RGBE vs float HDR

[supagu]

im looking at HDR rendering, now, im wondering if i should use RGBE or float textures.

what are the pro's and cons of each?

heres my list:

RGBE
pros:
-less memory

cons
-more work on shaders decompressing/compressing

FLOAT
pros:
-less work on shaders

cons
-more memory

i'm guessing i will end up using floats as it would make things simpler and provide better quality, plus im guessing it can support an alpha channel also.

[sqrt[-1]]

Have you also considered the DXT1 RGB + 16 bit greyscale method that Humus recommends?

You could also include alpha in this scheme if necessary..

[Humus]

Yes, since you'll get filtering all the way back to R300/NV30, plus less storage space and bandwidth needed, I recommend that method over FP textures. Decoding is three ALU instructions. You may want to check the "HDR Texturing" paper that's included in the latest SDK. It lists a whole range of different formats and encodings that you can use, with their pros and cons.