Introduction to develop a Unity3D plugin

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/