On 6/20/06, Luke Crook <[EMAIL PROTECTED]> wrote:
> Frank Buss <[EMAIL PROTECTED]> writes:
>
> >
> > Jeff Caldwell wrote:
> >
> > > I'm just wondering why it's worthwhile to lose the
> > > type information on points and colors, replacing them with
> > > arrays?
> >
> > It is easier to create it and to pass it to functions than with the SDL
> > low-level structs, because you have to remember when to delete it. And since
> > they are some kind of "value" objects (like a number or a string), this is
> > difficult when passing it around to other functions. The Lisp GC does a
> > better job for this kind of things
>
> To add to this, passing rectangles and colors as Vectors may actually provide
> increased performance. CFFI calls are quite expensive, so performing four CFFI
> calls to read the X, Y, W, H from the SDL_rect, performing a calculation (e.g.
> a move) and then performing another four CFFI calls to write these values back
> to the SDL _rect is more expensive than performing all calculations on a Lisp
> Vector and then converting the Vector to an SDL_rect at the end of the
> 'pipeline'.
>
>
> - Luke
>
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I had some problems with bugs with passing what I thought were
integers to the raw cffi calls, when in fact they were ratios or
floats. I think you're changes will help that kind of thing?

Justin
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