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Vrally
Up and Coming
August 8, 2014

TimeWarp not working when running with emulated device

Hi,

I have some issues with the TimeWarp shader when running with the emulated device, i.e. ovrHmd_CreateDebug(ovrHmd_DK1)

If I run with the time warp shader I get the following look:

If I run with ovrHmd_DK2 as a emulated device I get the same incorrect behavior (but in higher resolution).

If I connect my device (a DK1 in this case) I get the correct look:

Running emulated without TimeWarp also works fine.

I don't know if this is related but if I try running in debug mode with emulated device, I am running into the following ASSERT in the FrameTimeManager::BeginFrame(unsigned frameIndex) function:
OVR_ASSERT(FrameTiming.Inputs.ScreenDelay != 0);

    3 replies

    jherico
    Inspiring
    August 8, 2014
    "pixelminer" wrote:
    I don't know if this is related but if I try running in debug mode with emulated device, I am running into the following ASSERT in the FrameTimeManager::BeginFrame(unsigned frameIndex) function:
    OVR_ASSERT(FrameTiming.Inputs.ScreenDelay != 0);



    You have to call the ovrHmd_ResetFrameTiming method at least once before you call ovrHmd_BeginFrameTiming method.
    Brad Davis - Developer for High Fidelity Co-author of Oculus Rift in Action
    VrallyAuthor
    Up and Coming
    August 9, 2014
    This does not solve the problems with the TimeWarp shader when using an emulated device (It still looks like the above pictures).

    But it do solve the ASSERT problem. A problem I would say comes from a inconsistency in the SDK. Calling ovrHmd_Create() will automatically call ovrHmd_ResetFrameTiming() from inside that function (if we have a valid device connected). But ovrHmd_ResetFrameTiming() is oddly enough not called from inside ovrHmd_CreateDebug().

    A bit inconsistent but easy to fix:


    // Get first available HMD
    hmd = ovrHmd_Create(0);
    	
    // If no HMD is found try an emulated device
    if (!hmd) {
    	std::cout << "Warning: No device could be found. Creating emulated device " << std::endl;
    	hmd = ovrHmd_CreateDebug(ovrHmd_DK1);
    	ovrHmd_ResetFrameTiming(hmd, 0);
    }
    VrallyAuthor
    Up and Coming
    September 8, 2014
    I finally figured out why I was getting bogus matrixes as response from when running an emulated device:
    ovrHmd_GetEyeTimewarpMatrices(ovrHmd hmddesc, ovrEyeType eye, ovrPosef renderPose, ovrMatrix4f twmOut[2])


    The reason was that I was not initializing the renderPose struct correctly, so the ovrPosef struct was containing uninitialized variables.

    When running with a real device connected this struct was populated with data from the ovrHmd_GetEyePose() function. But I had that function inside conditional that never happened when running an emulated device:
    ovrPoseStatef headpose = ts.HeadPose;
    if (ts.StatusFlags & (ovrStatus_OrientationTracked | ovrStatus_PositionTracked)) {
    	...
    	for (int eyeIndex = 0; eyeIndex < ovrEye_Count; ++eyeIndex) {
    		ovrEyeType eye = m_hmdDevice->EyeRenderOrder[eyeIndex];
    		m_headPose[eye] = ovrHmd_GetEyePose(m_hmdDevice, eye);
    	}
    }


    Removing this conditional statement solved my issue.
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