GPU DO Tone Mapping in hdr(fp) game real time(every frame)?

[lightframe]

in the hdr game like fc1.4 age of empire3 Oblivion
when hdr enabled, gpu dose Tone Mapping on every frame?

 

[bloodbob]

Yes however "exposures" constants might not be calculated each frame.

 

[lightframe]

Yes however "exposures" constants might not be calculated each frame.

very thank for your reply

by the way, do the gpu do Tone Mapping in shader unit?

i find that, in splinter cell3 :chaos theroy, the Tone Mapping can be set off when hdr rendering is enabled.

if Tone Mapping is set off, how the gpu do hdr rendering,in splinter cell3 :chaos theroy?

 

[bloodbob]

Yes they are done in the shader unit. Most tonemapping have some calculate of the average brightness or something similar they use to scale the image with some how thats what I was talking about by "exposure" constants. If you don't use any form of tone mapping ( simplest being linear scaling ) then you simply take the 0.0 1.0 range of your image and display it. Obivously if it is an overly bright screen your aren't going to get as much "information" out of it as if it was tone mapped. However it can improve rendering particular in scenarios such as motion blur.

 

[lightframe]

ok,i see,very thanks.

 

[nAo]

in the hdr game like fc1.4 age of empire3 Oblivion
when hdr enabled, gpu dose Tone Mapping on every frame?

Yep, but don't worry, tone mapping is a very cheap process with standard implementations

 

[K.I.L.E.R]

I don't tone map, what I do is I render my scene, read back the colour values, grab the largest one, render the scene again, this time normalise all the colours values.

 

[Andrew Lauritzen]

I don't tone map, what I do is I render my scene, read back the colour values, grab the largest one, render the scene again, this time normalise all the colours values.

Um... may I ask why you do this? It seems rather redundant when you already have all of the un-"normalized" colour data.

 

[nAo]

I don't tone map, what I do is I render my scene, read back the colour values, grab the largest one, render the scene again, this time normalise all the colours values.

This is a tone mapper, a very inefficient (and primitive) one. You could just use you max colour value in the subsequent frame, without re-rendering your scene.