1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
precision highp float;
attribute vec2 position; // local (x, z) on the plane
uniform mat4 projection;
uniform mat4 view;
uniform mat4 model;
uniform float time;
uniform float amplitude;
varying vec3 vWorldPos;
varying vec3 vNormal;
float hash(vec2 p) {
p = fract(p * vec2(123.34, 456.21));
p += dot(p, p + 45.32);
return fract(p.x * p.y);
}
float valueNoise(vec2 p) {
vec2 i = floor(p);
vec2 f = fract(p);
float a = hash(i);
float b = hash(i + vec2(1.0, 0.0));
float c = hash(i + vec2(0.0, 1.0));
float d = hash(i + vec2(1.0, 1.0));
vec2 u = f * f * (3.0 - 2.0 * f);
return mix(mix(a, b, u.x), mix(c, d, u.x), u.y);
}
// Irregular height: non-harmonic directional sines plus two octaves of
// scrolling value noise so it never reads as a single clean wave.
float waveHeight(vec2 p, float t) {
float h = 0.0;
h += 0.30 * sin(dot(p, vec2(0.90, 0.30)) * 0.35 + t * 1.1);
h += 0.20 * sin(dot(p, vec2(-0.40, 1.00)) * 0.55 - t * 1.7);
h += 0.12 * sin(dot(p, vec2(0.70, -0.80)) * 0.90 + t * 2.3);
h += 0.08 * sin(dot(p, vec2(1.00, 0.60)) * 1.60 - t * 3.1);
h += 0.18 * (valueNoise(p * 0.25 + vec2(t * 0.15, t * 0.10)) - 0.5);
h += 0.09 * (valueNoise(p * 0.70 - vec2(t * 0.20, 0.0)) - 0.5);
return h;
}
void main() {
vec2 p = position;
float t = time;
float h = waveHeight(p, t) * amplitude;
// Analytic normal via central differences of the same height function.
float e = 2.0;
float hL = waveHeight(p - vec2(e, 0.0), t) * amplitude;
float hR = waveHeight(p + vec2(e, 0.0), t) * amplitude;
float hD = waveHeight(p - vec2(0.0, e), t) * amplitude;
float hU = waveHeight(p + vec2(0.0, e), t) * amplitude;
vec3 N = normalize(vec3(hL - hR, 2.0 * e, hD - hU));
vec4 worldPos = model * vec4(p.x, h, p.y, 1.0);
vWorldPos = worldPos.xyz;
vNormal = N; // model is translation-only, so no normal matrix needed
gl_Position = projection * view * worldPos;
}
|
