Lucas de Vries
37 lines
779 B
Plaintext
37 lines
779 B
Plaintext
#define pi 3.141592653589793238462643383279
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#define twopi (pi * 2.0)
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uniform float minRad;
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uniform float maxRad;
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varying vec2 rcoords;
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void main() {
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float r = length(rcoords);
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float width = 0.7;
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if(r >= 1.0 || r < 1.0 - width)
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discard;
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float ang = atan(rcoords.y, rcoords.x);
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if(ang < minRad && ang > maxRad - twopi)
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discard;
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if(ang > maxRad && ang < minRad + twopi)
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discard;
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float bdist = r - (1.0 - width);
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vec4 col = gl_Color;
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if(r < 0.95)
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col.a *= 0.5;
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else if(r < 0.96)
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col.a *= 0.5 + ((r - 0.95) / 0.01) * 0.5;
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else if(r > 0.99)
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col.a *= (1.0 - r) / 0.01;
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col.a *= bdist / width;
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float adist = min(abs(ang - minRad), abs(ang - maxRad));
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if(adist < 0.02)
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col.a *= adist / 0.02;
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gl_FragColor = col;
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}
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