【前端底层】BehaviorMining：挖矿行为的行为树实现

---挖矿行为树：找矿->挖矿->满载回城
function BehaviorMining.tick(mon, dt)
    if BehaviorMining.isBagFull(mon) then
        BehaviorMining.goHome(mon)
        return
    end
    local ore = BehaviorMining.findOre(mon)
    if ore then
        BehaviorMining.moveToOre(mon, ore)
        BehaviorMining.mine(mon, ore)
    else
        BehaviorMining.findNewArea(mon)
    end
end

function Mining.findOre(mon)
    local nearest = nil
    local minDist = 999
    for _, ore in ipairs(oreNodes) do
        if not ore.depleted and ore.mapId == mon.mapId then
            local dist = math.sqrt((ore.x - mon.x) ^ 2 + (ore.y - mon.y) ^ 2)
            if dist < minDist then
                minDist = dist
                nearest = ore
            end
        end
    end
    return nearest
end