Merge branch 'fix_thread_join' of https://github.com/GoaLitiuM/FlaxEngine into GoaLitiuM-fix_thread_join

Source/Engine/Platform/Base/ThreadBase.cpp

@@ -43,7 +43,10 @@ void ThreadBase::SetPriority(ThreadPriority priority)
 void ThreadBase::Kill(bool waitForJoin)
 {
     if (!_isRunning)
+    {
+        ClearHandleInternal();
         return;
+    }
     ASSERT(GetID());
     const auto thread = static_cast<Thread*>(this);
 
@@ -105,7 +108,6 @@ int32 ThreadBase::Run()
         _callAfterWork = false;
         _runnable->AfterWork(false);
     }
-    ClearHandleInternal();
     _isRunning = false;
     ThreadExiting(thread, exitCode);
     ThreadRegistry::Remove(thread);

Source/Engine/Platform/Unix/UnixThread.cpp

@@ -53,6 +53,7 @@ UnixThread* UnixThread::Setup(UnixThread* thread, uint32 stackSize)
 void UnixThread::Join()
 {
     pthread_join(_thread, nullptr);
+    ClearHandleInternal();
 }
 
 void UnixThread::ClearHandleInternal()

Source/Engine/Platform/Win32/Win32Thread.cpp

@@ -113,6 +113,7 @@ unsigned long Win32Thread::ThreadProc(void* pThis)
 void Win32Thread::Join()
 {
     WaitForSingleObject((HANDLE)_thread, INFINITE);
+    ClearHandleInternal();
 }
 
 void Win32Thread::ClearHandleInternal()