Game Optimization questions - mobile

Hello, I have a some questions that have been rolling around in my mind.

1). Draw calls: 1 3D Object, 2 materials/ textures, all atlased on one texture..but the UVs are overlapping.
does that texture atlas becomes worthless?, because of overlapping UV's.(if UV overlaps/it is two draw calls?
I purchased some assets that 'showed' atlas textures, but saw in maya that the UV's were tangled/overlapping.

2) Animation vs. Draw calls, Android: I have a airplane with 2 ailerons / 2 flaps / 1 elevator, 1 rudder, 1 spinning Prop, and the body..with normal maps.. so that is 9 draw calls right there + bump.. Could I just rig those elements, animate up/down...have one draw call?? my question, which is greater Per Frame overhead, For android mobile? Can I get that down to 2, specular/bump draw calls? that plane is one texture...is that faster than the multiple draw calls @ 1024X1024?

It's a lot of work for a test..so I thought I get some more informed opinions here..

Thanks.

Patrick

 

1) Overlapping UVs should not impact draw calls at all, just the number of meshes and materials per mesh.

2) If it was me, I would probably rig and animate them, which would be only as many draw calls as there are materials. You can them export them as a single skinned object or a collection of meshes parented to the joints. In any event, I find it easier to think of the plane as a single object and to allow myself to play animations on it if/when that makes sense.

 

Well, draw calls do influence frame rate, but one major overhead for some android devices is texture size: most low-end tabs, (like my good 'ol pendo pad... ) simply don't have the memory bandwidth to load big textures. and yes, where possible, try to reduce your textures down to one per-object to reduce the amount of textures needed.

and MakeCodeNow has a good point: if you are doing a plane game, rig the ailerons and other moving parts on the plane! not only will it save you time, it will perform a lot better too.

that also brings things down to another good point: optimize your scripts so that they execute in under 5ms, write efficient and good-looking shaders (or use the mobile ones... ) and your game will fly!

I have proof that this works, and so do a lot of people, as I am working on my own android game atm. if you wish me to do so, I will post a screenshot later and list what I used. (mine is a little different though; it uses the FFP for performance reasons... )

 

Yeah, I feel pretty stupid, not doing this from the start..the planes are in Poser format, which I can export to collada/fbx converter, saving the rig and animations...I did buy Sector Complete, I am about to test on 4X4 2048 terrain mesh, for a size of 4096 squared, split into 3 LODs/3 Lod Textures, 5,000+ buildings(3 atlased tetxures)...I'll post more on your thread..Thanks for the help!!

 

That is good advice, my first release was "just get it out there", now I am about squeezing every bit of performance from unity pro that I can...now that I have profiler, I can optimize like crazy!! (it's actually not that fun)..thanks for the feedback. Patrick

p.s what is it FFP ??

 

Oh, sorry about not cleaning that up, it stands for Fixed-function Pipeline, i.e. N64-quality graphics!

And nice to hear my advice helped you! feel free to give me a yell if you need anything.

 

My test


Before: 20,000 Tris / 12 draw calls


After: 8,000 Tris 1 Draw Call (any less poly's, becomes really destructive!!) Good enough for android?

 

It's definitely a big improvement. Whether it's good enough for android depends on how many planes are visible at once and which android devices you are targeting. The only way to really know is to test and profile

 

Not bad man!
Might have to ask all of you though: how come one of my games is taking 8-12 draw calls just to draw ONE CAR?

Here's the car (rendered in blender) :

It is only something like 200 polys, which is really small by today's standards. it also only has one material! so how come it i taking so many to draw one car? Also note I am using the most basic lighting shader you can get. (no surface, it's pure CG I wrote myself)

@MakeCodeNow: Remember that profiler is pro-only... Actually, time to yell for a profiler!

 

4 draw calls - Tires
1 draw calls - Body
2 draw calls - Light Covers
2 draw calls - Lights
------------------
9 Draw calls??
for some reason - your shader , is forcing unity to render it this way...
-Are they separate meshes w/ separate materials/textures?

It was the same issue with me, just atlas textures by material, combine meshes, rig smooth/rigid, otherwise
separate dynamic mesh parts even on the same texture map = separate draw calls.
but, without the actual topology and textures..it's tough to diagnose...
so...??

 

Well, your calculation's a little off: those light covers & lights are actually textures.
Also, would it take more to draw a UV map with separate faces? that could be the problem. and yes, multi-materials will do this too, I already addressed that problem.

I did forget one thing: there is a separate material for the tyres, might give a go at fixing that, so there's only one for all of the car. Oh, and for an interesting comparison: I have a game that draws in about 15 drawcalls, WITH a single skinned mesh & tunnels!

BTW, here's the mesh in blender:

This should help give you an idea of the mesh topology. (which, i would imagine, would be possibly the worst car topology on earth! )

EDIT: And the texture:


EDIT2: Who agrees this is turning into a general android optimization thread?

 

Y'all should check out this asset on the UAS... killer performance increase... (I'm not the author, nor do I know him, just really stoked about the perf increase)
X-Frame FPS Accelerator
https://www.assetstore.unity3d.com/en/#!/content/63965