135 lines
2.8 KiB
GLSL
135 lines
2.8 KiB
GLSL
/*
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* License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
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* Created by bal-khan
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*/
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vec2 march(vec3 pos, vec3 dir);
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vec3 camera(vec2 uv);
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void rotate(inout vec2 v, float angle);
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vec3 calcNormal( in vec3 pos, float e, vec3 dir);
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float loop_circle(vec3 p);
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float circle(vec3 p, float phase);
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float sdTorus( vec3 p, vec2 t, float phase );
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float mylength(vec2 p);
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float nrand( vec2 n );
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float t; // time
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vec3 ret_col; // torus color
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vec3 h; // light amount
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#define I_MAX 200.
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#define E 0.00001
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#define FAR 15.
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#define PI 3.14
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void mainImage(out vec4 c_out, in vec2 f)
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{
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t = iTime*.125;
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vec3 col = vec3(0., 0., 0.);
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vec2 R = iResolution.xy,
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uv = vec2(f-R/2.) / R.x;
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vec3 dir = camera(uv);
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vec3 pos = vec3(.0, .0, 0.0);
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pos.z = 4.5+1.5*sin(t*10.);
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h*=0.;
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vec2 inter = (march(pos, dir));
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if (inter.y <= FAR)
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col.xyz = ret_col*(1.-inter.x*.0025);
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else
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col *= 0.;
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col += h*.005125;
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c_out = vec4(col,1.0);
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}
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float scene(vec3 p)
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{
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float var;
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float mind = 1e5;
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p.z += 2.;
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rotate(p.xz, 1.57-.5*iTime);
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rotate(p.yz, 1.57-.5*iTime);
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vec2 q = vec2(mix(mylength(p.xy), length(p.xy), abs(sin(iTime)) )-2.,p.z);
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var = atan(p.x,p.y);
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rotate(q, var+iTime*2.);
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q = abs(q)-.5;
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rotate(q, var*-3.+iTime*2.);
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var = cos(floor(var*6.)*.5+iTime*3. );
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ret_col = 1.-vec3(.5-var*.5, .5, .3+var*.5);
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mind = mylength(q)-.125-.1*var;
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h += vec3(.5,.8,.5)*(var!=0.?0.:1.)*vec3(1.)*.0125/(.01+(mind-var*.1)*(mind-var*.1) );
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h += vec3(.5,.8,.5)*(var!=0.?1.:0.)*vec3(1.)*.0125/(.01+mind*mind);
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return (mind);
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}
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vec2 march(vec3 pos, vec3 dir)
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{
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vec2 dist = vec2(0.0, 0.0);
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vec3 p = vec3(0.0, 0.0, 0.0);
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vec2 s = vec2(0.0, 0.0);
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for (float i = -1.; i < I_MAX; ++i)
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{
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p = pos + dir * dist.y;
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dist.x = scene(p);
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dist.y += dist.x*.2; // makes artefacts disappear
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if (dist.x < E || dist.y > FAR)
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{
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break;
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}
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s.x++;
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}
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s.y = dist.y;
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return (s);
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}
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float mylength(vec2 p)
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{
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float ret;
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p = p*p*p*p;
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p = p*p;
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ret = (p.x+p.y);
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ret = pow(ret, 1./8.);
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return ret;
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}
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// Utilities
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void rotate(inout vec2 v, float angle)
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{
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v = vec2(cos(angle)*v.x+sin(angle)*v.y,-sin(angle)*v.x+cos(angle)*v.y);
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}
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vec2 rot(vec2 p, vec2 ang)
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{
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float c = cos(ang.x);
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float s = sin(ang.y);
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mat2 m = mat2(c, -s, s, c);
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return (p * m);
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}
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vec3 camera(vec2 uv)
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{
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float fov = 1.;
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vec3 forw = vec3(0.0, 0.0, -1.0);
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vec3 right = vec3(1.0, 0.0, 0.0);
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vec3 up = vec3(0.0, 1.0, 0.0);
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return (normalize((uv.x) * right + (uv.y) * up + fov * forw));
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}
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vec3 calcNormal( in vec3 pos, float e, vec3 dir)
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{
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vec3 eps = vec3(e,0.0,0.0);
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return normalize(vec3(
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march(pos+eps.xyy, dir).y - march(pos-eps.xyy, dir).y,
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march(pos+eps.yxy, dir).y - march(pos-eps.yxy, dir).y,
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march(pos+eps.yyx, dir).y - march(pos-eps.yyx, dir).y ));
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}
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// https://www.shadertoy.com/view/4lXBWj
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