Re: [AD] min/mag filters

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On August 12, 2010, Peter Wang wrote:
> On 2010-08-12, Elias Pschernig <elias.pschernig@xxxxxxxxxx> wrote:
> > Right now min/mag filters for drawing images can only be set in the
> > 
> > config file. But looking at this in ex_haiku:
> >    cfg = al_get_system_config();
> >    if (cfg) {
> >    
> >       /* This should probably become a display option. */
> >       default_cfg_value(cfg, "graphics", "min_filter", "linear");
> >       default_cfg_value(cfg, "graphics", "mag_filter", "linear");
> >    
> >    }
> > 
> > I completely agree with the comment. I was just going to remove those
> > two options and add a few new flags you can pass to
> > al_set_new_bitmap_flags:
> > 
> > ALLEGRO_MIN_FILTER_LINEAR
> > ALLEGRO_MIN_FILTER_ANISOTROPIC
> > ALLEGRO_MAG_FILTER_LINEAR
> > ALLEGRO_MAG_FILTER_ANISOTROPIC
> > 
> > For OpenGL the implementation is trivial as we can just pass them to
> > glTexParameter:
> > http://www.khronos.org/opengles/sdk/1.1/docs/man/glTexParameter.xml
> > 
> > For D3D I found this so it should be easy as well:
> > http://msdn.microsoft.com/en-us/library/bb172602%28v=VS.85%29.aspx
> > 
> > But not sure, maybe we want this as a display flag instead of bitmap
> > flag? So I better ask here before I go ahead.
> 
> Tentatively, I think the display flag would be better, otherwise we
> would need to call glTexParameter for every new source bitmap, right?
> Or does the flag apply to the destination bitmap?
> 
> On a practical note, a lot of code is likely to call
> al_set_new_bitmap_flag(ALLEGRO_VIDEO_BITMAP) without or'ing it
> with the old flags.

al_add_new_bitmap_flag?

or have al_set_new_bitmap_flag or one flag into existing, and 
al_set_new_bitmap_flags set the entire set.

> > Also, we might want to add another flag:
> > 
> > ALLEGRO_MIPMAP
> > 
> > When you scale bitmaps out then that's almost a must to use. Mipmaps
> > are automatically updated with opengl es 1 when you use glTexImage2d
> > so it's just another flag to add to glTexParameter. (I don't know what
> > happens when you modify the texture with FBO, or how it works in other
> > opengl versions or in D3D though).
> 
> Perhaps mipmaps should be on by default, and add the flag
> ALLEGRO_NO_MIPMAPS if you know you won't be scaling a particular
> bitmap.
> 
> Peter
> 
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-- 
Thomas Fjellstrom
tfjellstrom@xxxxxxxxxx




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