Hi,

I have a main object, and multiple smaller objects scrolling across the screen. Every frame, the smaller objects check to see if they have collided with the main object.

My question is: Which is the the less expensive way to do this? Firstly, To use dist() to check the distance is less than the two objects radius combined. Or secondly, with a bounding box and check the usual way you would with a button, so: beyond and below top left corner, but above and before bottom left corner of a rectangle.

Or perhaps there is another better way that I have yet to think of?

As a side note i'd also very much like to know how I can work something like this out for myself without having to trouble you all, profiling? common sense? 

Thanks in advance for your help.

Dave