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39 lines
887 B
GLSL
39 lines
887 B
GLSL
10 years ago
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#ifdef GL_ES
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precision mediump float;
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#endif
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uniform vec2 u_resolution;
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uniform float u_time;
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float line( vec2 _st,
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vec2 _p1, vec2 _p2,
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float _width, float _spread){
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_width = 1.0 / _width;
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vec2 p2p1 = _p1 - _p2;
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vec2 p1p2 = -(p2p1);
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vec2 p2p = _st - _p2;
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vec2 p1p = _st - _p1;
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vec2 pp1 = -(p1p);
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vec2 pd = normalize(vec2(p2p1.y, -p2p1.x));
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float proj = dot(pd, pp1);
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float pr1 = dot(p2p1, p2p);
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float pr2 = dot(p1p2, p1p);
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if(pr1 > 0.0 && pr2 > 0.0) {
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return pow(1.0 / abs(proj * _width), _spread);
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} else {
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return 0.0;
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}
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}
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void main(){
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vec2 st = gl_FragCoord.xy/u_resolution.xy;
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vec3 color = vec3( line(st,
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vec2(0.1),
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vec2(0.9),
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0.005, 3.0) );
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gl_FragColor = vec4(color,1.0);
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}
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