From 21d1827c9f7953065fc9dfd20bedcaa9901175f7 Mon Sep 17 00:00:00 2001
From: Erwin Coumans <erwin.coumans@gmail.com>
Date: Thu, 23 Mar 2017 17:30:59 -0700
Subject: [PATCH] revert previous cmake copy->symlink (doesn't work on Windows)
 fix timing issues at small timestep, disable default linear damping for
 btMultiBody

---
 examples/ExampleBrowser/CMakeLists.txt          |  3 ++-
 examples/SharedMemory/PhysicsServerExample.cpp  | 11 ++++++++++-
 src/BulletDynamics/Featherstone/btMultiBody.cpp |  2 +-
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/examples/ExampleBrowser/CMakeLists.txt b/examples/ExampleBrowser/CMakeLists.txt
index de69074ed..127ab11f5 100644
--- a/examples/ExampleBrowser/CMakeLists.txt
+++ b/examples/ExampleBrowser/CMakeLists.txt
@@ -378,11 +378,12 @@ ADD_EXECUTABLE(App_ExampleBrowser
 		${BulletExampleBrowser_SRCS} 
 )
 
+FILE( MAKE_DIRECTORY "${PROJECT_BINARY_DIR}/data" )
 
 ADD_CUSTOM_COMMAND(
                 TARGET App_ExampleBrowser
                 POST_BUILD
-                COMMAND ${CMAKE_COMMAND} ARGS -E create_symlink ${BULLET_PHYSICS_SOURCE_DIR}/data ${PROJECT_BINARY_DIR}/data
+                COMMAND ${CMAKE_COMMAND} ARGS -E copy_directory ${BULLET_PHYSICS_SOURCE_DIR}/data ${PROJECT_BINARY_DIR}/data
         )
 
 IF (BULLET2_MULTITHREADED_TBB_DEMO AND WIN32)
diff --git a/examples/SharedMemory/PhysicsServerExample.cpp b/examples/SharedMemory/PhysicsServerExample.cpp
index 970b209d3..7ca002b8d 100644
--- a/examples/SharedMemory/PhysicsServerExample.cpp
+++ b/examples/SharedMemory/PhysicsServerExample.cpp
@@ -305,7 +305,8 @@ void	MotionThreadFunc(void* userPtr,void* lsMemory)
 
 		double deltaTimeInSeconds = 0;
 		int numCmdSinceSleep1ms = 0;
-
+		unsigned long long int prevTime = clock.getTimeMicroseconds();
+		
 		do
 		{
 			BT_PROFILE("loop");
@@ -330,8 +331,16 @@ void	MotionThreadFunc(void* userPtr,void* lsMemory)
 				sleepClock.reset();
 				numCmdSinceSleep1ms = 0;
 			}
+
+			unsigned long long int curTime = clock.getTimeMicroseconds();
+			unsigned long long int dtMicro = curTime - prevTime;
+			prevTime = curTime;
+#if 1
+			double dt = double(dtMicro)/1000000.;
+#else
 			double dt = double(clock.getTimeMicroseconds())/1000000.;
 			clock.reset();
+#endif
 			deltaTimeInSeconds+= dt;
 			
 			{
diff --git a/src/BulletDynamics/Featherstone/btMultiBody.cpp b/src/BulletDynamics/Featherstone/btMultiBody.cpp
index c14aa2aea..07b2fcddb 100644
--- a/src/BulletDynamics/Featherstone/btMultiBody.cpp
+++ b/src/BulletDynamics/Featherstone/btMultiBody.cpp
@@ -112,7 +112,7 @@ btMultiBody::btMultiBody(int n_links,
 		m_userObjectPointer(0),
 		m_userIndex2(-1),
 		m_userIndex(-1),
-		m_linearDamping(0.04f),
+		m_linearDamping(0.0f),
 		m_angularDamping(0.04f),
 		m_useGyroTerm(true),
 			m_maxAppliedImpulse(1000.f),