The result will be NaN, if dx1===0 (GetLineToLine.js)

[finscn]

https://github.com/photonstorm/phaser/blob/c5d53f9e94928746770176ea1db3d29b495b9b05/src/geom/intersects/GetLineToLine.js#L66

if (x3 + dx2 * t - x1)===0 and dx1 === 0, u & s will be NaN. then the out.x & out.y will be NaN