1

在我的项目中，如果我拖动一个对象，则对一个对象施加一个力，另一个对象生成并沿手指滑动的方向移动，并且根据施加的力的大小，此代码可以正常工作。但我想根据手指滑动的角度旋转生成的第二个对象。我想知道如何获得手指滑动的角度并将第二个对象旋转到该角度，请提供任何建议。谢谢...手指滑动的代码如下

local Objectswipe = display.newImage( "object1.png") 
Objectswipe.x = 100
Objectswipe.y = 200

target = display.newImage( "target.png" )    
target.x = Objectswipe.x; target.y = Objectswipe.y; target.alpha = 0

local function fingerswipe( event )
    local t = event.target

    local phase = event.phase
    if "began" == phase then
        display.getCurrentStage():setFocus( t )
        t.isFocus = true


        t:setLinearVelocity( 0, 0 )
        t.angularVelocity = 0

        target.x = t.x
        target.y = t.y

        startRotation = function()
            target.rotation = target.rotation + 4
        end

        Runtime:addEventListener( "enterFrame", startRotation )

        local showTarget = transition.to( target, { alpha=0.4, xScale=0.4, yScale=0.4, time=200 } )
        myLine = nil

    elseif t.isFocus then
        if "moved" == phase then

            if ( myLine ) then
                myLine.parent:remove( myLine ) -- erase previous line, if any
            end
            myLine = display.newLine( t.x,t.y, event.x,event.y )
            myLine:setColor( 255, 255, 255, 50 )
            myLine.width = 8

        elseif "ended" == phase or "cancelled" == phase then
            display.getCurrentStage():setFocus( nil )
            t.isFocus = false

            local stopRotation = function()
                Runtime:removeEventListener( "enterFrame", startRotation )
            end

            local hideTarget = transition.to( target, { alpha=0, xScale=1.0, yScale=1.0, time=200, onComplete=stopRotation } )

            if ( myLine ) then
                myLine.parent:remove( myLine )
            end

            t:applyForce( (t.x - event.x), (t.y - event.y), t.x, t.y )

        end
    end

    return true
end

Objectswipe:addEventListener( "touch", fingerswipe )
4

2 回答 2

2

试试我创建的这个示例应用程序。我一直使用这个功能。

local physics = require("physics")
physics.start()
physics.setGravity(0,0)
physics.setDrawMode("debug")


function getAngle(x1,y1,x2,y2)
    local PI = 3.14159265358
    local deltaY = y2 - y1
    local deltaX = x2 - x1

    local angleInDegrees = (((math.atan2(deltaY, deltaX) * 180)/ PI)+360)%360

    local mult = 10^0

    return math.floor(angleInDegrees * mult + 0.5) / mult
end

local c = display.newCircle(0,0,50)
c.x = display.contentWidth/2
c.y = display.contentHeight/2
physics.addBody(c,"dynamic",{radius = 50})


Runtime:addEventListener("touch",function(event)
    if event.phase == "began" then

    elseif event.phase == "moved" then
        local angle = getAngle(c.x,c.y,event.x,event.y)
        print(angle)
        c.rotation = angle
    elseif event.phase == "ended" then

    end
end)
于 2013-08-09T16:25:27.863 回答
0

你做这样的事情：

local point1 = {}
local point2 = {}

--save the coordinates for the ended phase
if event.phase == "ended" then
    point1.x = event.xStart
    point1.y = event.yStart

    point2.x = event.x
    point2.y = event.y
end

--arbitrary third point
point3 = {}
point3.x = point2.x
point3.y = point1.y

然后你会得到三个点，并且可以计算角度。你应该能够在角度施加力。

于 2013-08-09T01:42:07.087 回答