add CCNode::getChildByIndex (geode-sdk#1454)

* add CCNode::getChildByIndex

* deprecate the free function getChild

Author: nytelytee

loader/include/Geode/cocos/base_nodes/CCNode.h

@@ -648,7 +648,7 @@ class CC_DLL CCNode : public CCObject
     inline auto getChildrenExt() {
         // CCArrayExt is defined in geode/utils/cocos.hpp, which we cannot include due to circular includes.
         // This is an incredibly hacky way to still be able to use the type
-        
+
         using CCArrayExt = geode::CCArrayExtCheck<T, PleaseDontChangeMe>::type;
         static_assert(!std::is_void_v<CCArrayExt>, "Please include <Geode/utils/cocos.hpp> to use getChildrenExt()");
 
@@ -1144,6 +1144,23 @@ class CC_DLL CCNode : public CCObject
     GEODE_DLL geode::EventListenerProtocol* getEventListener(std::string const& id);
     GEODE_DLL size_t getEventListenerCount();
 
+    /**
+     * Get child at index. Checks bounds. A negative
+     * index will get the child starting from the end
+     * @returns Child at index cast to the given type,
+     * or nullptr if index exceeds bounds
+     */
+    template <class InpT = cocos2d::CCNode*, class T = std::remove_pointer_t<InpT>>
+    T* getChildByIndex(int i) {
+        // start from end for negative index
+        if (i < 0) i = this->getChildrenCount() + i;
+        // check if backwards index is out of bounds
+        if (i < 0) return nullptr;
+        // check if forwards index is out of bounds
+        if (static_cast<int>(this->getChildrenCount()) <= i) return nullptr;
+        return static_cast<T*>(this->getChildren()->objectAtIndex(i));
+    }
+
     /**
      * Get nth child that is a given type. Checks bounds.
      * @returns Child at index cast to the given type,

loader/include/Geode/utils/cocos.hpp

@@ -642,18 +642,13 @@ namespace geode::cocos {
     /**
      * Get child at index. Checks bounds. A negative
      * index will get the child starting from the end
+     * @deprecated Use CCNode::getChildByIndex instead
      * @returns Child at index cast to the given type,
      * or nullptr if index exceeds bounds
      */
     template <class T = cocos2d::CCNode>
     static T* getChild(cocos2d::CCNode* x, int i) {
-        // start from end for negative index
-        if (i < 0) i = x->getChildrenCount() + i;
-        // check if backwards index is out of bounds
-        if (i < 0) return nullptr;
-        // check if forwards index is out of bounds
-        if (static_cast<int>(x->getChildrenCount()) <= i) return nullptr;
-        return static_cast<T*>(x->getChildren()->objectAtIndex(i));
+        return x->getChildByIndex<T>(i);
     }
 
     /**