GP3 is using your 3d card to draw all the triangles, just like any other
game. Maybe you don't know much about 3d accelerator cards, but before
nVidia introduced the first GPU (Geometry-Processing-Unit) on the GeForce
256, all 3d cards ever did was draw 2d screen triangles, which is exactly
what the 3d card is used for in GP3.
A card like a Voodoo 3 for instance, can do nothing but draw 2d triangles
straight onto the screen. The game engine has always been responsible for
transforming the triangles into screen-space, so when you say that GP3 is
only using D3D to display the results, well, that's how all games work.
As a programmer using D3D you have the option of writing your own
transformation code, or letting D3D do it itself, but both methods are done
entirely using your CPU, unless your card has a hardware transformation chip
on it, which of course, GP3 doesn't support anyway.
The graphical problems you see in GP3, like bad clipping, polygon
positioning errors, lack of perspective-correction on some textures, and
texture warping are all entirely fixable. They are hang-overs from the
software engine, which is obviously optimized for maximum speed, but these
things haven't been corrected in the D3D code. Clearly GP3 should have been
designed more with 3d cards in mind.
Simon.
> Before I begin, let me clarify that despite its shortcomings I do enjoy
GP3
> and find it to be a fun accessible sim-type game (careful choice of words
> there : ). Now on to my argument...
> After trying some tests, I've come to the conclusion that GP3 is not using
> 3D cards for acceleration. I believe the game is using 3D cards for
special
> effects and lighting ala Diablo II. In other words, the game is entirely a
> software engine. The only advantage of support for 3D accelerators, is for
> bi-linear filtering, lighting and higher resolutions. That's why the game
is
> limited to 25.6 fps out of the box. The game is using the software engine
to
> generate the polygons and just asking the Direct3D renderer to output its
> results. Notice that the game does not have a higher polygon count
depending
> on whether the software engine or the 3D accelerated engine is used? The
> main advantage of a 3D accelerator in GP3 is to allow for running in
higher
> resolutions. I have a GeForce 2 and no matter whether I run it at 640x480
or
> 1280x1024 in 3D mode, I get the exact same CPU occupancy.
> It's not unheard of to use a 3D card for lighting, Diablo II and Total
> Annihilation: Kingdoms both used 3D cards just for enhanced lighting and
> other effects. Just think of the performance they could get if GP3 was
> written from day one to use the onboard geometry of the newer 3D cards on
> the market? (Actually even the Voodoo2 released back in early 98 offloaded
a
> lot of the polygon processing from the CPU)
> Discuss amongst yourselves,
> Michael M
