This document provides guidance on developing plugins for Unity3D games. It discusses what plugins are, reasons for developing plugins, and interfaces for calling plugin code from Unity. It also provides platform-specific guidance on developing plugins for iOS and Android, including how to handle platform-dependent code, interface with native platforms, and address common issues. The document recommends tools and best practices for plugin development and offers to discuss the OAuth SDK and answer questions.

1. Unity3D Plugins
Development Guide
ChenKaiJung

2. Plugins Are?
● Libraries of native code written in C, C++,
Objective-C….etc
● Allow your game code to call functions from
these libraries

3. Why do you need to develop a Plugin?
●
●
●
●
●
●
Unity3D can’t Do That
Reuse C/C++/Objective-C components
Difficult customize in Unity3D Assets Store
Cross-Device
Cross-Platform
Security Issues

4. Interface?
● Just like call Unmanaged DLL in .NET
● Sync
○ Call the functions and get return values
● Async
○ Use UnitySendMessage
● Name mangling Issue
○ Use extern "C" { }
○ or _ZN·9funtown·7ios·6init·E

5. Plugins for Different Device
● Compile time - iOS
#if UNITY_IOS
#else
#endif
● Compile time - Android
#if UNITY_ANDROID
#else
#endif

6. Plugins for Different Device
● Runtime - iOS
if (Application.platform == RuntimePlatform.OSXPlayer)
● Runtime - Android
if (Application.platform == RuntimePlatform.Android)

7. iOS Plugins
● C# Dll Import
[DllImport ("__Internal")] private static extern void iosInit(bool cookie, bool
logging, bool status, bool frictionlessRequests);
● C/C++ Native Functions in xxx.mm
extern "C" {
void iosInit(bool _cookie, bool _logging, bool _status, bool
_frictionlessRequests) { [[FbUnityInterface alloc] initWithCookie:_cookie
logging:_logging status:_status frictionlessRequests:_frictionlessRequests]; } }

8. iOS Plugins
#ifdef __cplusplus
extern "C" {
#endif
void UnitySendMessage(const char* obj, const char* method, const char*
msg);
#ifdef __cplusplus
}
#endif

9. iOS 3rd Powerful tools
● XCode Editor for
Unity3D
{
"group": "Facebook",
"patches": [],
"libs": [
"Facebook/Editor/iOS/FacebookSDK/libfacebook_ios_sdk.a:<group>"
],
"librarysearchpaths": [
"Facebook/Editor/iOS/FacebookSDK/"
],
"frameworks": [
"Accounts.framework:weak"
],
"headerpaths": [
"Facebook/Editor/iOS"
],
"files": [
"Facebook/Editor/iOS/FbUnityInterface.mm",
"Facebook/Editor/iOS/FbUnityInterface.h"
],
"folders": [],
"excludes": [
"^.*.meta$",
"^.*.mdown^",
"^.*.pdf$"
]
○ Post Process Build
○ Json Configure
(fixup.projmods)
}

10. iOS Tips
● DO NOT call plugins Pre-Frame
● String passing should be encoded by UTF-8
● Wrappers your Message and let it easily
encodes and decodes cross language. Ex:
JSON,Query String
● Uses XCode Editor for building automation

11. Android Plugins
● C# Dll Import
[DllImport ("unityinapppurchase")] private static extern void androidFTInit
(bool cookie, bool logging, bool status, bool frictionlessRequests);
● C++ Native Functions in unityinapppurchase.
so
extern "C" {
void androidFTInit(bool _cookie, bool _logging, bool _status, bool
_frictionlessRequests) { LOGD("androidFTInit called"); } }

12. Android Plugins
● C# Load Java Class
ftJava = new AndroidJavaClass("tw.com.funtown.unity.FT");
ftjava.CallStatic("Init", "");
● Java Class
public class FT
{
public static void init(String params) {
Log.d("FTUnitySDK", "init called with params: " + params);
}
}

13. Android Plugins
● Overwrite onActivityResult
public class FTUnityPlayerActivity extends UnityPlayerActivity
{
public void onActivityResult(int requestCode, int resultCode, Intent data)
{
Log.d("FTUnityPlayerActivity", "onActivityResult: requestCode: " +
requestCode + ", resultCode:" + resultCode);
}
}

14. Android Plugins
● Modify your Manifest.xml Automatically
<activity android:name="tw.com.funtown.unity.FTUnityPlayerActivity" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="tw.com.funtown.LoginActivity" >
</activity>

15. Android Plugins
● Call UnitySendMessage using JNI
bool retval=JniHelper::getStaticMethodInfo(t, "com/unity3d/player/UnityPlayer" ,"UnitySendMessage"
,"(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V");
if(retval==false) return;
jstring objectStr = t.env->NewStringUTF(obj);
jstring methodStr = t.env->NewStringUTF(method);
jstring msgStr = t.env->NewStringUTF(msg);
t.env->CallStaticVoidMethod(t.classID,t.methodID,objectStr,methodStr,msgStr);
jthrowable exception = t.env->ExceptionOccurred();
if (exception) {
t.env->ExceptionDescribe();
t.env->DeleteLocalRef(exception);
t.env->ExceptionClear();
} else {
}
…..Please delete your allocated resource here

16. Android Tips
● DO NOT call plugins Pre-Frame
● Mono garbage collector by using(){..} or xx.
Dispose() in C#
● Put your *.jar *.so in
YOUR_PROJECT/Assets/Plugins
● Be careful of Android resource conflict
problem

17. Go through OAuth SDK

18. Q&A

19. References
● Unity3D Official Plugins document http://docs.unity3d.
com/Documentation/Manual/Plugins.html
● Facebook Unity3D Plugin https://developers.facebook.
com/docs/unity
● A company sells Unity3D Mobile Plugins http://prime31.
com/