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dbzprogrammer

HDR Zones

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Hello all, I'm looking to write an HDR shader, and my question is this: How does luminosity REALLY work? I've seen multiple examples, where the luminous intensity was exponential or it is linear. Or are there just multiple systems to try? Apparently, there are multiple zones, and each zone is twice as intense in light as the other. This is my basic idea: You render your scene in a large range, and then scale it down to the monitor's luminous zone. Depending on the aperture size of the camera, you darken/lighten the image due to the amount of photons reaching the camera. A glow blur is optional to soften the image.

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You want to check out some of the books from Ansel Adams :-) ... Eric Reinhard has a few good references in his original article on HDR. I would take some time and think about the whole thing. It is a powerful concept :-)

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No, but i think best answer is you just need to experiment. I've had a hard time finding tone mapping algorithms. But basically you use a luminance value(s) as inputs, and this algorithm should map the current pixels luminance to the output range described by the luminance inputs.

You're attempting to take a scene that is beyond the luminance range of your computer, and map it back. You want to do this in a way that loses as little detail as possible. This is why you use a logarithmic scale, like audio, we can preceive lower lighting levels non linearly less than we see bright colors. so you'll want to scale back the bright values more than the dark values.

I just started looking for some new examples but the fact is I'm just happy with the way my render currently looks. My tone mapping is too weak to mention, but I'm sure with a bit of experimentation you can find a simple solution.

I plan on keeping my luminance values in a small texture and not boiling them down to a single couple values and see if that can give me better tone mapping locality.

Caution this information could be entirely false.

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