Parallax Occlusion Mapping Deep Dive EP: 4 - Blending Multiple POM Textures

[@Hotrood999]

Great video as always!

[@TechArtAlex]

Thanks!

[@Ricky_Lauw]

Hey Alex, The parallax occlusion mapping function is easy to update, because it is a node based function. You can just double click it and adjust it. Only the POM node in the function is a custom expression node.

[@TechArtAlex]

Building in things like temporal jitter for steps, etc that I've shown earlier is trivial because you're just altering an input to the existing custom node. But what I'm saying is that altering it to accept multiple height maps or blend between them will require at least a few changes in the custom node. It's still fairly easy to do, but the video was already running long and complicated so I figured it'd be better to leave that to the links in the description for now.

[@quantumdeconstructor]

Hey, are you planning to cover Tri-planar projection + POM ?

[@jeremyb2120]

I'd be interested in this too!

[@TechArtAlex]

I recorded a video about it last night and released it this morning. It's a pretty quick one.

[@quantumdeconstructor]

@@TechArtAlex That one was useful, thanks, but what i mean is when you have Tri-planar heighmap from example - you need to use 3 POM functions for X, Y, Z projections, and how to go from there? I've heard something about swizzling camera vector but never got correct results.

[@TechArtAlex]

@@quantumdeconstructor Oh, I understand what you mean now. Using POM for tri-planar mapping, not tri-planar mapping onto POM. Yeah that gets tricky, not only for the reasons you mentioned but also the issues I covered here in the blending video - there's no way to guarantee the height map will have an intersection at the point you want to transition between projections. Maybe you can use my single sample tri-planar technique to still use just one POM node though. I'll test some things out.

[@ambbplayer]

Hi,nice work,could you share the hlsl version custom node or maybe make a video about it?thank you

[@TechArtAlex]

Thanks! I don't currently have a plan to get into this for a video, but there are links in the description showing some others' customizations.

[@ambbplayer]

@@TechArtAlex Yes, I understand that programming might not be that interesting for a video. About a month ago, I found those links myself, but I don't quite understand the URL you mentioned for the "advanced method for blending." I look forward to your clarification on this confusion. Thank you.

[@TechArtAlex]

@@ambbplayerBy that I mean there are are examples which blend together the height maps themselves which makes it so there is in fact a true blend/intersection and solves all of the issues I show like phantom blending and floating.

[@ambbplayer]

@@TechArtAlex Oh, I meant that I don't quite understand how to implement the method mentioned in that link in HLSL. Sorry for the misunderstanding. If possible, I would appreciate it if you could explain it to me. Thank you.

[@TechArtAlex]

@@ambbplayer It's probably a bit complex to get into over a youtube comment, but the crux of it is that you would alter the texture sampler input to be up to a float4 instead of a float. This allows a 4 channel heightmap to be passed into POM and evaluated which saves performance and prevents needing to set up multiple POM nodes (unless you need to blend more than 4 heightmaps, then things get dicer). As far as advanced blending goes, you would also pass the blend weights themselves into the POM node as a tex object. This makes it possible to make the material aware of the blend point at each level, so that it can shift the amount of displacement on each map to a specific point (such as the maximal point, or an average) and as a result it guarantees an intersection of the heightmaps. I'm not sure the latter its worth the trouble since this video shows you can get convincing enough intersections with some creative blending.

[@tomtomkowski7653]

Hi. How to change the tiling in such a texture?

[@TechArtAlex]

You would do so via the UV input of the parallax occlusion mapping node.

[@tomtomkowski7653]

@@TechArtAlex OH, that was easy :) Now, any idea why this is working on a plane but exactly the same setup doesn't work as a landscape Layer? Can't we use parallax to paint the landscape?

[@TechArtAlex]

@@tomtomkowski7653 I can't think of any reason why this wouldn't work on a landscape material.

[@tomtomkowski7653]

@@TechArtAlex I have no idea either. The layer is flat like any other texture. Would be nice maybe to make another video about this topic :)