[SDL] Re: Re[2]: [SDL] DirectX 7?

David Olofson david.olofson at reologica.se
Mon Sep 30 11:34:01 PDT 2002

On Monday 30 September 2002 17:36, Rainer Deyke wrote:
> David Olofson wrote:
> > glSDL handles that, although the current implementation has some
> > restrictions. This is just a matter of implementing it properly -
> > having
> > a 2D-over-3D wrapper "tiling" textures transparently is no major
> > issue.
> > (Not even with filtered scaling enabled, actually, since the wrapper
> > knows which tiles belong together.)
> But when you start assuming that tile A will *always* be next to tile
> B, you cripple the awesome power of tile maps.  You'd need separate
> copies of each tile, one for each combination of surrounding tiles.

We're not talking about tiled maps, but handling of surfaces that won't 
fit in a texture.

Tiled maps are indeed a problem, and I don't think there is a perfect 
solution that doesn't the API being aware of the tiles as well as the map 

> My current OpenGL renderer uses 'GL_CLAMP_TO_EDGE', which causes
> jitters but removes the worst edge artifacts.  I've also considered
> 'GL_POLYGON_SMOOTH', but that interferes with my use of blending.

Exactly. I can think of a few ways to deal with it properly, but nothing 
that completely avoids manipulating or generating tile textures on the 
fly. You can do tricks with blending, AA or whatever, but there's no way 
you can be certain that it'll look right on all cards (if any) unless you 
pass edges through the texture filtering, just like all other graphics.

//David Olofson - Programmer, Composer, Open Source Advocate

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