CCSpriteFrameCache添加plist时不同plist中存在重复的文件

最近在做一项工作，将基于cocos2d-iphone游戏转换为跨平台版本。

以下为OC代码：

[[CCSpriteFrameCache sharedSpriteFrameCache] addSpriteFramesWithFile:@"game_ui.plist"];
[[CCSpriteFrameCache sharedSpriteFrameCache] addSpriteFramesWithFile:@"game_effect.plist"];

 以下为Lua代码（我们的UI采用Lua编码）：

display.addSpriteFramesWithFile('game_ui.plist')
display.addSpriteFramesWithFile('game_effect.plist')

运行时，却发现了在OC版本中没有出现的异常“CCSprite is not using the same texture id”

跟踪该png文件，却发现health_bar.png文件同时存在于这两个plist。

这时候就产生疑问了，OC和C++版本的资源文件都是一样的。为什么cocos2d-x就会报异常呢？

好在cocos2d是开源的，所以开始研究addSpriteFramesWithFile的实现细节。

cocos2d-iphone

-(void) addSpriteFramesWithFile:(NSString*)plist
{
	NSAssert(plist, @"plist filename should not be nil");
	
	if( ! [_loadedFilenames member:plist] ) {

		NSString *path = [[CCFileUtils sharedFileUtils] fullPathForFilename:plist];
		NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:path];

		NSString *texturePath = nil;
		NSDictionary *metadataDict = [dict objectForKey:@"metadata"];
		if( metadataDict )
			// try to read  texture file name from meta data
			texturePath = [metadataDict objectForKey:@"textureFileName"];


		if( texturePath )
		{
			// build texture path relative to plist file
			NSString *textureBase = [plist stringByDeletingLastPathComponent];
			texturePath = [textureBase stringByAppendingPathComponent:texturePath];
		} else {
			// build texture path by replacing file extension
			texturePath = [plist stringByDeletingPathExtension];
			texturePath = [texturePath stringByAppendingPathExtension:@"png"];

			CCLOG(@"cocos2d: CCSpriteFrameCache: Trying to use file '%@' as texture", texturePath);
		}

		[self addSpriteFramesWithDictionary:dict textureFilename:texturePath];
		
		[_loadedFilenames addObject:plist];
	}
	else 
		CCLOGINFO(@"cocos2d: CCSpriteFrameCache: file already loaded: %@", plist);

}

cocos2d-x

void CCSpriteFrameCache::addSpriteFramesWithDictionary(CCDictionary* dictionary, CCTexture2D *pobTexture)
{
    /*
    Supported Zwoptex Formats:

    ZWTCoordinatesFormatOptionXMLLegacy = 0, // Flash Version
    ZWTCoordinatesFormatOptionXML1_0 = 1, // Desktop Version 0.0 - 0.4b
    ZWTCoordinatesFormatOptionXML1_1 = 2, // Desktop Version 1.0.0 - 1.0.1
    ZWTCoordinatesFormatOptionXML1_2 = 3, // Desktop Version 1.0.2+
    */

    CCDictionary *metadataDict = (CCDictionary*)dictionary->objectForKey("metadata");
    CCDictionary *framesDict = (CCDictionary*)dictionary->objectForKey("frames");
    int format = 0;

    // get the format
    if(metadataDict != NULL) 
    {
        format = metadataDict->valueForKey("format")->intValue();
    }

    // check the format
    CCAssert(format >=0 && format <= 3, "format is not supported for CCSpriteFrameCache addSpriteFramesWithDictionary:textureFilename:");

    CCDictElement* pElement = NULL;
    CCDICT_FOREACH(framesDict, pElement)
    {
        CCDictionary* frameDict = (CCDictionary*)pElement->getObject();
        std::string spriteFrameName = pElement->getStrKey();
        CCSpriteFrame* spriteFrame = (CCSpriteFrame*)m_pSpriteFrames->objectForKey(spriteFrameName);
        if (spriteFrame)
        {
            continue;
        }
        
        if(format == 0) 
        {
            float x = frameDict->valueForKey("x")->floatValue();
            float y = frameDict->valueForKey("y")->floatValue();
            float w = frameDict->valueForKey("width")->floatValue();
            float h = frameDict->valueForKey("height")->floatValue();
            float ox = frameDict->valueForKey("offsetX")->floatValue();
            float oy = frameDict->valueForKey("offsetY")->floatValue();
            int ow = frameDict->valueForKey("originalWidth")->intValue();
            int oh = frameDict->valueForKey("originalHeight")->intValue();
            // check ow/oh
            if(!ow || !oh)
            {
                CCLOGWARN("cocos2d: WARNING: originalWidth/Height not found on the CCSpriteFrame. AnchorPoint won't work as expected. Regenrate the .plist");
            }
            // abs ow/oh
            ow = abs(ow);
            oh = abs(oh);
            // create frame
            spriteFrame = new CCSpriteFrame();
            spriteFrame->initWithTexture(pobTexture, 
                                        CCRectMake(x, y, w, h), 
                                        false,
                                        CCPointMake(ox, oy),
                                        CCSizeMake((float)ow, (float)oh)
                                        );
        } 
        else if(format == 1 || format == 2) 
        {
            CCRect frame = CCRectFromString(frameDict->valueForKey("frame")->getCString());
            bool rotated = false;

            // rotation
            if (format == 2)
            {
                rotated = frameDict->valueForKey("rotated")->boolValue();
            }

            CCPoint offset = CCPointFromString(frameDict->valueForKey("offset")->getCString());
            CCSize sourceSize = CCSizeFromString(frameDict->valueForKey("sourceSize")->getCString());

            // create frame
            spriteFrame = new CCSpriteFrame();
            spriteFrame->initWithTexture(pobTexture, 
                frame,
                rotated,
                offset,
                sourceSize
                );
        } 
        else if (format == 3)
        {
            // get values
            CCSize spriteSize = CCSizeFromString(frameDict->valueForKey("spriteSize")->getCString());
            CCPoint spriteOffset = CCPointFromString(frameDict->valueForKey("spriteOffset")->getCString());
            CCSize spriteSourceSize = CCSizeFromString(frameDict->valueForKey("spriteSourceSize")->getCString());
            CCRect textureRect = CCRectFromString(frameDict->valueForKey("textureRect")->getCString());
            bool textureRotated = frameDict->valueForKey("textureRotated")->boolValue();

            // get aliases
            CCArray* aliases = (CCArray*) (frameDict->objectForKey("aliases"));
            CCString * frameKey = new CCString(spriteFrameName);

            CCObject* pObj = NULL;
            CCARRAY_FOREACH(aliases, pObj)
            {
                std::string oneAlias = ((CCString*)pObj)->getCString();
                if (m_pSpriteFramesAliases->objectForKey(oneAlias.c_str()))
                {
                    CCLOGWARN("cocos2d: WARNING: an alias with name %s already exists", oneAlias.c_str());
                }

                m_pSpriteFramesAliases->setObject(frameKey, oneAlias.c_str());
            }
            frameKey->release();
            // create frame
            spriteFrame = new CCSpriteFrame();
            spriteFrame->initWithTexture(pobTexture,
                            CCRectMake(textureRect.origin.x, textureRect.origin.y, spriteSize.width, spriteSize.height),
                            textureRotated,
                            spriteOffset,
                            spriteSourceSize);
        }

        // add sprite frame
        m_pSpriteFrames->setObject(spriteFrame, spriteFrameName);
        spriteFrame->release();
    }
}

void CCSpriteFrameCache::addSpriteFramesWithFile(const char *pszPlist, CCTexture2D *pobTexture)
{
    std::string fullPath = CCFileUtils::sharedFileUtils()->fullPathForFilename(pszPlist);
    CCDictionary *dict = CCDictionary::createWithContentsOfFileThreadSafe(fullPath.c_str());

    addSpriteFramesWithDictionary(dict, pobTexture);

    dict->release();
}

OK！事情明了了。cocos2d-x比cocos2d-iphone多做了一步校验。

CCSpriteFrame* spriteFrame = (CCSpriteFrame*)m_pSpriteFrames->objectForKey(spriteFrameName);
        if (spriteFrame)
        {
            continue;
        }

然后，我将c++版本的plist加载顺序调整一下。搞定。

多说一句，一个png就不应该同时添加到两个plist中。