Or just base your math on the simple idea that your map is a rectangular grid rotated by 45° and 60°, transform your mouse coordinates accordingly and you should get the same result
Wouldn't this actually be more complicated? I would need to create regular greed and rotate it 45 degrees, and than additionally transform mouse coordinates. Seems interesting but I am not quite sure how I would handle data in this case. Would I save out all data as if it was square greed and transform it on run-time?