Increase Height Limit, 1.18 Compatibility, Blue Noise Sampling
Added 2022-01-01 02:41:08 +0000 UTCToday I'm releasing OctrayRewrite v0.5.0. This update adds compatibility for Minecraft 1.18. Most notably, this includes raytracing support for the new [-64, 320] block height limit. As far as I know, OctrayRewrite is currently the only shader that supports raytracing the entire render distance (64x chunks, 384 height). This is partly enabled by the years of development that went into sparse voxelization, it's nice to see that work paying off.
Another new development is the inclusion of blue-noise for ambient lighting. Blue noise is a well known sampling technique in realtime graphics, and I had tried and failed in the past to incorporate it into Octray. The primary issue I ran into was that I wanted unlimited progressive sampling, whereas prior work on blue noise assumed you were only accumulating ~16 samples at maximum. Recently, some engineers at Nvidia figured out how to do temporal blue noise, and this spurred me to revisit the problem and find a solution that works for Octray. The new sampling method vastly improves perceived quality in regions of medium noise, and most importantly, does not degrade sampling quality in any situations. It makes some situations better, and no situations worse.
A side effect of the work on blue noise was that I fixed the sampling distribution for ambient lighting. I decided to plot the samples in Python for both the old and the new technique, and I realized that the function I was using before was not producing a uniform hemisphere of samples. This caused ambient light to be unrealistically dramatic and contrasty. It is a bit subjective, but I think the new, realistic distribution looks better in most scenes.
