107 lines
2.4 KiB
Forth
107 lines
2.4 KiB
Forth
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// cube02_0.jpg
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// License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
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// Created by S. Guillitte 2015
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float zoom=1.;
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vec2 cmul( vec2 a, vec2 b ) { return vec2( a.x*b.x - a.y*b.y, a.x*b.y + a.y*b.x ); }
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vec2 csqr( vec2 a ) { return vec2( a.x*a.x - a.y*a.y, 2.*a.x*a.y ); }
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mat2 rot(float a) {
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return mat2(cos(a),sin(a),-sin(a),cos(a));
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}
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vec2 iSphere( in vec3 ro, in vec3 rd, in vec4 sph )//from iq
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{
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vec3 oc = ro - sph.xyz;
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float b = dot( oc, rd );
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float c = dot( oc, oc ) - sph.w*sph.w;
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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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float map(in vec3 p) {
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float res = 0.;
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vec3 c = p;
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for (int i = 0; i < 10; ++i) {
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p =.7*abs(p)/dot(p,p) -.7;
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p.yz= csqr(p.yz);
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p=p.zxy;
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res += exp(-19. * abs(dot(p,c)));
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}
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return res/2.;
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}
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vec3 raymarch( in vec3 ro, vec3 rd, vec2 tminmax )
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{
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float t = tminmax.x;
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float dt = .02;
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//float dt = .2 - .195*cos(iGlobalTime*.05);//animated
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vec3 col= vec3(0.);
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float c = 0.;
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for( int i=0; i<64; i++ )
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{
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t+=dt*exp(-2.*c);
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if(t>tminmax.y)break;
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vec3 pos = ro+t*rd;
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c = map(ro+t*rd);
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col = .99*col+ .08*vec3(c*c, c, c*c*c);//green
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//col = .99*col+ .08*vec3(c*c*c, c*c, c);//blue
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}
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return col;
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}
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void mainImage( out vec4 fragColor, in vec2 fragCoord )
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{
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float time = iGlobalTime;
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vec2 q = fragCoord.xy / iResolution.xy;
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vec2 p = -1.0 + 2.0 * q;
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p.x *= iResolution.x/iResolution.y;
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vec2 m = vec2(0.);
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if( iMouse.z>0.0 )m = iMouse.xy/iResolution.xy*3.14;
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m-=.5;
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// camera
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vec3 ro = zoom*vec3(4.);
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ro.yz*=rot(m.y);
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ro.xz*=rot(m.x+ 0.1*time);
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vec3 ta = vec3( 0.0 , 0.0, 0.0 );
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vec3 ww = normalize( ta - ro );
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vec3 uu = normalize( cross(ww,vec3(0.0,1.0,0.0) ) );
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vec3 vv = normalize( cross(uu,ww));
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vec3 rd = normalize( p.x*uu + p.y*vv + 4.0*ww );
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vec2 tmm = iSphere( ro, rd, vec4(0.,0.,0.,2.) );
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// raymarch
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vec3 col = raymarch(ro,rd,tmm);
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if (tmm.x<0.)col = texture(iChannel0, rd.rg).rgb;
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else {
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vec3 nor=(ro+tmm.x*rd)/2.;
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nor = reflect(rd, nor);
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float fre = pow(.5+ clamp(dot(nor,rd),0.0,1.0), 3. )*1.3;
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col += texture(iChannel0, nor.rg).rgb * fre;
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}
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// shade
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col = .5 *(log(1.+col));
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col = clamp(col,0.,1.);
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fragColor = vec4( col, 1.0 );
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}
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