PICO-8 time based timer for animation example

timer.p8

pico-8 cartridge // http://www.pico-8.com
version 16
__lua__

function _init()
    timer = { elapsed = 0, last = time() }
    circle = {}
    circle.animation = { length = 0.25, elapsed = 0}
    circle.color = 0
end

function update_timer()
    timer.elapsed = (time() - timer.last)
    timer.last = time()
end

function update_circle()
    circle.animation.elapsed += timer.elapsed

    if (circle.animation.elapsed >= circle.animation.length) then
        circle.color = (circle.color + 1) % 15
        circle.animation.elapsed = 0
    end
end

function _update()
    update_timer()
    update_circle()
end

function _draw()
    cls(1)
    circfill(63, 63, 32, circle.color)
end