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123 lines
3.8 KiB
GLSL
123 lines
3.8 KiB
GLSL
#ifndef RANDOM_GLSL
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#define RANDOM_GLSL
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layout(set = 0, binding = 1) uniform texture2D t_noise;
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layout(set = 0, binding = 2) uniform sampler s_noise;
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float hash(vec4 p) {
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p = fract(p * 0.3183099 + 0.1) - fract(p + 23.22121);
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p *= 17.0;
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return (fract(p.x * p.y * (1.0 - p.z) * p.w * (p.x + p.y + p.z + p.w)) - 0.5) * 2.0;
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}
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#define M1 2047667443U
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#define M2 3883706873U
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#define M3 3961281721U
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float hash_one(uint q) {
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uint n = ((M3 * q) ^ M2) * M1;
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return float(n) * (1.0 / float(0xffffffffU));
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}
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float hash_two(uvec2 q) {
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q *= uvec2(M1, M2);
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uint n = q.x ^ q.y;
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n = n * (n ^ (n >> 15));
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return float(n) * (1.0 / float(0xffffffffU));
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}
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float hash_fast(uvec3 q) {
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q *= uvec3(M1, M2, M3);
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uint n = (q.x ^ q.y ^ q.z) * M1;
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return float(n) * (1.0 / float(0xffffffffU));
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}
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// 2D, but using shifted 2D textures
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float noise_2d(vec2 pos) {
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return textureLod(sampler2D(t_noise, s_noise), pos, 0).x;
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}
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// 3D, but using shifted 2D textures
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float noise_3d(vec3 pos) {
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pos.z *= 15.0;
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uint z = uint(trunc(pos.z));
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vec2 offs0 = vec2(hash_one(z), hash_one(z + 73u));
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vec2 offs1 = vec2(hash_one(z + 1u), hash_one(z + 1u + 73u));
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return mix(textureLod(sampler2D(t_noise, s_noise), pos.xy + offs0, 0).x, textureLod(sampler2D(t_noise, s_noise), pos.xy + offs1, 0).x, fract(pos.z));
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}
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// 3D version of `snoise`
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float snoise3(in vec3 x) {
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uvec3 p = uvec3(floor(x) + 10000.0);
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vec3 f = fract(x);
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//f = f * f * (3.0 - 2.0 * f);
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return mix(
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mix(
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mix(hash_fast(p + uvec3(0, 0, 0)), hash_fast(p + uvec3(1, 0, 0)), f.x),
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mix(hash_fast(p + uvec3(0, 1, 0)), hash_fast(p + uvec3(1, 1, 0)), f.x),
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f.y),
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mix(
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mix(hash_fast(p + uvec3(0, 0, 1)), hash_fast(p + uvec3(1, 0, 1)), f.x),
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mix(hash_fast(p + uvec3(0, 1, 1)), hash_fast(p + uvec3(1, 1, 1)), f.x),
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f.y),
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f.z);
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}
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// 4D noise
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float snoise(in vec4 x) {
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vec4 p = floor(x);
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vec4 f = fract(x);
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f = f * f * (3.0 - 2.0 * f);
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return mix(
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mix(
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mix(
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mix(hash(p + vec4(0, 0, 0, 0)), hash(p + vec4(1, 0, 0, 0)), f.x),
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mix(hash(p + vec4(0, 1, 0, 0)), hash(p + vec4(1, 1, 0, 0)), f.x),
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f.y),
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mix(
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mix(hash(p + vec4(0, 0, 1, 0)), hash(p + vec4(1, 0, 1, 0)), f.x),
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mix(hash(p + vec4(0, 1, 1, 0)), hash(p + vec4(1, 1, 1, 0)), f.x),
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f.y),
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f.z),
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mix(
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mix(
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mix(hash(p + vec4(0, 0, 0, 1)), hash(p + vec4(1, 0, 0, 1)), f.x),
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mix(hash(p + vec4(0, 1, 0, 1)), hash(p + vec4(1, 1, 0, 1)), f.x),
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f.y),
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mix(
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mix(hash(p + vec4(0, 0, 1, 1)), hash(p + vec4(1, 0, 1, 1)), f.x),
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mix(hash(p + vec4(0, 1, 1, 1)), hash(p + vec4(1, 1, 1, 1)), f.x),
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f.y),
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f.z),
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f.w);
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}
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vec3 rand_perm_3(vec3 pos) {
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return abs(sin(pos * vec3(1473.7 * pos.z + 472.3, 8891.1 * pos.x + 723.1, 3813.3 * pos.y + 982.5)));
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}
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vec4 rand_perm_4(vec4 pos) {
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return sin(473.3 * pos * vec4(317.3 * pos.w + 917.7, 1473.7 * pos.z + 472.3, 8891.1 * pos.x + 723.1, 3813.3 * pos.y + 982.5) / pos.yxwz);
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}
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vec3 smooth_rand(vec3 pos, float lerp_axis) {
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return vec3(snoise(vec4(pos, lerp_axis)), snoise(vec4(pos + 400.0, lerp_axis)), snoise(vec4(pos + 1000.0, lerp_axis)));
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vec3 r0 = rand_perm_3(vec3(pos.x, pos.y, pos.z) + floor(lerp_axis));
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vec3 r1 = rand_perm_3(vec3(pos.x, pos.y, pos.z) + floor(lerp_axis + 1.0));
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return r0 + (r1 - r0) * fract(lerp_axis);
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}
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// Transform normal distribution to triangle distribution.
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float norm2tri(float n) {
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// TODO: compare perf with adding two normal noise distributions
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bool flip = n > 0.5;
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n = flip ? 1.0 - n : n;
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n = sqrt(n / 2.0);
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n = flip ? 1.0 - n : n;
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return n;
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}
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#endif
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