Nerdson Labs: algoritmo de movimento estilo jogo TBS

tactics.js

$(document).ready(function(){

    $("#tactics form").submit(function(e){
        e.preventDefault();
    });
    
    //syntax highlight
    ChiliBook.recipeFolder = "./";

    //observação: criei variáveis globais aqui a nivel de exemplo, mas isso não é recomendado. O ideal é criar objetos para  armazenar esses valores. ;)
    var TILE = 30;
    var X, Y = 0;
    
    //matriz relativamente grande. Cuidado :)
    var grid = [[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
                [0,0,0,0,0,0,0,0,1,0,0,0,0,1,0,0,0,0,0],
                [0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0],
                [0,0,0,1,0,0,0,0,1,1,1,1,0,0,0,0,0,0,0],
                [0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0],
                [1,1,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0],
                [0,0,0,1,1,1,0,0,1,1,0,0,0,0,1,1,1,0,0],
                [0,0,0,1,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0],
                [0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,1,1],
                [0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0]];
    
    var WIDTH = grid[0].length;
    var HEIGHT = grid.length;
    
    var closed_tiles = {};
    var tiles = [];

    var MOV = 2;

    //helpers
    function get_x(obj){
        return parseInt(obj.css("left"), 10);
    }
    
    function get_y(obj){
        return parseInt(obj.css("top"), 10);
    }

    //Retorna os tiles ao normal
    function clear(){
        $.each(closed_tiles, function(key, value) {
            var coords = key.split(",");
            var tile = tiles[coords[1]][coords[0]];
            tile.css("background", "#DDD");
        });
        closed_tiles = {};
    }


    //função descrita no tutorial
    function tile_walk(xn, yn, movement)
    {
        // acrescentar custo do tile-alvo
        movement += 1;
        
        // não ultrapassar limite de pontos de movimento
        if (movement > MOV)
            return;
        
        // não passar dos limites da grade/tabuleiro
        if (xn < 0 || xn >= WIDTH || yn < 0 || yn >= HEIGHT)
            return;
        
        // não andar por cima de obstáculos
        if (grid[yn][xn] == 1)
            return;

        var coords = xn + "," + yn;
        if (!(coords in closed_tiles) || closed_tiles[coords] > movement) {
            closed_tiles[coords] = movement;
            tiles[yn][xn].css("background", "#88F");
            
            tile_walk(xn+1, yn, movement);
            tile_walk(xn-1, yn, movement);
            tile_walk(xn, yn+1, movement);
            tile_walk(xn, yn-1, movement);
        }
    }

    //constrói o cenário
    for(var j = 0; j < HEIGHT; j++)
    {
        tiles[j] = [];
        for(var i = 0; i < WIDTH; i++)
        {
            var type = "tile";
            if (grid[j][i] == 1)
                type = "obstacle";
            
            var elem = $("<div/>").attr("class", type).css("top", j*TILE).css("left", i*TILE);
            
            elem.click(function() {
                MOV = $("#mov").val();
                if (MOV < 1 || MOV > 7 || isNaN(MOV)) {
                    alert("Intervalo permitido: de 1 a 7");
                    MOV = 2;
                    $("#mov").val(2);
                } else {
                    MOV = parseInt(MOV, 10);
                    X = get_x($(this)) / TILE;
                    Y = get_y($(this)) / TILE;
                    clear();
                    tile_walk(X, Y, -1);
                }
            });
            
            tiles[j][i] = elem;
            
            $("#game").append(elem);
        }
    }
});