/// <summary>
        /// Identifies the binocular suppression ratio.
        /// </summary>
        /// <returns>The binocular suppression ratio.</returns>
        /// <param name="ratioController">Ratio controller. Where we get our signal from to alter the ratio - e.g. tilt angle of head</param>
        /// <param name="model">Model. The model that provides us the conflict images.</param>
        /// <param name="cameraRig">Camera rig. The cameras whose relative brightness we wish to alter.</param>
        /// <param name="stillness">Stillness. Where we get information from about whether or not the headset is still. Might have been better to pass this headset specific mechanism to the VRHeadsetInput, which could have implemented a generic interface for reporting "stillness"</param>
        /// <param name="indicator">Indicator. The element which informs the user about the progress of the stillness based selection</param>
        /// <param name="NextStep">Next step.</param>
        /// <param name="secondsOfStillnessForSelect">Seconds of stillness for select.</param>
        IEnumerator IdentifyBinocularSuppressionRatio(EyeSkillsVRHeadsetInput ratioController,
                                                      ConflictZoneModel model,
                                                      EyeSkillsCameraRig cameraRig,
                                                      EyeSkillsVRHeadsetSelectByStillness stillness,
                                                      SelectionIndicatorScaler indicator,
                                                      Action <float> NextStep,
                                                      float secondsOfStillnessForSelect)
        {
            float suppressionRatio = 0;
            float still            = 0;
            float brightnessRatio;

            stillness.StartTracking();

            //TODO : We probably need a maximum timeout for if the headset never appears to settle!
            still = stillness.getTimeStill();
            while (still < secondsOfStillnessForSelect)
            {
                //Update the luminance ratio for each eye
                brightnessRatio = Mathf.Clamp(ratioController.getVerticalDirection(), -1, 1);

                cameraRig.SetBinocularSuppressionRatio(brightnessRatio);

                //redraw the indicator and play a rising tone?!?
                float percentage = (still / secondsOfStillnessForSelect);
                //Debug.Log("Percentage still " + percentage);
                indicator.SetIndicatorPercentage(percentage);
                yield return(null);

                still = stillness.getTimeStill();

                //Debug.Log("ratio : "+ brightnessRatio + " %:" + percentage);
            }

            stillness.StopTracking();
            indicator.Reset();
            StopConflictEnvironment();
            NextStep(suppressionRatio);
        }
        /// <summary>
        /// Coordinating what the participant experiences on the basis of the atom's supplied physicsState.
        /// Doing things this way should actually simplify things like certifying the app is in known states.
        /// </summary>
        /// <param name="_completionCallback">Completion callback.</param>
        public override void Start(Action <String> _completionCallback)
        {
            base.Start(_completionCallback);

            Debug.Log("Making the camera look forward by default, without following headset rotation.");
            cameraRig.ImmediatelyLookToOrigin();
            cameraRig.SetLeftEyePositionOnly();
            cameraRig.SetRightEyePositionOnly();

            Debug.Log("UIMolecule disabled by default.");
            DeActivateUIMolecule();

            completionCallback = _completionCallback;


            if (atom.physicsState == 1) //Let the participant know what is coming.
            {
                ActivateUIMolecule();
                audioManager.Say(atom.audioFile, delegate()
                {
                    AtomExpiry(0, false, "Physics state 1 - After audio expires");
                });
            }
            else if (atom.physicsState == 2)  //Present them with a conflict image
            {
                audioManager.Say(atom.audioFile, StopConflictEnvironment, 5);
                StartConflictEnvironment();
            }
            else if (atom.physicsState == 3)  //How did they perceive the image?  The gallery.
            {
                //Allow the user to look around
                cameraRig.SetLeftEyeRotationAndPosition();
                cameraRig.SetRightEyeRotationAndPosition();

                audioManager.Say(atom.audioFile);
                StartPerceptionGallery(SelectedPerceptionImage);
            }
            else if (atom.physicsState == 5) //Now find out if blinkers can remove conflict for them
            {
                StartConflictEnvironment();
                conflictController.OutOfConflict();

                blinkerExperienceInSeconds = 6; //Allow some time after the audio has finished to keep observing
                audioManager.Say(atom.audioFile, delegate()
                {
                    coRoutineHelper.BeginCoroutine(TimeBlinkerExperience());
                });
            }
            else if (atom.physicsState == 6) //Did the blinkers remove conflict for them?
            {
                ReviewBlinkerExperience();
            }
            else if (atom.physicsState == 7) //TODO: Day1 - OBSOLETE?
            {
                UIMolecule m = ActivateUIMolecule();
                SetDefaultVRImage(m, atom.image);
                ActivateContinueButton(false);
                ExplainBlinkerExperience();
            }
            else if (atom.physicsState == 8)  //Day2 - Present a conflict environment for ten seconds after audio ends : Similar to state 2
            {
                audioManager.Say(atom.audioFile, StopConflictEnvironment, 10);
                StartConflictEnvironment();
            }
            else if (atom.physicsState == 9)  //Day2 - Show the static Blinker
            {
                Debug.Log("Explaining about Blinkers, after audio ends, we start blinking...");
                //Manually start the conflict environment.
                StartConflictEnvironment();
                conflictController.OutOfConflict();

                blinkerExperienceInSeconds = 10;
                audioManager.Say(atom.audioFile, delegate()
                {
                    coRoutineHelper.BeginCoroutine(TimeBlinkerExperience());
                });
            }
            else if (atom.physicsState == 10) //Now show the alternating Blinker toggling
            {
                blinkerExperienceInSeconds = 30;
                StartBlinkerEnvironment();
                audioManager.Say(atom.audioFile);
            }
            else if (atom.physicsState == 11)  //Present them with a conflict image
            {
                audioManager.Say(atom.audioFile, StopConflictEnvironment);
                StartConflictEnvironment();
            }
            else if (atom.physicsState == 12)
            { //Test they can tilt their heads upwards
              //Get hold of the HeadsetVRInput

                DemoSuppression();

                if (data.numberOfTiltAttempts >= maxNumberOfTiltAttempts)
                {
                    data.numberOfTiltAttempts = 0; //A hack for testing. Shouldn't affect production
                    data.Save();
                }

                audioManager.Say(atom.audioFile, delegate(){
                    DetectVerticalHeadTilt(EndUpwardTiltCheck, timeToWaitForHeadTiltCheck);//We pass "0" to the EndUpwardTiltCheck to signify we ran out of time.
                });
            }
            else if (atom.physicsState == 13)
            {
                DemoSuppression();

                if (data.numberOfTiltAttempts >= maxNumberOfTiltAttempts)
                {
                    data.numberOfTiltAttempts = 0; //A hack for testing. Shouldn't affect production
                    data.Save();
                }

                //Test they can tilt their heads downwards
                audioManager.Say(atom.audioFile, delegate() {
                    DetectVerticalHeadTilt(EndDownwardTiltCheck, timeToWaitForHeadTiltCheck);
                });
            }
            else if (atom.physicsState == 14) //Decide whether to repeat the tilt tests or not
            {
                if ((data.couldTiltUpward == false) || (data.couldTiltDownward == false))
                {
                    //Debug.Log("One of the tilts failed " + data.couldTiltUpward + data.couldTiltDownward);
                    if (data.numberOfTiltAttempts == (maxNumberOfTiltAttempts - 1))  //We've already tried enough times and still don't have adequate tilt
                    //Debug.Log("Too many attempts");
                    {
                        data.numberOfTiltAttempts = maxNumberOfTiltAttempts;
                        AtomExpiry(0, true, "Failed to tilt head adequately");
                    }
                    else
                    { //Let's have another go
                        AtomExpiry(1, true, "Trying another round of head tilt tests");
                    }
                }
                else     //They must have succeeded
                {
                    AtomExpiry(2, true, "Head tilt tests succeeded");
                }
            }
            else if (atom.physicsState == 15) //Time to detect the suppression ratio
            {
                //Enable head rotation
                cameraRig.SetLeftEyeRotationAndPosition();
                cameraRig.SetRightEyeRotationAndPosition();

                //Get hold of the HeadsetVRInput
                EyeSkillsVRHeadsetInput ratioController = GameObject.Find("Head").GetComponent <EyeSkillsVRHeadsetInput>();

                //Get hold of the conflict objects
                StartConflictEnvironment(); //Sets conflictZoneModel

                SelectionIndicatorScaler indicator = cameraRig.GetComponentInChildren <SelectionIndicatorScaler>();


                //Get hold of our Stillness Selector - adding it to the Head object
                EyeSkillsVRHeadsetSelectByStillness stillness = EyeSkillsVRHeadsetSelectByStillness.instance;

                audioManager.Say(atom.audioFile, delegate()
                {
                    //Start a couroutine which manages the brightness control and calls a finishing function with a suppression ratio
                    Coroutine c = coRoutineHelper.BeginCoroutine(IdentifyBinocularSuppressionRatio(
                                                                     ratioController,
                                                                     conflictController,
                                                                     cameraRig,
                                                                     stillness,
                                                                     indicator,
                                                                     delegate(float suppressionRatio)
                    {
                        data.binocularSuppressionRatio = suppressionRatio;
                        data.Save();
                        AtomExpiry(0, false, "SuppressionRatio captured");
                    },
                                                                     6f
                                                                     ));
                    coroutinesToShutdown.Add(c);
                });
            }
            else if (atom.physicsState == 16)
            {
                ActivateUIMolecule();
                //Allow the user to look around
                cameraRig.SetLeftEyeRotationAndPosition();
                cameraRig.SetRightEyeRotationAndPosition();

                audioManager.Say(atom.audioFile);
                StartPerceptionGallery(SelectedTolerancePerceptionImage);
            }
        }