Hi all,

We all know now that GBA isn't quite able of doing hardware-rendered 3D
scenes for games, as the viedo chipset is only aimed at 2D.
With software 3D rendering, one can manage to get around 50000 polygons /
second (if I can remember well the figures), which is really not enough for
a big, real 3D game.

So my question is, does anyone think it would be possible to incorporate
some kind of 3D video chipset in a cart, which would do the render of scenes
and blit it awesomely fast on the screen, for example in mode 3 or 4 ?

Let me explain.
Aperture size for cartidge is 32 Mb. So what if one uses, for example, 28 Mb
for the cartidge ROM, and the 4 last Mb would be to transmit data to what
I'd call the "3D chipset" in the "special cart" ?
As I see it, the "3D chipset" would work like this :
- On the first bytes of its address space, we have some controls (such as :
position of the camera for drawing, chipset enabled, chipset bliting etc.)
in read and / or write states.
- On the next Mbs the user would have to DMA the scene polygons data, and
then the texture data. The same data may remain for several frames
(background, wals etc.) or may be for just one frame (3D moving objects
etc.).
- The "3D chipset" would then do, when ordered (one control bit for "render"
maybe), the blitting of the resulting scene on the GBA display. The
rendering shall be made by the "3D chipset" without halting the GBA cpu (of
course).

As I don't know anything about electronics, I'm just wondering if such a
chip is only an utopia or may be madeable. What do you think about it ? Does
anything similar exist for another game system ?

Regards,

Mathieu -- The Night Howler