Cocos2d-x的粒子系統是通過加載plist生成的。plist包含兩部分內容:粒子系統屬性和粒子紋理。然而每次調用create都會對plist進行讀取解析,如果重複地使用同一個粒子效果,這樣的調用明顯是低效冗餘的。所以我們要做的是,將粒子系統屬性和粒子紋理分別抽出。
(1)將粒子系統屬性預加載並全局保存,避免每次進行讀取。
(2)粒子紋理可視且可以進行紋理打包,加載粒子紋理就和加載普通的圖片一樣。
本文通過增加ParticleSystemQuad的接口實現對粒子系統屬性和紋理幀的直接載入,來提高粒子系統的加載效率和實現內存紋理的優化。
1.ParticleSystemQuad
首先先看下ParticleSystemQuad,ParticleSystemQuad繼承於ParticleSystem,擁有後者的所有特性,並且增加了一些新的特性:(1)粒子大小支持浮點數
(2)支持縮放
(3)支持選擇
(4)支持subrect
(5)支持批渲染
ParticleSystemQuad同時也是其他特效的父類,創建一個粒子系統的函數調用順序爲:
Create→initWithFile→initWithDictionary
在initWithDictionary中對粒子數據和紋理進行了讀取和解析(這部分有興趣的可以直接看源碼)。
2.如何優化?
參考initWithDictionary的函參static bool initWithDictionary(ValueMap& dictionary, const std::string& dirname);
設計如下接口,當然你要傳入文件名也可以:static ParticleSystemQuad * create(ValueMap& valueMap, SpriteFrame *frame);
bool initWithValueMap(ValueMap &valueMap, SpriteFrame* frame);
源碼如下:ParticleSystemQuad * ParticleSystemQuad::create( ValueMap& map, SpriteFrame *frame)
{
ParticleSystemQuad *ret = new ParticleSystemQuad();
if (ret && ret->initWithValueMap(map, frame))
{
ret->autorelease();
return ret;
}
CC_SAFE_DELETE(ret);
return ret;
}
bool ParticleSystemQuad::initWithValueMap(ValueMap &valueMap, SpriteFrame* frame)
{
std::string dirname = "";
bool ret = false;
unsigned char *buffer = nullptr;
unsigned char *deflated = nullptr;
do
{
int maxParticles = valueMap["maxParticles"].asInt();
// self, not super
if(this->initWithTotalParticles(maxParticles))
{
// Emitter name in particle designer 2.0
_configName = valueMap["configName"].asString();
// angle
_angle = valueMap["angle"].asFloat();
_angleVar = valueMap["angleVariance"].asFloat();
// duration
_duration = valueMap["duration"].asFloat();
// blend function
if (_configName.length()>0)
{
_blendFunc.src = valueMap["blendFuncSource"].asFloat();
}
else
{
_blendFunc.src = valueMap["blendFuncSource"].asInt();
}
_blendFunc.dst = valueMap["blendFuncDestination"].asInt();
// color
_startColor.r = valueMap["startColorRed"].asFloat();
_startColor.g = valueMap["startColorGreen"].asFloat();
_startColor.b = valueMap["startColorBlue"].asFloat();
_startColor.a = valueMap["startColorAlpha"].asFloat();
_startColorVar.r = valueMap["startColorVarianceRed"].asFloat();
_startColorVar.g = valueMap["startColorVarianceGreen"].asFloat();
_startColorVar.b = valueMap["startColorVarianceBlue"].asFloat();
_startColorVar.a = valueMap["startColorVarianceAlpha"].asFloat();
_endColor.r = valueMap["finishColorRed"].asFloat();
_endColor.g = valueMap["finishColorGreen"].asFloat();
_endColor.b = valueMap["finishColorBlue"].asFloat();
_endColor.a = valueMap["finishColorAlpha"].asFloat();
_endColorVar.r = valueMap["finishColorVarianceRed"].asFloat();
_endColorVar.g = valueMap["finishColorVarianceGreen"].asFloat();
_endColorVar.b = valueMap["finishColorVarianceBlue"].asFloat();
_endColorVar.a = valueMap["finishColorVarianceAlpha"].asFloat();
// particle size
_startSize = valueMap["startParticleSize"].asFloat();
_startSizeVar = valueMap["startParticleSizeVariance"].asFloat();
_endSize = valueMap["finishParticleSize"].asFloat();
_endSizeVar = valueMap["finishParticleSizeVariance"].asFloat();
// position
float x = valueMap["sourcePositionx"].asFloat();
float y = valueMap["sourcePositiony"].asFloat();
this->setPosition( Point(x,y) );
_posVar.x = valueMap["sourcePositionVariancex"].asFloat();
_posVar.y = valueMap["sourcePositionVariancey"].asFloat();
// Spinning
_startSpin = valueMap["rotationStart"].asFloat();
_startSpinVar = valueMap["rotationStartVariance"].asFloat();
_endSpin= valueMap["rotationEnd"].asFloat();
_endSpinVar= valueMap["rotationEndVariance"].asFloat();
_emitterMode = (Mode) valueMap["emitterType"].asInt();
// Mode A: Gravity + tangential accel + radial accel
if (_emitterMode == Mode::GRAVITY)
{
// gravity
modeA.gravity.x = valueMap["gravityx"].asFloat();
modeA.gravity.y = valueMap["gravityy"].asFloat();
// speed
modeA.speed = valueMap["speed"].asFloat();
modeA.speedVar = valueMap["speedVariance"].asFloat();
// radial acceleration
modeA.radialAccel = valueMap["radialAcceleration"].asFloat();
modeA.radialAccelVar = valueMap["radialAccelVariance"].asFloat();
// tangential acceleration
modeA.tangentialAccel = valueMap["tangentialAcceleration"].asFloat();
modeA.tangentialAccelVar = valueMap["tangentialAccelVariance"].asFloat();
// rotation is dir
modeA.rotationIsDir = valueMap["rotationIsDir"].asBool();
}
// or Mode B: radius movement
else if (_emitterMode == Mode::RADIUS)
{
if (_configName.length()>0)
{
modeB.startRadius = valueMap["maxRadius"].asInt();
}
else
{
modeB.startRadius = valueMap["maxRadius"].asFloat();
}
modeB.startRadiusVar = valueMap["maxRadiusVariance"].asFloat();
if (_configName.length()>0)
{
modeB.endRadius = valueMap["minRadius"].asInt();
}
else
{
modeB.endRadius = valueMap["minRadius"].asFloat();
}
modeB.endRadiusVar = 0.0f;
if (_configName.length()>0)
{
modeB.rotatePerSecond = valueMap["rotatePerSecond"].asInt();
}
else
{
modeB.rotatePerSecond = valueMap["rotatePerSecond"].asFloat();
}
modeB.rotatePerSecondVar = valueMap["rotatePerSecondVariance"].asFloat();
} else {
CCASSERT( false, "Invalid emitterType in config file");
CC_BREAK_IF(true);
}
// life span
_life = valueMap["particleLifespan"].asFloat();
_lifeVar = valueMap["particleLifespanVariance"].asFloat();
// emission Rate
_emissionRate = _totalParticles / _life;
//don't get the internal texture if a batchNode is used
if (!_batchNode)
{
// Set a compatible default for the alpha transfer
_opacityModifyRGB = false;
if (!_configName.empty())
{
_yCoordFlipped = valueMap["yCoordFlipped"].asInt();
}
}
setDisplayFrame(frame);
ret = true;
}
} while (0);
free(buffer);
free(deflated);
return ret;
}
注意,這裏只是提供了通過粒子系統屬性和紋理創建粒子系統的接口,並沒有實現對粒子屬性的全局保存(可以參考Earth Warriors 3D中ParticleManager的實現)和圖片幀的預加載。粒子屬性的獲取:
ValueMap FileUtilsApple::getValueMapFromFile(const std::string& filename);
圖片幀的獲取(這個獲取方式就比較多了。。。):SpriteFrame* create(const std::string& filename, const Rect& rect);
3.如何使用?
auto plistData = FileUtils::getInstance()->getValueMapFromFile("Particles/emissionPart.plist");
auto emission_frame = SpriteFrame::create("Images/engine.jpg", Rect(0,0,25,32));
auto emitter = ParticleSystemQuad::create(plistData, emission_frame);
_background->addChild(_emitter, 10);
4.源碼下載
我也不知道3.0release會不會集成這個功能,這裏先發出pull request的鏈接:https://github.com/cocos2d/cocos2d-x/pull/5979/files