loverun.lua

--[[
    Original Author: https://github.com/Leandros
    Updated Author: https://github.com/jakebesworth
        MIT License
        Copyright (c) 2018 Jake Besworth
    Original Gist: https://gist.github.com/Leandros/98624b9b9d9d26df18c4
    Love.run 11.X: https://love2d.org/wiki/love.run
    Original Article, 4th algorithm: https://gafferongames.com/post/fix_your_timestep/
    Forum Discussion: https://love2d.org/forums/viewtopic.php?f=3&t=85166&start=10
    Add this code to bottom of main.lua to override love.run() for Love2D 11.X
    Tickrate is how many frames your simulation happens per second (Timestep)
    Max Frame Skip is how many frames to allow skipped due to lag of simulation outpacing (on slow PCs) tickrate
---]]

-- 1 / Ticks Per Second
local TICK_RATE = 1 / 100

-- How many Frames are allowed to be skipped at once due to lag (no "spiral of death")
local MAX_FRAME_SKIP = 25
if arg[#arg] == "vsc_debug" then
    MAX_FRAME_SKIP = 1  -- improve frame rate if debugging
end
-- No configurable framerate cap currently, either max frames CPU can handle (up to 1000), or vsync'd if conf.lua

function love.run()
    if love.load then love.load(love.arg.parseGameArguments(arg), arg) end

    -- We don't want the first frame's dt to include time taken by love.load.
    if love.timer then love.timer.step() end

    local lag = 0.0

    -- Main loop time.
    return function()
        -- Process events.
        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 or 0
                    end
                end
                love.handlers[name](a,b,c,d,e,f)
            end
        end

        -- Cap number of Frames that can be skipped so lag doesn't accumulate
        if love.timer then lag = math.min(lag + love.timer.step(), TICK_RATE * MAX_FRAME_SKIP) end

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

        if love.graphics and love.graphics.isActive() then
            love.graphics.origin()
            love.graphics.clear(love.graphics.getBackgroundColor())

            if love.draw then love.draw() end
            love.graphics.present()
        end

        -- Even though we limit tick rate and not frame rate, we might want to cap framerate at 1000 frame rate as mentioned https://love2d.org/forums/viewtopic.php?f=4&t=76998&p=198629&hilit=love.timer.sleep#p160881
        if love.timer then love.timer.sleep(0.001) end
    end
end