RPG游戏制作-07-特效层的创建

首先，先创建一个特效层，其主要负责特效，如帧动画或粒子特效。

#ifndef __EffectLayer_H__
#define __EffectLayer_H__
#include <vector>
#include <string>
#include "SDL_Engine/SDL_Engine.h"

using namespace std;
USING_NS_SDL;

class EffectLayer : public Layer
{
private:
	static const int ANIMATION_TAG;
private:
	vector<Sprite*> m_spritePool;
	Sprite* m_pClickPoint;
	LayerColor* m_pLayerColor;
public:
	EffectLayer();
	~EffectLayer();
	CREATE_FUNC(EffectLayer);
	bool init();

	bool showClickAnimation(const Point& position, Layer* layer = nullptr);
	//显示动画特效
	bool showAnimationEffect(const string& animationName, const Point& position, Layer* layer = nullptr);
	//淡入场景
	void fadeInScreen(float duration);
	//淡出场景
	void fadeOutScreen(float duration);
private:
	Sprite* popSpriteFromPool();
	void pushSpriteToPool(Sprite* sprite);

	bool showAnimationEffect(Sprite* sprite, const string& animationName, const Point& position, Layer* layer = nullptr);
};
#endif

EffectLayer中包含了一个精灵池，负责精灵的分配与回收；一个点击精灵，负责当点击地面时显示一个反馈动画；LayerColor则是为了淡入场景和淡出场景考虑(cocos2d-x给的场景切换特效并不适合此时的情况)。

bool EffectLayer::showAnimationEffect(Sprite* sprite, const string& animationName, const Point& position, Layer* layer)
{
	auto animation = AnimationCache::getInstance()->getAnimation(animationName);

	if (animation == nullptr)
		return false;
	//添加精灵
	if (layer != nullptr)
		layer->addChild(sprite);
	else
		this->addChild(sprite);

	sprite->setSpriteFrame(animation->getFrames().front()->getSpriteFrame());
	sprite->setPosition(position);
	sprite->setName(animationName);
	sprite->setVisible(true);
	//创建动画
	auto animate = Animate::create(animation);
	CallFunc* end = CallFunc::create([this, sprite]()
	{
		this->pushSpriteToPool(sprite);
	});
	auto seq = Sequence::createWithTwoActions(animate, end);
	seq->setTag(ANIMATION_TAG);
	//运行动画
	sprite->runAction(seq);

	return true;
}

先把精灵添加到对应的层中，然后再创建对应动画并运行动画(此时的特效层函数后续可能会修改)。

bool EffectLayer::showClickAnimation(const Point& position, Layer* layer)
{
	string animationName = "click_path";
	//当前为空 或者正在播放且名称不为click_path 表示被别人占用，另选
	if (m_pClickPoint == nullptr 
		|| (m_pClickPoint->getParent() != nullptr 
			&& m_pClickPoint->getName() != animationName))
	{
		m_pClickPoint = this->popSpriteFromPool();
	}
	else
	{
		m_pClickPoint->stopActionByTag(ANIMATION_TAG);
	}
	
	return this->showAnimationEffect(m_pClickPoint, animationName, position, layer);
}

这里增加了一个判断，主要是保证点击反馈动画在同一时间内只有一个，且为了保证利用率，当点击动画完成后，依然放入精灵池中。

bool EffectLayer::showAnimationEffect(const string& animationName, const Point& position, Layer* layer)
{
	Sprite* sprite = this->popSpriteFromPool();

	return this->showAnimationEffect(sprite, animationName, position, layer);
}

重载函数，只是选定了精灵的来源。

void EffectLayer::fadeInScreen(float duration)
{
	auto sprite = m_pLayerColor->getInnerSprite();

	m_pLayerColor->setVisible(true);
	sprite->setOpacity(0);

	FadeIn* fade = FadeIn::create(duration);
	CallFunc* end = CallFunc::create([this]()
	{
		this->m_pLayerColor->setVisible(false);
	});
	auto seq = Sequence::createWithTwoActions(fade,end);

	sprite->runAction(fade);
}

void EffectLayer::fadeOutScreen(float duration)
{
	auto sprite = m_pLayerColor->getInnerSprite();

	m_pLayerColor->setVisible(true);
	sprite->setOpacity(255);

	FadeOut* fade = FadeOut::create(duration);
	CallFunc* end = CallFunc::create([this]()
	{
		this->m_pLayerColor->setVisible(false);
	});
	auto seq = Sequence::createWithTwoActions(fade,end);

	sprite->runAction(fade);
}

淡入淡出函数，LayerColor中主要起到作用的是内部的精灵，故对内部精灵进行淡入淡出操作。(这里是SDL_Engien的实现问题。。)。

Sprite* EffectLayer::popSpriteFromPool()
{
	Sprite* sprite = nullptr;

	if (m_spritePool.empty())
	{
		sprite = Sprite::create();
	}
	else
	{
		sprite = m_spritePool.back();
		sprite->autorelease();

		m_spritePool.pop_back();
	}
	return sprite;
}

void EffectLayer::pushSpriteToPool(Sprite* sprite)
{
	SDL_SAFE_RETAIN(sprite);
	sprite->removeFromParent();

	m_spritePool.push_back(sprite);
}

由于把精灵放入精灵池中的时候，会SDL_SAFE_RETAIN即引用一下这个精灵，故在弹出可用精灵时，为保证其通用性，精灵主动调用了一下autorelease函数。

然后在GameScene类中添加特效层即可。

class GameScene : public Scene
{
private:
	static GameScene* s_pInstance;
public:
	static GameScene* getInstance();
	static void purge();
	SDL_SYNTHESIZE_READONLY(EventLayer*, m_pEventLayer, EventLayer);
	SDL_SYNTHESIZE_READONLY(MapLayer*, m_pMapLayer, MapLayer);
	SDL_SYNTHESIZE_READONLY(PlayerLayer*, m_pPlayerLayer, PlayerLayer);
	SDL_SYNTHESIZE_READONLY(ScriptLayer*, m_pScriptLayer, ScriptLayer);
	SDL_SYNTHESIZE_READONLY(EffectLayer*, m_pEffectLayer, EffectLayer);	SDL_SYNTHESIZE_READONLY(EventLayer*, m_pEventLayer, EventLayer);
	SDL_SYNTHESIZE_READONLY(MapLayer*, m_pMapLayer, MapLayer);
	SDL_SYNTHESIZE_READONLY(PlayerLayer*, m_pPlayerLayer, PlayerLayer);
	SDL_SYNTHESIZE_READONLY(ScriptLayer*, m_pScriptLayer, ScriptLayer);
	SDL_SYNTHESIZE_READONLY(EffectLayer*, m_pEffectLayer, EffectLayer);

这里使用了宏，其宏如下：

#define SDL_SYNTHESIZE_READONLY(varType,varName,funcName) \
protected:varType varName;                                \
public: varType get##funcName(void)const{return varName;}

即声明一个保护成员和一个getter方法，对应的getter方法会在以后注册c函数给lua时用到。

然后在onTouchBegan函数中添加即可。

	else if (!this->isPassing(tilePos))//目标不可达
		return false;
	//主角运动
	player->moveToward(tilePos);
	//显示点击特效
	auto collisionLayer = m_pMapLayer->getCollisionLayer();
	auto tileSize = tiledMap->getTileSize();
	Point pos((tilePos.x + 0.5f) * tileSize.width, (tilePos.y + 0.3f) * tileSize.height);

	m_pEffectLayer->showClickAnimation(pos, collisionLayer);	//显示点击特效
	auto collisionLayer = m_pMapLayer->getCollisionLayer();
	auto tileSize = tiledMap->getTileSize();
	Point pos((tilePos.x + 0.5f) * tileSize.width, (tilePos.y + 0.3f) * tileSize.height);

	m_pEffectLayer->showClickAnimation(pos, collisionLayer);

注意此时的显示仍有些绘制顺序问题，这个以后再解决。