Re: [AD] clipping off-by-1

[Peter Wang <novalazy@xxxxxxxxxx>]

On 2008-08-20, Elias Pschernig <elias@xxxxxxxxxx> wrote:
> I just fixed an off-by-1 problem in the clipping code. It had this in
> al_set_clipping_rectangle:
> 
> bitmap->cl = x;
> bitmap->cr = x + width;
> 
> but this in al_get_clipping_rectangle:
> 
> if (w) *w = bitmap->cr - bitmap->cl + 1;
> 
> The first one was assuming semantics where cr is the actual position of
> the clipping edge. The second was assuming that it is one less. The
> OpenGL implementation also was assuming the one-less semantics.
> 
> So, without any idea what the original implementator (likely myself)
> wanted, I now fixed it to never use the one-less semantics, as I think
> it's less obvious for the floating-point coordinates we use for all
> blitting and drawing primitives. Depending on what other implementations
> besides OpenGL assumed, they may need to be updated as well.

exnew_drawpixels.c doesn't show the bottom right pixel anymore,
at least for me.  Is this related?

Peter