36 lines
791 B
Plaintext
36 lines
791 B
Plaintext
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layout (location = 0) uniform float u_alpha;
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in vec2 v_uv;
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out vec4 o_color;
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float atan2(in vec2 p){
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return p.x == 0. ? sign(p.y)*PI/2. : atan(p.y, p.x);
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}
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float map(in vec2 p, in float t) {
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if (p.x >= 2.) return 0.;
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vec2 v = vec2(.3, .4 + t*.3);
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for (float i = 0.; i < 10.; ++i) {
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p = abs(p) - v;
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v /= dot(p, p);
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}
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return abs(p.x);
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}
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void main(void) {
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vec2 uv = v_uv * uni.resolution.xy / (4.*uni.dpi);
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vec2 polar = vec2(length(uv), atan2(uv));
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polar.y = abs(mod(polar.y, PI/3.) - PI/6.);
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vec2 p = vec2(cos(polar.y), sin(polar.y))*polar.x;
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o_color = vec4(0, 0, 0, .7*u_alpha);
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float t = 1.-pow(1.-u_alpha, 8.);
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float fractal = step(100.-t*100.+3., map(p*1.8, t)) * polar.x;
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o_color = mix(o_color, vec4(.4, .2, .2, .1), fractal);
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}
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