47 lines
1.1 KiB
GLSL
47 lines
1.1 KiB
GLSL
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#version 440
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layout( location = 0 ) in vec2 coord;
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layout( location = 0 ) out vec4 fragColor;
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layout( std140, binding = 0 ) uniform buf
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{
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mat4 matrix;
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vec4 color;
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/*
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arc.xy: cos/sin of the angle of the midpoint
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arc.zw: cos/sin of the angle between midpoint/endpoint
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*/
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vec4 arc;
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float spreadRadius;
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float blurRadius;
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float opacity;
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} ubuf;
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mat2 rotation( vec2 v ) { return mat2( v.x, -v.y, v.y, v.x ); }
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void main()
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{
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float radius = 0.5 - ubuf.blurRadius - ubuf.spreadRadius;
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float dist = abs( length( coord ) - radius ) - ubuf.spreadRadius;
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if ( ( ubuf.arc.z ) < 1.0 && ( dist < 1.0 ) )
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{
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vec2 v = coord * rotation( ubuf.arc.xy ); // x-axial symmetric
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v.y = abs( v.y );
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v *= rotation ( ubuf.arc.wz ); // end point to 90°
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if ( v.x < 0.0 )
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{
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v.y = max( 0.0, abs( v.y - radius ) - ubuf.spreadRadius );
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dist = max( dist, length( v ) );
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}
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}
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float a = 1.0 - smoothstep( 0.0, ubuf.blurRadius, dist );
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fragColor = ubuf.color * a * ubuf.opacity;
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}
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