PHP树的深度编历生成迷宫及A*自动寻路算法实例分析

本文实例讲述了php树的深度编历生成迷宫及a*自动寻路算法。分享给大家供大家参考。具体分析如下：

有一同事推荐了三思的迷宫算法，看了感觉还不错，就转成php
三思的迷宫算法是采用树的深度遍历原理，这样生成的迷宫相当的细，而且死胡同数量相对较少！
任意两点之间都存在唯一的一条通路。

至于a*寻路算法是最大众化的一全自动寻路算法

废话不多说，贴上带代码

迷宫生成类：

class maze{
    // maze create
    private $_w;
    private $_h;
    private $_grids;
    private $_walkhistory;
    private $_walkhistory2;
    private $_targetsteps;
    // construct
    public function maze() {
        $this->_w = 6;
        $this->_h = 6;
        $this->_grids = array();
    }
    // 设置迷宫大小
    public function set($width = 6, $height = 6) {
        if ( $width > 0 ) $this->_w = $width;
        if ( $height > 0 ) $this->_h = $height;
        return $this;
    }
    // 取到迷宫
    public function get() {
        return $this->_grids;
    }
    // 生成迷宫
    public function create() {
        $this->_init();
        return $this->_walk(rand(0, count($this->_grids) -1 ));
    }
    // 获取死胡同点
    public function block($n = 0, $rand = false) {
        $l = count($this->_grids);
        for( $i = 1; $i < $l; $i++ ) {
            $v = $this->_grids[$i];
            if ( $v == 1 || $v == 2 || $v == 4 || $v == 8 ) {
                $return[] = $i;
            }
        }
        // 随机取点
        if ( $rand ) shuffle($return);
 
        if ( $n == 0 ) return $return;
 
        if ( $n == 1 ) {
            return array_pop($return);
        } else {
            return array_slice($return, 0, $n);
        }
    }
    /**
    |---------------------------------------------------------------
    | 生成迷宫的系列函数
    |---------------------------------------------------------------
    */
    private function _walk($startpos) {
        $this->_walkhistory = array();
        $this->_walkhistory2 = array();
        $curpos = $startpos;
        while ($this->_getnext0() != -1) {
            $curpos = $this->_step($curpos);
            if ( $curpos === false ) break;
        }
        return $this;
    }
    private function _gettargetsteps($curpos) {
        $p = 0;
        $a = array();
        $p = $curpos - $this->_w;
        if ($p > 0 && $this->_grids[$p] === 0 && ! $this->_isrepeating($p)) {
            array_push($a, $p);
        } else {
            array_push($a, -1);
        }
        $p = $curpos + 1;
        if ($p % $this->_w != 0 && $this->_grids[$p] === 0 && ! $this->_isrepeating($p)) {
            array_push($a, $p);
        } else {
            array_push($a, -1);
        }
        $p = $curpos + $this->_w;
        if ($p < count($this->_grids) && $this->_grids[$p] === 0 && ! $this->_isrepeating($p)) {
            array_push($a, $p);
        } else {
            array_push($a, -1);
        }
        $p = $curpos - 1;
        if (($curpos % $this->_w) != 0 && $this->_grids[$p] === 0 && ! $this->_isrepeating($p)) {
            array_push($a, $p);
        } else {
            array_push($a, -1);
        }
        return $a;
    }
    private function _nostep() {
        $l = count($this->_targetsteps);
        for ($i = 0; $i < $l; $i ++) {
            if ($this->_targetsteps[$i] != -1) return false;
        }
        return true;
    }
    private function _step($curpos) {
        $this->_targetsteps = $this->_gettargetsteps($curpos);
        if ( $this->_nostep() ) {
            if ( count($this->_walkhistory) > 0 ) {
                $tmp = array_pop($this->_walkhistory);
            } else {
                return false;
            }
            array_push($this->_walkhistory2, $tmp);
            return $this->_step($tmp);
        }
        $r = rand(0, 3);
        while ( $this->_targetsteps[$r] == -1) {
            $r = rand(0, 3);
        }
        $nextpos = $this->_targetsteps[$r];
        $iscross = false;
        if ( $this->_grids[$nextpos] != 0)
            $iscross = true;
        if ($r == 0) {
            $this->_grids[$curpos] ^= 1;
            $this->_grids[$nextpos] ^= 4;
        } elseif ($r == 1) {
            $this->_grids[$curpos] ^= 2;
            $this->_grids[$nextpos] ^= 8;
        } elseif ($r == 2) {
            $this->_grids[$curpos] ^= 4;
            $this->_grids[$nextpos] ^= 1;
        } elseif ($r == 3) {
            $this->_grids[$curpos] ^= 8;
            $this->_grids[$nextpos] ^= 2;
        }
        array_push($this->_walkhistory, $curpos);
        return $iscross ? false : $nextpos;
    }
    private function _isrepeating($p) {
        $l = count($this->_walkhistory);
        for ($i = 0; $i < $l; $i ++) {
            if ($this->_walkhistory[$i] == $p) return true;
        }
        $l = count($this->_walkhistory2);
        for ($i = 0; $i < $l; $i ++) {
            if ($this->_walkhistory2[$i] == $p) return true;
        }
        return false;
    }
    private function _getnext0() {
        $l = count($this->_grids);
 
        for ($i = 0; $i <= $l; $i++ ) {
            if ( $this->_grids[$i] == 0) return $i;
        }
        return -1;
    }
    private function _init() {
        $this->_grids = array();
        for ($y = 0; $y < $this->_h; $y ++) {
            for ($x = 0; $x < $this->_w; $x ++) {
                array_push($this->_grids, 0);
            }
        }
        return $this;
    }
}

a*寻路算法

class astar{
    // a-star
    private $_open;
    private $_closed;
    private $_start;
    private $_end;
    private $_grids;
    private $_w;
    private $_h;
    // construct
    public function astar(){
        $this->_w = null;
        $this->_h = null;
        $this->_grids = null;
    }
    public function set($width, $height, $grids) {
        $this->_w = $width;
        $this->_h = $height;
        $this->_grids = $grids;
        return $this;
    }
    // 迷宫中寻路
    public function search($start = false, $end = false) {
        return $this->_search($start, $end);
    }
    /**
    |---------------------------------------------------------------
    | 自动寻路 - a-star 算法
    |---------------------------------------------------------------
    */
    public function _search($start = false, $end = false) {
        if ( $start !== false ) $this->_start = $start;
        if ( $end !== false ) $this->_end = $end;
        $_sh = $this->_geth($start);
        $point['i'] = $start;
        $point['f'] = $_sh;
        $point['g'] = 0;
        $point['h'] = $_sh;
        $point['p'] = null;
        $this->_open[] = $point;
        $this->_closed[$start] = $point;
        while ( 0 < count($this->_open) ) {
            $minf = false;
            foreach( $this->_open as $key => $maxnode ) {
                if ( $minf === false || $minf > $maxnode['f'] ) {
                    $minindex = $key;
                }
            }
            $nownode = $this->_open[$minindex];
            unset($this->_open[$minindex]);
            if ( $nownode['i'] == $this->_end ) {
                $tp = array();
                while( $nownode['p'] !== null ) {
                    array_unshift($tp, $nownode['p']);
                    $nownode = $this->_closed[$nownode['p']];
                }
                array_push($tp, $this->_end);
                break;
            }
            $this->_setpoint($nownode['i']);
        }
        $this->_closed = array();
        $this->_open = array();
        return $tp;
    }
    private function _setpoint($me) {
        $point = $this->_grids[$me];
        // 所有可选方向入队列
        if ( $point & 1 ) {
            $next = $me - $this->_w;
            $this->_checkpoint($me, $next);
        }
        if ( $point & 2 ) {
            $next = $me + 1;
            $this->_checkpoint($me, $next);
        }
        if ( $point & 4 ) {
            $next = $me + $this->_w;
            $this->_checkpoint($me, $next);
        }
        if ( $point & 8 ) {
            $next = $me - 1;
            $this->_checkpoint($me, $next);
        }
    }
    private function _checkpoint($pnode, $next) {
        if ( $this->_closed[$next] ) {
            $_g = $this->_closed[$pnode]['g'] + $this->_getg($next);
            if ( $_g < $check['g'] ) {
                $this->_closed[$next]['g'] = $_g;
                $this->_closed[$next]['f'] = $this->_closed[$next]['g'] + $this->_closed[$next]['h'];
                $this->_closed[$next]['p'] = $pnode;
            }
        } else {
            $point['p'] = $pnode;
            $point['h'] = $this->_geth($next);
            $point['g'] = $this->_getg($next);
            $point['f'] = $point['h'] + $point['g'];
            $point['i'] = $next;
            $this->_open[] = $point;
            $this->_closed[$next] = $point;
        }
    }
    private function _getg($point) {
        return abs($this->_start - $point);
    }
    private function _geth($point) {
        return abs($this->_end - $point);
    }
}

完整实例代码点击此处。

有需要大家可以直接下demo，看看效果！

希望本文所述对大家的php程序设计有所帮助。