Occlusion query support for Metal iOs.

General Feedback & Requests
1

Hello.

It would be great to have occlusion culling feature also support on iOS Metal. Occlusion queries have been support for ages on iOs and is supported on every Metal device.

We already use Static occlusion culling but usually this can only cull 20-40% of what dynamic occlusion queries cull on PC. Static occlusion system also does not work for Planar reflections at all. No cells below water and objects behind clip plane also cause occlusion which cause incorrect results. Our project is currently quite triangle heavy(1-2M per frame) and this is something that would help a lot.

Edit: Static visibility is also bugged with Landscape not occluding anything. Unreal Engine Issues and Bug Tracker (UE-30368)

2

I really would like to hear some feedback about this.

3

I’m not immediately aware of any support for occlusion queries on mobile, not to say that it won’t happen at some point, though.

I just wanted to mention that you should also use Cull Distance Volumes to help remove any actors to help reduce the number of actors visible. In any project and not just mobile making use of Cull Distance Volumes should be considered since Occlusion Queries are the most expensive method of culling.

4

I’m not immediately aware of any support for occlusion queries on mobile, not to say that it won’t happen at some point, though.

I just wanted to mention that you should also use Cull Distance Volumes to help remove any actors to help reduce the number of actors visible. In any project and not just mobile making use of Cull Distance Volumes should be considered since Occlusion Queries are the most expensive method of culling.
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On newer hardware there is even counting occlusion query support but that isn’t needed for simple binary occlusion test. https://developer.apple.com/metal/availability/

I am aware of distance culling mechanism and we are using that very aggressively. We also use LOD’s for most of the meshes.