From f110a269c8e77cad74d6ae38b3d335d72e9ac119 Mon Sep 17 00:00:00 2001
From: David Rose <david@ddrose.com>
Date: Tue, 3 Jan 2012 03:05:54 +0000
Subject: [PATCH] GraphicsEngine::get_render_lock()

---
 panda/src/display/graphicsEngine.I   | 14 ++++++++++++++
 panda/src/display/graphicsEngine.cxx |  1 +
 panda/src/display/graphicsEngine.h   |  3 +++
 3 files changed, 18 insertions(+)

diff --git a/panda/src/display/graphicsEngine.I b/panda/src/display/graphicsEngine.I
index 3d11ab325d..a634c71ca7 100644
--- a/panda/src/display/graphicsEngine.I
+++ b/panda/src/display/graphicsEngine.I
@@ -13,6 +13,20 @@
 ////////////////////////////////////////////////////////////////////
 
 
+////////////////////////////////////////////////////////////////////
+//     Function: GraphicsEngine::get_render_lock
+//       Access: Published
+//  Description: Returns a ReMutex object that is held by the
+//               GraphicsEngine during the entire call to
+//               render_frame().  While you hold this lock you can be
+//               confident that no part of the frame will be rendered
+//               (at least by the app thread).
+////////////////////////////////////////////////////////////////////
+INLINE const ReMutex &GraphicsEngine::
+get_render_lock() const {
+  return _public_lock;
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: GraphicsEngine::set_auto_flip
 //       Access: Published
diff --git a/panda/src/display/graphicsEngine.cxx b/panda/src/display/graphicsEngine.cxx
index 552f6b78bf..43156a37af 100644
--- a/panda/src/display/graphicsEngine.cxx
+++ b/panda/src/display/graphicsEngine.cxx
@@ -645,6 +645,7 @@ get_window(int n) const {
 void GraphicsEngine::
 render_frame() {
   Thread *current_thread = Thread::get_current_thread();
+  ReMutexHolder public_holder(_public_lock);
 
   // Since this gets called every frame, we should take advantage of
   // the opportunity to flush the cache if necessary.
diff --git a/panda/src/display/graphicsEngine.h b/panda/src/display/graphicsEngine.h
index 2a3a5233e3..7428a35da1 100644
--- a/panda/src/display/graphicsEngine.h
+++ b/panda/src/display/graphicsEngine.h
@@ -63,6 +63,8 @@ PUBLISHED:
   void set_threading_model(const GraphicsThreadingModel &threading_model);
   GraphicsThreadingModel get_threading_model() const;
 
+  INLINE const ReMutex &get_render_lock() const;
+
   INLINE void set_auto_flip(bool auto_flip);
   INLINE bool get_auto_flip() const;
 
@@ -325,6 +327,7 @@ private:
   bool _singular_warning_this_frame;
 
   ReMutex _lock;
+  ReMutex _public_lock;
 
   class LoadedTexture {
   public: