Predicted Billiards: fix dragging with predicted Rigidbody

Assets/Mirror/Examples/BilliardsPredicted/Ball/WhiteBallPredicted.cs

@@ -1,3 +1,4 @@
+using System;
 using UnityEngine;
 
 namespace Mirror.Examples.BilliardsPredicted
@@ -5,6 +6,7 @@ namespace Mirror.Examples.BilliardsPredicted
     public class WhiteBallPredicted : NetworkBehaviour
     {
         public LineRenderer dragIndicator;
+        public float dragTolerance = 1.0f;
         public Rigidbody rigidBody;
         public float forceMultiplier = 2;
         public float maxForce = 40;
@@ -12,6 +14,8 @@ public class WhiteBallPredicted : NetworkBehaviour
         // remember start position to reset to after entering a pocket
         Vector3 startPosition;
 
+        bool draggingStartedOverObject;
+
         // cast mouse position on screen to world position
         bool MouseToWorld(out Vector3 position)
         {
@@ -31,6 +35,77 @@ void Awake()
             startPosition = transform.position;
         }
 
+        [ClientCallback]
+        void Update()
+        {
+            // mouse down on the white ball?
+            if (Input.GetMouseButtonDown(0))
+            {
+                if (MouseToWorld(out Vector3 position))
+                {
+                    // allow dragging if mouse is 'close enough'.
+                    // balls are moving so we don't need to be exactly on it.
+                    float distance = Vector3.Distance(position, transform.position);
+                    if (distance <= dragTolerance)
+                    {
+                        // enable drag indicator
+                        dragIndicator.SetPosition(0, transform.position);
+                        dragIndicator.SetPosition(1, transform.position);
+                        dragIndicator.gameObject.SetActive(true);
+
+                        draggingStartedOverObject = true;
+                    }
+                }
+            }
+            // mouse button dragging?
+            else if (Input.GetMouseButton(0))
+            {
+                // cast mouse position to world
+                if (draggingStartedOverObject && MouseToWorld(out Vector3 current))
+                {
+                    // drag indicator
+                    dragIndicator.SetPosition(0, transform.position);
+                    dragIndicator.SetPosition(1, current);
+                }
+            }
+            // mouse button up?
+            else if (Input.GetMouseButtonUp(0))
+            {
+                // cast mouse position to world
+                if (draggingStartedOverObject && MouseToWorld(out Vector3 current))
+                {
+                    // calculate delta from ball to mouse
+                    // ball may have moved since we started dragging,
+                    // so always use current ball position here.
+                    Vector3 from = transform.position;
+
+                    // debug drawing: only works if Gizmos are enabled!
+                    Debug.DrawLine(from, current, Color.white, 2);
+
+                    // calculate pending force delta
+                    Vector3 delta = from - current;
+                    Vector3 force = delta * forceMultiplier;
+
+                    // there should be a maximum allowed force
+                    force = Vector3.ClampMagnitude(force, maxForce);
+
+                    // forward the event to the local player's object.
+                    // the ball isn't part of the local player.
+                    NetworkClient.localPlayer.GetComponent<PlayerPredicted>().OnDraggedBall(force);
+
+                    // disable drag indicator
+                    dragIndicator.gameObject.SetActive(false);
+                }
+
+                draggingStartedOverObject = false;
+            }
+        }
+
+        // OnMouse callbacks don't work for predicted objects because we need to
+        // move the collider out of the main object ocassionally.
+        // besides, having a drag tolerance and not having to click exactly on
+        // the white ball is nice.
+        /*
         [ClientCallback]
         void OnMouseDown()
         {
@@ -79,6 +154,7 @@ void OnMouseUp()
             // disable drag indicator
             dragIndicator.gameObject.SetActive(false);
         }
+        */
 
         // reset position when entering a pocket.
         // there's only one trigger in the scene (the pocket).