+ if(abs(vPosition.x) < vOptRectSize.x && abs(vPosition.y) < vOptRectSize.y)
+ {
+ return;
+ }
+ mediump float radius =
+ mix(
+ mix(vCornerRadius.x, vCornerRadius.y, sign(vPosition.x) * 0.5 + 0.5),
+ mix(vCornerRadius.w, vCornerRadius.z, sign(vPosition.x) * 0.5 + 0.5),
+ sign(vPosition.y) * 0.5 + 0.5
+ );
+
+ mediump vec2 diff = abs(vPosition) - vRectSize + radius;
+ mediump float dist = length(max(diff, vec2(0.0))) - radius;
+ if(dist > 1.0)
+ {
+ gl_FragColor = vec4(0.0);
+ }
+ else if(dist > -1.0)
+ {
+ if(min(diff.x, diff.y) < 0.0)
+ {
+ dist += min(diff.x, diff.y) / max(radius, 1.0);
+ }
+ gl_FragColor *= 1.0 - smoothstep(-1.0, 1.0, dist);
+ }