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DUGL and FreeDoom (Announce)

posted by FFK Homepage, 17.09.2009, 04:25

> Perhaps something simple at first?
You are right DUGL require at least a simple game.

> > We need a list of graphic functions needed by FreeDoom and
> > see if DUGL is able to provide them all.
> > By first look DUGL is missing :
> > - Perspective corrected texture mapping : solution is to split near/big
> > triangles into several triangles to reduce the bad effect.
> > - Texture wrapping : we have two solutions, make bigger textures with
> > replicated image, or again detect texture wrapping and split the
> triangle
> > into several triangles.
> > - VGA : not all VESA give access to low resolution graphic mode
> > (320x200..)
>
> Really? :no:
Here my reasons :
- Perspective corrected texture mapping :
Current algorithm of Perspective corrected are at best only 50% as fast as linear mapping.
This mean for example a bandwidth drop from 0.4GB/s to 0.2GB/s on my P4 D925.
If we take in account that inside a 3D Scene, only about 5-10% of triangles really require a perspective corrected mapping. I will choose the linear mapping, and split big/near triangles as said up.
- Texture wrapping :
It's a symbol of bad looking walls, terrain, water .. As the user can easily distinguish the repeated texture.
In fact when I started working on DUGL I got two choices : (1) supporting texture wrapping but only pow of 2 textures resolution (2) not supporting texture wrapping but any texture resolution. I choosed the second as it gives much more flexibility/speed for textured triangles (using a 640x480 screen directly as texture, optimized texture memory usage...)
- VGA :
Who want to play a game in 320x240 in 2009 ? Unless we make, as SONY PSP, a DPGS (DOS Portable Games Station) with a 320x240 LCD maybe powered by both FreeDOS and DUGL :hungry:
Any way emulating low res mode isn't hard as we can emulate them easily with the fast DUGL texture mapping.

> Yes, I forgot about that, but actually the "original" (pre-1999
> re-release) of DOOM was non-commercial only, not GPL, and I think some
> rare projects (ZDoom???) still use that (for whatever reason).
I downloaded ZDoom sources and I will see what I can do. And yes it's license is non-profit as DUGL, then usable.

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