From fea964a6f3c1facb51ef4985e3891ac2e5f816d6 Mon Sep 17 00:00:00 2001
From: Mads Buvik Sandvei <madssandvei@protonmail.com>
Date: Mon, 27 Jan 2020 18:34:48 +0100
Subject: [PATCH] Tightened prediction point

---
 apps/openmw/mwvr/openxrmanagerimpl.cpp | 26 +++++++++++++++-----------
 apps/openmw/mwvr/openxrview.cpp        |  4 ++++
 apps/openmw/mwvr/openxrviewer.cpp      |  1 -
 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/apps/openmw/mwvr/openxrmanagerimpl.cpp b/apps/openmw/mwvr/openxrmanagerimpl.cpp
index fb0c07952..c41b6e6b7 100644
--- a/apps/openmw/mwvr/openxrmanagerimpl.cpp
+++ b/apps/openmw/mwvr/openxrmanagerimpl.cpp
@@ -262,7 +262,7 @@ namespace MWVR
         // In some implementations xrWaitFrame might not return immediately when it should.
         // So i let it wait in a separate thread. xrBeginFrame() should wait on xrWaitFrame() 
         // and xrWaitFrame() doesn't happen again until xrEndFrame() so synchronization is not necessary.
-        std::thread([this]() {
+        //std::thread([this]() {
             static std::mutex waitFrameMutex;
             std::unique_lock<std::mutex> lock(waitFrameMutex);
 
@@ -277,7 +277,7 @@ namespace MWVR
 
             mTimeKeeper.progressToNextFrame(frameState);
 
-        }).detach();
+        //}).detach();
 
     }
 
@@ -425,7 +425,7 @@ namespace MWVR
             beginInfo.primaryViewConfigurationType = mViewConfigType;
             CHECK_XRCMD(xrBeginSession(mSession, &beginInfo));
             mSessionRunning = true;
-            waitFrame();
+            //waitFrame();
             break;
         }
         case XR_SESSION_STATE_STOPPING:
@@ -480,16 +480,20 @@ namespace MWVR
     {
         std::unique_lock<std::mutex> lock(mMutex);
 
-        auto prediction = mPredictedFrameTime;
-        auto predictedPeriod = mPredictedPeriod;
+        //auto prediction = mPredictedFrameTime;
+        //auto predictedPeriod = mPredictedPeriod;
 
-        auto futureFrames = frameIndex - OpenXRFrameIndexer::instance().renderIndex();
+        //auto futureFrames = frameIndex - OpenXRFrameIndexer::instance().renderIndex();
 
-        prediction += ( 0 + futureFrames) * predictedPeriod;
+        //prediction += ( 0 + futureFrames) * predictedPeriod;
 
-        Log(Debug::Verbose) << "Predicted: displayTime[" << futureFrames << "]=" << prediction;
+        //Log(Debug::Verbose) << "Predicted: displayTime[" << futureFrames << "]=" << prediction;
 
-        return prediction;
+        //return prediction;
+
+        //return mFrameState.predictedDisplayTime;
+
+        return mPredictedFrameTime;
     }
 
     void OpenXRTimeKeeper::progressToNextFrame(XrFrameState frameState)
@@ -515,8 +519,8 @@ namespace MWVR
         {
             // predictedDisplayTime refers to the midpoint of the display period
             // The upjustment must therefore only be half the magnitude
-            // mPredictedFrameTime += (realPeriod - mFrameState.predictedDisplayPeriod);
-            // mPredictedPeriod = realPeriod;
+             mPredictedFrameTime += (realPeriod - mFrameState.predictedDisplayPeriod) / 2;
+             mPredictedPeriod = realPeriod;
         }
 
 
diff --git a/apps/openmw/mwvr/openxrview.cpp b/apps/openmw/mwvr/openxrview.cpp
index 274fe9784..165937274 100644
--- a/apps/openmw/mwvr/openxrview.cpp
+++ b/apps/openmw/mwvr/openxrview.cpp
@@ -74,6 +74,10 @@ namespace MWVR {
 
     void OpenXRView::prerenderCallback(osg::RenderInfo& renderInfo)
     {
+
+        if(mName == "LeftEye")
+            mXR->waitFrame();
+
         Log(Debug::Verbose) << mName << ": prerenderCallback";
         if (mSwapchain)
         {
diff --git a/apps/openmw/mwvr/openxrviewer.cpp b/apps/openmw/mwvr/openxrviewer.cpp
index d77596e7e..1cfaaf70e 100644
--- a/apps/openmw/mwvr/openxrviewer.cpp
+++ b/apps/openmw/mwvr/openxrviewer.cpp
@@ -185,7 +185,6 @@ namespace MWVR
         mViews[OpenXRWorldView::RIGHT_VIEW]->swapchain().endFrame(gc);
         mXRMenu->swapchain().endFrame(gc);
         mXR->endFrame();
-        mXR->waitFrame();
         //gl->glBindFramebuffer(GL_DRAW_FRAMEBUFFER_EXT, 0);
         
         //mMirrorTextureSwapchain->renderBuffer()->blit(gc, 0, 0, mMirrorTextureSwapchain->width(), mMirrorTextureSwapchain->height());