clocktest.lua

local g = grid.connect()
local screen_dirty = false
local grid_dirty = false
local pixels = {}

local pattern = 0
local pattern1_metro = metro.init()
local pattern2_metro = metro.init()
local redraw_metro = metro.init()

function init()
    engine.name = 'PolyPerc'

    redraw_metro.event = redraw_event
    redraw_metro:start(1 / 30)

    pattern1_metro.count = 30
    pattern1_metro.time = 0.030
    pattern1_metro.event = function(stage)
        if math.fmod(stage, 30) == 1 then
            random_pattern(1, 8)
        else
            fadeout(1, 8)
        end
    end

    pattern2_metro.count = 30
    pattern2_metro.time = 0.030
    pattern2_metro.event = function(stage)
        if math.fmod(stage, 30) == 1 then
            random_pattern(9, 16)
        else
            fadeout(9, 16)
        end
    end

    for i = 1, g.cols * g.rows do
        pixels[i] = 0
    end
end

function key(k, z)
    if z == 0 then
        if k == 2 then
            clock.link.start()
        end
        if k == 3 then
            clock.link.stop()
        end
    end
end

function clock.transport.start()
    if pattern ~= 0 then
        return
    end

    pattern = clock.run(function()
        local tick = 0
        while true do
            clock.sync(1) -- 1 beat
            tick = tick + 1
            if math.fmod(tick, 4) == 1 then
                pattern1_metro:start()
            else
                pattern2_metro:start()
            end
        end
    end)
end

function clock.transport.stop()
    if pattern == 0 then
        return
    end

    clock.cancel(pattern)
    pattern1_metro:stop()
    pattern2_metro:stop()
    pattern = 0
end

function fadeout(start, stop)
    local pidx = 0
    for x = start, stop do
        for y = 1, g.rows do
            pidx = x + ((y - 1) * g.cols)
            if pixels[pidx] > 0 then
                pixels[pidx] = pixels[pidx] - 1
                grid_dirty = true
            end
        end
    end
end

function random_pattern(start, stop)
    local pidx = 0
    for x = start, stop do
        for y = 1, g.rows do
            pidx = x + ((y - 1) * g.cols)
            pixels[pidx] = math.random(0, 15)
        end
    end
    grid_dirty = true
end

function redraw_event()
    if screen_dirty then
        redraw()
        screen_dirty = false
    end
    if grid_dirty then
        grid_redraw()
        grid_dirty = false
    end
end

function grid_redraw()
    local pidx = 0
    g:intensity(15)
    for x = 1, g.cols do
        for y = 1, g.rows do
            pidx = x + ((y - 1) * g.cols)
            g:led(x, y, pixels[pidx])
        end
    end
    g:refresh()
end