Hello.lua注释

这个注释cocos2d-x给我们写的hello.lua

-- for CCLuaEngine traceback 输出绑定执行函数发生错误的信息function __G__TRACKBACK__(msg)    print("----------------------------------------")    print("LUA ERROR: " .. tostring(msg) .. "\n")    print(debug.traceback())    print("----------------------------------------")endlocal function main()    -- avoid memory leak 设置脚本内存回收参数 避免内存泄露    collectgarbage("setpause", 100)    collectgarbage("setstepmul", 5000)    -- 就是local function cclog(...) 定义局部Log函数    local cclog = function(...)         print(string.format(...))    end--类似c++的include,会检查是否重复引入    require "hello2"    cclog("result is " .. myadd(3, 5))    ----------------- 读取可视的区域    local visibleSize = CCDirector:sharedDirector():getVisibleSize()    local origin = CCDirector:sharedDirector():getVisibleOrigin()    -- add the moving dog 创建一个小松鼠    local function creatDog()        local frameWidth = 105        local frameHeight = 95        -- create dog animate        local textureDog = CCTextureCache:sharedTextureCache():addImage("dog.png")-- 读取纹理的区域大小        local rect = CCRectMake(0, 0, frameWidth, frameHeight)-- 读取纹理        local frame0 = CCSpriteFrame:createWithTexture(textureDog, rect)        rect = CCRectMake(frameWidth, 0, frameWidth, frameHeight)        local frame1 = CCSpriteFrame:createWithTexture(textureDog, rect)        local spriteDog = CCSprite:createWithSpriteFrame(frame0)        spriteDog.isPaused = false        spriteDog:setPosition(origin.x, origin.y + visibleSize.height / 4 * 3)        local animFrames = CCArray:create()        animFrames:addObject(frame0)        animFrames:addObject(frame1)        local animation = CCAnimation:createWithSpriteFrames(animFrames, 0.5)        local animate = CCAnimate:create(animation);-- 初始状态是frame0        spriteDog:runAction(CCRepeatForever:create(animate))        -- moving dog at every frame。这个是来决定松鼠往右走        local function tick()            if spriteDog.isPaused then return end            local x, y = spriteDog:getPosition()            if x > origin.x + visibleSize.width then                x = origin.x            else                x = x + 1            end            spriteDog:setPositionX(x)        end-- 生成一个schedule，每帧执行tick函数        CCDirector:sharedDirector():getScheduler():scheduleScriptFunc(tick, 0, false)        return spriteDog    end    -- create farm    local function createLayerFarm()        local layerFarm = CCLayer:create()        -- add in farm background   添加背景        local bg = CCSprite:create("farm.jpg")        bg:setPosition(origin.x + visibleSize.width / 2 + 80, origin.y + visibleSize.height / 2)        layerFarm:addChild(bg)        -- add land sprite   添加草地        for i = 0, 3 do            for j = 0, 1 do                local spriteLand = CCSprite:create("land.png")                spriteLand:setPosition(200 + j * 180 - i % 2 * 90, 10 + i * 95 / 2)                layerFarm:addChild(spriteLand)            end        end        -- add crop          添加植物        local frameCrop = CCSpriteFrame:create("crop.png", CCRectMake(0, 0, 105, 95))        for i = 0, 3 do            for j = 0, 1 do                local spriteCrop = CCSprite:createWithSpriteFrame(frameCrop);                spriteCrop:setPosition(10 + 200 + j * 180 - i % 2 * 90, 30 + 10 + i * 95 / 2)                layerFarm:addChild(spriteCrop)            end        end        -- add moving dog 添加移动的狗        local spriteDog = creatDog()        layerFarm:addChild(spriteDog)        -- handing touch events 手指触摸事件的处理        local touchBeginPoint = nil-- 如果有安到        local function onTouchBegan(x, y)            cclog("onTouchBegan: %0.2f, %0.2f", x, y)             touchBeginPoint = {x = x, y = y} -- 记住点击的位置            spriteDog.isPaused = true --将松鼠暂停            -- CCTOUCHBEGAN event must return true  这里要return true,否则后面将无法运行            return true        end        local function onTouchMoved(x, y) -- 结束的位置减去初始的位置就是移动的位置            -- cclog("onTouchMoved: %0.2f, %0.2f", x, y)            if touchBeginPoint then -- 这个变量是在上面声明的-- 将整个农场层拖动，因为之前已经将农场里面所有对象加入在layerFarm                 local cx, cy = layerFarm:getPosition()                layerFarm:setPosition(cx + x - touchBeginPoint.x,                                      cy + y - touchBeginPoint.y)                touchBeginPoint = {x = x, y = y}            end        end-- 手指离开        local function onTouchEnded(x, y)            cclog("onTouchEnded: %0.2f, %0.2f", x, y)            touchBeginPoint = nil -- 数据清空            spriteDog.isPaused = false -- 松鼠显示出来        end        local function onTouch(eventType, x, y)            if eventType == CCTOUCHBEGAN then                return onTouchBegan(x, y)            elseif eventType == CCTOUCHMOVED then                return onTouchMoved(x, y)            else                return onTouchEnded(x, y)            end        end-- 设置监听器        layerFarm:registerScriptTouchHandler(onTouch)        layerFarm:setTouchEnabled(true)         return layerFarm    end    -- create menu 建立目录    local function createLayerMenu()        local layerMenu = CCLayer:create()        local menuPopup, menuTools, effectID        local function menuCallbackClosePopup()            -- stop test sound effect 停止音乐            SimpleAudioEngine:sharedEngine():stopEffect(effectID)            menuPopup:setVisible(false)        end        local function menuCallbackOpenPopup()            -- loop test sound effect            local effectPath = CCFileUtils:sharedFileUtils():fullPathFromRelativePath("effect1.wav")            effectID = SimpleAudioEngine:sharedEngine():playEffect(effectPath)            menuPopup:setVisible(true)        end        -- add a popup menu 创建弹出的菜单面板        local menuPopupItem = CCMenuItemImage:create("menu2.png", "menu2.png")        menuPopupItem:setPosition(0, 0)        menuPopupItem:registerScriptTapHandler(menuCallbackClosePopup)        menuPopup = CCMenu:createWithItem(menuPopupItem)        menuPopup:setPosition(origin.x + visibleSize.width / 2, origin.y + visibleSize.height / 2)        menuPopup:setVisible(false)        layerMenu:addChild(menuPopup)        -- add the left-bottom "tools" menu to invoke menuPopup 这里是建立工具按钮        local menuToolsItem = CCMenuItemImage:create("menu1.png", "menu1.png")        menuToolsItem:setPosition(0, 0)        menuToolsItem:registerScriptTapHandler(menuCallbackOpenPopup) -- 响应函数        menuTools = CCMenu:createWithItem(menuToolsItem)        local itemWidth = menuToolsItem:getContentSize().width        local itemHeight = menuToolsItem:getContentSize().height        menuTools:setPosition(origin.x + itemWidth/2, origin.y + itemHeight/2)        layerMenu:addChild(menuTools)        return layerMenu    end    -- play background music, preload effect    -- uncomment below for the BlackBerry version    -- local bgMusicPath = CCFileUtils:sharedFileUtils():fullPathFromRelativePath("background.ogg")    local bgMusicPath = CCFileUtils:sharedFileUtils():fullPathFromRelativePath("background.mp3")    SimpleAudioEngine:sharedEngine():playBackgroundMusic(bgMusicPath, true)    local effectPath = CCFileUtils:sharedFileUtils():fullPathFromRelativePath("effect1.wav")    SimpleAudioEngine:sharedEngine():preloadEffect(effectPath)    -- run    local sceneGame = CCScene:create()    sceneGame:addChild(createLayerFarm())    sceneGame:addChild(createLayerMenu())    CCDirector:sharedDirector():runWithScene(sceneGame)endxpcall(main, __G__TRACKBACK__)--[[ xpcall( 调用函数, 错误捕获函数 ); lua提供了xpcall来捕获异常xpcall接受两个参数:调用函数、错误处理函数。 当错误发生时,Lua会在栈释放以前调用错误处理函数,因此可以使用debug库收集错误相关信息。两个常用的debug处理函数:debug.debug和debug.traceback 前者给出Lua的提示符,你可以自己动手察看错误发生时的情况;后者通过traceback创建更多的错误信息,也是控制台解释器用来构建错误信息的函数。--]]