Linux segfault

[Emil Fridriksson]

I'm trying to get ibex running on my LinuxMint 16, x86_64, with xfce and Intel HD4000 gfx card. I hacked the video player code so it would compile, doubt it actually works though, but I'm taking babysteps. The project compiles now, but I get a segfault when I try to run ibex.

GDB output: ...

$ gdb ./ibex Reading symbols from ~/ibex-build/ibex...done. (gdb) run Starting program: ~/ibex-build/./ibex [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". [New Thread 0x7fffe72c0700 (LWP 22646)]

Program received signal SIGSEGV, Segmentation fault. 0x000000000046c874 in OVR::SensorFusion::SensorFusion(OVR::SensorDevice*) ()

...

I've verified that my Rift is connected and both display and head tracking work in the Tuscani demo.

Please give Linux a little love, there is so little to choose from for the Rift on Linux.

I'll try to hack this a bit to see if I get it to work, but I have little experience in debugging C++ code on Linux. Sadly most of my experience is using the VS and WinDbg debuggers on Windows.

If there is any other info I can provide or testing I can do, please poke me. I'm pretty excited about ibex :)

[Christoph Haag]

Full backtrace:

CircularBuffer (capacity=10, this=0x65f058 <FusionResult+280>) at /home/chris/build/ibex-git/src/OculusSDK/LibOVR/Src/OVR_SensorFilter.h:44
44              Elements = (T*)OVR_ALLOC(capacity * sizeof(T));
(gdb) bt full
#0  CircularBuffer (capacity=10, this=0x65f058 <FusionResult+280>) at /home/chris/build/ibex-git/src/OculusSDK/LibOVR/Src/OVR_SensorFilter.h:44                                                                          
#1  SensorFilterBase (capacity=10, this=0x65f058 <FusionResult+280>) at /home/chris/build/ibex-git/src/OculusSDK/LibOVR/Src/OVR_SensorFilter.h:92                                                                        
#2  SensorFilter (capacity=10, this=0x65f058 <FusionResult+280>) at /home/chris/build/ibex-git/src/OculusSDK/LibOVR/Src/OVR_SensorFilter.h:191                                                                           
#3  OVR::SensorFusion::SensorFusion (this=0x65ef40 <FusionResult>, sensor=0x0) at /home/chris/build/ibex-git/src/OculusSDK/LibOVR/Src/OVR_SensorFusion.cpp:37                                                            
#4  0x000000000044e911 in __static_initialization_and_destruction_0 (__initialize_p=1, __priority=65535) at /home/chris/build/ibex-git/src/ibex/oculus/Rift.cpp:8                                                        
#5  0x000000000044e944 in _GLOBAL__sub_I_pManager () at /home/chris/build/ibex-git/src/ibex/oculus/Rift.cpp:76                                                                                                           
#6  0x000000000044f06d in __libc_csu_init ()                                                                                                                                                                             
#7  0x00007ffff4d8ff8f in __libc_start_main () from /usr/lib/libc.so.6                                                                                                                                                   
#8  0x0000000000425e79 in _start ()                                                                                                                                                                                      

And the macro where it probably (I'm not so strong with c++ debuggers) segfaults is defined as: #define OVR_ALLOC(s) OVR::Allocator::GetInstance()->Alloc((s))

Uneducated guess: The oculus rift sdk needs some sort of initialization for OVR::Allocator::GetInstance() to not be null or something.

[Alain Kalker]

Very good sleuthing :-) Luckily it is a known issue, please see: https://developer.oculusvr.com/forums/viewtopic.php?f=34&t=4655 and the updated Wiki article at https://developer.oculusvr.com/wiki/Minimal_Oculus_Application for the description and a suggested workaround.

[Christoph Haag]

I'm not strong with c++. Is this acceptable? (E.g. does it leak something references didn't leak?)

diff --git a/ibex.h b/ibex.h
index 7e1ff0d..9532936 100644
--- a/ibex.h
+++ b/ibex.h
@@ -34,7 +34,7 @@ extern DisplayShape displayShape;
 extern OVR::Ptr<OVR::DeviceManager>    pManager;
 extern OVR::Ptr<OVR::HMDDevice>        pHMD;
 extern OVR::Ptr<OVR::SensorDevice> pSensor;
-extern OVR::SensorFusion           FusionResult;
+extern OVR::SensorFusion           *FusionResult;
 extern OVR::HMDInfo                Info;

 extern bool                    InfoLoaded;
diff --git a/oculus/Rift.cpp b/oculus/Rift.cpp
index 9ac14d0..92e68b4 100644
--- a/oculus/Rift.cpp
+++ b/oculus/Rift.cpp
@@ -5,7 +5,7 @@
 OVR::Ptr<OVR::DeviceManager>   pManager;
 OVR::Ptr<OVR::HMDDevice>   pHMD;
 OVR::Ptr<OVR::SensorDevice>    pSensor;
-OVR::SensorFusion      FusionResult;
+OVR::SensorFusion      *FusionResult;
 OVR::HMDInfo           Info;
 bool               InfoLoaded = false;
 bool               riftConnected = false;
@@ -17,7 +17,7 @@ int riftResolutionY = 0;

 void initRift() {
   OVR::System::Init(OVR::Log::ConfigureDefaultLog(OVR::LogMask_All));
-
+  FusionResult = new OVR::SensorFusion();
   pManager = *OVR::DeviceManager::Create();

   //pManager->SetMessageHandler(this);
@@ -47,11 +47,11 @@ void initRift() {

   if (pSensor)
     {
-      FusionResult.AttachToSensor(pSensor);
-      FusionResult.SetPredictionEnabled(true);
-      float motionPred = FusionResult.GetPredictionDelta(); // adjust in 0.01 increments
+      FusionResult->AttachToSensor(pSensor);
+      FusionResult->SetPredictionEnabled(true);
+      float motionPred = FusionResult->GetPredictionDelta(); // adjust in 0.01 increments
       if(motionPred < 0) motionPred = 0;
-      FusionResult.SetPrediction(motionPred);
+      FusionResult->SetPrediction(motionPred);

       if(InfoLoaded) {
    riftConnected = true;
diff --git a/oculus/Rift.h b/oculus/Rift.h
index b4b5d76..2997ddd 100644
--- a/oculus/Rift.h
+++ b/oculus/Rift.h
@@ -13,7 +13,7 @@
 extern OVR::Ptr<OVR::DeviceManager> pManager;
 extern OVR::Ptr<OVR::HMDDevice> pHMD;
 extern OVR::Ptr<OVR::SensorDevice> pSensor;
-extern OVR::SensorFusion FusionResult;
+extern OVR::SensorFusion *FusionResult;
 extern OVR::HMDInfo Info;
 extern bool InfoLoaded;
 extern bool riftConnected;
diff --git a/simpleworld_plugin/SimpleWorldRendererPlugin.cpp b/simpleworld_plugin/SimpleWorldRendererPlugin.cpp
index e3e10ba..6555f07 100644
--- a/simpleworld_plugin/SimpleWorldRendererPlugin.cpp
+++ b/simpleworld_plugin/SimpleWorldRendererPlugin.cpp
@@ -290,8 +290,8 @@ double orientationRift[16] = {1, 0, 0, 0,
                               0, 0, 1, 0,
                               0, 0, 0, 1};
 double *getRiftOrientation() {
-    if(!FusionResult.IsAttachedToSensor()) return orientationRift;
-        Quatf quaternion = FusionResult.GetPredictedOrientation();//FusionResult.GetOrientation();
+    if(!FusionResult->IsAttachedToSensor()) return orientationRift;
+        Quatf quaternion = FusionResult->GetPredictedOrientation();//FusionResult.GetOrientation();

   //float yaw, pitch, roll;
   //quaternion.GetEulerAngles<Axis_Y, Axis_X, Axis_Z>(&yaw, &pitch, &roll);
diff --git a/x11/x11.cpp b/x11/x11.cpp
index db48f37..607ff12 100644
--- a/x11/x11.cpp
+++ b/x11/x11.cpp
@@ -949,7 +949,7 @@ int main(int argc, char ** argv)
   getcwd(mResourcePath, sizeof(mResourcePath));

   initRift();
-  FusionResult.Reset();
+  FusionResult->Reset();

   // Instance of the class that tracks position/orientation of desktop
   Desktop3DLocation desktop3DLocation;