增加双击中键缩放到全部的特性.

dist/CameraControls.js

@@ -93,6 +93,8 @@ class CameraControls {
             this.m_StartClickPoint.copy(this.m_EndClickPoint);
             this.m_Viewer.m_bNeedUpdate = true;
         };
+        //最后一次按中键的时间
+        this.lastMiddleClickTime = 0;
         //鼠标    
         this.onMouseDown = (event) => {
             event.preventDefault();
@@ -109,6 +111,13 @@ class CameraControls {
                     }
                 case KeyEnum_1.MouseKey.Middle:
                     {
+                        let curTime = Date.now();
+                        let t = curTime - this.lastMiddleClickTime;
+                        this.lastMiddleClickTime = curTime;
+                        if (t < 350) {
+                            this.m_Viewer.ZoomAll();
+                            return;
+                        }
                         if (this.m_KeyDown.get(KeyEnum_1.KeyBoard.Control)) {
                             this.beginRotate();
                         }