3 files changed, 16 insertions, 3 deletions
diff --git a/o3d/core/cross/client.cc b/o3d/core/cross/client.cc
index 0097d67..a6f9c32 100644
--- a/o3d/core/cross/client.cc
+++ b/o3d/core/cross/client.cc
@@ -82,6 +82,7 @@ Client::Client(ServiceLocator* service_locator)
       render_mode_(RENDERMODE_CONTINUOUS),
       texture_on_hold_(false),
       event_manager_(),
+      is_ticking_(false),
       last_tick_time_(0),
       root_(NULL),
 #ifdef OS_WIN
@@ -175,6 +176,7 @@ void Client::ClearTickCallback() {
 }
 
 bool Client::Tick() {
+  is_ticking_ = true;
   ElapsedTimeTimer timer;
   float seconds_elapsed = tick_elapsed_time_timer_.GetElapsedTimeAndReset();
   tick_event_.set_elapsed_time(seconds_elapsed);
@@ -216,6 +218,7 @@ bool Client::Tick() {
     }
   }
 
+  is_ticking_ = false;
   return message_check_ok;
 }
 
diff --git a/o3d/core/cross/client.h b/o3d/core/cross/client.h
index 158f1eb..1dcb36d 100644
--- a/o3d/core/cross/client.h
+++ b/o3d/core/cross/client.h
@@ -298,6 +298,12 @@ class Client {
   //   true if message check was ok.
   bool Tick();
 
+  // Indicates whether a call to Tick() is in progress. This is needed
+  // to avoid reentrancy problems on some platforms.
+  bool IsTicking() const {
+    return is_ticking_;
+  }
+
   // Searches in the Client for an object by its id. This function is for
   // Javascript.
   // Parameters:
@@ -497,6 +503,9 @@ class Client {
   // Timer for getting the elapsed time between tick updates.
   ElapsedTimeTimer tick_elapsed_time_timer_;
 
+  // Whether a call to Tick() is currently active.
+  bool is_ticking_;
+
   // Used to gather render time from mulitple RenderTree calls.
   float total_time_to_render_;
 
diff --git a/o3d/plugin/mac/plugin_mac.mm b/o3d/plugin/mac/plugin_mac.mm
index 488a7b6..26c8f7c 100644
--- a/o3d/plugin/mac/plugin_mac.mm
+++ b/o3d/plugin/mac/plugin_mac.mm
@@ -237,9 +237,10 @@ void RenderTimer::TimerCallback(CFRunLoopTimerRef timer, void* info) {
     NPP instance = instances_[i];
     PluginObject* obj = static_cast<PluginObject*>(instance->pdata);
 
-    // RenderClient() may cause events to be processed, leading to
-    // reentrant calling of this code. Detect and avoid this case.
-    if (obj->client()->IsRendering()) {
+    // RenderClient() and Tick() may cause events to be processed,
+    // leading to reentrant calling of this code. Detect and avoid
+    // this case.
+    if (obj->client()->IsRendering() || obj->client()->IsTicking()) {
       continue;
     }