Re: [AD] update bitmap drawing after addition of transformations

[Peter Wang <novalazy@xxxxxxxxxx>]

On 2010-08-14, Elias Pschernig <elias.pschernig@xxxxxxxxxx> wrote:
> On Sat, 2010-08-14 at 10:25 +1000, Peter Wang wrote:
> > I found a couple of problems (didn't try to debug them)
> > 
> > * run ex_subbitmap, 's' for scaling mode
> >   When the source subbitmap is outside the parent bitmap there is
> >   garbage drawn to the destination, and/or an assertion failure.
> > 
> > src/bitmap.c:372: al_lock_bitmap_region: Assertion `y+height <= bitmap->h' failed.
> > 
> 
> Hm, yeah. In SVN, it's broken with the -v parameter instead (trying to
> fix that prompted me to make this whole change, to reduce the mess we
> have right now first). I hope it will be easy afterwards to fix both
> problems by doing the source clipping (which we unwittingly introduced
> with the negative sub-bitmap offset) at the single al_draw_bitmap point.

Do you mean the texture clamping(?)?

> > * run ex_scale, press 's' to use memory source bitmap
> >   A black line sometimes flickers across the screen just under the
> >   scaled bitmap.
> > 
> 
> In current SVN, nothing at all is drawn if you use 's' in ex_scale - so
> the version with an occasional black line is definitely an improvement
> to that :P I have no idea about the cause of either.

Oh, I didn't realise that it was broken in 4.9.21.

Author: Matthew Leverton <konforce@xxxxxxxxxx>
Date:   Fri Jul 2 22:16:28 2010 +0000

    merge sub-bitmap and parent bitmap clipping; clip source bitmap to (0,0)-(w,h); fix flipping to/from clipped bitmaps
    
    git-svn-id: https://alleg.svn.sourceforge.net/svnroot/alleg/allegro/branches/4.9@xxxxxxxxxx 198e8dbc-0e07-0410-9fd0-dca9db973e3e


Peter