threejs/examples/jsm/nodes/materialx/lib/mx_noise.js

import { code, fn } from '../../Nodes.js';

// Original shader code from:
// https://github.com/AcademySoftwareFoundation/MaterialX/blob/main/libraries/stdlib/genglsl/lib/mx_noise.glsl

export const mx_noise = code( `float mx_select(bool b, float t, float f)
{
    return b ? t : f;
}

float mx_negate_if(float val, bool b)
{
    return b ? -val : val;
}

int mx_floor(float x)
{
    return int(floor(x));
}

// return mx_floor as well as the fractional remainder
float mx_floorfrac(float x, out int i)
{
    i = mx_floor(x);
    return x - float(i);
}

float mx_bilerp(float v0, float v1, float v2, float v3, float s, float t)
{
    float s1 = 1.0 - s;
    return (1.0 - t) * (v0*s1 + v1*s) + t * (v2*s1 + v3*s);
}
vec3 mx_bilerp(vec3 v0, vec3 v1, vec3 v2, vec3 v3, float s, float t)
{
    float s1 = 1.0 - s;
    return (1.0 - t) * (v0*s1 + v1*s) + t * (v2*s1 + v3*s);
}
float mx_trilerp(float v0, float v1, float v2, float v3, float v4, float v5, float v6, float v7, float s, float t, float r)
{
    float s1 = 1.0 - s;
    float t1 = 1.0 - t;
    float r1 = 1.0 - r;
    return (r1*(t1*(v0*s1 + v1*s) + t*(v2*s1 + v3*s)) +
            r*(t1*(v4*s1 + v5*s) + t*(v6*s1 + v7*s)));
}
vec3 mx_trilerp(vec3 v0, vec3 v1, vec3 v2, vec3 v3, vec3 v4, vec3 v5, vec3 v6, vec3 v7, float s, float t, float r)
{
    float s1 = 1.0 - s;
    float t1 = 1.0 - t;
    float r1 = 1.0 - r;
    return (r1*(t1*(v0*s1 + v1*s) + t*(v2*s1 + v3*s)) +
            r*(t1*(v4*s1 + v5*s) + t*(v6*s1 + v7*s)));
}

// 2 and 3 dimensional gradient functions - perform a dot product against a
// randomly chosen vector. Note that the gradient vector is not normalized, but
// this only affects the overal "scale" of the result, so we simply account for
// the scale by multiplying in the corresponding "perlin" function.
float mx_gradient_float(uint hash, float x, float y)
{
    // 8 possible directions (+-1,+-2) and (+-2,+-1)
    uint h = hash & 7u;
    float u = mx_select(h<4u, x, y);
    float v = 2.0 * mx_select(h<4u, y, x);
    // compute the dot product with (x,y).
    return mx_negate_if(u, bool(h&1u)) + mx_negate_if(v, bool(h&2u));
}
float mx_gradient_float(uint hash, float x, float y, float z)
{
    // use vectors pointing to the edges of the cube
    uint h = hash & 15u;
    float u = mx_select(h<8u, x, y);
    float v = mx_select(h<4u, y, mx_select((h==12u)||(h==14u), x, z));
    return mx_negate_if(u, bool(h&1u)) + mx_negate_if(v, bool(h&2u));
}
vec3 mx_gradient_vec3(uvec3 hash, float x, float y)
{
    return vec3(mx_gradient_float(hash.x, x, y), mx_gradient_float(hash.y, x, y), mx_gradient_float(hash.z, x, y));
}
vec3 mx_gradient_vec3(uvec3 hash, float x, float y, float z)
{
    return vec3(mx_gradient_float(hash.x, x, y, z), mx_gradient_float(hash.y, x, y, z), mx_gradient_float(hash.z, x, y, z));
}
// Scaling factors to normalize the result of gradients above.
// These factors were experimentally calculated to be:
//    2D:   0.6616
//    3D:   0.9820
float mx_gradient_scale2d(float v) { return 0.6616 * v; }
float mx_gradient_scale3d(float v) { return 0.9820 * v; }
vec3 mx_gradient_scale2d(vec3 v) { return 0.6616 * v; }
vec3 mx_gradient_scale3d(vec3 v) { return 0.9820 * v; }

/// Bitwise circular rotation left by k bits (for 32 bit unsigned integers)
uint mx_rotl32(uint x, int k)
{
    return (x<<k) | (x>>(32-k));
}

void mx_bjmix(inout uint a, inout uint b, inout uint c)
{
    a -= c; a ^= mx_rotl32(c, 4); c += b;
    b -= a; b ^= mx_rotl32(a, 6); a += c;
    c -= b; c ^= mx_rotl32(b, 8); b += a;
    a -= c; a ^= mx_rotl32(c,16); c += b;
    b -= a; b ^= mx_rotl32(a,19); a += c;
    c -= b; c ^= mx_rotl32(b, 4); b += a;
}

// Mix up and combine the bits of a, b, and c (doesn't change them, but
// returns a hash of those three original values).
uint mx_bjfinal(uint a, uint b, uint c)
{
    c ^= b; c -= mx_rotl32(b,14);
    a ^= c; a -= mx_rotl32(c,11);
    b ^= a; b -= mx_rotl32(a,25);
    c ^= b; c -= mx_rotl32(b,16);
    a ^= c; a -= mx_rotl32(c,4);
    b ^= a; b -= mx_rotl32(a,14);
    c ^= b; c -= mx_rotl32(b,24);
    return c;
}

// Convert a 32 bit integer into a floating point number in [0,1]
float mx_bits_to_01(uint bits)
{
    return float(bits) / float(uint(0xffffffff));
}

float mx_fade(float t)
{
   return t * t * t * (t * (t * 6.0 - 15.0) + 10.0);
}

uint mx_hash_int(int x)
{
    uint len = 1u;
    uint seed = uint(0xdeadbeef) + (len << 2u) + 13u;
    return mx_bjfinal(seed+uint(x), seed, seed);
}

uint mx_hash_int(int x, int y)
{
    uint len = 2u;
    uint a, b, c;
    a = b = c = uint(0xdeadbeef) + (len << 2u) + 13u;
    a += uint(x);
    b += uint(y);
    return mx_bjfinal(a, b, c);
}

uint mx_hash_int(int x, int y, int z)
{
    uint len = 3u;
    uint a, b, c;
    a = b = c = uint(0xdeadbeef) + (len << 2u) + 13u;
    a += uint(x);
    b += uint(y);
    c += uint(z);
    return mx_bjfinal(a, b, c);
}

uint mx_hash_int(int x, int y, int z, int xx)
{
    uint len = 4u;
    uint a, b, c;
    a = b = c = uint(0xdeadbeef) + (len << 2u) + 13u;
    a += uint(x);
    b += uint(y);
    c += uint(z);
    mx_bjmix(a, b, c);
    a += uint(xx);
    return mx_bjfinal(a, b, c);
}

uint mx_hash_int(int x, int y, int z, int xx, int yy)
{
    uint len = 5u;
    uint a, b, c;
    a = b = c = uint(0xdeadbeef) + (len << 2u) + 13u;
    a += uint(x);
    b += uint(y);
    c += uint(z);
    mx_bjmix(a, b, c);
    a += uint(xx);
    b += uint(yy);
    return mx_bjfinal(a, b, c);
}

uvec3 mx_hash_vec3(int x, int y)
{
    uint h = mx_hash_int(x, y);
    // we only need the low-order bits to be random, so split out
    // the 32 bit result into 3 parts for each channel
    uvec3 result;
    result.x = (h      ) & 0xFFu;
    result.y = (h >> 8 ) & 0xFFu;
    result.z = (h >> 16) & 0xFFu;
    return result;
}

uvec3 mx_hash_vec3(int x, int y, int z)
{
    uint h = mx_hash_int(x, y, z);
    // we only need the low-order bits to be random, so split out
    // the 32 bit result into 3 parts for each channel
    uvec3 result;
    result.x = (h      ) & 0xFFu;
    result.y = (h >> 8 ) & 0xFFu;
    result.z = (h >> 16) & 0xFFu;
    return result;
}

float mx_perlin_noise_float(vec2 p)
{
    int X, Y;
    float fx = mx_floorfrac(p.x, X);
    float fy = mx_floorfrac(p.y, Y);
    float u = mx_fade(fx);
    float v = mx_fade(fy);
    float result = mx_bilerp(
        mx_gradient_float(mx_hash_int(X  , Y  ), fx    , fy     ),
        mx_gradient_float(mx_hash_int(X+1, Y  ), fx-1.0, fy     ),
        mx_gradient_float(mx_hash_int(X  , Y+1), fx    , fy-1.0),
        mx_gradient_float(mx_hash_int(X+1, Y+1), fx-1.0, fy-1.0),
        u, v);
    return mx_gradient_scale2d(result);
}

float mx_perlin_noise_float(vec3 p)
{
    int X, Y, Z;
    float fx = mx_floorfrac(p.x, X);
    float fy = mx_floorfrac(p.y, Y);
    float fz = mx_floorfrac(p.z, Z);
    float u = mx_fade(fx);
    float v = mx_fade(fy);
    float w = mx_fade(fz);
    float result = mx_trilerp(
        mx_gradient_float(mx_hash_int(X  , Y  , Z  ), fx    , fy    , fz     ),
        mx_gradient_float(mx_hash_int(X+1, Y  , Z  ), fx-1.0, fy    , fz     ),
        mx_gradient_float(mx_hash_int(X  , Y+1, Z  ), fx    , fy-1.0, fz     ),
        mx_gradient_float(mx_hash_int(X+1, Y+1, Z  ), fx-1.0, fy-1.0, fz     ),
        mx_gradient_float(mx_hash_int(X  , Y  , Z+1), fx    , fy    , fz-1.0),
        mx_gradient_float(mx_hash_int(X+1, Y  , Z+1), fx-1.0, fy    , fz-1.0),
        mx_gradient_float(mx_hash_int(X  , Y+1, Z+1), fx    , fy-1.0, fz-1.0),
        mx_gradient_float(mx_hash_int(X+1, Y+1, Z+1), fx-1.0, fy-1.0, fz-1.0),
        u, v, w);
    return mx_gradient_scale3d(result);
}

vec3 mx_perlin_noise_vec3(vec2 p)
{
    int X, Y;
    float fx = mx_floorfrac(p.x, X);
    float fy = mx_floorfrac(p.y, Y);
    float u = mx_fade(fx);
    float v = mx_fade(fy);
    vec3 result = mx_bilerp(
        mx_gradient_vec3(mx_hash_vec3(X  , Y  ), fx    , fy     ),
        mx_gradient_vec3(mx_hash_vec3(X+1, Y  ), fx-1.0, fy     ),
        mx_gradient_vec3(mx_hash_vec3(X  , Y+1), fx    , fy-1.0),
        mx_gradient_vec3(mx_hash_vec3(X+1, Y+1), fx-1.0, fy-1.0),
        u, v);
    return mx_gradient_scale2d(result);
}

vec3 mx_perlin_noise_vec3(vec3 p)
{
    int X, Y, Z;
    float fx = mx_floorfrac(p.x, X);
    float fy = mx_floorfrac(p.y, Y);
    float fz = mx_floorfrac(p.z, Z);
    float u = mx_fade(fx);
    float v = mx_fade(fy);
    float w = mx_fade(fz);
    vec3 result = mx_trilerp(
        mx_gradient_vec3(mx_hash_vec3(X  , Y  , Z  ), fx    , fy    , fz     ),
        mx_gradient_vec3(mx_hash_vec3(X+1, Y  , Z  ), fx-1.0, fy    , fz     ),
        mx_gradient_vec3(mx_hash_vec3(X  , Y+1, Z  ), fx    , fy-1.0, fz     ),
        mx_gradient_vec3(mx_hash_vec3(X+1, Y+1, Z  ), fx-1.0, fy-1.0, fz     ),
        mx_gradient_vec3(mx_hash_vec3(X  , Y  , Z+1), fx    , fy    , fz-1.0),
        mx_gradient_vec3(mx_hash_vec3(X+1, Y  , Z+1), fx-1.0, fy    , fz-1.0),
        mx_gradient_vec3(mx_hash_vec3(X  , Y+1, Z+1), fx    , fy-1.0, fz-1.0),
        mx_gradient_vec3(mx_hash_vec3(X+1, Y+1, Z+1), fx-1.0, fy-1.0, fz-1.0),
        u, v, w);
    return mx_gradient_scale3d(result);
}

float mx_cell_noise_float(float p)
{
    int ix = mx_floor(p);
    return mx_bits_to_01(mx_hash_int(ix));
}

float mx_cell_noise_float(vec2 p)
{
    int ix = mx_floor(p.x);
    int iy = mx_floor(p.y);
    return mx_bits_to_01(mx_hash_int(ix, iy));
}

float mx_cell_noise_float(vec3 p)
{
    int ix = mx_floor(p.x);
    int iy = mx_floor(p.y);
    int iz = mx_floor(p.z);
    return mx_bits_to_01(mx_hash_int(ix, iy, iz));
}

float mx_cell_noise_float(vec4 p)
{
    int ix = mx_floor(p.x);
    int iy = mx_floor(p.y);
    int iz = mx_floor(p.z);
    int iw = mx_floor(p.w);
    return mx_bits_to_01(mx_hash_int(ix, iy, iz, iw));
}

vec3 mx_cell_noise_vec3(float p)
{
    int ix = mx_floor(p);
    return vec3(
            mx_bits_to_01(mx_hash_int(ix, 0)),
            mx_bits_to_01(mx_hash_int(ix, 1)),
            mx_bits_to_01(mx_hash_int(ix, 2))
    );
}

vec3 mx_cell_noise_vec3(vec2 p)
{
    int ix = mx_floor(p.x);
    int iy = mx_floor(p.y);
    return vec3(
            mx_bits_to_01(mx_hash_int(ix, iy, 0)),
            mx_bits_to_01(mx_hash_int(ix, iy, 1)),
            mx_bits_to_01(mx_hash_int(ix, iy, 2))
    );
}

vec3 mx_cell_noise_vec3(vec3 p)
{
    int ix = mx_floor(p.x);
    int iy = mx_floor(p.y);
    int iz = mx_floor(p.z);
    return vec3(
            mx_bits_to_01(mx_hash_int(ix, iy, iz, 0)),
            mx_bits_to_01(mx_hash_int(ix, iy, iz, 1)),
            mx_bits_to_01(mx_hash_int(ix, iy, iz, 2))
    );
}

vec3 mx_cell_noise_vec3(vec4 p)
{
    int ix = mx_floor(p.x);
    int iy = mx_floor(p.y);
    int iz = mx_floor(p.z);
    int iw = mx_floor(p.w);
    return vec3(
            mx_bits_to_01(mx_hash_int(ix, iy, iz, iw, 0)),
            mx_bits_to_01(mx_hash_int(ix, iy, iz, iw, 1)),
            mx_bits_to_01(mx_hash_int(ix, iy, iz, iw, 2))
    );
}

float mx_fractal_noise_float(vec3 p, int octaves, float lacunarity, float diminish)
{
    float result = 0.0;
    float amplitude = 1.0;
    for (int i = 0;  i < octaves; ++i)
    {
        result += amplitude * mx_perlin_noise_float(p);
        amplitude *= diminish;
        p *= lacunarity;
    }
    return result;
}

vec3 mx_fractal_noise_vec3(vec3 p, int octaves, float lacunarity, float diminish)
{
    vec3 result = vec3(0.0);
    float amplitude = 1.0;
    for (int i = 0;  i < octaves; ++i)
    {
        result += amplitude * mx_perlin_noise_vec3(p);
        amplitude *= diminish;
        p *= lacunarity;
    }
    return result;
}

vec2 mx_fractal_noise_vec2(vec3 p, int octaves, float lacunarity, float diminish)
{
    return vec2(mx_fractal_noise_float(p, octaves, lacunarity, diminish),
                mx_fractal_noise_float(p+vec3(19, 193, 17), octaves, lacunarity, diminish));
}

vec4 mx_fractal_noise_vec4(vec3 p, int octaves, float lacunarity, float diminish)
{
    vec3  c = mx_fractal_noise_vec3(p, octaves, lacunarity, diminish);
    float f = mx_fractal_noise_float(p+vec3(19, 193, 17), octaves, lacunarity, diminish);
    return vec4(c, f);
}

float mx_worley_distance(vec2 p, int x, int y, int xoff, int yoff, float jitter, int metric)
{
    vec3  tmp = mx_cell_noise_vec3(vec2(x+xoff, y+yoff));
    vec2  off = vec2(tmp.x, tmp.y);

    off -= 0.5f;
    off *= jitter;
    off += 0.5f;

    vec2 cellpos = vec2(float(x), float(y)) + off;
    vec2 diff = cellpos - p;
    if (metric == 2)
        return abs(diff.x) + abs(diff.y);       // Manhattan distance
    if (metric == 3)
        return max(abs(diff.x), abs(diff.y));   // Chebyshev distance
    // Either Euclidian or Distance^2
    return dot(diff, diff);
}

float mx_worley_distance(vec3 p, int x, int y, int z, int xoff, int yoff, int zoff, float jitter, int metric)
{
    vec3  off = mx_cell_noise_vec3(vec3(x+xoff, y+yoff, z+zoff));

    off -= 0.5f;
    off *= jitter;
    off += 0.5f;

    vec3 cellpos = vec3(float(x), float(y), float(z)) + off;
    vec3 diff = cellpos - p;
    if (metric == 2)
        return abs(diff.x) + abs(diff.y) + abs(diff.z); // Manhattan distance
    if (metric == 3)
        return max(max(abs(diff.x), abs(diff.y)), abs(diff.z)); // Chebyshev distance
    // Either Euclidian or Distance^2
    return dot(diff, diff);
}

float mx_worley_noise_float(vec2 p, float jitter, int metric)
{
    int X, Y;
    vec2 localpos = vec2(mx_floorfrac(p.x, X), mx_floorfrac(p.y, Y));
    float sqdist = 1e6f;        // Some big number for jitter > 1 (not all GPUs may be IEEE)
    for (int x = -1; x <= 1; ++x)
    {
        for (int y = -1; y <= 1; ++y)
        {
            float dist = mx_worley_distance(localpos, x, y, X, Y, jitter, metric);
            sqdist = min(sqdist, dist);
        }
    }
    if (metric == 0)
        sqdist = sqrt(sqdist);
    return sqdist;
}

vec2 mx_worley_noise_vec2(vec2 p, float jitter, int metric)
{
    int X, Y;
    vec2 localpos = vec2(mx_floorfrac(p.x, X), mx_floorfrac(p.y, Y));
    vec2 sqdist = vec2(1e6f, 1e6f);
    for (int x = -1; x <= 1; ++x)
    {
        for (int y = -1; y <= 1; ++y)
        {
            float dist = mx_worley_distance(localpos, x, y, X, Y, jitter, metric);
            if (dist < sqdist.x)
            {
                sqdist.y = sqdist.x;
                sqdist.x = dist;
            }
            else if (dist < sqdist.y)
            {
                sqdist.y = dist;
            }
        }
    }
    if (metric == 0)
        sqdist = sqrt(sqdist);
    return sqdist;
}

vec3 mx_worley_noise_vec3(vec2 p, float jitter, int metric)
{
    int X, Y;
    vec2 localpos = vec2(mx_floorfrac(p.x, X), mx_floorfrac(p.y, Y));
    vec3 sqdist = vec3(1e6f, 1e6f, 1e6f);
    for (int x = -1; x <= 1; ++x)
    {
        for (int y = -1; y <= 1; ++y)
        {
            float dist = mx_worley_distance(localpos, x, y, X, Y, jitter, metric);
            if (dist < sqdist.x)
            {
                sqdist.z = sqdist.y;
                sqdist.y = sqdist.x;
                sqdist.x = dist;
            }
            else if (dist < sqdist.y)
            {
                sqdist.z = sqdist.y;
                sqdist.y = dist;
            }
            else if (dist < sqdist.z)
            {
                sqdist.z = dist;
            }
        }
    }
    if (metric == 0)
        sqdist = sqrt(sqdist);
    return sqdist;
}

float mx_worley_noise_float(vec3 p, float jitter, int metric)
{
    int X, Y, Z;
    vec3 localpos = vec3(mx_floorfrac(p.x, X), mx_floorfrac(p.y, Y), mx_floorfrac(p.z, Z));
    float sqdist = 1e6f;
    for (int x = -1; x <= 1; ++x)
    {
        for (int y = -1; y <= 1; ++y)
        {
            for (int z = -1; z <= 1; ++z)
            {
                float dist = mx_worley_distance(localpos, x, y, z, X, Y, Z, jitter, metric);
                sqdist = min(sqdist, dist);
            }
        }
    }
    if (metric == 0)
        sqdist = sqrt(sqdist);
    return sqdist;
}

vec2 mx_worley_noise_vec2(vec3 p, float jitter, int metric)
{
    int X, Y, Z;
    vec3 localpos = vec3(mx_floorfrac(p.x, X), mx_floorfrac(p.y, Y), mx_floorfrac(p.z, Z));
    vec2 sqdist = vec2(1e6f, 1e6f);
    for (int x = -1; x <= 1; ++x)
    {
        for (int y = -1; y <= 1; ++y)
        {
            for (int z = -1; z <= 1; ++z)
            {
                float dist = mx_worley_distance(localpos, x, y, z, X, Y, Z, jitter, metric);
                if (dist < sqdist.x)
                {
                    sqdist.y = sqdist.x;
                    sqdist.x = dist;
                }
                else if (dist < sqdist.y)
                {
                    sqdist.y = dist;
                }
            }
        }
    }
    if (metric == 0)
        sqdist = sqrt(sqdist);
    return sqdist;
}

vec3 mx_worley_noise_vec3(vec3 p, float jitter, int metric)
{
    int X, Y, Z;
    vec3 localpos = vec3(mx_floorfrac(p.x, X), mx_floorfrac(p.y, Y), mx_floorfrac(p.z, Z));
    vec3 sqdist = vec3(1e6f, 1e6f, 1e6f);
    for (int x = -1; x <= 1; ++x)
    {
        for (int y = -1; y <= 1; ++y)
        {
            for (int z = -1; z <= 1; ++z)
            {
                float dist = mx_worley_distance(localpos, x, y, z, X, Y, Z, jitter, metric);
                if (dist < sqdist.x)
                {
                    sqdist.z = sqdist.y;
                    sqdist.y = sqdist.x;
                    sqdist.x = dist;
                }
                else if (dist < sqdist.y)
                {
                    sqdist.z = sqdist.y;
                    sqdist.y = dist;
                }
                else if (dist < sqdist.z)
                {
                    sqdist.z = dist;
                }
            }
        }
    }
    if (metric == 0)
        sqdist = sqrt(sqdist);
    return sqdist;
}` );

const includes = [ mx_noise ];

export const mx_perlin_noise_float = fn( 'float mx_perlin_noise_float( any p )', includes );
export const mx_perlin_noise_vec2 = fn( 'vec2 mx_perlin_noise_vec2( any p )', includes );
export const mx_perlin_noise_vec3 = fn( 'vec3 mx_perlin_noise_vec3( any p )', includes );

export const mx_cell_noise_float = fn( 'float mx_cell_noise_float( vec3 p )', includes );

export const mx_worley_noise_float = fn( 'float mx_worley_noise_float( any p, float jitter, int metric )', includes );
export const mx_worley_noise_vec2 = fn( 'float mx_worley_noise_vec2( any p, float jitter, int metric )', includes );
export const mx_worley_noise_vec3 = fn( 'float mx_worley_noise_vec3( any p, float jitter, int metric )', includes );

export const mx_fractal_noise_float = fn( 'float mx_fractal_noise_float( vec3 p, int octaves, float lacunarity, float diminish )', includes );
export const mx_fractal_noise_vec2 = fn( 'float mx_fractal_noise_vec2( vec3 p, int octaves, float lacunarity, float diminish )', includes );
export const mx_fractal_noise_vec3 = fn( 'float mx_fractal_noise_vec3( vec3 p, int octaves, float lacunarity, float diminish )', includes );
export const mx_fractal_noise_vec4 = fn( 'float mx_fractal_noise_vec4( vec3 p, int octaves, float lacunarity, float diminish )', includes );