Question

我目前正在处理某个项目，它包含一个要绘制的行的选项。但我通常不能设置最大线长度。我怎么能这样做？

以下是距离公式的代码（我认为）：

local function distanceBetween( e, prev ) 
        local distanceBetween = 0
    local dist_x = e.x - prevX ; local dist_y = e.y - prevY;
    local distanceBetween = math.sqrt((dist_x*dist_x) + (dist_y*dist_y))
    return distanceBetween
end

这是一个行代码：

local lines = {}
    local myLines = {}      
    local prevX,prevY



    local i = 1

    --prevX = x1, prevY = y1, e.x = x2, e.y = y2

    local function drawLine(e)
        distanceBetween = false
      if(e.phase == "began") then
        myLines[i] = {}
        prevX = e.x
        prevY = e.y
           elseif(e.phase == "moved")then
                if prevX then
                    myLines[i][#myLines[i] + 1] = display.newLine(prevX,prevY,e.x,e.y)
                    myLines[i][#myLines[i]]:setColor(255,255,0)
                    myLines[i][#myLines[i]].width = 5
                    myLines[i][#myLines[i]].alpha=1
                    myLines[i][#myLines[i]].myName = "Line"
                    dist_x = e.x - prevX
                    dist_y = e.y - prevY
                    physics.addBody(myLines[i][#myLines[i]], "static", { density = 1, friction = 0.5, bounce = 1.6, shape = {0, 0, dist_x, dist_y, 0, 0} } )
                    lineGroup:insert(myLines[i][#myLines[i]])



                    distanceBetween = true
                        if (distanceBetween > 50) then
                        drawLine("ended")
                        end
                    end -- this is how i think line should be maximized

                    prevX = e.x
                    prevY = e.y
           elseif(e.phase == "ended")then
              prevX = nil
              prevY = nil
              i = i + 1
              removeLine(myLines[#myLines-1])
           end
       end
       Runtime:addEventListener("touch",drawLine);

Answer 1

编辑：这在我的Corona应用程序中运行良好。这是你想要做的吗？

local physics = require "physics"
physics.start()

local lines = {}
local lineGroup = display.newGroup()
local prevX,prevY
local isDrawing = false
local i = 0

local function distanceBetween(x1, y1, x2, y2)
    local dist_x = x2 - x1
    local dist_y = y2 - y1
    local distanceBetween = math.sqrt((dist_x*dist_x) + (dist_y*dist_y))
    return distanceBetween
end

local function drawLine(e)
    if(e.phase == "began") then
        prevX = e.x
        prevY = e.y
        isDrawing = true
        i = i + 1
    elseif(e.phase == "moved") then
        local distance = distanceBetween(prevX, prevY, e.x, e.y)
        if(isDrawing and distance < 100) then
            if(lines[i]) then lineGroup:remove(i) end
            lines[i] = display.newLine(prevX, prevY, e.x, e.y)
            lines[i]:setColor(255, 255, 0)
            lines[i].width = 5

            local dist_x = e.x - prevX
            local dist_y = e.y - prevY
            physics.addBody(lines[i], "static", { density = 1, friction = 0.5, bounce = 1.6, shape = {0, 0, dist_x, dist_y, 0, 0} } )
            lineGroup:insert(lines[i])
        end
    elseif(e.phase == "ended") then
        isDrawing = false
    end
end

Runtime:addEventListener("touch",drawLine)

如何设置绘制线的最大长度？（Corona SDK）

1 个答案: