完成下列功能:

1.板件显示
2.板件选中状态
3.标注显示
4.相机控制.

src/PointPick.ts

@@ -0,0 +1,58 @@
+import { Object3D, Raycaster, Face3, Vector3, Vector2, Mesh } from "three";
+import { Viewer } from ".";
+
+interface Intersect
+{
+    distance: number;
+    face: Face3;
+    faceIndex: number;
+    object: Object3D;
+    point: Vector3;
+    uv: Vector2;
+}
+
+
+/**
+ * 点选
+ * 
+ * @export
+ * @param {Viewer} view 
+ * @param {number} ptx 
+ * @param {number} pty 
+ * @returns {(Mesh | undefined)} 
+ */
+export function PointPick(view: Viewer, ptx: number, pty: number): Mesh | undefined
+{
+    let raycaster = new Raycaster();
+    raycaster.setFromCamera({
+        x: (ptx / view._Width) * 2 - 1,   //-1 到 1  所以 (x-(w/2))/(w/2) =>
+        y: - (pty / view._Height) * 2 + 1 //y轴相反
+    }, view.m_Camera.Camera);
+
+    //https://github.com/mrdoob/three.js/issues/14128
+    raycaster.ray.origin.set((ptx / view._Width) * 2 - 1, - (pty / view._Height) * 2 + 1, -1).unproject(view.m_Camera.Camera);
+
+
+    let minDis = Infinity;
+    let minObj = undefined;
+
+    view.m_Scene.children.forEach(obj =>
+    {
+        if (obj instanceof Mesh)
+        {
+            let intersects: Intersect[] = [];
+            obj.raycast(raycaster, intersects);
+
+            for (let i of intersects)
+            {
+                if (i.distance < minDis)
+                {
+                    minObj = obj;
+                    minDis = i.distance;
+                }
+            }
+        }
+    });
+
+    return minObj;
+}