age of technical reproducibility

/* * "Seascape" by Alexander Alekseev aka TDM - 2014 * License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. * Contact: tdmaav@gmail.com */ const int NUM_STEPS = 8; const float PI = 3.141592; const float EPSILON = 1e-3; #define EPSILON_NRM (0.1 / iResolution.x) // sea const int ITER_GEOMETRY = 3; const int ITER_FRAGMENT = 5; const float SEA_HEIGHT = 0.6; const float SEA_CHOPPY = 4.0; const float SEA_SPEED = 0.8; const float SEA_FREQ = 0.16; const vec3 SEA_BASE = vec3(0.1,0.19,0.22); const vec3 SEA_WATER_COLOR = vec3(0.8,0.9,0.6); #define SEA_TIME (1.0 + iTime * SEA_SPEED) const mat2 octave_m = mat2(1.6,1.2,-1.2,1.6); // math mat3 fromEuler(vec3 ang) { vec2 a1 = vec2(sin(ang.x),cos(ang.x)); vec2 a2 = vec2(sin(ang.y),cos(ang.y)); vec2 a3 = vec2(sin(ang.z),cos(ang.z)); mat3 m; 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); m[1] = vec3(-a2.y*a1.x,a1.y*a2.y,a2.x); 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); return m; } float hash( vec2 p ) { float h = dot(p,vec2(127.1,311.7)); return fract(sin(h)*43758.5453123); } float noise( in vec2 p ) { vec2 i = floor( p ); vec2 f = fract( p ); vec2 u = f*f*(3.0-2.0*f); return -1.0+2.0*mix( mix( hash( i + vec2(0.0,0.0) ), hash( i + vec2(1.0,0.0) ), u.x), mix( hash( i + vec2(0.0,1.0) ), hash( i + vec2(1.0,1.0) ), u.x), u.y); } // lighting float diffuse(vec3 n,vec3 l,float p) { return pow(dot(n,l) * 0.4 + 0.6,p); } float specular(vec3 n,vec3 l,vec3 e,float s) { float nrm = (s + 8.0) / (PI * 8.0); return pow(max(dot(reflect(e,n),l),0.0),s) * nrm; } // sky vec3 getSkyColor(vec3 e) { e.y = max(e.y,0.0); return vec3(pow(1.0-e.y,2.0), 1.0-e.y, 0.6+(1.0-e.y)*0.4); } // sea float sea_octave(vec2 uv, float choppy) { uv += noise(uv); vec2 wv = 1.0-abs(sin(uv)); vec2 swv = abs(cos(uv)); wv = mix(wv,swv,wv); return pow(1.0-pow(wv.x * wv.y,0.65),choppy); } float map(vec3 p) { float freq = SEA_FREQ; float amp = SEA_HEIGHT; float choppy = SEA_CHOPPY; vec2 uv = p.xz; uv.x *= 0.75; float d, h = 0.0; for(int i = 0; i < ITER_GEOMETRY; i++) { d = sea_octave((uv+SEA_TIME)*freq,choppy); d += sea_octave((uv-SEA_TIME)*freq,choppy); h += d * amp; uv *= octave_m; freq *= 1.9; amp *= 0.22; choppy = mix(choppy,1.0,0.2); } return p.y - h; } float map_detailed(vec3 p) { float freq = SEA_FREQ; float amp = SEA_HEIGHT; float choppy = SEA_CHOPPY; vec2 uv = p.xz; uv.x *= 0.75; float d, h = 0.0; for(int i = 0; i < ITER_FRAGMENT; i++) { d = sea_octave((uv+SEA_TIME)*freq,choppy); d += sea_octave((uv-SEA_TIME)*freq,choppy); h += d * amp; uv *= octave_m; freq *= 1.9; amp *= 0.22; choppy = mix(choppy,1.0,0.2); } return p.y - h; } vec3 getSeaColor(vec3 p, vec3 n, vec3 l, vec3 eye, vec3 dist) { float fresnel = clamp(1.0 - dot(n,-eye), 0.0, 1.0); fresnel = pow(fresnel,3.0) * 0.65; vec3 reflected = getSkyColor(reflect(eye,n)); vec3 refracted = SEA_BASE + diffuse(n,l,80.0) * SEA_WATER_COLOR * 0.12; vec3 color = mix(refracted,reflected,fresnel); float atten = max(1.0 - dot(dist,dist) * 0.001, 0.0); color += SEA_WATER_COLOR * (p.y - SEA_HEIGHT) * 0.18 * atten; color += vec3(specular(n,l,eye,60.0)); return color; } // tracing vec3 getNormal(vec3 p, float eps) { vec3 n; n.y = map_detailed(p); n.x = map_detailed(vec3(p.x+eps,p.y,p.z)) - n.y; n.z = map_detailed(vec3(p.x,p.y,p.z+eps)) - n.y; n.y = eps; return normalize(n); } float heightMapTracing(vec3 ori, vec3 dir, out vec3 p) { float tm = 0.0; float tx = 1000.0; float hx = map(ori + dir * tx); if(hx > 0.0) return tx; float hm = map(ori + dir * tm); float tmid = 0.0; for(int i = 0; i < NUM_STEPS; i++) { tmid = mix(tm,tx, hm/(hm-hx)); p = ori + dir * tmid; float hmid = map(p); if(hmid < 0.0) { tx = tmid; hx = hmid; } else { tm = tmid; hm = hmid; } } return tmid; } // main void mainImage( out vec4 fragColor, in vec2 fragCoord ) { vec2 uv = fragCoord.xy / iResolution.xy; uv = uv * 2.0 - 1.0; uv.x *= iResolution.x / iResolution.y; float time = iTime * 0.3 + iMouse.x*0.01; // ray vec3 ang = vec3(sin(time*3.0)*0.1,sin(time)*0.2+0.3,time); vec3 ori = vec3(0.0,3.5,time*5.0); vec3 dir = normalize(vec3(uv.xy,-2.0)); dir.z += length(uv) * 0.15; dir = normalize(dir) * fromEuler(ang); // tracing vec3 p; heightMapTracing(ori,dir,p); vec3 dist = p - ori; vec3 n = getNormal(p, dot(dist,dist) * EPSILON_NRM); vec3 light = normalize(vec3(0.0,1.0,0.8)); // color vec3 color = mix( getSkyColor(dir), getSeaColor(p,n,light,dir,dist), pow(smoothstep(0.0,-0.05,dir.y),0.3)); // post fragColor = vec4(pow(color,vec3(0.75)), 1.0); }