yum-archive/SoggyShaders

Old Unity shaders.

git clone https://git.yummers.dev/yum-archive/SoggyShaders

yumAdd parallax shader40f81f1

master
branchesmasterall refs →
1.8 KiB77 linesraw
1#ifndef __MATH_INC
2#define __MATH_INC
3
4#include "pema99.cginc"
5
6// Differentiable approximation of the standard `max` function.
7float dmax(float a, float b, float k)
8{
9  return log2(exp2(k * a) + exp2(k * b)) / k;
10}
11
12// Differentiable approximation of the standard `min` function.
13float dmin(float a, float b, float k)
14{
15  return -1.0 * dmax(-1.0 * a, -1.0 * b, k);
16}
17
18// Generate a random number on [0, 1].
19float rand2(float3 p)
20{
21  return frac(sin(dot(p, float2(561.0, 885.0))) * 776.2) / 2.0;
22}
23
24// Generate a random number on [0, 1].
25float rand3(float3 p)
26{
27  return frac(sin(dot(p, float3(897.0, 367.0, 197.0))) * 1073.6) / 2.0;
28}
29
30// 3 dimensional value noise. `p` is assumed to be a point inside a unit cube.
31// Theory: https://en.wikipedia.org/wiki/Value_noise
32float vnoise3d(float3 p)
33{
34  float3 pu = floor(p);
35  float3 pv = glsl_mod(frac(p), 1.0);
36
37  // Assign random numbers to the corner of a cube.
38  float n000 = rand3(pu + float3(0,0,0));
39  float n001 = rand3(pu + float3(0,0,1));
40  float n010 = rand3(pu + float3(0,1,0));
41  float n011 = rand3(pu + float3(0,1,1));
42  float n100 = rand3(pu + float3(1,0,0));
43  float n101 = rand3(pu + float3(1,0,1));
44  float n110 = rand3(pu + float3(1,1,0));
45  float n111 = rand3(pu + float3(1,1,1));
46
47  float n00 = lerp(n000, n001, pv.z);
48  float n01 = lerp(n010, n011, pv.z);
49  float n10 = lerp(n100, n101, pv.z);
50  float n11 = lerp(n110, n111, pv.z);
51
52  float n0 = lerp(n00, n01, pv.y);
53  float n1 = lerp(n10, n11, pv.y);
54  
55  float n = lerp(n0, n1, pv.x);
56
57  return n;
58}
59
60float fbm(float3 p, const int n_octaves, float w)
61{
62  float g = exp2(-w);
63  float a = 1.0;
64  float p_scale = 1.0;
65
66  float res = 0.0;
67  for (int i = 0; i < n_octaves; i++) {
68    res += a * vnoise3d(p * p_scale);
69
70    p_scale /= w;
71    a *= g;
72  }
73  return res;
74}
75
76#endif  // __MATH_INC
77