Love2D Fixed Timestep

main.lua

local TICKRATE = 1/60

function love.update(dt)
end

function love.draw(dt)
end

function love.run()
    if love.math then
        love.math.setRandomSeed(os.time())
    end

    if love.load then love.load(arg) end

    local previous = love.timer.getTime()
    local lag = 0.0
    while true do
        local current = love.timer.getTime()
        local elapsed = current - previous
        previous = current
        lag = lag + elapsed

        if love.event then
            love.event.pump()
            for name, a,b,c,d,e,f in love.event.poll() do
                if name == "quit" then
                    if not love.quit or not love.quit() then
                        return a
                    end
                end
                love.handlers[name](a,b,c,d,e,f)
            end
        end

        while lag >= TICKRATE do
            if love.update then love.update(TICKRATE) end
            lag = lag - TICKRATE
        end

        if love.graphics and love.graphics.isActive() then
            love.graphics.clear(love.graphics.getBackgroundColor())
            love.graphics.origin()
            if love.draw then love.draw(lag / TICKRATE) end
            love.graphics.present()
        end
    end
end

Great job Leandros!

I also stumbled across: https://gafferongames.com/post/fix_your_timestep/
And your post: https://www.reddit.com/r/love2d/comments/47v1b6/little_thing_i_made_to_add_fixed_timestep/d0gs76g/

The goal being trying to get constant game tick rate, and variable frame rate (such as users with vsync, or disabling, but having same game experience, or custom FPS cap).

I noticed that your current code differs from 11.X sample here: https://love2d.org/wiki/love.run

I noticed this because your code doesn't work with: https://love2d.org/wiki/love.timer.getFPS Fixed by using love.timer.step()

I took the liberty of converting your version to 11.X:

The updated code is available here: https://gist.github.com/jakebesworth/ac09d54cc05690250096f977105a41f8

Also there was some nice discussion about it here: https://love2d.org/forums/viewtopic.php?f=3&t=85166&start=10 where I added a "spiral of death" fix or otherwise mentioned near the end of the Fix your Timestep article (if simulation takes longer than tick rate)

Last issue was Licensing, it'd be nice if you could provide a license for this. For my updated version, assuming I consider it a forked gist, would be MIT 2018