;
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// For the 3D case, the simplex shape is a slightly irregular tetrahedron.
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// Determine which simplex we are in.
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int i1, j1, k1; // Offsets for second corner of simplex in (i,j,k) coords
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int i2, j2, k2; // Offsets for third corner of simplex in (i,j,k) coords
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/* This code would benefit from a backport from the GLSL version! */
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if (x0 >= y0)
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{
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if (y0 >= z0)
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{
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i1 = 1;
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j1 = 0;
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k1 = 0;
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i2 = 1;
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j2 = 1;
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k2 = 0;
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} // X Y Z order
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else if (x0 >= z0)
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{
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i1 = 1;
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j1 = 0;
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k1 = 0;
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i2 = 1;
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j2 = 0;
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k2 = 1;
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} // X Z Y order
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else
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{
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i1 = 0;
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j1 = 0;
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k1 = 1;
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i2 = 1;
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j2 = 0;
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k2 = 1;
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} // Z X Y order
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}
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else
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{
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// x0<y0
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if (y0 < z0)
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{
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i1 = 0;
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j1 = 0;
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k1 = 1;
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i2 = 0;
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j2 = 1;
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k2 = 1;
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} // Z Y X order
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else if (x0 < z0)
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{
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i1 = 0;
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j1 = 1;
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k1 = 0;
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i2 = 0;
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j2 = 1;
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k2 = 1;
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} // Y Z X order
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else
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{
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i1 = 0;
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j1 = 1;
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k1 = 0;
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i2 = 1;
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j2 = 1;
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k2 = 0;
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} // Y X Z order
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}
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// A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
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// a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
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// a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
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// c = 1/6.
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float x1 = x0 - i1 + G3; // Offsets for second corner in (x,y,z) coords
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float y1 = y0 - j1 + G3;
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float z1 = z0 - k1 + G3;
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float x2 = x0 - i2 + 2.0f * G3; // Offsets for third corner in (x,y,z) coords
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float y2 = y0 - j2 + 2.0f * G3;
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float z2 = z0 - k2 + 2.0f * G3;
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float x3 = x0 - 1.0f + 3.0f * G3; // Offsets for last corner in (x,y,z) coords
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float y3 = y0 - 1.0f + 3.0f * G3;
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float z3 = z0 - 1.0f + 3.0f * G3;
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// Wrap the integer indices at 256, to avoid indexing perm[] out of bounds
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int ii = NoiseGenerator_Mod(i, 256);
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int jj = NoiseGenerator_Mod(j, 256);
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int kk = NoiseGenerator_Mod(k, 256);
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// Calculate the contribution from the four corners
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float t0 = 0.6f - x0 * x0 - y0 * y0 - z0 * z0;
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if (t0 < 0.0f) n0 = 0.0f;
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else
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{
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t0 *= t0;
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n0 = t0 * t0 * NoiseGenerator_Grad(perm[ii + perm[jj + perm[kk]]], x0, y0, z0);
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}
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float t1 = 0.6f - x1 * x1 - y1 * y1 - z1 * z1;
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if (t1 < 0.0f) n1 = 0.0f;
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else
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{
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t1 *= t1;
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n1 = t1 * t1 * NoiseGenerator_Grad(perm[ii + i1 + perm[jj + j1 + perm[kk + k1]]], x1, y1, z1);
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}
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float t2 = 0.6f - x2 * x2 - y2 * y2 - z2 * z2;
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if (t2 < 0.0f) n2 = 0.0f;
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else
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{
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t2 *= t2;
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n2 = t2 * t2 * NoiseGenerator_Grad(perm[ii + i2 + perm[jj + j2 + perm[kk + k2]]], x2, y2, z2);
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}
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float t3 = 0.6f - x3 * x3 - y3 * y3 - z3 * z3;
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if (t3 < 0.0f) n3 = 0.0f;
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else
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{
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t3 *= t3;
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n3 = t3 * t3 * NoiseGenerator_Grad(perm[ii + 1 + perm[jj + 1 + perm[kk + 1]]], x3, y3, z3);
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}
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// Add contributions from each corner to get the final noise value.
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// The result is scaled to stay just inside [-1,1]
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return 32.0f * (n0 + n1 + n2 + n3); // TODO: The scale factor is preliminary!
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}
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float NoiseGenerator_GetNormalisedValue(float x, float y)
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{
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return clamp((NoiseGenerator_Generate(x, y) + 1.0f) / 2.0f, 0.0f, 1.0f);
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}
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//-----------------------------------------------------------------------------
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// END - NOISE GENERATOR
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//-----------------------------------------------------------------------------
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#endif
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