如何在Corona中查找手指在物体上滑动时的角度

2013-8-8 15:1:28
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在我的项目中，如果我拖动一个对象，会在一个对象上施加一个力，并生成另一个对象 并根据施加的力的数量向滑动方向移动，此代码正常工作。但我想根据手指滑动的角度旋转生成的第二个对象。我想知道如何获取手指滑动的角度并将第二个对象旋转到该角度，请提出任何建议。谢谢... 以下是手指滑动的代码

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 )
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用户2333874
用户2333874

你可以像这样做：

local point1 = {}
local point2 = {}

--保存结束时的坐标
if event.phase == "ended" then
    point1.x = event.xStart
    point1.y = event.yStart

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

--任意的第三个点
point3 = {}
point3.x = point2.x
point3.y = point1.y

这样你就有了三个点，可以计算出角度。然后你就可以在这个角度上施加力。

2013-08-09 01:42:07
用户1605727
用户1605727

试用我创建的这个示例应用程序。我经常使用这个函数。

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)
2013-08-09 16:25:27

作者:

用户2588337

用户2588337
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