Re: SV: Re: [pygame] Pixel perfect collision detection sugestion

[Bob the Hamster <Bob-pygame-users@xxxxxxxxxxxxxxxxxxx>]

On Fri, Sep 09, 2005 at 09:29:21AM +0100, John Eriksson wrote:
> Njaeee...
> 
> > "...probably also be faster than the rect-based one we have now..."
> 
> Theoretically circle algorithms are always more expensive than the
> rectangular ones (if you dont start to rotate the rectangles *smile*).
> 
> In real life though...the theoritical trade off can be ignored. ;-)
> 
> /John

Normally circle algorithms are slow, but colision detection between 
circles needs not be. Because you only care about collision, and not 
specific distance, you can skip the square-root step of the pythagoran 
theorum, making it hella faster. Circle collision is every bit as simple 
and fast as rectangle collision.

---
Bob the Hamster