43 lines
1011 B
GLSL
43 lines
1011 B
GLSL
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uniform lowp float opacity;
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uniform lowp float blurExtent;
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uniform lowp vec4 radius;
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uniform lowp vec4 color;
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uniform lowp vec2 aspect;
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varying lowp vec2 coord;
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lowp float effectiveRadius( in lowp vec4 radii, in lowp vec2 point )
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{
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if ( point.x > 0.0 )
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return ( point.y > 0.0) ? radii.x : radii.y;
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else
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return ( point.y > 0.0) ? radii.z : radii.w;
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}
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void main()
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{
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lowp vec4 col = vec4(0.0);
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if ( opacity > 0.0 )
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{
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const lowp float minRadius = 0.05;
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lowp float e2 = 0.5 * blurExtent;
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lowp float r = 2.0 * effectiveRadius( radius, coord );
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lowp float f = minRadius / max( r, minRadius );
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r += e2 * f;
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lowp vec2 d = r + blurExtent - aspect * ( 1.0 - abs( 2.0 * coord ) );
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lowp float l = min( max(d.x, d.y), 0.0) + length( max(d, 0.0) );
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lowp float shadow = l - r;
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lowp float v = smoothstep( -e2, e2, shadow );
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col = mix( color, vec4(0.0), v ) * opacity;
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}
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gl_FragColor = col;
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}
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