Bug Why emscriptenArgs no longer takes effect in the Unity2021？

How to pass the initial memory size of WebAssembly? In the past we could pass TOTAL_MEMORY, but now it seems to have no effect. It can be seen from editor.log that the parameters of the emcc command are not passed in TOTAL_MEMORY.

Code (CSharp):

1.  PlayerSettings.WebGL.emscriptenArgs += $" -s TOTAL_MEMORY={totalMemory}MB";

Why do you want to do this? Our game runs on mobile devices, especially under iOS. When the memory continues to grow 256MB, memory spikes will appear and cause memory crashes. But when the initial value is set, such as 384MB, it will not. Is it because there will be special mechanisms at the bottom of the browser when it continues to grow from 256, such as allocating new space for copying?
Therefore, we hope that the initial value of memory can be set in the previous Unity version to alleviate this memory crash.

 

This is the memory graph in iOS (purple represents memory footprint). When the memory exceeds 1024MB, the game is very prone to memory crash. When the initial memory is set, such memory spikes will not appear.

 

Just hit this today with Unity 2021.2.5f1 - any word on when it'll get fixed?

 

Ah, I see you posted your report about an update coming soon, just yesterday. Sorry, looking forward to that update as this is blocking us.

 

Are there any known work arounds?

 

Thanks for following up! The WebGL target seems much improved in 2021 otherwise. Fingers crossed for a quick release. We've found a way by modifying the lines in Library/Bee/rsp/<somenumber>.rsp to resolve it on a second build, but no preprocessor seems to get called after that file is generated, but before its contents are used so we can't fix the first run.

 

Was able to bind to BuildPlayerWindow.RegisterBuildPlayerHandler and try, fail, detect, patch, try again to work around it in most cases. Still eating that failed first build though and looking forward to the fix coming in!

 

As well as

emscriptenArgs

not working in Unity 2021, if that problem's worked around, it's got

EM_FROZEN_CACHE

set. This prevents options like

USE_ZLIB

being set, as that'd build and cache Emscripten's zlib port, which can't be done if the cache is frozen. Native plugins that use Emscripten's ports need to be able to pass these flags at link time, and it worked in Unity 2019 and 2020.

 

Still keep waiting for fixed.

 

Does it mean that we cannot use native .a plugins now?

 

Any news on this topic? I can't find a way to set the Initial Heap Size since upgrading to 2021

 

We're still using .a files built with emscripten in Unity WebGL projects without issue (though work arounds needed depending on their content).

 

Can you confirm is this will be coming with at least 2021.3?

 

We tested that this property is in effect (starting from 2021.2.11), but I don't know if it also applies to your situation：
PlayerSettings.WebGL.emscriptenArgs += $" -s TOTAL_MEMORY={totalMemory}MB";

 

Eight months later, and Unity 2021 support for our WebGL plugin is back on the menu. The frozen cache is still making

-s USE_ZLIB=1

a hassle. The problem can be worked around by building something with this flag with standalone Emscripten, and then copying the relevant cache entries into the Unity install directory, but this isn't an acceptable solution for our customers to use on their machines.