How to get good performance with realtime lighting on mobile

Hi, I'm developing low-poly 3d side scroller on mobile. Now I have one realtime dir. light and both realtime lighting and mixed lightning disabled in lightning settings. Scene isn't big, no terrain, since it's low poly, every object use the same material, so everything batched. And still I can get 60 fps only on lowest settings in HD resolution. On medium settings in FHD (my phone's native resolution) fps drops to 30 and on Ultra with shadows and FHD it drops to ~25.
But my phone had snapdragon 625, which is quite powerful CPU. I can run games such as CASE: Animatronics on Ultra with FHD, GTA SA in Ultra, etc.
I don't use backed lighting because of size problem, the game suppose to have 50+ levels and baking light for every level wouldn't be effective.
Does anyone have experience in developing realtime lighting mobile games?

 

Mobile devices are normally capped at 60 fps.

Unless you want to turn the phone to a heater and drain the battery really fast, you should target 30 fps or lower instead. Newer phones feature something named thermal throttling, means if you run your game at 60 fps, it becomes really warm and then the performance is throttled to lets say 20 fps. Nothing you can do against, thus you want to avoid running in thermal issues.

Running games at 30 fps or lower where possible it what mobile games often do. You still want to optimize the hell out of it to be able to run at 60 fps in theory, but then limit it to 30 fps instead. This way your game is 50% in idle and hopefully won't cause the device to heat up. Epic did this with Fortnite mobile, see video below.

Lectures of interest...

Spoiler: Optimizing UE4 for Fortnite: Battle Royale - Part 2 | GDC 2018 | Unreal Engine

Starts at 12:13

Spoiler: Megacity on mobile: How we optimized it with Adaptive Performance - Unity at GDC 2019

 

Reltime shadows?

 

Thanks for reply!
I didn't mean that I want more than 60 fps, I want stable 60 fps on low-medium settings
Also I've never seen 3d games capped at 30 fps, it usually runs at 60

 

Only on the highest quality settings

 

Realtime shadows and standard shader are most often cause performance problems on mobile.

 

I've been doing mobile games since 2010 so some experiences:

• baking lightmaps for every level is the correct way to do mobile. crunch and other compression strategies reduce lightmaps to almost nothing, especially if you use small lightmaps or light using lightprobes (saves even more).
• transparency is OK on mobile but attempt to reduce overlaps (few big is better than lots of small) and ensure the shader for any transparent rendering is kept very, very simple - just vert/frag minimal.
• Post effects should either be custom or made by yourself.
• I did this app with full spec with my own pbr invention just by multiplying combined maps together with some made up math. Stripped down custom shaders are the best for performance. Vignetting is 4 meshes in the corners with vert colouring:
• 

 

Thanks for tips! Could you share your experience about lightmap baking? Because I've tried to bake level with progressive lightmaper, lowest settings, compressed lightmap and awful result, I've got 17mb lightmap. It's too big for 50+ levels game

 

Forgot to mention - I use Mobile/Diffuse shader

 

Why don't you just connect a CPU and GPU Profiler to your game and let those tools tell you exactly what is causing this performance issue?

 

Because it shows me that rendering image uses almost nothing, about 5% of all power. But in built I can see the opposite

 

Can you elaborate on this?

You connect those Profiler tools to your game, that is running on the target device (phone) and it reports 5% is spent in "rendering image"? 5% where, CPU or GPU? Where are the remaining 95% being spent? Where do you get those "opposite" numbers from?

 

1. You should use legacy diffuse shader to optimize gpu, also don't use post processing.
2. If is not gpu, try to get scripts optimized for cpu perfomance: try to use less GetComponent and GameObject.Find. Also comparing tags is less powerfull than GetComponent, so use it to check collisions. Try to kepp everything from Update in the FixedUpdate. Use get, set instead of checking value changed every frame.
3. If there are many static objects, combine it to one mesh. The way i did it is using a fbx exporter to export fbx file of scene and then import it to blender and export to obj format. The less objects cast shadow, the more perfomance you get.
4. If you are using physics, go to the project settings, then physics, optimize you layer collision matrix, for example if you have big triggers, that check triggerEnter only for same triggers, take them to new layer and make it don't collides with default layer. If you don't need very good physics quality, set world subbdivisions and default slover iterations to smallest value. Try to keep more colliders on static objects and less on rigidbody. Never use mesh colliders.
5. Setup quality in project settings. Mostly shadows. This is my values:
Pixel Light Count - 1
Texture Quality - Full Res
Anisotropoc - Disabled
Anti Aliasing - Disabled
Soft Particles - False
Realtime Reflection Probes - False
Resolution Scaling - 1
Texture Streaming - False
Shadowmask Mode - Shadowmask
Shadows - Hard Shadows
Shadow Resolution - Medium
Shadow Projection - Close Fit
Shadow Distance - Set here the less value you possable, i have 27 because of top-down camera, and you can have performance with not bad realtime shadows.
In other
VSync - False
Other values are default on lowest settings.
6. Setup Player Settings - Other
If you dont have to many objects - disable dynamic batching.
If you use new version of unity, then enable Graphics Jobs (Experemental), i don't know what is it, but i hear you should enable it to speed up your game.
Set scripting backend to IL2CPP
7. If you use good quality textures, then compress it.
With following this, we get stable 60 fps on small low poly scenes with realtime light on a not powerfull mobile (in fact Huawei Y6 2019).
P. S. Sorry for my english.