If developers start to implement fog in DirectX shaders, we may see the feature rolled into the programmable shaders in future versions of DirectX. Presently fog is supported in the pipeline as a separate feature. Developers will probably end up doing better fog with their own shader routines then using existing fixed function support. That's probably not a bad assumption.

There should be support for Displacement Mapping. More on that in my next article in the section on Matrox (they gave a pretty a in-depth presentation on displacement mapping). There'll be a minimum upgrade to the Vertex Shader, V.s.2.0. Flow control should be introduced, adding jumps, loops and subroutine rules. This is just adding more flexibility to the programmability of the shader, and increasing the instruction count.

There'll be an upgrade to the Pixel Shader, P.s.2.0 (Hmm, remarkable, reads PS2. Could be Freudian slip or Microsoft console-envy. You tell me.). There are two levels of support for Pixel Shader programming, one for higher level languages, and one for Assembly Code. In P.s.2.0 the Assembly Language should allow for even more direct control of hardware. This can be done through exposing register and instruction counts on the hardware. In addition, developers can embed their Assembly code within their higher language effects routines. Basically, P.s.2.0 will just open up the hardware, and that should unload Microsoft from the burden of accounting for every new texture register or blending operation that a hardware vendor throws up.

We should expect to see tighter integration between the Vertex and Pixel Shaders in DirectX, probably leading to an eventual unification. Future hardware units may even allow the two shaders to share the same math unit, which could be a benefit to low cost graphics vendors. Right now, DirectX 8 and in future, DirectX 9, are turning the graphics processor into a co-CPU, as much as anything else. So, maybe a GPU wasn't such a bad marketing term to begin with. Maybe it is an accurate reflection of where we're pushing the graphics subsystem. Be that as it may, not everyone is going to want to pay for a full GPU. There is still a market for the low-end.

The other interesting inclusion for DirectX 9 is going to be support for Gamma Correction. You can read a definition of Gamma Correction here . Gamma Correction on the PC has been a specialized function, but mainstream graphics hardware is getting precise enough to support it now. Color is used for appearance, atmosphere, and realism so, it's use needs to be handled with care. Adding Gamma Correction gives developers one more tool to enhance the viewing experience, and will also allow for better lit texture effects, among other things. It's been there in some hardware products, mostly at the very high-end. Now, it slips into the mainstream.