【cocos2d-x IOS游戏开发-城市跑酷8】实现街区房子的摆放

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【cocos2d-x IOS游戏开发-捕鱼达人1】内容介绍

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【cocos2d-x IOS游戏开发-城市跑酷7】设计烟囱与烟的效果

有了街区的一系列元素，你就可以开始摆放房子了。

这里，首先介绍STL的一种随机算法：random_shuffle()，用来对一个元素序列进行重新排序（随机的），包含在头文件 algorithm.h中。

函数原型如下：

template<class RandomAccessIterator>

   void random_shuffle(

      RandomAccessIterator _First, //指向序列首元素的迭代器

      RandomAccessIterator _Last  //指向序列最后一个元素的下一个位置的迭代器

   );

template<class RandomAccessIterator, class RandomNumberGenerator>

   void random_shuffle(

      RandomAccessIterator _First,

      RandomAccessIterator _Last,

      RandomNumberGenerator& _Rand //调用随机数产生器的函数

   );

random_shuffle()是一个完全通用的算法，适用于内置数据类型和用户自定义类型。同时，由于STL算法不仅适用于容器，也适用于序列，因此，random_shuffle()算法可用于内置数组。

默认的random_shuffle中, 被操作序列的index 与 rand() % N 两个位置的值交换，来达到乱序的目的。

来看具体是用法：

为了随机的生成街区，设置的一组模式；

//随机的模式、宽、高、及类型
int patterns[] = {1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,3,3,3};
int widths[] = {2,2,2,2,2,3,3,3,3,3,3,4,4,4,4,4,4};
int heights[] = {0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,2,2,2,3,3,3,3,3,3,4};
int types[] = {1,2,3,4,1,3,2,4,3,2,1,4,2,3,1,4,2,3,1,2,3,2,3,4,1,2,4,3,1,3,1,4,2,4,2,1,2,3};

//街区模式
vector<int> _blockPattern (patterns, patterns + sizeof(patterns) / sizeof(int));
//街区宽度
vector<int> _blockWidths (widths, widths + sizeof(widths) / sizeof(int));
//街区高度
vector<int> _blockHeights (heights, heights + sizeof(heights) / sizeof(int));
//街区类型
vector<int> _blockTypes (types, types + sizeof(types) / sizeof(int));

就可以直接使用算法了：

	random_shuffle(_blockPattern.begin(), _blockPattern.end());
	random_shuffle(_blockWidths.begin(), _blockWidths.end());
	random_shuffle(_blockHeights.begin(), _blockHeights.end());

来看街区的初始化：

blockWidth = _blockWidths[_currentWidthIndex];

			_currentWidthIndex++;
			if (_currentWidthIndex == _blockWidths.size()) {
				random_shuffle(_blockWidths.begin(), _blockWidths.end());
				_currentWidthIndex = 0;
			}

			if (_blockHeights[_currentHeightIndex] != 0) {

				//change height of next block
				blockHeight = _blockHeights[_currentHeightIndex];
				//if difference too high, decrease it
				if (blockHeight - _lastBlockHeight > 2 && _gapSize == 2) {
					blockHeight = 1;
				}

			} else {
				blockHeight = _lastBlockHeight;
			}
			_currentHeightIndex++;
			if (_currentHeightIndex == _blockHeights.size()) {
				_currentHeightIndex = 0;
				random_shuffle(_blockHeights.begin(), _blockHeights.end());

			}

			block->setupBlock (blockWidth, blockHeight, type);
			_lastBlockWidth = blockWidth;
			_lastBlockHeight = blockHeight;

			//select next block series pattern
			_currentPatternCnt++;
			if (_currentPatternCnt > _blockPattern[_currentPatternIndex]) {
				_showGap = true;
				//start new pattern
				_currentPatternIndex++;
				if (_currentPatternIndex == _blockPattern.size()) {
					random_shuffle(_blockPattern.begin(), _blockPattern.end());
					_currentPatternIndex = 0;
				}
				_currentPatternCnt = 1;
			}
		}

然后初始化地形图：

//设计一个街区块pool用数组存起来
	_blockPool = CCArray::createWithCapacity(20);
	_blockPool->retain();

	//init object pools
	Block * block;
	for (int i = 0; i < 20; i++) {
		//初始化街区块
		block = Block::create();
		this->addChild(block);
		_blockPool->addObject(block);
	}

	_blocks = CCArray::createWithCapacity(20);
	_blocks->retain();

	_minTerrainWidth = _screenSize.width * 1.5f;

	random_shuffle(_blockPattern.begin(), _blockPattern.end());
	random_shuffle(_blockWidths.begin(), _blockWidths.end());
	random_shuffle(_blockHeights.begin(), _blockHeights.end());

	this->addBlocks(0);

添加街区实现：

void Terrain::addBlocks(int currentWidth) {

	Block * block;
	while (currentWidth < _minTerrainWidth)
	{	
		block = (Block *) _blockPool->objectAtIndex(_blockPoolIndex);
		_blockPoolIndex++;
		if (_blockPoolIndex == _blockPool->count()) {
			_blockPoolIndex = 0;
		}
		this->initBlock(block);
		currentWidth +=  block->getWidth();
		_blocks->addObject(block);

	}

	this->distributeBlocks();
}

//分配街区块
void Terrain::distributeBlocks() {
	int count = _blocks->count();

	Block * block;
	Block * prev_block;
	int i;

	for (i = 0; i < count; i++) {
		block = (Block *) _blocks->objectAtIndex(i);
		if (i != 0) {
			prev_block = (Block *) _blocks->objectAtIndex(i - 1);
			block->setPositionX( prev_block->getPositionX() + prev_block->getWidth());
		}
		else
		{
			block->setPositionX ( 0 ); 
		}
	}
}

下节：设计陷阱