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Passing variables to jslib : WebGL [B14]

Discussion in 'Unity 5 Pre-order Beta' started by d12frosted, Dec 3, 2014.

  1. d12frosted

    d12frosted

    Joined:
    Feb 3, 2014
    Posts:
    43
    Hi everyone!

    I wanted to use new cool jslib stuff. And created file in `Assets/Plugins/WebGL/MyPlugin.jslib` with content:

    Code (JavaScript):
    1. var MyPlugin = {
    2.   LogId: function(id) {
    3.     console.log("app id is: " + id);
    4.   }
    5. }
    6.  
    7. mergeInto(LibraryManager.library, MyPlugin);

    Then I went to class that should call this `LogId` function and did this:

    Code (csharp):
    1. #if UNITY_WEBGL
    2.     [DllImport("__Internal")]
    3.     private static extern void LogId(string id);
    4. #endif
    5.  
    6. ...
    7.  
    8. void SomeMethod(string id) {
    9.    // stuff to do before log
    10.    LogId(id);
    11.    // stuff to do after log
    12. }

    So I was expecting to see, for example, '918090405799497', but instead I got some junk: '34XXXX64'. This value is always the same for the same id. So I thought that `id` variable is changing somewhere in code (but that's really weird, it should not), so I tried to call LogId like

    Code (csharp):
    1. LogId(string.Copy(id));
    And anyway I got that junk value.
    Then I tried to use old fashioned way to call functions in browser - by Application.ExternalCall.

    Code (csharp):
    1. Application.ExternalCall("LogId", id);
    So I made WebGL build with this change and added script to generated index.html:

    Code (JavaScript):
    1. function FBWebGLInit(id) {
    2.   console.log("app id is: " + id);
    3. }
    4.  

    And after I run index.html I saw in console 'app id is: 918090405799497'. And that's what I was expecting.

    Have anyone faced such problem?
     
    Last edited: Dec 3, 2014
    d12frosted, Dec 3, 2014
    #1

  2. jonas-echterhoff

    jonas-echterhoff

    Unity Technologies

    Joined:
    Aug 18, 2005
    Posts:
    1,666
    It's not quite as easy: you need to handle string marshalling between C# and JS. Passing without marshalling will only work for simple, numeric types.

    For an example which uses string marshalling in a jslib, check:
    http://files.unity3d.com/jonas/WebSockets.unitypackage

    The above works right now.

    You can expect this to change a little, still: We are adding support for string marshalling to IL2Cpp, so you will be able to simply pass a string in on the C# side in the future (like in your current code). You will still need to load the string from memory in JavaScript, however, like in the example from my link.
     
    jonas-echterhoff, Dec 3, 2014
    #2
    made-on-jupiter likes this.

  3. d12frosted

    d12frosted

    Joined:
    Feb 3, 2014
    Posts:
    43
    @Jonas
    Thank you very much for your reply. I will look into the package you provided.
    And I hope that in future sending strings from C# to JS will be as easy as calling a function :)
     
    d12frosted, Dec 3, 2014
    #3