Atmospheric fog is not completely correct, because fog will be picked up underneath the water plane. I haven’t done enough tests to know how big of an this is in practice. It’s probably not solveable either, due to the precomputation implementation of atmosphere.
Occlusion culling does work with the reflection pass (objects in the reflection pass occlude each other).
The performance cost of a planar reflection is completely dependent on what’s in your scene. In other words - you control it. Scenes with a lot of triangles and meshes in particular will be heavy because those costs are unaffected by the planar reflection’s
ScreenPercentage.
Yep we need controls for what features are rendered. Material quality level is a good idea. LOD controls will be important too.
The planar reflection pass is using a different camera position and angle so you can’t compare it directly to the main view - it sees different things.
There is occlusion culling on the planar reflection component - the whole reflection pass is skipped when it is invisible. It really only kicks in for localized components like a mirror. There’s a limitation in the occlusion system where if the camera near plane intersects the bounds of a component, that component is always visible. That will cause the planar reflection for water to continue rendering when you are above it and you look up. That’s something we could improve.