愚蠢的问题。 Cocos2d围绕父子层次结构构建。我想知道是否可以使用父类(例如GameScene)并使用指向父类成员的指针(例如CCSpriteBatchNode *)初始化子类(例如SpriteHandler)。
我正在尝试这样做以优化CCSpriteBatchNodes的数量。这是我的主类(GameScene样式)的代码片段。
#import <Foundation/Foundation.h>
#import "cocos2d.h"
enum ShooterSceneLayerTags {
HudLayerTag = 0,
};
@interface ShooterScene : CCLayer {
CCSpriteBatchNode* sharedSpriteBatchNode;
}
-(id) initWithSharedBatchNodeReference:( CCSpriteBatchNode*) sharedSpriteBatchNode;
+ (id) sceneWithId:(int)sceneId;
@end
#import "ShooterScene.h"
#import "MainMenuScene.h"
//Layers
#import "LevelSpritesLayer.h"
#import "HudLayer.h"
@interface ShooterScene (PrivateMethods)
-(void) addLayers:(int)sceneId;
-(void) loadGameArtFile;
-(BOOL) verifyAndHandlePause;
@end
@implementation ShooterScene
+ (id) sceneWithId:(int)sceneId
{
CCScene *scene = [CCScene node];
ShooterScene * shooterLayer = [[self alloc] initWithId:sceneId];
[scene addChild:shooterLayer];
return scene;
}
-(id) initWithId:(int)sceneId
{
if ((self = [super init]))
{
//Load game art before adding layers - This will initialize the batch node
[self loadGameArtFile:sceneId];
//Will add sprites to shared batch node for performance
[self addLayers:sceneId];
[self addChild:sharedSpriteBatchNode];
//Do other stuff..
[self scheduleUpdate];
}
return self;
}
-(void) addLayers:(int)sceneId
{
LevelSpritesLayer * levelData = [LevelSpritesLayer node];
[levelData initWithSharedBatchNodeReference:sharedSpriteBatchNode];
[self addChild:levelData];
switch (sceneId) {
case 1:
[levelData loadLevelOneSprites];
break;
case 2:
[levelData loadLevelTwoSprites];
break;
default:
break;
}
HudLayer * hud = [HudLayer node];
[hud setUpPauseMenu];
[self addChild:hud z:1 tag:HudLayerTag];
}
-(BOOL) verifyAndHandlePause
{
HudLayer * hud = [self getChildByTag:HudLayerTag];
if(hud.pauseRequested){
[[CCDirector sharedDirector] replaceScene:[MainMenuScene scene]];
return true;
}
else {
return false;
}
}
-(void) update:(ccTime)delta
{
if([self verifyAndHandlePause]==false)
{
//Continue with animation etc..
}
}
/**
This is tricky. Could have loaded this in LevelData but as I am expecting to use the same SpriteSheet for HudLayer as well then
I prefer to have the control here of this. Also, the same sheet could be used for more level, hence specific function is not bad
**/
-(void) loadGameArtFile:(int) sceneId
{
CCSpriteFrameCache* frameCache = [CCSpriteFrameCache sharedSpriteFrameCache];
[frameCache addSpriteFramesWithFile:@"game-art-hd.plist"];
sharedSpriteBatchNode = [CCSpriteBatchNode batchNodeWithFile:@"game-art-hd.png"];
}
//As dealloc is deprecated, I prefer to remove unused sprites and texture on cleanup
-(void) cleanup
{
[[CCSpriteFrameCache sharedSpriteFrameCache] removeUnusedSpriteFrames];
}
这里是loadLevelData方法之一,它使用sharedSpriteBAtchNodeReference
-(void) loadLevelOneSprites
{
//Just a proof of concept example
testSprite = [CCSprite spriteWithSpriteFrameName:@"File0.png"];
testSprite.anchorPoint = CGPointMake(0.5f, 0.5f);
testSprite.position = CGPointMake(160.0f, 240.0f);
[sharedSpriteBatchNodeReference addChild:testSprite];
}
答案 0 :(得分:3)
你可以这样做但是如果你使用ARC,你应该让你的sharedSpriteBatchNode成为弱指针。如果不这样做,您最终可能会得到循环引用。
循环参考会发生什么事情,当导演在完成游戏场景运行后释放你的游戏场景时,仍然会让你的孩子保留它,你的游戏场景仍将保留那个孩子。这个圆圈将浮出水面,因为它被抛弃而永远无法被释放。
答案 1 :(得分:1)
[Ben]说的是什么。它不应该是保留或强引用,后者是ARC中的默认实例变量。
有一种方法可以确保在ARC下,即使您使用强引用,您也可以保持周期安全。覆盖清理方法并在那里没有引用(在MRC下你也应该在这里调用release,如果你保留了引用):
-(void) cleanup
{
sharedSpriteBatchNode = nil;
[super cleanup];
}
在dealloc中执行此操作无效。只要子节点具有对父节点的强引用,它就不会被释放。因此,您需要在清理中执行此操作,并确保可以设置清除标志的所有方法调用都将该参数设置为YES。
但是除了在初始化程序中传递父节点之外,还有其他的,我认为更好的解决方案。例如,您可以通过父级的公共标记获取共享批处理节点,并在每次需要时将其包装(将其包装到一个小函数中)或将其存储在弱(非保留)实例var中:
// onEnter is typically called right after init (during addChild)
// parent is already set here
-(void) onEnter
{
[super onEnter];
CCSpriteBatchNode* sharedBatchNode = [parent getChildByTag:kSharedBatchNodeTag];
}
或者获取父节点并将其强制转换,假设sharedBatchNode是父类的属性:
-(void) whereEver
{
ShooterScene* scene = (ShooterScene*)parent;
CCSpriteBatchNode* sharedBatchNode = scene.sharedSpriteBatchNode;
…
// you can also reduce the above to a single line:
CCSpriteBatchNode* batch = ((ShooterScene*)parent).sharedSpriteBatchNode;
}
特别推荐使用后一种解决方案。即使您需要经常这样做,也很快。投射是免费的,财产访问不超过发送消息。请确保父实际上是您要将其投射到的类的对象。