[CloudBox] 環狀捲動背景控件

緣起

爲了我的下一個橫向卷軸遊戲，所以想設計一個卷軸遊戲的捲動背景專用的類。

思路

思路其實是很簡單，一般來說卷軸遊戲的背景，是一張大張的圖，前後可以環狀的接合

所以我需要載入一張圖片，將其設定爲兩個圖，用前後貼的方式讓它看起來有捲動的效果

提供了捲動座標(X或Y),捲動的間隔時間，捲動距離等屬性

圖形的捲動則是利用兩張圖的位置互換來模擬

代碼

/*
 *  CBRingScrollImage.h
 *  CloudBox Cross-Platform Framework Project
 *
 *  Created by Cloud on 2012/4/18.
 *  Copyright 2012 Orz. All rights reserved.
 *
 */

#ifndef _CBRINGSCROLLIMAGE_
#define _CBRINGSCROLLIMAGE_

#include "CBView.h"

class CBImage;

enum ScrollCoordinate
{
	ScrollX = 0,
	ScrollY = 1
};

class CBRingScrollImage : public CBView
{
private:
	CBImage* m_image1;
	CBImage* m_image2;
	ScrollCoordinate m_scrollCoordinate;
	float m_distance;
	float m_duration;
	float m_swapLocation;
	void initial();
	void scrollImage(CBView* target);
	void resetImage2();
protected:
	void draw();
public:
	CBRingScrollImage();
	CBRingScrollImage(const string& imageName, ScrollCoordinate scrollCoordinate, float distance, float duration);
	~CBRingScrollImage();
	
	void startScroll();
	
	void setImage(const string& imageName);
	
	inline const ScrollCoordinate getScrollCoordinate() { return m_scrollCoordinate; }
	inline void setScrollCoordinate(ScrollCoordinate scrollCoordinate) { m_scrollCoordinate = scrollCoordinate; }
	
	inline const float getDistance() { return m_distance; }
	inline void setDistance(float distance) { m_distance = distance; }
	
	inline const float getDuration() { return m_duration; }
	inline void setDuration(float duration) { m_duration = duration; }
};

#endif

/*
 *  CBRingScrollImage.cpp
 *  CloudBox Cross-Platform Framework Project
 *
 *  Created by Cloud on 2012/4/18.
 *  Copyright 2012 Orz. All rights reserved.
 *
 */

#include "CBRingScrollImage.h"
#include "CBImage.h"
#include "CBAction.h"
#include "CBEnvironment.h"

CBRingScrollImage::CBRingScrollImage()
:CBView(), m_image1(NULL), m_image2(NULL)
{
	initial();
}

CBRingScrollImage::CBRingScrollImage(const string& imageName, ScrollCoordinate scrollCoordinate, float distance, float duration)
:CBView(), m_image1(NULL), m_image2(NULL), m_scrollCoordinate(scrollCoordinate),
m_distance(distance), m_duration(duration)
{
	initial();
	setImage(imageName);
}

CBRingScrollImage::~CBRingScrollImage()
{
	DELETE(m_image1);
	DELETE(m_image2);
}

void CBRingScrollImage::initial()
{
	this->setWidth(CBEnvironment::getScreenWidth());
	this->setHeight(CBEnvironment::getScreenHeight());
}

void CBRingScrollImage::setImage(const string& imageName)
{
	m_image1 = new CBImage(imageName);
	m_image2 = new CBImage(imageName);
	m_image1->moveTo(0, 0);
	m_swapLocation = 0;
	resetImage2();
}

void CBRingScrollImage::resetImage2()
{
	if(m_scrollCoordinate == ScrollX)
	{
		if(m_distance < 0)
			m_image2->moveTo(m_image1->getWidth(), 0);
		else if(m_distance > 0)
			m_image2->moveTo(m_image1->getX() - m_image1->getWidth(), 0);
	}
	else if(m_scrollCoordinate == ScrollY)
	{
		if(m_distance < 0)
			m_image2->moveTo(0, m_image1->getHeight());
		else if(m_distance > 0)
			m_image2->moveTo(0, m_image1->getY() - m_image1->getHeight());
	}
}

void CBRingScrollImage::scrollImage(CBView* target)
{
	bool isSwap = false;
	if(m_scrollCoordinate == ScrollX)
	{
		m_image1->move(m_distance, 0);
		m_image2->move(m_distance, 0);
		if((m_image2->getX() <= 0 && m_distance < 0) ||
		   (m_image2->getX() + m_image2->getWidth() >= this->getWidth() && m_distance > 0))
			isSwap = true;
	}
	else if(m_scrollCoordinate == ScrollY)
	{
		m_image1->move(0, m_distance);
		m_image2->move(0, m_distance);
		if((m_image2->getY() <= 0 && m_distance < 0) ||
		   (m_image2->getY() + m_image2->getHeight() >= this->getHeight() && m_distance > 0))
			isSwap = true;
	}
	if(isSwap)
	{
		CBImage* temp = m_image1;
		m_image1 = m_image2;
		m_image2 = temp;
		temp = NULL;
		resetImage2();
	}
}

void CBRingScrollImage::startScroll()
{
	CBAction* action = new CBAction(m_duration,REPEAT_ALWAYS);
	action->addTriggerEvent(this,&CBRingScrollImage::scrollImage);
	action->commit(this);
}

void CBRingScrollImage::draw()
{
	if(!this->getVisible())
		return;
	m_image1->visit();
	m_image2->visit();
}