Merge pull request #293 from Unity-Technologies/fix_large_deltatime

Fixed issue with simulation delta times larger than 100

com.unity.perception/CHANGELOG.md

 
 ### Fixed
 
+Fixed an issue where Simulation Delta Time values larger than 100 seconds (in Perception Camera) would cause incorrect capture scheduling behavior.
+
 ## [0.8.0-preview.3] - 2021-03-24
 ### Changed
 

com.unity.perception/Editor/GroundTruth/PerceptionCameraEditor.cs

         }
 
         const string k_FrametimeTitle = "Simulation Delta Time";
-
+        const float k_DeltaTimeTooLarge = 200;
         public override void OnInspectorGUI()
         {
             using(new EditorGUI.DisabledScope(EditorApplication.isPlaying))
                     GUILayout.BeginVertical("TextArea");
                     EditorGUILayout.LabelField("Scheduled Capture Properties", EditorStyles.boldLabel);
 
-                    EditorGUILayout.PropertyField(serializedObject.FindProperty(nameof(perceptionCamera.simulationDeltaTime)),new GUIContent(k_FrametimeTitle, $"Sets Unity's Time.{nameof(Time.captureDeltaTime)} to the specified number, causing a fixed number of frames to be simulated for each second of elapsed simulation time regardless of the capabilities of the underlying hardware. Thus, simulation time and real time will not be synchronized."));
+                    EditorGUILayout.PropertyField(serializedObject.FindProperty(nameof(perceptionCamera.simulationDeltaTime)),new GUIContent(k_FrametimeTitle, $"Sets Unity's Time.{nameof(Time.captureDeltaTime)} to the specified number, causing a fixed number of frames to be simulated for each second of elapsed simulation time regardless of the capabilities of the underlying hardware. Thus, simulation time and real time will not be synchronized. Note that large {k_FrametimeTitle} values will lead to lower performance as the engine will need to simulate longer periods of elapsed time for each rendered frame."));
+
+                    if (perceptionCamera.simulationDeltaTime > k_DeltaTimeTooLarge)
+                    {
+                        EditorGUILayout.HelpBox($"Large {k_FrametimeTitle} values can lead to significantly lower simulation performance.", MessageType.Warning);
+                    }
 
                     var interval = (perceptionCamera.framesBetweenCaptures + 1) * perceptionCamera.simulationDeltaTime;
                     var startTime = perceptionCamera.simulationDeltaTime * perceptionCamera.firstCaptureFrame;

com.unity.perception/Runtime/GroundTruth/SimulationState.cs

         const float k_SimulationTimingAccuracy = 0.01f;
         const int k_MinPendingCapturesBeforeWrite = 150;
         const int k_MinPendingMetricsBeforeWrite = 150;
-        const float k_MaxDeltaTime = 100f;
 
         public SimulationState(string outputDirectory)
         {
             }
 
             //find the deltatime required to land on the next active sensor that needs simulation
-            float nextFrameDt = k_MaxDeltaTime;
+            var nextFrameDt = float.PositiveInfinity;
             foreach (var activeSensor in m_ActiveSensors)
             {
                 float thisSensorNextFrameDt = -1;
                 }
 
                 if (thisSensorNextFrameDt > 0f && thisSensorNextFrameDt < nextFrameDt)
+                {
+                }
-            if (Math.Abs(nextFrameDt - k_MaxDeltaTime) < 0.0001)
+            if (float.IsPositiveInfinity(nextFrameDt))
             {
                 //means no sensor is controlling simulation timing, so we set Time.captureDeltaTime to 0 (default) which means the setting does not do anything
                 nextFrameDt = 0;

com.unity.perception/Tests/Runtime/GroundTruthTests/DatasetCaptureSensorSchedulingTests.cs

         }
 
         [UnityTest]
+        [TestCase(1, 0, 0, 1, 2, 3, ExpectedResult = (IEnumerator)null)]
+        [TestCase(10, 5, 50, 60, 70, 80, ExpectedResult = (IEnumerator)null)]
+        [TestCase(55, 0, 0, 55, 110, 165, ExpectedResult = (IEnumerator)null)]
+        [TestCase(235, 10, 2350, 2585, 2820, 3055, ExpectedResult = (IEnumerator)null)]
+        public IEnumerator SequenceTimeOfNextCapture_ReportsCorrectTime_VariedDeltaTimesAndStartFrames(float simulationDeltaTime, int firstCaptureFrame, float firstCaptureTime, float secondCaptureTime, float thirdCaptureTime, float fourthCaptureTime)
+        {
+            var ego = DatasetCapture.RegisterEgo("ego");
+            var sensorHandle = DatasetCapture.RegisterSensor(ego, "cam", "", firstCaptureFrame, CaptureTriggerMode.Scheduled, simulationDeltaTime, 0);
+
+            float[] sequenceTimesExpected =
+            {
+                firstCaptureTime,
+                secondCaptureTime,
+                thirdCaptureTime,
+                fourthCaptureTime
+            };
+
+            for (var i = 0; i < firstCaptureFrame; i++)
+            {
+                //render the non-captured frames before firstCaptureFrame
+                yield return null;
+            }
+
+            for (var i = 0; i < sequenceTimesExpected.Length; i++)
+            {
+                var sensorData = m_TestHelper.GetSensorData(sensorHandle);
+                var sequenceTimeActual = m_TestHelper.CallSequenceTimeOfNextCapture(sensorData);
+                Assert.AreEqual(sequenceTimesExpected[i], sequenceTimeActual, 0.0001f);
+                yield return null;
+            }
+        }
+
+        [UnityTest]
         public IEnumerator SequenceTimeOfManualCapture_ReportsCorrectTime_ManualSensorDoesNotAffectTimings()
         {
             var ego = DatasetCapture.RegisterEgo("ego");