VST Protoplug midi plugin - Simple Arp with CH2 note exclusive

arpmelodymaker.lua

require "include/protoplug"

speed = 0.25
notelength = 0.2
notes = {0,7,12}

buffer = {}
buffer2 = {}
time = 0
lasttime = 0
lastnote = -1
blockarp = false
 
function plugin.processBlock(samples, smax, midiBuf)
    pos = plugin.getCurrentPosition ()
    rate = plugin.getSampleRate()
    noteduration = (( rate * 1 * 60 ) / pos.bpm) * speed
    
    for ev in midiBuf:eachEvent() do
        if ev:isNoteOn() and ev:getChannel()==1 then
            if lastnote ~= -1 then
                table.insert(buffer2,{lastnote,0})
                lastnote = -1
            end
            time = 0
            lasttime = -1
            offset = 0
            buffer = {}
            for i=1, #notes do 
                table.insert(buffer,{0+offset,ev:getNote()+notes[i],127})
                table.insert(buffer,{(noteduration*notelength)+offset,ev:getNote()+notes[i],0})
                offset = offset + noteduration
            end
        elseif ev:isNoteOff() and ev:getChannel()==1 then
            if lastnote ~= -1 then
                table.insert(buffer2,{lastnote,0})
                lastnote = -1
            end
            buffer = {}
        elseif ev:isNoteOn() and ev:getChannel()==2 then
            table.insert(buffer2,{ev:getNote(),127})
            if lastnote ~= -1 then
                table.insert(buffer2,{lastnote,0})
                lastnote = -1
            end
            blockarp = true
        elseif ev:isNoteOff() and ev:getChannel()==2 then
            table.insert(buffer2,{ev:getNote(),0})
            blockarp = false
        end
    end
    midiBuf:clear()
    
    if #buffer2 then
        for k,n in ipairs(buffer2) do
            ev = midi.Event.noteOn(1, n[1], n[2])
            midiBuf:addEvent(ev)
            table.remove(buffer2,k)
        end
    end
    
    if #buffer and not blockarp then
        for k,n in ipairs(buffer) do 
            if n[1]<time + smax and n[1]>=lasttime then
                offset = math.ceil(math.max (0, math.min ((noteduration - time), smax - 1)))
                ev = midi.Event.noteOn(1, n[2], n[3])
                ev.time = offset --not sure if this will fix timing issues
                if n[3]>0 then
                    lastnote = n[2]
                else
                    lastnote = -1
                end
                midiBuf:addEvent(ev)
            end
        end
    end
    
    time = (time + smax) % (#notes * noteduration)
    if lasttime>time then
        lasttime = -1
    end
end