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Old 03-30-03, 03:36 PM   #20
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Join Date: Mar 2003
Location: Tulsa
Posts: 5,101

Originally posted by walkndude
Chris, the r300 is fixed at 24fp.

It will run any application that asks for 16fp at 24fp... not a good or a bad thing just the way its designed...

Hmm From what I have read, The Radeon 9700 Pro supports 64 Bit floating point frame buffers,

To me that actually seems very limited, As doom 3 is run in 16 bit precision on the r200 pathway.

My understanding of DirectX 9.0 thats actually overkill forcing 24 bit all the time in situations where its not neccasary

This is my understanding of the DirectX 9.0 specifications.

Hardware Support:
ATI R3xx - offers 16FP and 24FP (32-bit formats must therefore be reduced) pixel shader precision
NVIDIA NV3x - offers 16FP and 32FP pixel shader precision

DX9 specification requirements:
PS2.0 registers
colour = 8-bit integer only

constant float = minimum 16-bit FP but this limits the actual number of constants that can be used

input texture coordinate = minimum 24-bit FP, preferred 32-bit FP, 16-bit FP partial precision for dependent reads(

sampler = minimum 16-bit FP to support 16-bit texture formats

temporary = minimum 16-bit to support anything taken from a 16-bit FP source
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