Untitled

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Aug 25th, 2016
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1. varying vec2 vUv;
2. uniform float time;
3. uniform vec2 resolution;
4.
5. const int NUM_STEPS = 8;
6. const float PI = 3.1415;
7. const float EPSILON = 1e-3;
8.
9. // sea
10. const int ITER_GEOMETRY = 3;
11. const int ITER_FRAGMENT = 5;
12. const float SEA_HEIGHT = 0.6;
13. const float SEA_CHOPPY = 4.0;
14. const float SEA_SPEED = 0.8;
15. const float SEA_FREQ = 0.16;
16. const vec3 SEA_BASE = vec3(0.1,0.19,0.22);
17. const vec3 SEA_WATER_COLOR = vec3(0.8,0.9,0.6);
18.
19. uniform float speedRotation;
20.
21. mat2 octave_m = mat2(1.6,1.2,-1.2,1.6);
22.
23. // math
24. mat3 fromEuler(vec3 ang) {
25.     vec2 a1 = vec2(sin(ang.x),cos(ang.x));
26.     vec2 a2 = vec2(sin(ang.y),cos(ang.y));
27.     vec2 a3 = vec2(sin(ang.z),cos(ang.z));
28.     mat3 m;
29.     m[0] = vec3(a1.y*a3.y+a1.x*a2.x*a3.x,a1.y*a2.x*a3.x+a3.y*a1.x,-a2.y*a3.x);
30.     m[1] = vec3(-a2.y*a1.x,a1.y*a2.y,a2.x);
31.     m[2] = vec3(a3.y*a1.x*a2.x+a1.y*a3.x,a1.x*a3.x-a1.y*a3.y*a2.x,a2.y*a3.y);
32.     return m;
33. }
34.
35. float hash( vec2 p ) {
36.     float h = dot(p,vec2(127.1,311.7));
37.     return fract(sin(h)*43758.5453123);
38. }
39.
40. float noise( in vec2 p ) {
41.     vec2 i = floor( p );
42.     vec2 f = fract( p );
43.     vec2 u = f*f*(3.0-2.0*f);
44.     return -1.0+2.0*mix( mix( hash( i + vec2(0.0,0.0) ),
45.                      hash( i + vec2(1.0,0.0) ), u.x),
46.                 mix( hash( i + vec2(0.0,1.0) ),
47.                      hash( i + vec2(1.0,1.0) ), u.x), u.y);
48. }
49.
50. // lighting
51. float diffuse(vec3 n,vec3 l,float p) {
52.     return pow(abs(dot(n,l) * 0.4 + 0.6),p);
53. }
54.
55. float specular(vec3 n,vec3 l,vec3 e,float s) {
56.     float nrm = (s + 8.0) / (PI * 8.0);
57.     return pow(abs(max(dot(reflect(e,n),l),0.0)),s) * nrm;
58. }
59.
60. // sky
61. vec3 getSkyColor(vec3 e) {
62.     e.y = max(e.y,0.0);
63.     vec3 ret;
64.     ret.x = pow(abs(1.0-e.y),2.0);
65.     ret.y = 1.0-e.y;
66.     ret.z = 0.6+(1.0-e.y)*0.4;
67.     return ret;
68. }
69.
70. // sea
71. float sea_octave(vec2 uv, float choppy) {
72.     uv += noise(uv);
73.     vec2 wv = 1.0-abs(sin(uv));
74.     vec2 swv = abs(cos(uv));
75.     wv = mix(wv,swv,wv);
76.     return pow(abs(1.0-pow(abs(wv.x * wv.y),0.65)),choppy);
77. }
78.
79. float maps(vec3 p) {
80.     float freq = SEA_FREQ;
81.     float amp = SEA_HEIGHT;
82.     float choppy = SEA_CHOPPY;
83.     vec2 uv = p.xz; uv.x *= 0.75;
84.     float d, h = 0.0;
85.     for(int i = 0; i < ITER_GEOMETRY; i++) {
86.         d = sea_octave((uv+(time * SEA_SPEED))*freq,choppy);
87.         d += sea_octave((uv-(time * SEA_SPEED))*freq,choppy);
88.         h += d * amp;
89.         uv *= octave_m; freq *= 1.9; amp *= 0.22;
90.         choppy = mix(choppy,1.0,0.2);
91.     }
92.     return p.y - h;
93. }
94.
95. float map_detailed(vec3 p) {
96.     float freq = SEA_FREQ;
97.     float amp = SEA_HEIGHT;
98.     float choppy = SEA_CHOPPY;
99.     vec2 uv = p.xz; uv.x *= 0.75;
100.     float d, h = 0.0;
101.     for(int i = 0; i < ITER_FRAGMENT; i++) {
102.         d = sea_octave((uv+(time * SEA_SPEED))*freq,choppy);
103.         d += sea_octave((uv-(time * SEA_SPEED))*freq,choppy);
104.         h += d * amp;
105.         uv *= octave_m; freq *= 1.9; amp *= 0.22;
106.         choppy = mix(choppy,1.0,0.2);
107.     }
108.     return p.y - h;
109. }
110.
111. vec3 getSeaColor(vec3 p, vec3 n, vec3 l, vec3 eye, vec3 dist) {
112.     float fresnel = 1.0 - max(dot(n,-eye),0.0);
113.     fresnel = pow(abs(fresnel),3.0) * 0.65;
114.     vec3 reflected = getSkyColor(reflect(eye,n));
115.     vec3 refracted = SEA_BASE + diffuse(n,l,80.0) * SEA_WATER_COLOR * 0.12;
116.     vec3 color = mix(refracted,reflected,fresnel);
117.     float atten = max(1.0 - dot(dist,dist) * 0.001, 0.0);
118.     color += SEA_WATER_COLOR * (p.y - SEA_HEIGHT) * 0.18 * atten;
119.     color += vec3(specular(n,l,eye,60.0));
120.     return color;
121. }
122.
123. // tracing
124. vec3 getNormal(vec3 p, float eps) {
125.     vec3 n;
126.     n.y = map_detailed(p);
127.     n.x = map_detailed(vec3(p.x+eps,p.y,p.z)) - n.y;
128.     n.z = map_detailed(vec3(p.x,p.y,p.z+eps)) - n.y;
129.     n.y = eps;
130.     return normalize(n);
131. }
132.
133. float heightMapTracing(vec3 ori, vec3 dir, out vec3 p) {
134.     float tm = 0.0;
135.     float tx = 1000.0;
136.     float hx = maps(ori + dir * tx);
137.     if(hx > 0.0) return tx;
138.     float hm = maps(ori + dir * tm);
139.     float tmid = 0.0;
140.     for(int i = 0; i < NUM_STEPS; i++) {
141.         tmid = mix(tm,tx, hm/(hm-hx));
142.         p = ori + dir * tmid;
143.         float hmid = maps(p);
144.         if(hmid < 0.0) {
145.             tx = tmid;
146.             hx = hmid;
147.         } else {
148.             tm = tmid;
149.             hm = hmid;
150.         }
151.     }
152.     return tmid;
153. }
154.
155. void main() {
156.     vec2 uv = gl_FragCoord.xy / resolution.xy;
157.     uv = uv * 2.0 - 1.5;
158.     uv.x *= resolution.x / resolution.y;
159.
160.     float EPSILON_NRM = 0.1 / resolution.x;
161.
162.     float ttime = time * speedRotation;
163.     vec3 ang = vec3(sin(ttime*2.0)*0.1,sin(ttime)*0.2+0.3,ttime);
164.     vec3 ori = vec3(0.85,3.5,ttime*5.0);
165.     vec3 dir = normalize(vec3(uv.xy,-2.0));
166.     dir.z += length(uv) * 0.15;
167.     dir = normalize(dir) * fromEuler(ang);
168.
169.     // tracing
170.     vec3 p;
171.     heightMapTracing(ori,dir,p);
172.     vec3 dist = p - ori;
173.     vec3 n = getNormal(p, dot(dist,dist) * EPSILON_NRM);
174.     vec3 light = normalize(vec3(0.0,1.0,0.8));
175.
176.     // color
177.     vec3 color = mix(
178.         getSkyColor(dir),
179.         getSeaColor(p,n,light,dir,dist),
180.         pow(abs(smoothstep(0.0,-0.05,dir.y)),0.3));
181.
182.     gl_FragColor = vec4(pow(abs(color),vec3(0.75)), 1.0);
183. }