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authorSven Gothel <[email protected]>2014-06-19 17:03:28 +0200
committerSven Gothel <[email protected]>2014-06-19 17:03:28 +0200
commitd9a584844a60542519d813b5dc1a62428f14a0ae (patch)
tree942c10a5ebcd0aab65e9d6facb59778468f39d3b /LibOVR/Src/CAPI/CAPI_FrameTimeManager.h
Add OculusSDK 0.3.2 Linux Source Code w/o Samples, docs or binaries (libs or tools)
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+/************************************************************************************
+
+Filename : CAPI_FrameTimeManager.h
+Content : Manage frame timing and pose prediction for rendering
+Created : November 30, 2013
+Authors : Volga Aksoy, Michael Antonov
+
+Copyright : Copyright 2014 Oculus VR, Inc. All Rights reserved.
+
+Licensed under the Oculus VR Rift SDK License Version 3.1 (the "License");
+you may not use the Oculus VR Rift SDK except in compliance with the License,
+which is provided at the time of installation or download, or which
+otherwise accompanies this software in either electronic or hard copy form.
+
+You may obtain a copy of the License at
+
+http://www.oculusvr.com/licenses/LICENSE-3.1
+
+Unless required by applicable law or agreed to in writing, the Oculus VR SDK
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+************************************************************************************/
+
+#ifndef OVR_CAPI_FrameTimeManager_h
+#define OVR_CAPI_FrameTimeManager_h
+
+#include "../OVR_CAPI.h"
+#include "../Kernel/OVR_Timer.h"
+#include "../Kernel/OVR_Math.h"
+#include "../Util/Util_Render_Stereo.h"
+#include "../Util/Util_LatencyTest2.h"
+
+namespace OVR { namespace CAPI {
+
+//-------------------------------------------------------------------------------------
+
+// Helper class to collect median times between frames, so that we know
+// how long to wait.
+struct TimeDeltaCollector
+{
+ TimeDeltaCollector() : Count(0) { }
+
+ void AddTimeDelta(double timeSeconds);
+ void Clear() { Count = 0; }
+
+ double GetMedianTimeDelta() const;
+
+ double GetCount() const { return Count; }
+
+ enum { Capacity = 12 };
+private:
+ int Count;
+ double TimeBufferSeconds[Capacity];
+};
+
+
+//-------------------------------------------------------------------------------------
+// ***** FrameLatencyTracker
+
+// FrameLatencyTracker tracks frame Present to display Scan-out timing, as reported by
+// the DK2 internal latency tester pixel read-back. The computed value is used in
+// FrameTimeManager for prediction. View Render and TimeWarp to scan-out latencies are
+// also reported for debugging.
+//
+// The class operates by generating color values from GetNextDrawColor() that must
+// be rendered on the back end and then looking for matching values in FrameTimeRecordSet
+// structure as reported by HW.
+
+class FrameLatencyTracker
+{
+public:
+
+ enum { FramesTracked = Util::LT2_IncrementCount-1 };
+
+ FrameLatencyTracker();
+
+ // DrawColor == 0 is special in that it doesn't need saving of timestamp
+ unsigned char GetNextDrawColor();
+
+ void SaveDrawColor(unsigned char drawColor, double endFrameTime,
+ double renderIMUTime, double timewarpIMUTime );
+
+ void MatchRecord(const Util::FrameTimeRecordSet &r);
+
+ void GetLatencyTimings(float latencies[3]);
+
+ void Reset();
+
+public:
+
+ struct FrameTimeRecordEx : public Util::FrameTimeRecord
+ {
+ bool MatchedRecord;
+ double RenderIMUTimeSeconds;
+ double TimewarpIMUTimeSeconds;
+ };
+
+ // True if rendering read-back is enabled.
+ bool TrackerEnabled;
+
+ enum SampleWaitType {
+ SampleWait_Zeroes, // We are waiting for a record with all zeros.
+ SampleWait_Match // We are issuing & matching colors.
+ };
+
+ SampleWaitType WaitMode;
+ int MatchCount;
+ // Records of frame timings that we are trying to measure.
+ FrameTimeRecordEx FrameEndTimes[FramesTracked];
+ int FrameIndex;
+ // Median filter for (ScanoutTimeSeconds - PostPresent frame time)
+ TimeDeltaCollector FrameDeltas;
+ // Latency reporting results
+ double RenderLatencySeconds;
+ double TimewarpLatencySeconds;
+ double LatencyRecordTime;
+};
+
+
+
+//-------------------------------------------------------------------------------------
+// ***** FrameTimeManager
+
+// FrameTimeManager keeps track of rendered frame timing and handles predictions for
+// orientations and time-warp.
+
+class FrameTimeManager
+{
+public:
+ FrameTimeManager(bool vsyncEnabled = true);
+
+ // Data that affects frame timing computation.
+ struct TimingInputs
+ {
+ // Hard-coded value or dynamic as reported by FrameTimeDeltas.GetMedianTimeDelta().
+ double FrameDelta;
+ // Screen delay from present to scan-out, as potentially reported by ScreenLatencyTracker.
+ double ScreenDelay;
+ // Negative value of how many seconds before EndFrame we start timewarp. 0.0 if not used.
+ double TimewarpWaitDelta;
+
+ TimingInputs()
+ : FrameDelta(0), ScreenDelay(0), TimewarpWaitDelta(0)
+ { }
+ };
+
+ // Timing values for a specific frame.
+ struct Timing
+ {
+ TimingInputs Inputs;
+
+ // Index of a frame that started at ThisFrameTime.
+ unsigned int FrameIndex;
+ // Predicted absolute times for when this frame will show up on screen.
+ // Generally, all values will be >= NextFrameTime, since that's the time we expect next
+ // vsync to succeed.
+ double ThisFrameTime;
+ double TimewarpPointTime;
+ double NextFrameTime;
+ double MidpointTime;
+ double EyeRenderTimes[2];
+ double TimeWarpStartEndTimes[2][2];
+
+ Timing()
+ {
+ memset(this, 0, sizeof(Timing));
+ }
+
+ void InitTimingFromInputs(const TimingInputs& inputs, HmdShutterTypeEnum shutterType,
+ double thisFrameTime, unsigned int frameIndex);
+ };
+
+
+ // Called on startup to provided data on HMD timing.
+ void Init(HmdRenderInfo& renderInfo);
+
+ // Called with each new ConfigureRendering.
+ void ResetFrameTiming(unsigned frameIndex,
+ bool dynamicPrediction, bool sdkRender);
+
+ void SetVsync(bool enabled) { VsyncEnabled = enabled; }
+
+ // BeginFrame returns time of the call
+ // TBD: Should this be a predicted time value instead ?
+ double BeginFrame(unsigned frameIndex);
+ void EndFrame();
+
+ // Thread-safe function to query timing for a future frame
+ Timing GetFrameTiming(unsigned frameIndex);
+
+ double GetEyePredictionTime(ovrEyeType eye);
+ Transformf GetEyePredictionPose(ovrHmd hmd, ovrEyeType eye);
+
+ void GetTimewarpPredictions(ovrEyeType eye, double timewarpStartEnd[2]);
+ void GetTimewarpMatrices(ovrHmd hmd, ovrEyeType eye, ovrPosef renderPose, ovrMatrix4f twmOut[2]);
+
+ // Used by renderer to determine if it should time distortion rendering.
+ bool NeedDistortionTimeMeasurement() const;
+ void AddDistortionTimeMeasurement(double distortionTimeSeconds);
+
+
+ // DK2 Lateny test interface
+
+ // Get next draw color for DK2 latency tester
+ unsigned char GetFrameLatencyTestDrawColor()
+ { return ScreenLatencyTracker.GetNextDrawColor(); }
+
+ // Must be called after EndFrame() to update latency tester timings.
+ // Must pass color reported by NextFrameColor for this frame.
+ void UpdateFrameLatencyTrackingAfterEndFrame(unsigned char frameLatencyTestColor,
+ const Util::FrameTimeRecordSet& rs);
+
+ void GetLatencyTimings(float latencies[3])
+ { return ScreenLatencyTracker.GetLatencyTimings(latencies); }
+
+
+ const Timing& GetFrameTiming() const { return FrameTiming; }
+
+private:
+
+ double calcFrameDelta() const;
+ double calcScreenDelay() const;
+ double calcTimewarpWaitDelta() const;
+
+
+ HmdRenderInfo RenderInfo;
+ // Timings are collected through a median filter, to avoid outliers.
+ TimeDeltaCollector FrameTimeDeltas;
+ TimeDeltaCollector DistortionRenderTimes;
+ FrameLatencyTracker ScreenLatencyTracker;
+
+ // Timing changes if we have no Vsync (all prediction is reduced to fixed interval).
+ bool VsyncEnabled;
+ // Set if we are rendering via the SDK, so DistortionRenderTimes is valid.
+ bool DynamicPrediction;
+ // Set if SDk is doing teh rendering.
+ bool SdkRender;
+
+ // Total frame delay due to VsyncToFirstScanline, persistence and settle time.
+ // Computed from RenderInfor.Shutter.
+ double VSyncToScanoutDelay;
+ double NoVSyncToScanoutDelay;
+ double ScreenSwitchingDelay;
+
+ // Current (or last) frame timing info. Used as a source for LocklessTiming.
+ Timing FrameTiming;
+ // TBD: Don't we need NextFrame here as well?
+ LocklessUpdater<Timing> LocklessTiming;
+
+
+ // IMU Read timings
+ double RenderIMUTimeSeconds;
+ double TimewarpIMUTimeSeconds;
+};
+
+
+}} // namespace OVR::CAPI
+
+#endif // OVR_CAPI_FrameTimeManager_h
+
+