增加拖拽功能

2 files changed, 81 insertions, 0 deletions

diff --git a/Assets/Scripts/DragItem.cs b/Assets/Scripts/DragItem.cs
new file mode 100644
index 0000000..46ba50f
--- /dev/null
+++ b/Assets/Scripts/DragItem.cs
@@ -0,0 +1,79 @@
+using UnityEngine;
+
+public class DragItem : MonoBehaviour
+{
+    private Vector3 SelfPivot
+    { 
+        get 
+        {
+            var p = transform.position;
+            return new Vector3(p.x, 0, p.z);
+        }
+    }
+        
+    private Vector3 DraggerPivot
+    {
+        get
+        {
+            var p = dragger.position;
+            return new Vector3(p.x, 0, p.z);
+        }
+    }
+
+    private bool _dragging;
+    public Transform dragger;
+
+    private Vector3 _lastDirection;
+    private Vector3 _lastSelfPivot;
+    private float _lastAngle;
+    private float _lastLength;
+    private int _currentStep;
+
+    private void FixedUpdate()
+    {
+        FixedUpdateDragger();
+        
+        // 判断是否在拖拽
+        if (! _dragging) return;
+            
+        // 位置计算
+        var draggerPivot = DraggerPivot;
+        var selfPivot = SelfPivot;
+        var direction = (_lastSelfPivot - draggerPivot).normalized;
+        var position = draggerPivot + direction * _lastLength;
+        var y = transform.position.y;
+        transform.position = new Vector3(
+            position.x,
+            y,
+            position.z
+            );
+            
+        // 角度计算
+        if (direction != _lastDirection)
+        {
+            var angle = Vector3.SignedAngle(direction, _lastDirection, Vector3.up);
+            var selfAngle = transform.eulerAngles;
+            selfAngle.y -= angle;
+            transform.eulerAngles = selfAngle;
+        }
+            
+        // 记录值
+        _lastSelfPivot = selfPivot;
+        _lastDirection = direction;
+    }
+
+    private void FixedUpdateDragger()
+    {
+        if (!_dragging && dragger != null)
+        {
+            _dragging = true;
+            var draggerPivot = DraggerPivot;
+            _lastSelfPivot = SelfPivot;
+            _lastLength = Vector3.Distance(draggerPivot, SelfPivot);
+            _lastDirection = (_lastSelfPivot - draggerPivot).normalized;
+        }
+
+        if (_dragging && dragger == null)
+            _dragging = false;
+    }
+}
diff --git a/Assets/Scripts/DragItem.cs.meta b/Assets/Scripts/DragItem.cs.meta
new file mode 100644
index 0000000..d32339a
--- /dev/null
+++ b/Assets/Scripts/DragItem.cs.meta
@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: c69e2aa4d45550a818a819efbd91c846
\ No newline at end of file