question about r300

[muppy]

I've read that r300 woks with FP24, I knew that r300 reach 128bit precision. FP24 means 24 bit per channel, right? There are 4 channels, and 4*24=96, where are the remaining 32 bits (128-96=32) ??
Thanks
Muppy

 

[Tahir2]

It reaches 96bit internal precision not 128bit.

 

[muppy]

It reaches 96bit internal precision not 128bit.

i have a bit of confusion: on many site, there is write tath r300 reach 128bit precesion..

 

[Hyp-X]

The R300 supports 128bit textures and render-targets.
It means it drops the extra bits when reading of fills them with zeros when writing to.

There are no 96bit textures or render-targets so the only way to use R300 to it's full precision is to use 128bit surfaces.

 

[Pete]

I think ATi's DX9 cards have 96-bit pixel shader precision, but 128-bit texture precision. (Hopefully this doesn't contradict what has already been said.)

 

[Humus]

Yes, 96 bit in the fragment shader, but 128bit in texture coordinate interpolators. The sampled textures get no more precision than its format, usually 32bit.