From a68c9ca845fd29b20c86cde400e94b378b7a5702 Mon Sep 17 00:00:00 2001
From: erwin coumans <erwincoumans@google.com>
Date: Thu, 18 Aug 2016 21:43:43 -0700
Subject: [PATCH] avoid MT crash in VR/physics server due to printf from
 separate thread. add fps display in VR use 1./240. internal substep for
 real-time physics sim in VR/physics server for more accurate robotics sim.

---
 .../ExampleBrowser/OpenGLExampleBrowser.cpp     |  6 +++---
 .../PhysicsServerCommandProcessor.cpp           |  2 +-
 examples/SharedMemory/PhysicsServerExample.cpp  | 17 ++++++++++++++++-
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/examples/ExampleBrowser/OpenGLExampleBrowser.cpp b/examples/ExampleBrowser/OpenGLExampleBrowser.cpp
index a3238f358..be8d0f2e8 100644
--- a/examples/ExampleBrowser/OpenGLExampleBrowser.cpp
+++ b/examples/ExampleBrowser/OpenGLExampleBrowser.cpp
@@ -490,7 +490,7 @@ void	MyComboBoxCallback(int comboId, const char* item)
 void MyGuiPrintf(const char* msg)
 {
 	printf("b3Printf: %s\n",msg);
-	if (gui2)
+	if (!gDisableDemoSelection)
 	{
 		gui2->textOutput(msg);
 		gui2->forceUpdateScrollBars();
@@ -502,7 +502,7 @@ void MyGuiPrintf(const char* msg)
 void MyStatusBarPrintf(const char* msg)
 {
 	printf("b3Printf: %s\n", msg);
-	if (gui2)
+	if (!gDisableDemoSelection)
 	{
 		bool isLeft = true;
 		gui2->setStatusBarMessage(msg,isLeft);
@@ -513,7 +513,7 @@ void MyStatusBarPrintf(const char* msg)
 void MyStatusBarError(const char* msg)
 {
 	printf("Warning: %s\n", msg);
-	if (gui2)
+	if (!gDisableDemoSelection)
 	{
 		bool isLeft = false;
 		gui2->setStatusBarMessage(msg,isLeft);
diff --git a/examples/SharedMemory/PhysicsServerCommandProcessor.cpp b/examples/SharedMemory/PhysicsServerCommandProcessor.cpp
index b0adbd12d..96dc083a7 100644
--- a/examples/SharedMemory/PhysicsServerCommandProcessor.cpp
+++ b/examples/SharedMemory/PhysicsServerCommandProcessor.cpp
@@ -2445,7 +2445,7 @@ void PhysicsServerCommandProcessor::stepSimulationRealTime(double dtInSec)
 			loadUrdf("plane.urdf", btVector3(0, 0, 0), btQuaternion(0, 0, 0, 1), true, true, &bodyId, &bufferServerToClient[0], bufferServerToClient.size());
 		}
 
-		m_data->m_dynamicsWorld->stepSimulation(dtInSec);
+		m_data->m_dynamicsWorld->stepSimulation(dtInSec,10,1./240.);
 	}
 }
 
diff --git a/examples/SharedMemory/PhysicsServerExample.cpp b/examples/SharedMemory/PhysicsServerExample.cpp
index 59e81ac4c..489d9526f 100644
--- a/examples/SharedMemory/PhysicsServerExample.cpp
+++ b/examples/SharedMemory/PhysicsServerExample.cpp
@@ -872,7 +872,22 @@ void PhysicsServerExample::renderScene()
 		static int frameCount=0;
 		frameCount++;
 		char bla[1024];
-		sprintf(bla,"VR sub-title text test, frame %d", frameCount/2);
+
+		static btScalar prevTime = m_clock.getTimeSeconds();
+		btScalar curTime = m_clock.getTimeSeconds();
+		static btScalar deltaTime = 0.f;
+		static int count = 10;
+		if (count-- < 0)
+		{
+			count = 10;
+			deltaTime = curTime - prevTime;
+		}
+		if (deltaTime == 0)
+			deltaTime = 1000;
+
+		prevTime = curTime;
+		
+		sprintf(bla,"VR sub-title text test,fps = %f, frame %d", 1./deltaTime, frameCount/2);
 		float pos[4];
 		m_guiHelper->getAppInterface()->m_renderer->getActiveCamera()->getCameraTargetPosition(pos);
 		btTransform viewTr;