Lua Love2d 编写代码实例一次，多次使用，每次唯一

Question

我问过一个与此类似的问题，但我问的是 Processing.JS。现在我正在用 LOVE2D Lua 制作一些东西，我想做的是我有一个按钮，当点击它时，它会在屏幕上添加一个圆圈。我已经有代码，当我单击并按住圆圈时，我可以移动它。但是当我添加第二个圆圈时，他们都使用相同的变量。我想要它，所以我编写了一次代码实例来移动和添加圆圈，但我可以多次调用它并且每个都是唯一的，而无需编写代码来预测无限数量的圆圈。这是我的代码：

obn = 0
ellipsex = 50
ellipsey = 50
ellipsew = 50
ellipseh = 50
ellipser = 255
ellipseg = 0
ellipseb = 0
function love.draw()
mousex, mousey = love.mouse.getPosition()
for i=0,obn,1 do
ellipse()
end
end


function love.mousereleased(x, y, button)
   if button == 2 then
      obn = obn + 1
   end

end




function love.update(dt)
    if love.mouse.isDown(1) then
           if mousex > ellipsex and mousex < ellipsex + ellipsew and mousey > ellipsey and mousey < ellipsey + ellipseh then
ellipsex = mousex
ellipsey = mousey
end
    end
end





function ellipse()






love.graphics.setColor(ellipser, ellipseg, ellipseb)
love.graphics.ellipse("fill", ellipsex, ellipsey, ellipsew, ellipseh)

end

但是当我右键单击添加一个圆圈（增加 for 循环运行的次数）时，它不会添加第二个圆圈让我独立于第一个圆圈移动。帮忙？

Answer 1

我处理多个椭圆实例的方法是为每个椭圆创建一个表格，其中包含其属性和draw 函数。

local ellipses = {} -- store all ellipses into a table

function create_ellipse(x,y,w,h,r,g,b)
    local ellipse = {
        x = x,
        y = y,

        w = w,
        h = h,

        r = r,
        g = g,
        b = b
    }

    function ellipse.draw()
        love.graphics.setColor(ellipse.r,ellipse.g,ellipse.b)
        love.graphics.ellipse("fill",ellipse.x,ellipse.y,ellipse.w,ellipse.h)
    end

    ellipses[#ellipses+1] = ellipse -- insert new ellipse into ellipses table

    return ellipse
end

function love.draw()
    for i = 1,#ellipses do
        ellipses[i].draw(); -- call each ellipse's separate draw function
    end
end

function love.mousereleased(x,y,button)
    if button == 2 then
        create_ellipse(x,y,50,50,255,0,0) -- bonus: every ellipse is created where the user clicked
    end
end

function love.update(dt)
    if love.mouse.isDown(1) then
        local mousex,mousey = love.mouse.getPosition() -- there is no need to request the mouse position every frame, but only when a user clicks anywhere on the screen

        for i = 1,#ellipses do
            local current_ellipse = ellipses[i]

            if mousex >= current_ellipse.x and mousex <= current_ellipse.x+current_ellipse.w and mousey >= current_ellipse.y and mousey <= current_ellipse.y+current_ellipse.h then
                current_ellipse.x = mousex
                current_ellipse.y = mousey
            end
        end
    end
end

如果您喜欢 OOP，您甚至可以创建自己的 Ellipse 类。