precision highp float; uniform vec2 resolution; uniform float time; uniform sampler2D backbuffer; const float PI=acos(-1.); // reading evvvvils raymarching shader from // Revision 2019, Shader Showdown //https://www.youtube.com/watch?v=YKtvYAn-v2Y float tt,b,bb,bs,f,g; float bo(vec3 p,vec3 r){p=abs(p)-r;return max(max(p.x,p.y),p.z);} vec2 rot(vec2 p,float a){return vec2(p.x*cos(a)-p.y*sin(a),p.x*sin(a)+p.y*cos(a));} vec3 mod289(vec3 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; } vec2 mod289(vec2 x) { return x - floor(x * (1.0 / 289.0)) * 289.0; } vec3 permute(vec3 x) { return mod289(((x*34.0) + 1.0)*x); } float snoise(vec2 v) { const vec4 C = vec4(0.211324865405187, 0.366025403784439, -0.577350269189626, 0.024390243902439); vec2 i = floor(v + dot(v, C.yy)); vec2 x0 = v - i + dot(i, C.xx); // Other two corners (x1, x2) vec2 i1 = vec2(0.0,0.0); i1 = (x0.x > x0.y) ? vec2(1.0, 0.0) : vec2(0.0, 1.0); vec2 x1 = x0.xy + C.xx - i1; vec2 x2 = x0.xy + C.zz; i = mod289(i); vec3 p = permute( permute(i.y + vec3(0.0, i1.y, 1.0)) + i.x + vec3(0.0, i1.x, 1.0)); vec3 m = max(0.5 - vec3( dot(x0, x0), dot(x1, x1), dot(x2, x2) ), 0.0); m = m * m; m = m * m; vec3 x = 2.0 * fract(p * C.www) - 1.0; vec3 h = abs(x) - 0.5; vec3 ox = floor(x + 0.5); vec3 a0 = x - ox; m *= 1.79284291400159 - 0.85373472095314 * (a0*a0 + h * h); vec3 g = vec3(.0); g.x = a0.x * x0.x + h.x * x0.y; g.yz = a0.yz * vec2(x1.x, x2.x) + h.yz * vec2(x1.y, x2.y); return 130.0 * dot(m, g); } float aastep(float threshold, float value) { return step(threshold, value); } vec3 halftone(vec3 texcolor, vec2 st, float frequency) { float n = 0.1*snoise(st*200.0); // Fractal noise n += 0.05*snoise(st*400.0); n += 0.025*snoise(st*800.0); vec3 white = vec3(n*0.2 + 0.97); vec3 black = vec3(n + 0.1); // Perform a rough RGB-to-CMYK conversion vec4 cmyk; cmyk.xyz = 1.0 - texcolor; cmyk.w = min(cmyk.x, min(cmyk.y, cmyk.z)); // Create K cmyk.xyz -= cmyk.w; // Subtract K equivalent from CMY // Distance to nearest point in a grid of // (frequency x frequency) points over the unit square vec2 Kst = frequency*mat2(0.707, -0.707, 0.707, 0.707)*st; vec2 Kuv = 2.0*fract(Kst)-1.0; float k = aastep(0.0, sqrt(cmyk.w)-length(Kuv)+n); vec2 Cst = frequency*mat2(0.966, -0.259, 0.259, 0.966)*st; vec2 Cuv = 2.0*fract(Cst)-1.0; float c = aastep(0.0, sqrt(cmyk.x)-length(Cuv)+n); vec2 Mst = frequency*mat2(0.966, 0.259, -0.259, 0.966)*st; vec2 Muv = 2.0*fract(Mst)-1.0; float m = aastep(0.0, sqrt(cmyk.y)-length(Muv)+n); vec2 Yst = frequency*st; // 0 deg vec2 Yuv = 2.0*fract(Yst)-1.0; float y = aastep(0.0, sqrt(cmyk.z)-length(Yuv)+n); vec3 rgbscreen = 1.0 - 0.9*vec3(c,m,y) + n; return mix(rgbscreen, black, 0.85*k + 0.3*n); } vec2 fb(vec3 p){ vec2 t=vec2(bo(abs(p)-vec3(2,0,0),vec3(.6,8,.5)),3); vec2 h=vec2(bo(abs(p)-vec3(2,0,0),vec3(.4,8,.7)),5); t=t.x90.){t.x=0.;break;} t.x+=h.x;t.y=h.y; ray+=h.x*rd; j=i; } float dif=.5+.5*max(dot(N,L),.0); if(c<6.){ col=vec3(.25,.75,.5); col*=dif; }else{ col=vec3(.75,.25,.5); col*=dif; } col=mix(col,fo,1.-exp(-.000005*t.x*t.x*t.x)); col+=.0625*g; col+=float(j)/4096.; vec3 htcol = halftone(col,bp,48.); col=mix(col,htcol,ease_in_out_circ(abs(fract(time))-.5)); gl_FragColor = vec4(pow(col,vec3(.4545)),1.); }