Lua Love2d Write Code Instance Once, Use Multiple Times With Each One Being Unique

Question

I have asked a question similar to this, but i was asking it for Processing.JS. Now i am making something out of LOVE2D Lua, what I'm trying to do is that i have a button where when clicked it adds a circle on-screen. I already have code that when i click and hold on the circle, i can move it around. But when i add a second circle, they both are using he same variables. I want it so i write once instance of the code to move and add the circle, but i can call it multiple times and each one be unique without writing code to anticipate an infinite amount of circles. Here is my code:

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

But when i right-click to add a circle(increment how many times the for-loop runs) it doesnt add a second circle for me to move independent from the first one. Help?

cheez3d cheez3d · Accepted Answer · 2016-01-03T19:45:48

The way I would go about handling multiple instances of ellipses is creating a table for every ellipse that would hold it's properties and a draw function.

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

You could even make your own Ellipse class if you're into OOP.

Lua Love2d Write Code Instance Once, Use Multiple Times With Each One Being Unique

1 Answers