小小菜之Cocos2d-x游戏开发旅程——Lua之摇杆实现

多的不说了，直接上代码吧。注释写的挺清楚的

local Joystick = class("Joystick" , function ()
    return cc.Layer:create()
end)

function Joystick:ctor()
    self.visibleSize = cc.Director:getInstance():getVisibleSize()
    self.frame = nil
    self.stick = nil
    self.controlDiameter = nil    --直径
    self.isCanMove = nil
    self.angle = nil
end

function Joystick:handleTouchChange(pos1 , pos2)
    --得到两点坐标的x，y坐标值
    local px1 = pos1.x
    local py1 = pos1.y
    local px2 = pos2.x
    local py2 = pos2.y

    --求出两边的长度
    local x = px2 - px1
    local y = py1 - py2

    --求出距离 及 角度
    local xie = math.sqrt(math.pow(x , 2) + math.pow( y , 2))
    local cos = x/xie

    --反余弦定理 ， 知道两边长求角度 cos = 邻边/斜边
    local rad = math.acos(cos)

    --当触屏Y坐标 < 摇杆的Y坐标时，取反值
    if py1 > py2 then
        rad = -rad
    end

    return rad
end

--得到与角度对应的半径为r的圆上一坐标点
function Joystick:getAnglePosition(r , angle)

    local x = r*math.cos(self.angle)
    local y = r*math.sin(self.angle)
    return cc.p(x , y)
end

function Joystick:load()
    --摇杆背景层
    self.frame = cc.Sprite:createWithSpriteFrameName("zuojian1.png")
    self.frame:setAnchorPoint(0 , 0)
    self.frame:setPosition(cc.p(25 , 25))
    ccui.Helper:doLayout(self.frame)
    self:addChild(self.frame)

    --摇杆层
    self.stick = cc.Sprite:createWithSpriteFrameName("youjian1png.png")
    self.stick:setPosition(self.frame:getContentSize().width/2 , self.frame:getContentSize().height/2)
    self.stick:setScale(0.8)
    self.frame:addChild(self.stick , 1)

    self.controlDiameter = self.frame:getContentSize().width - self.stick:getContentSize().width
    self.angle = 0
    --添加点击事件
    local function onTouchesBegan(touches ,event)
        if cc.rectContainsPoint(self:getBoundingBox(),touches[1]:getLocation()) then
            return true
        end
        return false    
    end

    local function onTouchesMoved(touches , event)
        if cc.rectContainsPoint(self:getBoundingBox(),touches[1]:getLocation()) then
            local point = touches[1]:getLocation()

            local x = point.x - self.frame:getContentSize().width/2
            local y = point.y - self.frame:getContentSize().height/2
            local pos = cc.p(self.frame:getContentSize().width/2 , self.frame:getContentSize().height/2)
            if math.sqrt(math.pow(x , 2) + math.pow( y , 2)) >= self.frame:getContentSize().width/2 then
                --得到触点与摇杆背景圆心形成的角度
                self.angle = self:handleTouchChange(pos , point)
                --确保小圆的运动范围在背景园内
                if self.angle > 1.51046 or self.angle < -0.8075908 then
                    return
                end
                self.stick:setPosition(cc.pAdd(self:getAnglePosition(self.frame:getContentSize().width/2 , angle) , cc.p(self.frame:getContentSize().width/2 , self.frame:getContentSize().height/2)))
            else
                self.angle = self:handleTouchChange(pos , point)
                --触点在背景圆内跟随触点运动
                if self.angle > 1.51046 or self.angle < -0.8075908 then
                    return
                end
                self.stick:setPosition(point)
            end
            self:changeAngleForBone()
            kx_paodan = self.stick:getPositionX() / math.sqrt(math.pow(self.stick:getPositionX() , 2) + math.pow(self.stick:getPositionY() , 2 ))
            ky_paodan = self.stick:getPositionY() / math.sqrt(math.pow(self.stick:getPositionX() , 2) + math.pow(self.stick:getPositionY() , 2 ))
            -- cclog("kx : "..kx_paodan..", ky : "..ky_paodan)
        end 
    end

    local function onTouchesEnded(touches , event)
        local origin = cc.p(self.frame:getContentSize().width/2 , self.frame:getContentSize().height/2)
        self.stick:setPosition(origin)
    end

    local function onTouchesCancelled(touches , event)
        onTouchEnded(touch , event)
    end

    local listener = cc.EventListenerTouchAllAtOnce:create()
    listener:registerScriptHandler(onTouchesBegan , cc.Handler.EVENT_TOUCHES_BEGAN)
    listener:registerScriptHandler(onTouchesMoved , cc.Handler.EVENT_TOUCHES_MOVED)
    listener:registerScriptHandler(onTouchesEnded , cc.Handler.EVENT_TOUCHES_ENDED)
    listener:registerScriptHandler(onTouchesCancelled , cc.Handler.EVENT_TOUCHES_CANCELLED)
    cc.Director:getInstance():getEventDispatcher():addEventListenerWithSceneGraphPriority(listener , self)

end

function Joystick:init()
    self:load()
end

function Joystick:create()
    local newLayer = Joystick.new()
    newLayer:init()
    return newLayer
end

return Joystick

有什么不对的地方请指出，一起进步，O(∩_∩)O哈哈~