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16bit half-float linear HDR images as (diffuse/albedo) textures?
show user profile  Nanne
So I been thinking about this for a while and tried to google for an answer but without any success.

HDRI for IBL is a very popular workflow these days, and Physically Based(/Plauseable) Shaders are also being more common, even for real-time game engines. In these new PBR-shaders the Diffuse texture is now called Albedo texture and there is often a slot for a occlusion texture, like Ambien Occlusion.

I've been looking at some tutorials for creating Albedo textures and it pretty much looks like a brighter or less saturated/grayer version of the old diffuse texture. They seem to remove the shadows from the diffuse since that's what the occlusion map (AO map) should include, since it's only the ambient light that should be blocked, not the direct light.

One question I have is: why is it now called Albedo, what's the difference between Diffuse and Albedo?

But back to the main question.

If all your textures are 8bit LDR images, like JPEGs, couldn't that potentially cause conflicts with exposure control/tone mapping when rendering. That is if you adjust the rendering exposure of your image that should expose detail in the textures that aren't really there, since they been clamped out by the low dynamic range. So wouldn't it make sense to also have the textures as HDR images, saved as .exr, in linear colour space with 16bit half-float to get a good colour representation (32bit "full" float might be overkill?). To have more detailed and correct colour values might also, I figure, have an effect on GI and how colour bleed is calculated?

Or is it simply not necessary since the end result of the rendering we want is probably going to be similar to the exposure level of the texture when it was photographed any way? And since camera mostly shoot in 12-14bit you would have to take multiple exposures of the texture and do all that extra work to piece them all together to one HDRI.

Kristoffer Helander
www.kristofferhelander.se
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read 251 times
5/6/2016 11:14:52 AM (last edit: 5/6/2016 11:14:52 AM)
show user profile  herfst1
Albedo is exactly as you said, the photo texture (for example) minus shadows, highlights and any detail that can be implemented via one of the other maps. A clean albedo is a flat albedo. Microsurface is where a lot of your former diffuse details get dumped.


read 242 times
5/6/2016 12:50:33 PM (last edit: 5/6/2016 12:50:33 PM)
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