Games Look Bad: HDR and Tone Mapping

Re:Games Look Bad: HDR and Tone Mapping by Dylan16807 on Tuesday October 24, 2017 @02:27AM (#15539647)

> For computational purposes, 16 bit floats can build up a lot of numerical error very quickly. It's OK for small bit of math (moderate real-time shaders), but when things get complicated, it's necessary to go full 32-bit float.

What kind of graphics calculation would build up enough error to matter? You don't exactly need to do A + 10000 - 10000 in a rendering pipeline.

If you're summing huge amounts of numbers in a raytracer it's appropriate. Where else?

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Re:Games Look Bad: HDR and Tone Mapping by tripzilch on Saturday October 28, 2017 @08:40AM (#15574958)

You're completely right to question that assumption. It's very much possible to quantify the amount of error, or even just ballpark it. But numerical math is hard! :)

And .. even a raytracer doesn't sum that many numbers, maybe a few thousand[0]? So even then it's still a very reasonable question to ask.

[0] assuming a Monte Carlo pathtracer type of thing with 5-10 bounces or so. BTW, do you think you'd ever need more than five? Unless you're rendering close-to-parallel reflective surfaces, but the appearance of those is often as confusing in real life as it is when rendered correctly.

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