feat(SDK): add method to auto generate controller pointer origins

It may be plausible that some SDKs require to provide a custom
pointer origin by default as the default transform may not be oriented
in the correct way.

This new method allows each SDK to provide a custom transform if one
is required.

Assets/VRTK/SDK/Base/SDK_BaseController.cs

@@ -103,6 +103,12 @@ public enum ControllerHand
         /// <returns>A Transform containing the origin of the controller.</returns>
         public abstract Transform GetControllerOrigin(GameObject controller);
 
+        /// <summary>
+        /// The GenerateControllerPointerOrigin method can create a custom pointer origin Transform to represent the pointer position and forward.
+        /// </summary>
+        /// <returns>A generated Transform that contains the custom pointer origin.</returns>
+        public abstract Transform GenerateControllerPointerOrigin();
+
         /// <summary>
         /// The GetControllerLeftHand method returns the GameObject containing the representation of the left hand controller.
         /// </summary>

Assets/VRTK/SDK/Fallback/SDK_FallbackController.cs

@@ -63,6 +63,15 @@ public override Transform GetControllerOrigin(GameObject controller)
             return null;
         }
 
+        /// <summary>
+        /// The GenerateControllerPointerOrigin method can create a custom pointer origin Transform to represent the pointer position and forward.
+        /// </summary>
+        /// <returns>A generated Transform that contains the custom pointer origin.</returns>
+        public override Transform GenerateControllerPointerOrigin()
+        {
+            return null;
+        }
+
         /// <summary>
         /// The GetControllerLeftHand method returns the GameObject containing the representation of the left hand controller.
         /// </summary>

Assets/VRTK/SDK/SteamVR/SDK_SteamVRController.cs

@@ -106,6 +106,15 @@ public override Transform GetControllerOrigin(GameObject controller)
             return null;
         }
 
+        /// <summary>
+        /// The GenerateControllerPointerOrigin method can create a custom pointer origin Transform to represent the pointer position and forward.
+        /// </summary>
+        /// <returns>A generated Transform that contains the custom pointer origin.</returns>
+        public override Transform GenerateControllerPointerOrigin()
+        {
+            return null;
+        }
+
         /// <summary>
         /// The GetControllerLeftHand method returns the GameObject containing the representation of the left hand controller.
         /// </summary>

Assets/VRTK/SDK/VRTK_SDK_Bridge.cs

@@ -34,6 +34,11 @@ public static Transform GetControllerOrigin(GameObject controller)
             return GetControllerSDK().GetControllerOrigin(controller);
         }
 
+        public static Transform GenerateControllerPointerOrigin()
+        {
+            return GetControllerSDK().GenerateControllerPointerOrigin();
+        }
+
         public static GameObject GetControllerLeftHand(bool actual)
         {
             return GetControllerSDK().GetControllerLeftHand(actual);

Assets/VRTK/Scripts/Pointers/VRTK_BasePointer.cs

@@ -114,6 +114,9 @@ protected virtual void Awake()
         protected override void OnEnable()
         {
             base.OnEnable();
+
+            pointerOriginTransform = (pointerOriginTransform == null ? VRTK_SDK_Bridge.GenerateControllerPointerOrigin() : pointerOriginTransform);
+
             AttemptSetController();
 
             var tmpMaterial = Resources.Load("WorldPointer") as Material;

Assets/VRTK/Scripts/UI/VRTK_UIPointer.cs

@@ -303,6 +303,8 @@ public Vector3 GetOriginForward()
 
         private void OnEnable()
         {
+            pointerOriginTransform = (pointerOriginTransform == null ? VRTK_SDK_Bridge.GenerateControllerPointerOrigin() : pointerOriginTransform);
+
             if (controller == null)
             {
                 controller = GetComponent<VRTK_ControllerEvents>();

DOCUMENTATION.md

@@ -5092,6 +5092,17 @@ The GetControllerByIndex method returns the GameObject of a controller with a sp
 
 The GetControllerOrigin method returns the origin of the given controller.
 
+#### GenerateControllerPointerOrigin/0
+
+  > `public abstract Transform GenerateControllerPointerOrigin();`
+
+  * Parameters
+   * _none_
+  * Returns
+   * `Transform` - A generated Transform that contains the custom pointer origin.
+
+The GenerateControllerPointerOrigin method can create a custom pointer origin Transform to represent the pointer position and forward.
+
 #### GetControllerLeftHand/1
 
   > `public abstract GameObject GetControllerLeftHand(bool actual = false);`
@@ -5857,6 +5868,17 @@ The GetControllerByIndex method returns the GameObject of a controller with a sp
 
 The GetControllerOrigin method returns the origin of the given controller.
 
+#### GenerateControllerPointerOrigin/0
+
+  > `public override Transform GenerateControllerPointerOrigin()`
+
+  * Parameters
+   * _none_
+  * Returns
+   * `Transform` - A generated Transform that contains the custom pointer origin.
+
+The GenerateControllerPointerOrigin method can create a custom pointer origin Transform to represent the pointer position and forward.
+
 #### GetControllerLeftHand/1
 
   > `public override GameObject GetControllerLeftHand(bool actual = false)`
@@ -6616,6 +6638,17 @@ The GetControllerByIndex method returns the GameObject of a controller with a sp
 
 The GetControllerOrigin method returns the origin of the given controller.
 
+#### GenerateControllerPointerOrigin/0
+
+  > `public override Transform GenerateControllerPointerOrigin()`
+
+  * Parameters
+   * _none_
+  * Returns
+   * `Transform` - A generated Transform that contains the custom pointer origin.
+
+The GenerateControllerPointerOrigin method can create a custom pointer origin Transform to represent the pointer position and forward.
+
 #### GetControllerLeftHand/1
 
   > `public override GameObject GetControllerLeftHand(bool actual = false)`