1 uniform lowp vec4 uColor;
2 varying lowp vec2 vCoefficient;
6 lowp float C = (vCoefficient.x*vCoefficient.x-vCoefficient.y);
7 lowp float Cdx = dFdx(C);
8 lowp float Cdy = dFdy(C);
10 lowp float distance = float(C / sqrt(Cdx*Cdx + Cdy*Cdy));
11 lowp float alpha = 0.5 - distance;
12 gl_FragColor = vec4( uColor.rgb, uColor.a * alpha );