LOD Textures - Multiple or MipMap ?

Ziboo

Hi guys,

I just have a question regarding the best practice for doing LODs.
I have 3 LODs by building, LOD0, LOD1, LOD2.
I have used Simplygon to do the lower LODs, and ended up with different textures for each LODs with downgraded resolution.

That's fine, but my question is:

Would it be more optimized to actually only use the LOD0 texture on LOD1 and LOD2 and let the MipMapping do the work ?
(I'm talking really in the overall performance, Ram, VRam, disk swapping, etc...)

I was wondering what best practices they're using in AAA.

If you have insight, please let me know.

Thank you

RyanB

Using one texture is going to save memory but probably increase the chance of seeing popping between LOD levels.  Mipmapping adds about 30% onto the size of the original texture so there may be no savings at all.
You would save memory by using fewer LOD meshes.

Overall performance depends on each game's hardware specs, camera, view distance, etc.  You need to use a profiler to know what is best for each game.  Profile -> Optimize ->Test -> Repeat

Ziboo

Thanks for your answer.

It's an RTS like camera, so always going from close to far range all the time, lods switching a lot, textures too.

Used the profiler a lot, but was wondering if someone has already tested the two approach .

Ziboo

bump. Anyone else ?

echofourpapa

I would look at if you really need multiple textures if they are just down-sampled versions of the original.  If the UV layout changed between LODs then use the different textures, but otherwise I would stick with a single texture with mips.