DX9 on DX8 or earlier hardware

[chrisdent]

with all the fp stuff that is to be done in dx9 how on earth will this be processed in integer pipelines? Will the cpu try to do the lot? will it simply convert to the fp to the closest 32bit integer equvilant and we have to put up with the lesser image quality?

Are the fp pipelines going to be as fast as integer processing or is there going to be a huge performance difference bewteen integer and fp data on the same processor?

 

[MDolenc]

If GPU won't support floating point then there will be no pixel shaders 2.0. Floating point precision is required for ps.2.0. There also is no integer processing in ps.2.0. If application will use integer texture for input it will get converted to float when fetched to pixel shader.

 

[Nappe1]

first, there isn't going to be PS 2.0 card with only Integer precision.
second, Legacy PS 2.0 software will not run on PS 1.x Hardware.

So, if programmer doesn't make fallback support for PS 1.x, game will not run on older HW.