334 lines
9.1 KiB
GLSL
334 lines
9.1 KiB
GLSL
// Created by inigo quilez - iq/2018
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// License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
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// Pretty much a modification to Klems' shader (https://www.shadertoy.com/view/XlcfRs)
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// Youtube version: https://www.youtube.com/watch?v=q1OBrqtl7Yo
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#version 330 core
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// Change AA to 1 if it renders too slow for you
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#define AA 1
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uniform vec2 uResolution;
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uniform float uTime; // shader playback time (in seconds)
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uniform vec4 uMouse;
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// there is tearing on my box. is this because this isn't working? -- jcarr
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uniform int iFrame; // shader playback frame
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out vec4 fragColor;
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// in vec2 fragCoord;
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mat3 makeBase( in vec3 w )
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{
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float k = inversesqrt(1.0-w.y*w.y);
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return mat3( vec3(-w.z,0.0,w.x)*k,
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vec3(-w.x*w.y,1.0-w.y*w.y,-w.y*w.z)*k,
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w);
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}
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#define ZERO (min(iFrame,0))
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// http://iquilezles.org/www/articles/intersectors/intersectors.htm
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vec2 sphIntersect( in vec3 ro, in vec3 rd, in float rad )
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{
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float b = dot( ro, rd );
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float c = dot( ro, ro ) - rad*rad;
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float h = b*b - c;
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if( h<0.0 ) return vec2(-1.0);
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h = sqrt(h);
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return vec2(-b-h,-b+h);
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}
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// http://iquilezles.org/www/articles/distfunctions/distfunctions.htm
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float sdCapsule( in vec3 p, in float b, in float r )
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{
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float h = clamp( p.z/b, 0.0, 1.0 );
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return length( p - vec3(0.0,0.0,b)*h ) - r;//*(0.2+1.6*h);
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}
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// modified Keinert et al's inverse Spherical Fibonacci Mapping
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vec4 inverseSF( in vec3 p, const in float n )
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{
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const float PI = 3.14159265359;
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const float PHI = 1.61803398875;
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float phi = min(atan(p.y,p.x),PI);
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float k = max(floor(log(n*PI*sqrt(5.0)*(1.-p.z*p.z))/log(PHI+1.)),2.0);
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float Fk = pow(PHI,k)/sqrt(5.0);
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vec2 F = vec2(round(Fk),round(Fk*PHI));
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vec2 G = PI*(fract((F+1.0)*PHI)-(PHI-1.0));
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mat2 iB = mat2(F.y,-F.x,G.y,-G.x)/(F.y*G.x-F.x*G.y);
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vec2 c = floor(iB*0.5*vec2(phi,n*p.z-n+1.0));
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float ma = 0.0;
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vec4 res = vec4(0);
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for( int s=0; s<4; s++ )
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{
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vec2 uv = vec2(s&1,s>>1);
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float i = dot(F,uv+c);
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float phi = 2.0*PI*fract(i*PHI);
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float cT = 1.0 - (2.0*i+1.0)/n;
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float sT = sqrt(1.0-cT*cT);
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vec3 q = vec3(cos(phi)*sT, sin(phi)*sT,cT);
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float a = dot(p,q);
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if (a > ma)
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{
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ma = a;
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res.xyz = q;
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res.w = i;
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}
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}
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return res;
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}
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float map( in vec3 p, out vec4 color, const in bool doColor )
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{
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float lp = length(p);
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float dmin = lp-1.0;
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{
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vec3 w = p/lp;
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vec4 fibo = inverseSF(w, 700.0);
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float hh = 1.0 - smoothstep(0.05,0.1,length(fibo.xyz-w));
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dmin -= 0.07*hh;
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color = vec4(0.05,0.1,0.1,1.0)*hh * (1.0+0.5*sin(fibo.w*111.1));
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}
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float s = 1.0;
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for( int i=0; i<3; i++ )
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{
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float h = float(i)/float(3-1);
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vec4 f = inverseSF(normalize(p), 65.0 + h*75.0);
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// snap
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p -= f.xyz;
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// orient to surface
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p = p*makeBase(f.xyz);
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// scale
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float scale = 6.6 + 2.0*sin(111.0*f.w);
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p *= scale;
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p.xy *= 1.2;
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//translate
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p.z -= 3.0 - length(p.xy)*0.6*sin(f.w*212.1);
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// measure distance
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s *= scale;
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float d = sdCapsule( p, -6.0, 0.42 );
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d /= s;
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if( d<dmin )
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{
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if( doColor )
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{
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color.w *= smoothstep(0.0, 5.0/s, dmin-d);
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if( i==0 )
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{
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color.xyz = vec3(0.425,0.36,0.1)*1.1; // fall
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//color.xyz = vec3(0.4,0.8,0.1); // summer
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//color.xyz = vec3(0.4,0.4,0.8); // winter
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}
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color.zyx += 0.3*(1.0-sqrt(h))*sin(f.w*1111.0+vec3(0.0,1.0,2.0));
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color.xyz = max(color.xyz,0.0);
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}
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dmin = d;
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}
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else
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{
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color.w *= 0.4*(0.1 + 0.9*smoothstep(0.0, 1.0/s, d-dmin));
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}
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}
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return dmin;
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}
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// http://iquilezles.org/www/articles/normalsSDF/normalsSDF.htm
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vec3 calcNormal( in vec3 pos, in float ep )
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{
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vec4 kk;
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#if 0
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vec2 e = vec2(1.0,-1.0)*0.5773;
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return normalize( e.xyy*map( pos + e.xyy*ep, kk, false ) +
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e.yyx*map( pos + e.yyx*ep, kk, false ) +
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e.yxy*map( pos + e.yxy*ep, kk, false ) +
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e.xxx*map( pos + e.xxx*ep, kk, false ) );
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#else
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// prevent the compiler from inlining map() 4 times
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vec3 n = vec3(0.0);
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for( int i=ZERO; i<4; i++ )
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{
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vec3 e = 0.5773*(2.0*vec3((((i+3)>>1)&1),((i>>1)&1),(i&1))-1.0);
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n += e*map(pos+e*ep, kk, false);
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}
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return normalize(n);
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#endif
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}
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// http://iquilezles.org/www/articles/rmshadows/rmshadows.htm
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float calcSoftshadow( in vec3 ro, in vec3 rd, float tmin, float tmax, const float k )
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{
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vec2 bound = sphIntersect( ro, rd, 2.1 );
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tmin = max(tmin,bound.x);
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tmax = min(tmax,bound.y);
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float res = 1.0;
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float t = tmin;
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for( int i=0; i<50; i++ )
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{
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vec4 kk;
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float h = map( ro + rd*t, kk, false );
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res = min( res, k*h/t );
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t += clamp( h, 0.02, 0.20 );
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if( res<0.005 || t>tmax ) break;
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}
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return clamp( res, 0.0, 1.0 );
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}
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float raycast(in vec3 ro, in vec3 rd, in float tmin, in float tmax )
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{
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vec4 kk;
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float t = tmin;
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for( int i=0; i<512; i++ )
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{
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vec3 p = ro + t*rd;
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float h = map(p,kk,false);
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if( abs(h)<(0.15*t/uResolution.x) ) break;
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t += h*0.5;
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if( t>tmax ) return -1.0;;
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}
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//if( t>tmax ) t=-1.0;
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return t;
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}
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// void mainImage( out vec4 fragColor, in vec2 fragCoord )
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// gl_FragCoord.xy
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void main()
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{
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float an = (uTime-10.0)*0.05;
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// camera
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vec3 ro = vec3( 4.5*sin(an), 0.0, 4.5*cos(an) );
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vec3 ta = vec3( 0.0, 0.0, 0.0 );
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// camera-to-world rotation
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mat3 ca = makeBase( normalize(ta-ro) );
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// render
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vec3 tot = vec3(0.0);
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#if AA>1
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for( int m=ZERO; m<AA; m++ )
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for( int n=ZERO; n<AA; n++ )
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{
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// pixel coordinates
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vec2 o = vec2(float(m),float(n)) / float(AA) - 0.5;
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vec2 p = (-uResolution.xy + 2.0*(gl_FragCoord.xy+o))/uResolution.y;
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#else
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vec2 p = (-uResolution.xy + 2.0*gl_FragCoord.xy)/uResolution.y;
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#endif
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// ray direction
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vec3 rd = ca * normalize( vec3(p.xy,2.2) );
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// background
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vec3 col = vec3(0.1,0.14,0.18) + 0.1*rd.y;
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// bounding volume
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vec2 bound = sphIntersect( ro, rd, 2.1 );
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if( bound.x>0.0 )
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{
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// raycast
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float t = raycast(ro, rd, bound.x, bound.y );
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if( t>0.0 )
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{
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// local geometry
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vec3 pos = ro + t*rd;
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vec3 nor = calcNormal(pos, 0.01);
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vec3 upp = normalize(pos);
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// color and occlusion
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vec4 mate; map(pos, mate, true);
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// lighting
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col = vec3(0.0);
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// key ligh
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{
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// dif
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vec3 lig = normalize(vec3(1.0,0.0,0.7));
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float dif = clamp(0.5+0.5*dot(nor,lig),0.0,1.0);
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float sha = calcSoftshadow( pos+0.0001*nor, lig, 0.0001, 2.0, 6.0 );
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col += mate.xyz*dif*vec3(1.8,0.6,0.5)*1.1*vec3(sha,sha*0.3+0.7*sha*sha,sha*sha);
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// spec
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vec3 hal = normalize(lig-rd);
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float spe = clamp( dot(nor,hal), 0.0, 1.0 );
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float fre = clamp( dot(-rd,lig), 0.0, 1.0 );
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fre = 0.2 + 0.8*pow(fre,5.0);
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spe *= spe;
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spe *= spe;
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spe *= spe;
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col += 1.0*(0.25+0.75*mate.x)*spe*dif*sha*fre;
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}
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// back light
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{
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vec3 lig = normalize(vec3(-1.0,0.0,0.0));
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float dif = clamp(0.5+0.5*dot(nor,lig),0.0,1.0);
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col += mate.rgb*dif*vec3(1.2,0.9,0.6)*0.2*mate.w;
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}
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// dome light
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{
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float dif = clamp(0.3+0.7*dot(nor,upp),0.0,1.0);
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#if 0
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dif *= 0.05 + 0.95*calcSoftshadow( pos+0.0001*nor, upp, 0.0001, 1.0, 1.0 );
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col += mate.xyz*dif*5.0*vec3(0.1,0.1,0.3)*mate.w;
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#else
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col += mate.xyz*dif*3.0*vec3(0.1,0.1,0.3)*mate.w*(0.2+0.8*mate.w);
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#endif
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}
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// fake sss
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{
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float fre = clamp(1.0+dot(rd,nor),0.0,1.0);
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col += 0.3*vec3(1.0,0.3,0.2)*mate.xyz*mate.xyz*fre*fre*mate.w;
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}
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// grade/sss
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{
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col = 2.0*pow( col, vec3(0.7,0.85,1.0) );
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}
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// exposure control
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col *= 0.7 + 0.3*smoothstep(0.0,25.0,abs(uTime-31.0));
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// display fake occlusion
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//col = mate.www;
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}
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}
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// gamma
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col = pow( col, vec3(0.4545) );
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tot += col;
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#if AA>1
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}
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tot /= float(AA*AA);
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#endif
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// vignetting
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vec2 q = gl_FragCoord.xy/uResolution.xy;
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tot *= pow( 16.0*q.x*q.y*(1.0-q.x)*(1.0-q.y), 0.2 );
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fragColor = vec4( tot, 1.0 );
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}
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