simplify logic (#16966)

* simplify logic
* the same logic in c++

cocos/scene-graph/node.ts

@@ -2106,27 +2106,30 @@ export class Node extends CCObject implements ISchedulable, CustomSerializable {
     public setPosition(x: number, y: number, z?: number): void;
 
     public setPosition (val: Readonly<Vec3> | number, y?: number, z?: number): void {
-        let x: number;
         const localPosition = this._lpos;
 
-        if (y === undefined && z === undefined) {
-            x = (val as Vec3).x;
-            y = (val as Vec3).y;
-            z = (val as Vec3).z;
-        } else if (z === undefined) {
-            x = val as number;
-            z = localPosition.z;
-        } else {
-            x = val as number;
-        }
+        if (y === undefined) {
+            // The type of val is Readonly<Vec3>
+            if (localPosition.equals(val as Vec3)) {
+                return;
+            }
 
-        if (x !== localPosition.x || y !== localPosition.y || z !== localPosition.z) {
-            this._lpos.set(x, y, z);
-            this.invalidateChildren(TransformBit.POSITION);
+            Vec3.copy(this._lpos, val as Vec3);
+        } else {
+            if (z === undefined) {
+                z = localPosition.z;
+            }
 
-            if (this._eventMask & TRANSFORM_ON) {
-                this.emit(NodeEventType.TRANSFORM_CHANGED, TransformBit.POSITION);
+            if (val as number === localPosition.x && y === localPosition.y && z === localPosition.z) {
+                return;
             }
+
+            Vec3.set(this._lpos, val as number, y, z);
+        }
+
+        this.invalidateChildren(TransformBit.POSITION);
+        if (this._eventMask & TRANSFORM_ON) {
+            this.emit(NodeEventType.TRANSFORM_CHANGED, TransformBit.POSITION);
         }
     }
 

native/cocos/core/scene-graph/Node.cpp

@@ -395,6 +395,10 @@ Node *Node::getChildByPath(const ccstd::string &path) const {
 
 //
 void Node::setPositionInternal(float x, float y, float z, bool calledFromJS) {
+    if (_localPosition.approxEquals({x, y, z})) {
+        return;
+    }
+
     _localPosition.set(x, y, z);
     invalidateChildren(TransformBit::POSITION);