POM Landscape performance optimization help requested

[ComposingCoder]

@Deathrey

Optimization steps for POM include the following:

1. Rewrite POM function to use several refinement steps instead of one, tracing in n coarse steps and m fine steps.
2. Use bi linear filtering on heightmap with calculated LOD instead of automatic LOD calculation and anisotropic filtering.
3. Consider using lower resolution heightmap.
4. Make sure that you use either RGB texture compression, where heightmap is one of the channels, or single channel compression for heightmap. Heightmap in alpha channel is a strict no-go.
5. Consider using fixed number of steps and unrolled loops for POM.
6. Consider re-writing self-shadowing to be horizon-based, sampling through all relevant LOD levels of the texture.

With that in mind, POM should perform 3-4 times faster than stock material function.

Note, that using more than 4 layers with this is unrealistic.
Likewise, tessellation on large landscape is unrealistic with stock terrain rendering system.

Thank you for your reply. As far as the texture resolution I am using 2048 resolution that in the POM I shrink to 64. I’m not sure how to rewrite the POM function as you instruct. How would I increase the refinement steps and change to bilinear? While I have programmed quite a bit in c++, I haven’t ever messed with the custom coded shaders like POM. Lastly how would I make the shadowing horizon based? Also, I am at the moment only using my auto layer which only has 4 layers, so the performance is only based on 4, but I also have a distance blend to blend out the POM.

Thanks again!