src/pixi/utils/Polyk.js
function convex(ax, ay, bx, by, cx, cy, sign)
{
    return ((ay-by)*(cx-bx) + (bx-ax)*(cy-by) >= 0) === sign;
}
function convex(ax, ay, bx, by, cx, cy, sign)
{
    return ((ay-by)*(cx-bx) + (bx-ax)*(cy-by) >= 0) === sign;
}
function convex ( ax , ay , bx , by , cx , cy , sign ) { return ( ( ay - by ) * ( cx - bx ) + ( bx - ax ) * ( cy - by ) >= 0 ) === sign ; }
Checks if a shape is convex

@private
Checks if a shape is convex