perf(scene): 使用哈希表优化节点添加和删除操作

优化 Scene 和 Node 类的子节点管理，通过引入 unordered_map 存储节点索引，将删除操作的时间复杂度从 O(n) 降低到 O(1)。同时防止重复添加相同节点。

include/scene/node.h

@@ -6,6 +6,7 @@
 #include <types/math/mat4.h>
 #include <types/ptr/intrusive_ptr.h>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 namespace extra2d {
@@ -315,6 +316,7 @@ private:
     bool visible_ = true;
     Node* parent_ = nullptr;
     std::vector<Ptr<Node>> children_;
+    std::unordered_map<Node*, size_t> childIndices_;
     std::vector<Ptr<Component>> components_;
     TransformComponent* transform_ = nullptr;
 };

include/scene/scene.h

@@ -3,6 +3,7 @@
 #include <scene/node.h>
 #include <types/ptr/intrusive_ptr.h>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
 namespace extra2d {
@@ -115,6 +116,7 @@ public:
 
 protected:
     std::vector<Ptr<Node>> rootNodes_;
+    std::unordered_map<Node*, size_t> rootNodeIndices_;
     CameraComponent* mainCamera_ = nullptr;
     bool entered_ = false;
 };

src/scene/node.cpp

@@ -29,6 +29,7 @@ Node::~Node() {
 
 void Node::addChild(Ptr<Node> child) {
     if (!child || child.get() == this) return;
+    if (childIndices_.find(child.get()) != childIndices_.end()) return;
 
     // 从原父节点移除
     if (child->parent_) {
@@ -36,18 +37,25 @@ void Node::addChild(Ptr<Node> child) {
     }
 
     child->parent_ = this;
+    childIndices_[child.get()] = children_.size();
     children_.push_back(child);
 }
 
 void Node::removeChild(Node* child) {
     if (!child) return;
 
-    for (auto it = children_.begin(); it != children_.end(); ++it) {
-        if (it->get() == child) {
-            child->parent_ = nullptr;
-            children_.erase(it);
-            return;
-        }
+    auto indexIt = childIndices_.find(child);
+    if (indexIt == childIndices_.end()) {
+        return;
+    }
+
+    const size_t removeIndex = indexIt->second;
+    child->parent_ = nullptr;
+    children_.erase(children_.begin() + removeIndex);
+    childIndices_.erase(indexIt);
+
+    for (size_t i = removeIndex; i < children_.size(); ++i) {
+        childIndices_[children_[i].get()] = i;
     }
 }
 
@@ -62,6 +70,7 @@ void Node::removeAllChildren() {
         child->parent_ = nullptr;
     }
     children_.clear();
+    childIndices_.clear();
 }
 
 // ========================================

src/scene/scene.cpp

@@ -16,21 +16,29 @@ Scene::~Scene() {
 
 void Scene::addChild(Ptr<Node> node) {
     if (!node) return;
+    if (rootNodeIndices_.find(node.get()) != rootNodeIndices_.end()) return;
 
     node->removeFromParent();
     node->onEnter();
+    rootNodeIndices_[node.get()] = rootNodes_.size();
     rootNodes_.push_back(node);
 }
 
 void Scene::removeChild(Node* node) {
     if (!node) return;
 
-    for (auto it = rootNodes_.begin(); it != rootNodes_.end(); ++it) {
-        if (it->get() == node) {
-            node->onExit();
-            rootNodes_.erase(it);
-            return;
-        }
+    auto indexIt = rootNodeIndices_.find(node);
+    if (indexIt == rootNodeIndices_.end()) {
+        return;
+    }
+
+    const size_t removeIndex = indexIt->second;
+    node->onExit();
+    rootNodes_.erase(rootNodes_.begin() + removeIndex);
+    rootNodeIndices_.erase(indexIt);
+
+    for (size_t i = removeIndex; i < rootNodes_.size(); ++i) {
+        rootNodeIndices_[rootNodes_[i].get()] = i;
     }
 }
 
@@ -39,6 +47,7 @@ void Scene::removeAllChildren() {
         node->onExit();
     }
     rootNodes_.clear();
+    rootNodeIndices_.clear();
 }
 
 Node* Scene::findNode(const std::string& name) {