Fix for bug with frame timings.

Author: JonathanHUnity

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

@@ -49,7 +49,7 @@ public static EgoHandle RegisterEgo(string description)
         /// <param name="egoHandle">The ego container for the sensor. Sensor orientation will be reported in the context of the given ego.</param>
         /// <param name="modality">The kind of the sensor (ex. "camera", "lidar")</param>
         /// <param name="description">A human-readable description of the sensor (ex. "front-left rgb camera")</param>
-        /// <param name="firstCaptureFrame">The time, in seconds, from the start of the sequence on which this sensor should first be scheduled.</param>
+        /// <param name="firstCaptureFrame">The offset from the current frame on which this sensor should first be scheduled.</param>
         /// <param name="captureTriggerMode">The method of triggering captures for this sensor.</param>
         /// <param name="simulationDeltaTime">The simulation frame time (seconds) requested by this sensor.</param>
         /// <param name="framesBetweenCaptures">The number of frames to simulate and render between the camera's scheduled captures. Setting this to 0 makes the camera capture every frame.</param>

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

@@ -373,7 +373,7 @@ public void AddSensor(EgoHandle egoHandle, string modality, string description,
             {
                 modality = modality,
                 description = description,
-                firstCaptureTime = firstCaptureFrame * renderingDeltaTime,
+                firstCaptureTime = UnscaledSequenceTime + firstCaptureFrame * renderingDeltaTime,
                 captureTriggerMode = captureTriggerMode,
                 renderingDeltaTime = renderingDeltaTime,
                 framesBetweenCaptures = framesBetweenCaptures,
@@ -382,7 +382,7 @@ public void AddSensor(EgoHandle egoHandle, string modality, string description,
                 lastCaptureFrameCount = -1
             };
             sensorData.sequenceTimeOfNextCapture = GetSequenceTimeOfNextCapture(sensorData);
-            sensorData.sequenceTimeOfNextRender = 0;
+            sensorData.sequenceTimeOfNextRender = UnscaledSequenceTime;
             m_ActiveSensors.Add(sensor);
             m_Sensors.Add(sensor, sensorData);
             m_Ids.Add(sensor.Id);