自己写的贪吃蛇（2）

下面来实现蛇的移动，我们在initArrows()里面初始化方向按钮时对点击事件做了处理，记录点击的方向作为蛇的移动方向self.direction

function SnakeGame:doMove()     -- 蛇的移动   if not self.is_failed then       -- 蛇有头部(self.snakes[1]) 和身体组成，它又很多个“节点”组成的       -- 蛇的移动可以看着头部的移动，然后身体尾随头部移动而已       for i = #self.snakes, 1, -1 do                   if i > 1 then               -- 当前身体“节点”部分的坐标设置为它的前一个“节点”的坐标               self.snakes[i]:setPosition(self.snakes[i - 1]:getPosition())               self.snakes[i].index = self.snakes[i - 1].index           else               -- 头部的坐标依据移动方向来设定！               if self.direction == SnakeGame.Dir.LEFT then                                   self.snakes[i]:setPosition(self.snakes[i]:getPositionX() - self.cell_width, self.snakes[i]:getPositionY())                   self.snakes[i].index = self.snakes[i].index - 1               elseif self.direction == SnakeGame.Dir.RIGHT then                                   self.snakes[i]:setPosition(self.snakes[i]:getPositionX() + self.cell_width, self.snakes[i]:getPositionY())                   self.snakes[i].index = self.snakes[i].index + 1               elseif self.direction == SnakeGame.Dir.DOWN then                                   self.snakes[i]:setPosition(self.snakes[i]:getPositionX(), self.snakes[i]:getPositionY() - self.cell_width)                   self.snakes[i].index = self.snakes[i].index - self.column_num               elseif self.direction == SnakeGame.Dir.UP then                                   self.snakes[i]:setPosition(self.snakes[i]:getPositionX(), self.snakes[i]:getPositionY() + self.cell_width)                   self.snakes[i].index = self.snakes[i].index + self.column_num               end           end               end      end end

检测蛇是否死亡，头部到达边界或者与身体有碰撞则认为死亡！

function SnakeGame:checkBoundary()    local head_x = self.snakes[1]:getPositionX()    local head_y = self.snakes[1]:getPositionY()    if head_x >= self.column_num * self.cell_width or head_y >= self.row_num * self.cell_width or head_x < 0 or head_y < 0 then        self.tipsLabel:setString(string.format("failed! eated : %d", #self.snakes - self.start_body_length))        self.is_failed = true                return    end    for k, v in ipairs(self.snakes) do        if k > 2 then            if head_x == v:getPositionX() and head_y == v:getPositionY() then                self.tipsLabel:setString(string.format("failed! eated : %d", #self.snakes - self.start_body_length))                self.is_failed = true                                break            end        end    endend

检测目标物是否可以吞噬，判断头部在移动方向上是否可以通过下一步移动来到达目标

function SnakeGame:checkSwallow()        local head_x = self.snakes[1]:getPositionX()    local head_y = self.snakes[1]:getPositionY()    local body_pos = self.cells[self.tail.index]    local b = false    if self.direction == SnakeGame.Dir.LEFT then                        b = head_x == body_pos.x + self.cell_width and head_y == body_pos.y    elseif self.direction == SnakeGame.Dir.RIGHT then                        b = head_x == body_pos.x - self.cell_width and head_y == body_pos.y    elseif self.direction == SnakeGame.Dir.DOWN then                        b = head_x == body_pos.x and head_y == body_pos.y + self.cell_width    elseif self.direction == SnakeGame.Dir.UP then                        b = head_x == body_pos.x and head_y == body_pos.y - self.cell_width    end    if b then                     local body = self:generateSnake(self.tail.index)        -- 吞噬后的目标作为新的头部，放在数组的第一个位置        table.insert(self.snakes, 1, body)        -- 重新生成目标物        self:generateBody()        self.tipsLabel:setString(string.format("eated: %d", #self.snakes - self.start_body_length))        return true    endend

修改doMove里面增加判断让碰撞到边界不再做移动，实现吞噬时当前也不移动(因为吞噬时将目标已经加入到了snakes的头部)

function SnakeGame:doMove()    if self:checkSwallow() then        return    end    self:checkBoundary()    if not self.is_failed then        for i = #self.snakes, 1, -1 do                    if i > 1 then                self.snakes[i]:setPosition(self.snakes[i - 1]:getPosition())                self.snakes[i].index = self.snakes[i - 1].index            else                if self.direction == SnakeGame.Dir.LEFT then                                    self.snakes[i]:setPosition(self.snakes[i]:getPositionX() - self.cell_width, self.snakes[i]:getPositionY())                    self.snakes[i].index = self.snakes[i].index - 1                elseif self.direction == SnakeGame.Dir.RIGHT then                                    self.snakes[i]:setPosition(self.snakes[i]:getPositionX() + self.cell_width, self.snakes[i]:getPositionY())                    self.snakes[i].index = self.snakes[i].index + 1                elseif self.direction == SnakeGame.Dir.DOWN then                                    self.snakes[i]:setPosition(self.snakes[i]:getPositionX(), self.snakes[i]:getPositionY() - self.cell_width)                    self.snakes[i].index = self.snakes[i].index - self.column_num                elseif self.direction == SnakeGame.Dir.UP then                                    self.snakes[i]:setPosition(self.snakes[i]:getPositionX(), self.snakes[i]:getPositionY() + self.cell_width)                    self.snakes[i].index = self.snakes[i].index + self.column_num                end            end                end       end end

让蛇自己移动起来！ 每调用一次doMove函数蛇就沿direction方向移动一格
在onEnter函数的update里面做处理

function SnakeGame:onEnter()    -- 从c++那边导出的一个取得当前毫秒的函数(lua中我不知道哪个函数可以实现这个)    local time1 = tsixi.THelper:currentMilliseconds()    local update = function(dt)        -- 没有死亡则下一步        if not self.is_failed then            local now = tsixi.THelper:currentMilliseconds()            -- 每500ms移动一次或者点了方向按钮立即做一次移动            if not self.parse and (now - time1 >= 500 or self.must) then                self.must = false                time1 = now                                   self:doMove()                            end             end    end    self:scheduleUpdateWithPriorityLua(update, 0) end

基本上传统的贪吃蛇就完成了！
用到的图片

接下来准备用A*算法来写一个贪吃蛇的自动寻路，有点意思