kopia lustrzana https://github.com/m1el/woscope
39 wiersze
1.2 KiB
Plaintext
39 wiersze
1.2 KiB
Plaintext
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precision highp float;
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#define EPS 1E-6
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#define TAU 6.283185307179586
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#define TAUR 2.5066282746310002
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#define SQRT2 1.4142135623730951
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uniform float uSize;
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uniform float uIntensity;
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precision highp float;
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varying vec4 uvl;
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float gaussian(float x, float sigma) {
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return exp(-(x * x) / (2.0 * sigma * sigma)) / (TAUR * sigma);
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}
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float erf(float x) {
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float s = sign(x), a = abs(x);
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x = 1.0 + (0.278393 + (0.230389 + (0.000972 + 0.078108 * a) * a) * a) * a;
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x *= x;
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return s - s / (x * x);
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}
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void main (void)
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{
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float len = uvl.z;
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vec2 xy = vec2((len/2.0+uSize)*uvl.x+len/2.0, uSize*uvl.y);
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float alpha;
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float sigma = uSize/4.0;
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if (len < EPS) {
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// If the beam segment is too short, just calculate intensity at the position.
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alpha = exp(-pow(length(xy),2.0)/(2.0*sigma*sigma))/2.0/sqrt(uSize);
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} else {
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// Otherwise, use analytical integral for accumulated intensity.
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alpha = erf((len-xy.x)/SQRT2/sigma) + erf(xy.x/SQRT2/sigma);
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alpha *= exp(-xy.y*xy.y/(2.0*sigma*sigma))/2.0/len*uSize;
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}
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float afterglow = smoothstep(0.0, 0.33, uvl.w/2048.0);
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alpha *= afterglow * uIntensity;
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gl_FragColor = vec4(1./32., 1.0, 1./32., alpha);
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}
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