also if we combine most of environment assets into single mesh I dont think occlusion culling will work properly ?
Hi again.
Interesting point and one I can speak too specifically, as I tested this exact use case out for my mobile vr game when i was learning meshbaker and how unitys culling and static batching all played well together.
What I found was for an s7 class machine (what the go and quest are designed around) was that draw calls were more important then texture bandwidth or even vert calls... but there are limits. In fact the hard limit is: 100,000 verts and 100 draw calls...
What I found for my level design was not to build out the entire level as one big mesh object, but instead was to use mesh baker to built out areas of the level, or "rooms" of my level with each level making up of 12-20 of these "rooms" stung together and set ass static. (for culling) In my case rooms were actual rooms of a dungeon, but the idea could be used for subareas of an outside terrain, or a space game, or any type of 3d level...
These rooms were just complied prefab objects of tables, walls, stairs, bookcases and the like, all mesh combined into one mesh object with a corresponding texture atlas.
Each "room" would be about 20-40k verts with a 4012x4012 texture atlas and would be two draw calls. One for the geometry and one for the texture call.
The camera would have culling on, so only two or three of these rooms would be visible at any one time, resulting in maybe 10-15 draw calls in total. This DRAMATICALY sped up performance for me. where as before ,just using unity static batching, I was getting 150-200-ish draw calls and fps were 25-30, but using this level building technique, I got 72 fps native and could sustain 90fps if I overclocked the device.
Add a few dynamic objects and enemies and a UI and you can get to 30-50 draw calls witch should be well within the prefmon budget of older 2-3 generation legacy mobile systems and absolutly within modern smobile standards.
I was doing this for mobile vr, so had to design for 360 degree, but if you are flat mobile, you can stream line this process a tad more for 2d.
Anyway, cheers mate!