Re: [AD] clipping line algorithm

[Robert Jr Ohannessian <rohannessian@xxxxxxxxxx>]

Eric Botcazou wrote:
[snip]
> > And rotate.c, gsprite.c and c/cstretch.c need modifications to take care
> > of case (3).

Can we use parallelogram_map / stretch_* outside of the vtable? If not, 
then this is not really needed as the driver's vtable can implement 
rotation and scaling however it wants; AllegroGL can work comfortably 
this way.



> > It is of course invalid for a bitmap to have both BMP_ID_PLANAR and
> > BMP_ID_NONLINEAR_NONPLANAR flags set at the same time. Only add-ons like
> > AllegroGL need to set the BMP_ID_NONLINEAR_NONPLANAR flag.
> >
> > I think that with this fix, any piece of code that currently assumes no
> > bitmaps are of type (3) will still work fine with type (1) and (2)
> > bitmaps. We can easily fix Allegro to allow case (3). Also, this
> > solution does not imply any problems with flags saved on disk. What do
> > you think?
>
>
> I think this is interesting and could be worth implementing, but I'd like to 
> hear from Bob before. One minor nit: the name of the flag is ugly :-)

> So, basically, if this new flag is not set, the library would be allowed to 
> bypass entirely the vtable of the bitmap? I'm still a bit uncomfortable with 
> this idea.

I don't like the idea of bypassing the vtable. If we can, we should have 
a putpixel and _putpixel vtable entry. This should solve most of the 
issues. By default, _putpixel() can be aliased to putpixel() if the 
implementation doesn't (or can't) accelerate the case of non-clipped 
putpixels.


--
- Robert Jr Ohannessian
http://bob.allegronetwork.com/