Merge pull request #37 from DuFF14/LatencyUpdates

Latency improvements. 
Read display descriptor file from disk as opposed to being hard-coded

Author: Yuval Boger

OSVR-Unity/Assets/OSVRUnity/src/ClientKit.cs

@@ -102,9 +102,22 @@ void OnEnable()
             void FixedUpdate()
             {
                 EnsureStarted();
+                //Debug.Log("ClientKit FixedUpdate: frame # " + Time.frameCount + " " + Time.time);
+                contextObject.update();
+            }
+          
+            //may seem superfluous. the goal here is to update the client more often to make sure we have the most recent tracker data
+            //this helps reduce latency
+            void Update()
+            {
+                contextObject.update();
+            }
+            //may seem superfluous. the goal here is to update the client more often to make sure we have the most recent tracker data
+            //this helps reduce latency
+            void LateUpdate()
+            {
                 contextObject.update();
             }
-
             void Stop()
             {
                 if (null != contextObject)

OSVR-Unity/Assets/OSVRUnity/src/DisplayInterface.cs

@@ -22,6 +22,7 @@
 using UnityEngine;
 using Newtonsoft.Json;
 using System.IO;
+using System.Collections;
 
 namespace OSVR
 {
@@ -35,21 +36,49 @@ namespace Unity
         /// </summary>
         public class DisplayInterface : MonoBehaviour
         {
+            const string HmdJsonFileName = "hmd.json"; //hardcoded filename of hmd config in Data folder
             private string _deviceDescriptorJson; //a string that is the JSON file to be parsed
             public TextAsset JsonDescriptorFile; //drop the json file into this slot in the Unity inspector
+            public bool Initialized
+            {
+                get { return _initialized; }
+            }
+            private bool _initialized = false; //flag set when _deviceDescriptorJson has data
+
             void Awake()
             {
-                if (JsonDescriptorFile != null)
+                //check to see if "hmd.json" is provided in the Data folder
+                //if so, load it
+                string filePath = Application.dataPath + "/" + HmdJsonFileName;
+                if (System.IO.File.Exists(filePath))
                 {
-                    _deviceDescriptorJson = JsonDescriptorFile.text; //read JSON file directly from Unity if provided
+                    StartCoroutine(LoadJsonFile(filePath));
                 }
-                else
+                else //if not, load the json file provided in the Unity editor
                 {
-                    _deviceDescriptorJson = ClientKit.instance.context.getStringParameter("/display"); //otherwise read from /display
-                }
+                    if (JsonDescriptorFile != null)
+                    {
+                        _deviceDescriptorJson = JsonDescriptorFile.text; //read JSON file directly from Unity if provided
+                    }
+                    else
+                    {
+                        _deviceDescriptorJson = ClientKit.instance.context.getStringParameter("/display"); //otherwise read from /display
+                    }
+                    _initialized = true;
+                }  
+            }
+
+            //coroutine for loading an external json config file
+            //this could be more generic, but I'm not sure we will be loading external files
+            //this will eventually go away anyway when we get display config data from /display
+            private IEnumerator LoadJsonFile(string filePath)
+            {
+                WWW jsonFile = new WWW("file://" + filePath);
+                yield return jsonFile;
+                _initialized = true;
+                _deviceDescriptorJson = jsonFile.text;
             }
 
-            
 
             /// <summary>
             /// This function will parse the device parameters from a device descriptor json file.

OSVR-Unity/Assets/OSVRUnity/src/PoseInterface.cs

@@ -32,15 +32,30 @@ namespace Unity
         /// </summary>
         public class PoseInterface : InterfaceGameObject
         {
+            //private int currentFrame = 0;
+            //private int frameCount = 0;
             new void Start()
             {
                 osvrInterface.RegisterCallback(callback);
+                //currentFrame = Time.frameCount;
+                //frameCount = 0;
             }
 
             private void callback(string source, Vector3 position, Quaternion rotation)
             {
                 transform.localPosition = position;
                 transform.localRotation = rotation;
+                //keeping this here for now for debugging purposes
+                /*if(currentFrame != Time.frameCount)
+                {
+                    Debug.Log("Time.frameCount = " + currentFrame + ", Time.time = " + Time.time + ". Callbacks per frame = " + frameCount);
+                    frameCount = 0;
+                    currentFrame = Time.frameCount;
+                }
+                else
+                {
+                    frameCount++;
+                }*/              
             }
         }
     }

OSVR-Unity/Assets/OSVRUnity/src/VREye.cs

@@ -37,12 +37,14 @@ public class VREye : MonoBehaviour
         {
             #region Private Variables
             private Camera _camera;
+            private ClientKit clientKit;
             #endregion
             #region Public Variables
             public Eye eye;
             public Camera Camera { get { return _camera; } set { _camera = value; } }
             [HideInInspector]
             public Transform cachedTransform;
+            
             #endregion
 
             #region Init
@@ -90,6 +92,10 @@ public void SetEyeRoll(float rollAmount)
             #region Private Methods
             void Init()
             {
+                if(clientKit == null)
+                {
+                    clientKit = GameObject.FindObjectOfType<ClientKit>();
+                }
                 //cache:
                 cachedTransform = transform;
 
@@ -122,6 +128,14 @@ private void SetViewportRects()
                         break;
                 }
             }
+
+            //Called after a camera finishes rendering the scene.
+            //the goal here is to update the client often to make sure we have the most recent tracker data
+            //this helps reduce latency
+            void OnPostRender()
+            {
+                clientKit.context.update();
+            }
             #endregion
 
 

OSVR-Unity/Assets/OSVRUnity/src/VRHead.cs

@@ -53,6 +53,7 @@ public class VRHead : MonoBehaviour
             private Camera _camera;
             private DeviceDescriptor _deviceDescriptor;
             private OsvrDistortion _distortionEffect;
+            private bool _initDisplayInterface = false;
             #endregion
 
             #region Init
@@ -65,23 +66,24 @@ void Start()
                 {
                     _distortionEffect.enabled = (viewMode == ViewMode.mono);
                 }
-                GetDeviceDescription();
-                MatchEyes(); //copy camera properties to each eye
-                //rotate each eye based on overlap percent, must do this after match eyes
-                if (_deviceDescriptor != null)
+
+                //update VRHead with info from the display interface if it has been initialized
+                //it might not be initialized if it is still loading/parsing a display json file
+                //in that case, we will try to initialize asap in the update function
+                if (GetComponent<DisplayInterface>().Initialized)
                 {
-                    SetEyeRotation(_deviceDescriptor.OverlapPercent, _deviceDescriptor.MonocularHorizontal);
-                    SetEyeRoll(_deviceDescriptor.LeftRoll, _deviceDescriptor.RightRoll);
-                }
-                
-                
-                
-            }
+                    UpdateDisplayInterface();                  
+                }              
+            }         
             #endregion
 
             #region Loop
             void Update()
             {
+                if(!_initDisplayInterface && GetComponent<DisplayInterface>().Initialized)
+                {
+                    UpdateDisplayInterface();
+                }
                 UpdateStereoAmount();
                 UpdateViewMode();
             }
@@ -91,6 +93,18 @@ void Update()
             #endregion
 
             #region Private Methods
+            private void UpdateDisplayInterface()
+            {
+                GetDeviceDescription();
+                MatchEyes(); //copy camera properties to each eye
+                //rotate each eye based on overlap percent, must do this after match eyes
+                if (_deviceDescriptor != null)
+                {
+                    SetEyeRotation(_deviceDescriptor.OverlapPercent, _deviceDescriptor.MonocularHorizontal);
+                    SetEyeRoll(_deviceDescriptor.LeftRoll, _deviceDescriptor.RightRoll);
+                }
+                _initDisplayInterface = true;
+            }
             void UpdateViewMode()
             {
                 if (Time.realtimeSinceStartup < 100 || _previousViewMode != viewMode)
@@ -170,6 +184,8 @@ void Init()
 
                 //60 FPS whenever possible:
                 Application.targetFrameRate = 60;
+
+                _initDisplayInterface = false;
             }
 
             /// <summary>
@@ -178,10 +194,10 @@ void Init()
             /// </summary>
             private void GetDeviceDescription()
             {
-                _deviceDescriptor = GetComponent<DisplayInterface>().GetDeviceDescription();
-                Debug.Log(_deviceDescriptor.ToString());
+                _deviceDescriptor = GetComponent<DisplayInterface>().GetDeviceDescription();              
                 if (_deviceDescriptor != null)
                 {
+                    Debug.Log(_deviceDescriptor.ToString());
                     switch (_deviceDescriptor.DisplayMode)
                     {
                         case "full_screen":

OSVR-Unity/CHANGES.md

@@ -3,13 +3,16 @@
 This is an abbreviated changelog for the OSVR Unity Plugin.
 
 Use git for a full changelog.
-##Recent Changes (updated 18-March-2015)
-##Distortion (20-March-2015)
+##Recent Changes (updated 28-March-2015)
+##External Json File v0.1-56-gf2d8bab (20-March-2015)
+- The JSON file containing display configuration can now be read from a file at runtime. To do this, add a config file "hmd.json" to the _Data folder that is created in a build. The format of the JSON file has not changed at all. It is the same file you would drag-and-drop onto the DisplayInterface component on your VRDisplayTracked prefab. If "hmd.json" does not exist in the Data folder (and it won't by default unless you put it there), then the plugin will look for the JSON file assigned in the DisplayInterface component in your scene. If that also has not been assigned, it will fall back to reading OSVR's /display parameter (this will eventually be the default).
+
+##Distortion v0.1-55-g046c709(20-March-2015)
 - Unity 4 Free limitations. The new distortion shader will not work with Unity 4 Free version. It will work with Unity 4 Pro or Unity 5. If you are using Unity 4 Free, everything will still work but there won't be any distortion. This is due to the distortion shader using a render to texture pass.
 - Fixed Timestep was changed from 0.2 to 0.01667. This is how often FixedUpdate() gets called. The change should result in a more comfortable VR experience, but make sure it doesn't break any physics in your game.
 - Changed the default quality settings. Turned on 4x AA and disabled shadows.
 
-##Unity 5 Update (updated 18-March-2015)
+##Unity 5 Update v0.1-55-g046c709 (updated 18-March-2015)
 - Refactored VRHead.cs and VREye.cs to be Unity 5-friendly (mostly instances of "camera" that needed to become GetComponent<Camera>()). Upgrading from Unity 4 to Unity 5 should be seamless.
 - VRDisplayTracked.prefab has been updated to use the json descriptor file for the HDK by default. If you are using another HMD, be sure to set the corresponding json file on the VRDisplayTracked prefab's DisplayInterface script. 
 - Fixed issue with stereo overlap and roll for HMDs with multiple video inputs.