SessionDetails: Add some helper function for common display data.

Author: CrossVR

Revive/REV_CAPI.cpp

@@ -1021,16 +1021,15 @@ OVR_PUBLIC_FUNCTION(double) ovr_GetPredictedDisplayTime(ovrSession session, long
 if (session->FrameIndex == 0)
 return ovr_GetTimeInSeconds();
 
-float fVsyncToPhotons = vr::VRSystem()->GetFloatTrackedDeviceProperty(vr::k_unTrackedDeviceIndex_Hmd, vr::Prop_SecondsFromVsyncToPhotons_Float);
-double predictAhead = vr::VRCompositor()->GetFrameTimeRemaining() + fVsyncToPhotons;
+double predictAhead = vr::VRCompositor()->GetFrameTimeRemaining() + session->Details->GetVsyncToPhotons();
 if (session)
 {
 // Some applications ask for frames ahead of the current frame
-const ovrHmdDesc* pHmd = session->Details->GetHmdDesc();
+float refreshRate = session->Details->GetRefreshRate();
 if (frameIndex > 0)
-predictAhead += double(frameIndex - session->FrameIndex) / pHmd->DisplayRefreshRate;
+predictAhead += double(frameIndex - session->FrameIndex) / refreshRate;
 else
-predictAhead += 1.0 / pHmd->DisplayRefreshRate;
+predictAhead += 1.0 / refreshRate;
 }
 return ovr_GetTimeInSeconds() + predictAhead;
 }

Revive/SessionDetails.cpp

@@ -17,9 +17,11 @@ SessionDetails::HackInfo SessionDetails::m_known_hacks[] = {
 };
 
 SessionDetails::SessionDetails()
-: HmdDesc()
+: TrackerCount(0)
+, fVsyncToPhotons(0.0f)
+, HmdDesc()
+, RenderDesc()
 , TrackerDesc()
-, TrackerCount(0)
 {
 char filepath[MAX_PATH];
 GetModuleFileNameA(NULL, filepath, MAX_PATH);
@@ -137,6 +139,7 @@ void SessionDetails::UpdateHmdDesc()
 HmdDesc.Resolution = size;
 HmdDesc.Resolution.w *= 2; // Both eye ports
 HmdDesc.DisplayRefreshRate = vr::VRSystem()->GetFloatTrackedDeviceProperty(vr::k_unTrackedDeviceIndex_Hmd, vr::Prop_DisplayFrequency_Float);
+fVsyncToPhotons = vr::VRSystem()->GetFloatTrackedDeviceProperty(vr::k_unTrackedDeviceIndex_Hmd, vr::Prop_SecondsFromVsyncToPhotons_Float);
 }
 
 void SessionDetails::UpdateTrackerDesc()

Revive/SessionDetails.h

@@ -70,6 +70,9 @@ class SessionDetails
 return index < vr::k_unMaxTrackedDeviceCount ? &TrackerDesc[index] : nullptr;
 }
 
+float GetRefreshRate() const { return HmdDesc.DisplayRefreshRate; }
+float GetVsyncToPhotons() const { return fVsyncToPhotons; }
+
 private:
 struct HackInfo
 {
@@ -82,6 +85,7 @@ class SessionDetails
 static HackInfo m_known_hacks[];
 std::map<Hack, HackInfo> m_hacks;
 
+float fVsyncToPhotons;
 ovrHmdDesc HmdDesc;
 ovrEyeRenderDesc RenderDesc[ovrEye_Count];
 ovrTrackerDesc TrackerDesc[vr::k_unMaxTrackedDeviceCount];