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livetrax/share/scripts/raptor_arp.lua

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ardour {
["type"] = "dsp",
name = "Arpeggiator (Raptor)",
category = "Effect",
author = "Albert Gräf",
license = "GPL",
description = [[Raptor: The Random Arpeggiator (Raptor 6, Ardour implementation v0.3)
Advanced arpeggiator with random note generation, harmonic controls, input pitch and velocity tracking, and automatic modulation of various parameters.
In memory of Clarence Barlow (27 December 1945 29 June 2023).
]]
}
-- Raptor Random Arpeggiator for Ardour, ported from the pd-lua version at
-- https://github.com/agraef/raptor-lua.
-- Author: Albert Gräf <aggraef@gmail.com>, Dept. of Music-Informatics,
-- Johannes Gutenberg University (JGU) of Mainz, Germany, please check
-- https://agraef.github.io/ for a list of my software.
-- Copyright (c) 2021 by Albert Gräf <aggraef@gmail.com>
-- Distributed under the GPLv3+, please check the accompanying COPYING file
-- for details.
-- As the Ardour Lua interface wants everything in a single Lua module, this
-- is a hodgeposge of the modules making up the pd-lua version, with the
-- Ardour dsp thrown on top that.
-- -------------------------------------------------------------------------
-- Various helper functions to compute Barlow meters and harmonicities using
-- the methods from Clarence Barlow's Ratio book (Feedback Papers, Cologne,
-- 2001)
local M = {}
-- list helper functions
-- concatenate tables
function M.tableconcat(t1, t2)
local res = {}
for i=1,#t1 do
table.insert(res, t1[i])
end
for i=1,#t2 do
table.insert(res, t2[i])
end
return res
end
-- reverse a table
function M.reverse(list)
local res = {}
for _, v in ipairs(list) do
table.insert(res, 1, v)
end
return res
end
-- arithmetic sequences
function M.seq(from, to, step)
step = step or 1;
local sgn = step>=0 and 1 or -1
local res = {}
while sgn*(to-from) >= 0 do
table.insert(res, from)
from = from + step
end
return res
end
-- cycle through a table
function M.cycle(t, i)
local n = #t
if n > 0 then
while i > n do
i = i - n
end
end
return t[i]
end
-- some functional programming goodies
function M.map(list, fn)
local res = {}
for _, v in ipairs(list) do
table.insert(res, fn(v))
end
return res
end
function M.reduce(list, acc, fn)
for _, v in ipairs(list) do
acc = fn(acc, v)
end
return acc
end
function M.collect(list, acc, fn)
local res = {acc}
for _, v in ipairs(list) do
acc = fn(acc, v)
table.insert(res, acc)
end
return res
end
function M.sum(list)
return M.reduce(list, 0, function(a,b) return a+b end)
end
function M.prd(list)
return M.reduce(list, 1, function(a,b) return a*b end)
end
function M.sums(list)
return M.collect(list, 0, function(a,b) return a+b end)
end
function M.prds(list)
return M.collect(list, 1, function(a,b) return a*b end)
end
-- Determine the prime factors of an integer. The result is a list with the
-- prime factors in non-decreasing order.
function M.factor(n)
local factors = {}
if n<0 then n = -n end
while n % 2 == 0 do
table.insert(factors, 2)
n = math.floor(n / 2)
end
local p = 3
while p <= math.sqrt(n) do
while n % p == 0 do
table.insert(factors, p)
n = math.floor(n / p)
end
p = p + 2
end
if n > 1 then -- n must be prime
table.insert(factors, n)
end
return factors
end
-- Collect the factors of the integer n and return them as a list of pairs
-- {p,k} where p are the prime factors in ascending order and k the
-- corresponding (nonzero) multiplicities. If the given number is a pair {p,
-- q}, considers p/q as a rational number and returns its prime factors with
-- positive or negative multiplicities.
function M.factors(x)
if type(x) == "table" then
local n, m = table.unpack(x)
local pfs, nfs, mfs = {}, M.factors(n), M.factors(m)
-- merge the factors in nfs and mfs into a single list
local i, j, k, N, M = 1, 1, 1, #nfs, #mfs
while i<=N or j<=M do
if j>M or (i<=N and mfs[j][1]>nfs[i][1]) then
pfs[k] = nfs[i]
k = k+1; i = i+1
elseif i>N or (j<=M and nfs[i][1]>mfs[j][1]) then
pfs[k] = mfs[j]
pfs[k][2] = -mfs[j][2]
k = k+1; j = j+1
else
pfs[k] = nfs[i]
pfs[k][2] = nfs[i][2] - mfs[j][2]
k = k+1; i = i+1; j = j+1
end
end
return pfs
else
local pfs, pf = {}, M.factor(x)
if next(pf) then
local j, n = 1, #pf
pfs[j] = {pf[1], 1}
for i = 2, n do
if pf[i] == pfs[j][1] then
pfs[j][2] = pfs[j][2] + 1
else
j = j+1
pfs[j] = {pf[i], 1}
end
end
end
return pfs
end
end
-- Probability functions. These are used with some of the random generation
-- functions below.
-- Create random permutations. Chooses n random values from a list ms of input
-- values according to a probability distribution given by a list ws of
-- weights. NOTES: ms and ws should be of the same size, otherwise excess
-- elements will be chosen at random. In particular, if ws is empty or missing
-- then shuffle(n, ms) will simply return n elements chosen from ms at random
-- using a uniform distribution. ms and ws and are modified *in place*,
-- removing chosen elements, so that their final contents will be the elements
-- *not* chosen and their corresponding weight distribution.
function M.shuffle(n, ms, ws)
local res = {}
if ws == nil then
-- simply choose elements at random, uniform distribution
ws = {}
end
while next(ms) ~= nil and n>0 do
-- accumulate weights
local sws = M.sums(ws)
local s = sws[#sws]
table.remove(sws, 1)
-- pick a random index
local k, r = 0, math.random()*s
--print("r = ", r, "sws = ", table.unpack(sws))
for i = 1, #sws do
if r < sws[i] then
k = i; break
end
end
-- k may be out of range if ws and ms aren't of the same size, in which
-- case we simply pick an element at random
if k==0 or k>#ms then
k = math.random(#ms)
end
table.insert(res, ms[k])
n = n-1; table.remove(ms, k);
if k<=#ws then
table.remove(ws, k)
end
end
return res
end
-- Calculate modulated values. This is used for all kinds of parameters which
-- can vary automatically according to pulse strength, such as note
-- probability, velocity, gate, etc.
function M.mod_value(x1, x2, b, w)
-- x2 is the nominal value which is always output if b==0. As b increases
-- or decreases, the range extends downwards towards x1. (Normally,
-- x2>x1, but you can reverse bounds to have the range extend upwards.)
if b >= 0 then
-- positive bias: mod_value(w) -> x1 as w->0, -> x2 as w->1
-- zero bias: mod_value(w) == x2 (const.)
return x2-b*(1-w)*(x2-x1)
else
-- negative bias: mod_value(w) -> x1 as w->1, -> x2 as w->0
return x2+b*w*(x2-x1)
end
end
-- Barlow meters. This stuff is mostly a verbatim copy of the guts of
-- meter.pd_lua, please check that module for details.
-- Computes the best subdivision q in the range 1..n and pulse p in the range
-- 0..q so that p/q matches the given phase f in the floating point range 0..1
-- as closely as possible. Returns p, q and the absolute difference between f
-- and p/q. NB: Seems to work best for q values up to 7.
function M.subdiv(n, f)
local best_p, best_q, best = 0, 0, 1
for q = 1, n do
local p = math.floor(f*q+0.5) -- round towards nearest pulse
local diff = math.abs(f-p/q)
if diff < best then
best_p, best_q, best = p, q, diff
end
end
return best_p, best_q, best
end
-- Compute pulse strengths according to Barlow's indispensability formula from
-- the Ratio book.
function M.indisp(q)
local function ind(q, k)
-- prime indispensabilities
local function pind(q, k)
local function ind1(q, k)
local i = ind(M.reverse(M.factor(q-1)), k)
local j = i >= math.floor(q / 4) and 1 or 0;
return i+j
end
if q <= 3 then
return (k-1) % q
elseif k == q-2 then
return math.floor(q / 4)
elseif k == q-1 then
return ind1(q, k-1)
else
return ind1(q, k)
end
end
local s = M.prds(q)
local t = M.reverse(M.prds(M.reverse(q)))
return
M.sum(M.map(M.seq(1, #q), function(i) return s[i] * pind(q[i], (math.floor((k-1) % t[1] / t[i+1]) + 1) % q[i]) end))
end
if type(q) == "number" then
q = M.factor(q)
end
if type(q) ~= "table" then
error("invalid argument, must be an integer or table of primes")
else
return M.map(M.seq(0,M.prd(q)-1), function(k) return ind(q,k) end)
end
end
-- Barlow harmonicities from the Ratio book. These are mostly ripped out of an
-- earlier version of the Raptor random arpeggiator programs (first written in
-- Q, then rewritten in Pure, and now finally ported to Lua).
-- Some "standard" 12 tone scales and prime valuation functions to play with.
-- Add others as needed. We mostly use the just scale and the standard Barlow
-- valuation here.
M.just = -- standard just intonation, a.k.a. the Ptolemaic (or Didymic) scale
{ {1,1}, {16,15}, {9,8}, {6,5}, {5,4}, {4,3}, {45,32},
{3,2}, {8,5}, {5,3}, {16,9}, {15,8}, {2,1} }
M.pyth = -- pythagorean (3-limit) scale
{ {1,1}, {2187,2048}, {9,8}, {32,27}, {81,64}, {4,3}, {729,512},
{3,2}, {6561,4096}, {27,16}, {16,9}, {243,128}, {2,1} }
M.mean4 = -- 1/4 comma meantone scale, Barlow (re-)rationalization
{ {1,1}, {25,24}, {10,9}, {6,5}, {5,4}, {4,3}, {25,18},
{3,2}, {25,16}, {5,3}, {16,9}, {15,8}, {2,1} }
function M.barlow(p) return 2*(p-1)*(p-1)/p end
function M.euler(p) return p-1 end
-- "mod 2" versions (octave is eliminated)
function M.barlow2(p) if p==2 then return 0 else return M.barlow(p) end end
function M.euler2(p) if p==2 then return 0 else return M.euler(p) end end
-- Harmonicity computation.
-- hrm({p,q}, pv) computes the disharmonicity of the interval p/q using the
-- prime valuation function pv.
-- hrm_dist({p1,q1}, {p2,q2}, pv) computes the harmonic distance between two
-- pitches, i.e., the disharmonicity of the interval between {p1,q1} and
-- {p2,q2}.
-- hrm_scale(S, pv) computes the disharmonicity metric of a scale S, i.e., the
-- pairwise disharmonicities of all intervals in the scale. The input is a
-- list of intervals as {p,q} pairs, the output is the distance matrix.
function M.hrm(x, pv)
return M.sum(M.map(M.factors(x),
function(f) local p, k = table.unpack(f)
return math.abs(k) * pv(p)
end))
end
function M.hrm_dist(x, y, pv)
local p1, q1 = table.unpack(x)
local p2, q2 = table.unpack(y)
return M.hrm({p1*q2,p2*q1}, pv)
end
function M.hrm_scale(S, pv)
return M.map(S,
function(s)
return M.map(S, function(t) return M.hrm_dist(s, t, pv) end)
end)
end
-- Some common tables for convenience and testing. These are all based on a
-- standard 12-tone just tuning. NOTE: The given reference tables use rounded
-- values, but are good enough for most practical purposes; you might want to
-- employ these to avoid the calculation cost.
-- Barlow's "indigestibility" harmonicity metric
-- M.bgrad = {0,13.07,8.33,10.07,8.4,4.67,16.73,3.67,9.4,9.07,9.33,12.07,1}
M.bgrad = M.map(M.just, function(x) return M.hrm(x, M.barlow) end)
-- Euler's "gradus suavitatis" (0-based variant)
-- M.egrad = {0,10,7,7,6,4,13,3,7,6,8,9,1}
M.egrad = M.map(M.just, function(x) return M.hrm(x, M.euler) end)
-- In an arpeggiator we might want to treat different octaves of the same
-- pitch as equivalent, in which case we can use the following "mod 2" tables:
M.bgrad2 = M.map(M.just, function(x) return M.hrm(x, M.barlow2) end)
M.egrad2 = M.map(M.just, function(x) return M.hrm(x, M.euler2) end)
-- But in the following we stick to the standard Barlow table.
M.grad = M.bgrad
-- Calculate the harmonicity of the interval between two (MIDI) notes.
function M.hm(n, m)
local d = math.max(n, m) - math.min(n, m)
return 1/(1+M.grad[d%12+1])
end
-- Use this instead if you also want to keep account of octaves.
function M.hm2(n, m)
local d = math.max(n, m) - math.min(n, m)
return 1/(1+M.grad[d%12+1]+(d//12)*M.grad[13])
end
-- Calculate the average harmonicity (geometric mean) of a MIDI note relative
-- to a given chord (specified as a list of MIDI notes).
function M.hv(ns, m)
if next(ns) ~= nil then
local xs = M.map(ns, function(n) return M.hm(m, n) end)
return M.prd(xs)^(1/#xs)
else
return 1
end
end
-- Sort the MIDI notes in ms according to descending average harmonicities
-- w.r.t. the MIDI notes in ns. This allows you to quickly pick the "best"
-- (harmonically most pleasing) MIDI notes among given alternatives ms
-- w.r.t. a given chord ns.
function M.besthv(ns, ms)
local mhv = M.map(ms, function(m) return {m, M.hv(ns, m)} end)
table.sort(mhv, function(x, y) return x[2]>y[2] or
(x[2]==y[2] and x[1]<y[1]) end)
return M.map(mhv, function(x) return x[1] end)
end
-- Randomized note filter. This is the author's (in)famous Raptor algorithm.
-- It needs a whole bunch of parameters, but also delivers much more
-- interesting results and can produce randomized chords as well. Basically,
-- it performs a random walk guided by Barlow harmonicities and
-- indispensabilities. The parameters are:
-- ns: input notes (chord memory of the arpeggiator, as in besthv these are
-- used to calculate the average harmonicities)
-- ms: candidate output notes (these will be filtered and participate in the
-- random walk)
-- w: indispensability value used to modulate the various parameters
-- nmax, nmod: range and modulation of the density (maximum number of notes
-- in each step)
-- smin, smax, smod: range and modulation of step widths, which limits the
-- steps between notes in successive pulses
-- dir, mode, uniq: arpeggio direction (0 = random, 1 = up, -1 = down), mode
-- (0 = random, 1 = up, 2 = down, 3 = up-down, 4 = down-up), and whether
-- repeated notes are disabled (uniq flag)
-- hmin, hmax, hmod: range and modulation of eligible harmonicities, which are
-- used to filter candidate notes based on average harmonicities w.r.t. the
-- input notes
-- pref, prefmod: range and modulation of harmonic preference. This is
-- actually one of the most important and effective parameters in the Raptor
-- algorithm which drives the random note selection process. A pref value
-- between -1 and 1 determines the weighted probabilities used to pick notes
-- at random. pref>0 gives preference to notes with high harmonicity, pref<0
-- to notes with low harmonicity, and pref==0 ignores harmonicity (in which
-- case all eligible notes are chosen with the same probability). The prefs
-- parameter can also be modulated by pulse strengths as indicated by prefmod
-- (prefmod>0 lowers preference on weak pulses, prefmod<0 on strong pulses).
function M.harm_filter(w, hmin, hmax, hmod, ns, ms)
-- filters notes according to harmonicities and a given pulse weight w
if next(ns) == nil then
-- empty input (no eligible notes)
return {}
else
local res = {}
for _,m in ipairs(ms) do
local h = M.hv(ns, m)
-- modulate: apply a bias determined from hmod and w
if hmod > 0 then
h = h^(1-hmod*(1-w))
elseif hmod < 0 then
h = h^(1+hmod*w)
end
-- check that the (modulated) harmonicity is within prescribed bounds
if h>=hmin and h<=hmax then
table.insert(res, m)
end
end
return res
end
end
function M.step_filter(w, smin, smax, smod, dir, mode, cache, ms)
-- filters notes according to the step width parameters and pulse weight w,
-- given which notes are currently playing (the cache)
if next(ms) == nil or dir == 0 then
return ms, dir
end
local res = {}
while next(res) == nil do
if next(cache) ~= nil then
-- non-empty cache, going any direction
local lo, hi = cache[1], cache[#cache]
-- NOTE: smin can be negative, allowing us, say, to actually take a
-- step *down* while going upwards. But we always enforce that smax
-- is non-negative in order to avoid deadlock situations where *no*
-- step is valid anymore, and even restarting the pattern doesn't
-- help. (At least that's what I think, I don't really recall what
-- the original rationale behind all this was, but since it's in the
-- original Raptor code, it must make sense somehow. ;-)
smax = math.max(0, smax)
smax = math.floor(M.mod_value(math.abs(smin), smax, smod, w)+0.5)
local function valid_step_min(m)
if dir==0 then
return (m>=lo+smin) or (m<=hi-smin)
elseif dir>0 then
return m>=lo+smin
else
return m<=hi-smin
end
end
local function valid_step_max(m)
if dir==0 then
return (m>=lo-smax) and (m<=hi+smax)
elseif dir>0 then
return (m>=lo+math.min(0,smin)) and (m<=hi+smax)
else
return (m>=lo-smax) and (m<=hi-math.min(0,smin))
end
end
for _,m in ipairs(ms) do
if valid_step_min(m) and valid_step_max(m) then
table.insert(res, m)
end
end
elseif dir == 1 then
-- empty cache, going up, start at bottom
local lo = ms[1]
local max = math.floor(M.mod_value(smin, smax, smod, w)+0.5)
for _,m in ipairs(ms) do
if m <= lo+max then
table.insert(res, m)
end
end
elseif dir == -1 then
-- empty cache, going down, start at top
local hi = ms[#ms]
local max = math.floor(M.mod_value(smin, smax, smod, w)+0.5)
for _,m in ipairs(ms) do
if m >= hi-max then
table.insert(res, m)
end
end
else
-- empty cache, random direction, all notes are eligible
return ms, dir
end
if next(res) == nil then
-- we ran out of notes, restart the pattern
-- print("raptor: no notes to play, restart!")
cache = {}
if mode==0 then
dir = 0
elseif mode==1 or (mode==3 and dir==0) then
dir = 1
elseif mode==2 or (mode==4 and dir==0) then
dir = -1
else
dir = -dir
end
end
end
return res, dir
end
function M.uniq_filter(uniq, cache, ms)
-- filters out repeated notes (removing notes already in the cache),
-- depending on the uniq flag
if not uniq or next(ms) == nil or next(cache) == nil then
return ms
end
local res = {}
local i, j, k, N, M = 1, 1, 1, #cache, #ms
while i<=N or j<=M do
if j>M then
-- all elements checked, we're done
return res
elseif i>N or ms[j]<cache[i] then
-- current element not in cache, add it
res[k] = ms[j]
k = k+1; j = j+1
elseif ms[j]>cache[i] then
-- look at next cache element
i = i+1
else
-- current element in cache, skip it
i = i+1; j = j+1
end
end
return res
end
function M.pick_notes(w, n, pref, prefmod, ns, ms)
-- pick n notes from the list ms of eligible notes according to the
-- given harmonic preference
local ws = {}
-- calculate weighted harmonicities based on preference; this gives us the
-- probability distribution for the note selection step
local p = M.mod_value(0, pref, prefmod, w)
if p==0 then
-- no preference, use uniform distribution
for i = 1, #ms do
ws[i] = 1
end
else
for i = 1, #ms do
-- "Frankly, I don't know where the exponent came from," probably
-- experimentation. ;-)
ws[i] = M.hv(ns, ms[i]) ^ (p*10)
end
end
return M.shuffle(n, ms, ws)
end
-- The note generator. This is invoked with the current pulse weight w, the
-- current cache (notes played in the previous step), the input notes ns, the
-- candidate output notes ms, and all the other parameters that we need
-- (density: nmax, nmod; harmonicity: hmin, hmax, hmod; step width: smin,
-- smax, smod; arpeggiator state: dir, mode, uniq; harmonic preference: pref,
-- prefmod). It returns a selection of notes chosen at random for the given
-- parameters, along with the updated direction dir of the arpeggiator.
function M.rand_notes(w, nmax, nmod,
hmin, hmax, hmod,
smin, smax, smod,
dir, mode, uniq,
pref, prefmod,
cache,
ns, ms)
-- uniqueness filter: remove repeated notes
local res = M.uniq_filter(uniq, cache, ms)
-- harmonicity filter: select notes based on harmonicity
res = M.harm_filter(w, hmin, hmax, hmod, ns, res)
-- step filter: select notes based on step widths and arpeggiator state
-- (this must be the last filter!)
res, dir = M.step_filter(w, smin, smax, smod, dir, mode, cache, res)
-- pick notes
local n = math.floor(M.mod_value(1, nmax, nmod, w)+0.5)
res = M.pick_notes(w, n, pref, prefmod, ns, res)
return res, dir
end
local barlow = M
-- -------------------------------------------------------------------------
-- quick and dirty replacement for kikito's inspect; we mostly need this for
-- debugging messages, but also when saving data, so the output doesn't need
-- to be pretty, but should be humanly readable and conform to Lua syntax
local function inspect(x)
if type(x) == "string" then
return string.format("%q", x)
elseif type(x) == "table" then
local s = ""
local n = 0
for k,v in pairs(x) do
if n > 0 then
s = s .. ", "
end
s = s .. string.format("[%s] = %s", inspect(k), inspect(v))
n = n+1
end
return string.format("{ %s }", s)
else
return tostring(x)
end
end
-- -------------------------------------------------------------------------
-- Arpeggiator object. In the Pd external, this takes input from the object's
-- inlets and returns results on the object's outlets. In the Ardour
-- implementation, the inlets are just method arguments, and the outlets
-- become the method's return values (there can be more than one, up to one
-- for each outlet, which are represented as tuples).
-- Also, the Ardour implementation replaces the hold toggle with a latch
-- control, which can be used in a similar fashion but is much more useful.
arpeggio = {}
arpeggio.__index = arpeggio
function arpeggio:new(m) -- constructor
local x = setmetatable(
{
-- some reasonable defaults (see also arpeggio:initialize below)
debug = 0, idx = 0, chord = {}, pattern = {},
latch = nil, down = -1, up = 1, mode = 0,
minvel = 60, maxvel = 120, velmod = 1,
wmin = 0, wmax = 1,
pmin = 0.3, pmax = 1, pmod = 0,
gate = 1, gatemod = 0,
veltracker = 1, minavg = nil, maxavg = nil,
gain = 1, g = math.exp(-1/3),
loopstate = 0, loopsize = 0, loopidx = 0, loop = {}, loopdir = "",
nmax = 1, nmod = 0,
hmin = 0, hmax = 1, hmod = 0,
smin = 1, smax = 7, smod = 0,
uniq = 1,
pref = 1, prefmod = 0,
pitchtracker = 0, pitchlo = 0, pitchhi = 0,
n = 0
},
arpeggio)
x:initialize(m)
return x
end
function arpeggio:initialize(m)
-- debugging (bitmask): 1 = pattern, 2 = input, 4 = output
self.debug = 0
-- internal state variables
self.idx = 0
self.chord = {}
self.pattern = {}
self.latch = nil
self.down, self.up, self.mode = -1, 1, 0
self.minvel, self.maxvel, self.velmod = 60, 120, 1
self.pmin, self.pmax, self.pmod = 0.3, 1, 0
self.wmin, self.wmax = 0, 1
self.gate, self.gatemod = 1, 0
-- velocity tracker
self.veltracker, self.minavg, self.maxavg = 1, nil, nil
-- This isn't really a "gain" control any more, it's more like a dry/wet
-- mix (1 = dry, 0 = wet) between set values (minvel, maxvel) and the
-- calculated envelope of MIDI input notes (minavg, maxavg).
self.gain = 1
-- smoothing filter, time in pulses (3 works for me, YMMV)
local t = 3
-- filter coefficient
self.g = math.exp(-1/t)
-- looper
self.loopstate = 0
self.loopsize = 0
self.loopidx = 0
self.loop = {}
self.loopdir = ""
-- Raptor params, reasonable defaults
self.nmax, self.nmod = 1, 0
self.hmin, self.hmax, self.hmod = 0, 1, 0
self.smin, self.smax, self.smod = 1, 7, 0
self.uniq = 1
self.pref, self.prefmod = 1, 0
self.pitchtracker = 0
self.pitchlo, self.pitchhi = 0, 0
-- Barlow meter
-- XXXTODO: We only do integer pulses currently, so the subdivisions
-- parameter self.n is currently disabled. Maybe we can find some good use
-- for it in the future, e.g., for ratchets?
self.n = 0
if m == nil then
m = {4} -- default meter (common time)
end
-- initialize the indispensability tables and reset the beat counter
self.indisp = {}
self:prepare_meter(m)
-- return the initial number of beats
return self.beats
end
-- Barlow indispensability meter computation, cf. barlow.pd_lua. This takes a
-- zero-based beat number, optionally with a phase in the fractional part to
-- indicate a sub-pulse below the beat level. We then compute the closest
-- matching subdivision and compute the corresponding pulse weight, using the
-- precomputed indispensability tables. The returned result is a pair w,n
-- denoting the Barlow indispensability weight of the pulse in the range
-- 0..n-1, where n denotes the total number of beats (number of beats in the
-- current meter times the current subdivision).
-- list helpers
local tabcat, reverse, cycle, map, seq = barlow.tableconcat, barlow.reverse, barlow.cycle, barlow.map, barlow.seq
-- Barlow indispensabilities and friends
local factor, indisp, subdiv = barlow.factor, barlow.indisp, barlow.subdiv
-- Barlow harmonicities and friends
local mod_value, rand_notes = barlow.mod_value, barlow.rand_notes
function arpeggio:meter(b)
if b < 0 then
error("meter: beat index must be nonnegative")
return
end
local beat, f = math.modf(b)
-- take the beat index modulo the total number of beats
beat = beat % self.beats
if self.n > 0 then
-- compute the closest subdivision for the given fractional phase
local p, q = subdiv(self.n, f)
if self.last_q then
local x = self.last_q / q
if math.floor(x) == x then
-- If the current best match divides the previous one, stick to
-- it, in order to prevent the algorithm from quickly changing
-- back to the root meter at each base pulse. XXFIXME: This may
-- stick around indefinitely until the meter changes. Maybe we'd
-- rather want to reset this automatically after some time (such
-- as a complete bar without non-zero phases)?
p, q = x*p, x*q
end
end
self.last_q = q
-- The overall zero-based pulse index is beat*q + p. We add 1 to
-- that to get a 1-based index into the indispensabilities table.
local w = self.indisp[q][beat*q+p+1]
return w, self.beats*q
else
-- no subdivisions, just return the indispensability and number of beats
-- as is
local w = self.indisp[1][beat+1]
return w, self.beats
end
end
function arpeggio:numarg(x)
if type(x) == "table" then
x = x[1]
end
if type(x) == "number" then
return x
else
error("arpeggio: expected number, got " .. tostring(x))
end
end
function arpeggio:intarg(x)
if type(x) == "table" then
x = x[1]
end
if type(x) == "number" then
return math.floor(x)
else
error("arpeggio: expected integer, got " .. tostring(x))
end
end
-- the looper
function arpeggio:loop_clear()
-- reset the looper
self.loopstate = 0
self.loopidx = 0
self.loop = {}
end
function arpeggio:loop_set()
-- set the loop and start playing it
local n, m = #self.loop, self.loopsize
local b, p, q = self.beats, self.loopidx, self.idx
-- NOTE: Use Ableton-style launch quantization here. We quantize start and
-- end of the loop, as well as m = the target loop size to whole bars, to
-- account for rhythmic inaccuracies. Otherwise it's just much too easy to
-- miss bar boundaries when recording a loop.
m = math.ceil(m/b)*b -- rounding up
-- beginning of last complete bar in cyclic buffer
local k = (p-q-b) % 256
if n <= 0 or m <= 0 or m > 256 or k >= n then
-- We haven't recorded enough steps for a bar yet, or the target size is
-- 0, bail out with an empty loop.
self.loop = {}
self.loopidx = 0
self.loopstate = 1
if m == 0 then
print("loop: zero loop size")
else
print(string.format("loop: got %d steps, need %d.", p>=n and math.max(0, p-q) or q==0 and n or math.max(0, n-b), b))
end
return
end
-- At this point we have at least 1 bar, starting at k+1, that we can grab;
-- try extending the loop until we hit the target size.
local l = b
while l < m do
if k >= b then
k = k-b
elseif p >= n or (k-b) % 256 < p then
-- in this case either the cyclic buffer hasn't been filled yet, or
-- wrapping around would take us past the buffer pointer, so bail out
break
else
-- wrap around to the end of the buffer
k = (k-b) % 256
end
l = l+b
end
-- grab l (at most m) steps
--print(string.format("loop: recorded %d/%d steps %d-%d", l, m, k+1, k+m))
print(string.format("loop: recorded %d/%d steps", l, m))
local loop = {}
for i = k+1, k+l do
loop[i-k] = cycle(self.loop, i)
end
self.loop = loop
self.loopidx = q % l
self.loopstate = 1
end
function arpeggio:loop_add(notes, vel, gate)
-- we only start recording at the first note
local have_notes = type(notes) == "number" or
(notes ~= nil and next(notes) ~= nil)
if have_notes or next(self.loop) ~= nil then
self.loop[self.loopidx+1] = {notes, vel, gate}
-- we always *store* up to 256 steps in a cyclic buffer
self.loopidx = (self.loopidx+1) % 256
end
end
function arpeggio:loop_get()
local res = {{}, 0, 0}
local p, n = self.loopidx, math.max(1, math.min(#self.loop, self.loopsize))
if p < n then
res = self.loop[p+1]
-- we always *read* exactly n steps in a cyclic buffer
self.loopidx = (p+1) % n
if p % self.beats == 0 then
local a, b = p // self.beats + 1, n // self.beats
print(string.format("loop: playing bar %d/%d", a, b))
end
end
-- we maybe should return the current loopidx here which is used to give
-- visual feedback about the loop cycle in the Pd external; not sure how to
-- do this in Ardour, though
return res
end
local function fexists(name)
local f=io.open(name,"r")
if f~=nil then io.close(f) return true else return false end
end
function arpeggio:loop_file(file, cmd)
-- default for cmd is 1 (save) if loop is playing, 0 (load) otherwise
cmd = cmd or self.loopstate
-- apply the loopdir if any
local path = self.loopdir .. file
if cmd == 1 then
-- save: first create a backup copy if the file already exists
if fexists(path) then
local k, bakname = 1
repeat
bakname = string.format("%s~%d~", path, k)
k = k+1
until not fexists(bakname)
-- ignore errors, if we can't rename the file, we probably can't
-- overwrite it either
os.rename(path, bakname)
end
local f, err = io.open(path, "w")
if type(err) == "string" then
print(string.format("loop: %s", err))
return
end
-- shorten the table to the current loop size if needed
local loop, n = {}, math.min(#self.loop, self.loopsize)
table.move(self.loop, 1, n, 1, loop)
-- add some pretty-printing
local function bars(level, count)
if level == 1 and count%self.beats == 0 then
return string.format("-- bar %d", count//self.beats+1)
end
end
f:write(string.format("-- saved by Raptor %s\n", os.date()))
f:write(inspect(loop, {extra = 1, addin = bars}))
f:close()
print(string.format("loop: %s: saved %d steps", file, n))
elseif cmd == 0 then
-- load: check that file exists and is loadable
local f, err = io.open(path, "r")
if type(err) == "string" then
print(string.format("loop: %s", err))
return
end
local fun, err = load("return " .. f:read("a"))
f:close()
if type(err) == "string" or type(fun) ~= "function" then
print(string.format("loop: %s: invalid format", file))
else
local loop = fun()
if type(loop) ~= "table" then
print(string.format("loop: %s: invalid format", file))
else
self.loop = loop
self.loopsize = #loop
self.loopidx = self.idx % math.max(1, self.loopsize)
self.loopstate = 1
print(string.format("loop: %s: loaded %d steps", file, #loop))
return self.loopsize
end
end
elseif cmd == 2 then
-- check that file exists, report result
return fexists(path) and 1 or 0
end
end
function arpeggio:set_loopsize(x)
x = self:intarg(x)
if type(x) == "number" then
self.loopsize = math.max(0, math.min(256, x))
if self.loopstate == 1 then
-- need to update the loop index in case the loopsize changed
if self.loopsize > 0 then
-- also resynchronize the loop with the arpeggiator if needed
self.loopidx = math.max(self.idx, self.loopidx % self.loopsize)
else
self.loopidx = 0
end
end
end
end
function arpeggio:set_loop(x)
if type(x) == "string" then
x = {x}
end
if type(x) == "table" and type(x[1]) == "string" then
-- file operations
self:loop_file(table.unpack(x))
else
x = self:intarg(x)
if type(x) == "number" then
if x ~= 0 and self.loopstate == 0 then
self:loop_set()
elseif x == 0 and self.loopstate == 1 then
self:loop_clear()
end
end
end
end
function arpeggio:set_loopdir(x)
if type(x) == "string" then
x = {x}
end
if type(x) == "table" and type(x[1]) == "string" then
-- directory for file operations
self.loopdir = x[1] .. "/"
end
end
-- velocity tracking
function arpeggio:update_veltracker(chord, vel)
if next(chord) == nil then
-- reset
self.minavg, self.maxavg = nil, nil
if self.debug&2~=0 then
print(string.format("min = %s, max = %s", self.minavg, self.maxavg))
end
elseif vel > 0 then
-- calculate the velocity envelope
if not self.minavg then
self.minavg = self.minvel
end
self.minavg = self.minavg*self.g + vel*(1-self.g)
if not self.maxavg then
self.maxavg = self.maxvel
end
self.maxavg = self.maxavg*self.g + vel*(1-self.g)
if self.debug&2~=0 then
print(string.format("vel min = %g, max = %g", self.minavg, self.maxavg))
end
end
end
function arpeggio:velrange()
if self.veltracker ~= 0 then
local g = self.gain
local min = self.minavg or self.minvel
local max = self.maxavg or self.maxvel
min = g*self.minvel + (1-g)*min
max = g*self.maxvel + (1-g)*max
return min, max
else
return self.minvel, self.maxvel
end
end
-- output the next note in the pattern and switch to the next pulse
-- The result is a tuple notes, vel, gate, w, n, where vel is the velocity,
-- gate the gate value (normalized duration), w the pulse weight
-- (indispensability), and n the total number of pulses. The first return
-- value indicates the notes to play. This may either be a singleton number or
-- a list (which can also be empty, or contain multiple note numbers).
function arpeggio:pulse()
local w, n = self:meter(self.idx)
-- normalized pulse strength
local w1 = w/math.max(1,n-1)
-- corresponding MIDI velocity
local minvel, maxvel = self:velrange()
local vel =
math.floor(mod_value(minvel, maxvel, self.velmod, w1))
local gate, notes = 0, nil
if self.loopstate == 1 and self.loopsize > 0 then
-- notes come straight from the loop, input is ignored
notes, vel, gate = table.unpack(self:loop_get())
self.idx = (self.idx + 1) % self.beats
return notes, vel, gate, w, n
end
if type(self.pattern) == "function" then
notes = self.pattern(w1)
elseif next(self.pattern) ~= nil then
notes = cycle(self.pattern, self.idx+1)
end
if notes ~= nil then
-- note filtering
local ok = true
local wmin, wmax = self.wmin, self.wmax
if w1 >= wmin and w1 <= wmax then
local pmin, pmax = self.pmin, self.pmax
-- Calculate the filter probablity. We allow for negative pmod values
-- here, in which case stronger pulses tend to be filtered out first
-- rather than weaker ones.
local p = mod_value(pmin, pmax, self.pmod, w1)
local r = math.random()
if self.debug&4~=0 then
print(string.format("w = %g, wmin = %g, wmax = %g, p = %g, r = %g",
w1, wmin, wmax, p, r))
end
ok = r <= p
else
ok = false
end
if ok then
-- modulated gate value
gate = mod_value(0, self.gate, self.gatemod, w1)
-- output notes (there may be more than one in Raptor mode)
if self.debug&4~=0 then
print(string.format("idx = %g, notes = %s, vel = %g, gate = %g", self.idx, inspect(notes), vel, gate))
end
else
notes = {}
end
else
notes = {}
end
self:loop_add(notes, vel, gate)
self.idx = (self.idx + 1) % self.beats
return notes, vel, gate, w, n
end
-- panic clears the chord memory and pattern
function arpeggio:panic()
self.chord = {}
self.pattern = {}
self.last_q = nil
-- XXXFIXME: Catch 22 here. This method gets invoked when transport starts
-- rolling (at which time Ardour sends a bunch of all-note-offs to all
-- channels). Unfortunately, the following line would then override the
-- latch control of the plugin, which we don't want. So we have to disable
-- the following call for now. This means that even the panic button won't
-- really get rid of the latched notes, you must turn off the latch control
-- explicitly to make them go away. (However, the current pattern gets
-- cleared anyway, so hopefully nobody will ever notice.)
--self:set_latch(0)
self:update_veltracker({}, 0)
end
-- change the current pulse index
function arpeggio:set_idx(x)
x = self:intarg(x)
if type(x) == "number" and self.idx ~= x then
self.idx = math.max(0, x) % self.beats
if self.loopstate == 1 then
self.loopidx = self.idx % math.max(1, math.min(#self.loop, self.loopsize))
end
end
end
-- pattern computation
local function transp(chord, i)
return map(chord, function (n) return n+12*i end)
end
function arpeggio:pitchrange(a, b)
if self.pitchtracker == 0 then
-- just octave range
a = math.max(0, math.min(127, a+12*self.down))
b = math.max(0, math.min(127, b+12*self.up))
elseif self.pitchtracker == 1 then
-- full range tracker
a = math.max(0, math.min(127, a+12*self.down+self.pitchlo))
b = math.max(0, math.min(127, b+12*self.up+self.pitchhi))
elseif self.pitchtracker == 2 then
-- treble tracker
a = math.max(0, math.min(127, b+12*self.down+self.pitchlo))
b = math.max(0, math.min(127, b+12*self.up+self.pitchhi))
elseif self.pitchtracker == 3 then
-- bass tracker
a = math.max(0, math.min(127, a+12*self.down+self.pitchlo))
b = math.max(0, math.min(127, a+12*self.up+self.pitchhi))
end
return seq(a, b)
end
function arpeggio:create_pattern(chord)
-- create a new pattern using the current settings
local pattern = chord
-- By default we do outside-in by alternating up-down (i.e., lo-hi), set
-- this flag to true to get something more Logic-like which goes down-up.
local logic_like = false
if next(pattern) == nil then
-- nothing to see here, move along...
return pattern
elseif self.raptor ~= 0 then
-- Raptor mode: Pick random notes from the eligible range based on
-- average Barlow harmonicities (cf. barlow.lua). This also combines
-- with mode 0..5, employing the corresponding Raptor arpeggiation
-- modes. Note that these patterns may contain notes that we're not
-- actually playing, if they're harmonically related to the input
-- chord. Raptor can also play chords rather than just single notes, and
-- with the right settings you can make it go from plain tonal to more
-- jazz-like and free to completely atonal, and everything in between.
local a, b = pattern[1], pattern[#pattern]
-- NOTE: As this kind of pattern is quite costly to compute, we
-- implement it as a closure which gets evaluated lazily for each pulse,
-- rather than precomputing the entire pattern at once as in the
-- deterministic modes.
if self.mode == 5 then
-- Raptor by itself doesn't support mode 5 (outside-in), so we
-- emulate it by alternating between mode 1 and 2. This isn't quite
-- the same, but it's as close to outside-in as I can make it. You
-- might also consider mode 0 (random) as a reasonable alternative
-- instead.
local cache, mode, dir
local function restart()
-- print("raptor: restart")
cache = {{}, {}}
if logic_like then
mode, dir = 2, -1
else
mode, dir = 1, 1
end
end
restart()
pattern = function(w1)
local notes, _
if w1 == 1 then
-- beginning of bar, restart pattern
restart()
end
notes, _ =
rand_notes(w1,
self.nmax, self.nmod,
self.hmin, self.hmax, self.hmod,
self.smin, self.smax, self.smod,
dir, mode, self.uniq ~= 0,
self.pref, self.prefmod,
cache[mode],
chord, self:pitchrange(a, b))
if next(notes) ~= nil then
cache[mode] = notes
end
if dir>0 then
mode, dir = 2, -1
else
mode, dir = 1, 1
end
return notes
end
else
local cache, mode, dir
local function restart()
-- print("raptor: restart")
cache = {}
mode = self.mode
dir = 0
if mode == 1 or mode == 3 then
dir = 1
elseif mode == 2 or mode == 4 then
dir = -1
end
end
restart()
pattern = function(w1)
local notes
if w1 == 1 then
-- beginning of bar, restart pattern
restart()
end
notes, dir =
rand_notes(w1,
self.nmax, self.nmod,
self.hmin, self.hmax, self.hmod,
self.smin, self.smax, self.smod,
dir, mode, self.uniq ~= 0,
self.pref, self.prefmod,
cache,
chord, self:pitchrange(a, b))
if next(notes) ~= nil then
cache = notes
end
return notes
end
end
else
-- apply the octave range (not used in raptor mode)
pattern = {}
for i = self.down, self.up do
pattern = tabcat(pattern, transp(chord, i))
end
if self.mode == 0 then
-- random: this is just the run-of-the-mill random pattern permutation
local n, pat = #pattern, {}
local p = seq(1, n)
for i = 1, n do
local j = math.random(i, n)
p[i], p[j] = p[j], p[i]
end
for i = 1, n do
pat[i] = pattern[p[i]]
end
pattern = pat
elseif self.mode == 1 then
-- up (no-op)
elseif self.mode == 2 then
-- down
pattern = reverse(pattern)
elseif self.mode == 3 then
-- up-down
local r = reverse(pattern)
-- get rid of the repeated note in the middle
table.remove(pattern)
pattern = tabcat(pattern, r)
elseif self.mode == 4 then
-- down-up
local r = reverse(pattern)
table.remove(r)
pattern = tabcat(reverse(pattern), pattern)
elseif self.mode == 5 then
-- outside-in
local n, pat = #pattern, {}
local p, q = n//2, n%2
if logic_like then
for i = 1, p do
-- highest note first (a la Logic?)
pat[2*i-1] = pattern[n+1-i]
pat[2*i] = pattern[i]
end
else
for i = 1, p do
-- lowest note first (sounds better IMHO)
pat[2*i-1] = pattern[i]
pat[2*i] = pattern[n+1-i]
end
end
if q > 0 then
pat[n] = pattern[p+1]
end
pattern = pat
end
end
if self.debug&1~=0 then
print(string.format("chord = %s", inspect(chord)))
print(string.format("pattern = %s", inspect(pattern)))
end
return pattern
end
-- latch: keep chord notes when released until new chord or reset
function arpeggio:set_latch(x)
x = self:intarg(x)
if type(x) == "number" then
if x ~= 0 then
self.latch = {table.unpack(self.chord)}
elseif self.latch then
self.latch = nil
self.pattern = self:create_pattern(self.chord)
end
end
end
function arpeggio:get_chord()
return self.latch and self.latch or self.chord
end
-- change the range of the pattern
function arpeggio:set_up(x)
x = self:intarg(x)
if type(x) == "number" then
self.up = math.max(-2, math.min(2, x))
self.pattern = self:create_pattern(self:get_chord())
end
end
function arpeggio:set_down(x)
x = self:intarg(x)
if type(x) == "number" then
self.down = math.max(-2, math.min(2, x))
self.pattern = self:create_pattern(self:get_chord())
end
end
function arpeggio:set_pitchtracker(x)
x = self:intarg(x)
if type(x) == "number" then
self.pitchtracker = math.max(0, math.min(3, x))
self.pattern = self:create_pattern(self:get_chord())
end
end
function arpeggio:set_pitchlo(x)
x = self:intarg(x)
if type(x) == "number" then
self.pitchlo = math.max(-36, math.min(36, x))
self.pattern = self:create_pattern(self:get_chord())
end
end
function arpeggio:set_pitchhi(x)
x = self:intarg(x)
if type(x) == "number" then
self.pitchhi = math.max(-36, math.min(36, x))
self.pattern = self:create_pattern(self:get_chord())
end
end
-- change the mode (up, down, etc.)
function arpeggio:set_mode(x)
x = self:intarg(x)
if type(x) == "number" then
self.mode = math.max(0, math.min(5, x))
self.pattern = self:create_pattern(self:get_chord())
end
end
-- this enables Raptor mode with randomized note output
function arpeggio:set_raptor(x)
x = self:intarg(x)
if type(x) == "number" then
self.raptor = math.max(0, math.min(1, x))
self.pattern = self:create_pattern(self:get_chord())
end
end
-- change min/max velocities, gate, and note probabilities
function arpeggio:set_minvel(x)
x = self:numarg(x)
if type(x) == "number" then
self.minvel = math.max(0, math.min(127, x))
end
end
function arpeggio:set_maxvel(x)
x = self:numarg(x)
if type(x) == "number" then
self.maxvel = math.max(0, math.min(127, x))
end
end
function arpeggio:set_velmod(x)
x = self:numarg(x)
if type(x) == "number" then
self.velmod = math.max(-1, math.min(1, x))
end
end
function arpeggio:set_veltracker(x)
x = self:intarg(x)
if type(x) == "number" then
self.veltracker = math.max(0, math.min(1, x))
end
end
function arpeggio:set_gain(x)
x = self:numarg(x)
if type(x) == "number" then
self.gain = math.max(0, math.min(1, x))
end
end
function arpeggio:set_gate(x)
x = self:numarg(x)
if type(x) == "number" then
self.gate = math.max(0, math.min(10, x))
end
end
function arpeggio:set_gatemod(x)
x = self:numarg(x)
if type(x) == "number" then
self.gatemod = math.max(-1, math.min(1, x))
end
end
function arpeggio:set_pmin(x)
x = self:numarg(x)
if type(x) == "number" then
self.pmin = math.max(0, math.min(1, x))
end
end
function arpeggio:set_pmax(x)
x = self:numarg(x)
if type(x) == "number" then
self.pmax = math.max(0, math.min(1, x))
end
end
function arpeggio:set_pmod(x)
x = self:numarg(x)
if type(x) == "number" then
self.pmod = math.max(-1, math.min(1, x))
end
end
function arpeggio:set_wmin(x)
x = self:numarg(x)
if type(x) == "number" then
self.wmin = math.max(0, math.min(1, x))
end
end
function arpeggio:set_wmax(x)
x = self:numarg(x)
if type(x) == "number" then
self.wmax = math.max(0, math.min(1, x))
end
end
-- change the raptor parameters (harmonicity, etc.)
function arpeggio:set_nmax(x)
x = self:numarg(x)
if type(x) == "number" then
self.nmax = math.max(0, math.min(10, x))
end
end
function arpeggio:set_nmod(x)
x = self:numarg(x)
if type(x) == "number" then
self.nmod = math.max(-1, math.min(1, x))
end
end
function arpeggio:set_hmin(x)
x = self:numarg(x)
if type(x) == "number" then
self.hmin = math.max(0, math.min(1, x))
end
end
function arpeggio:set_hmax(x)
x = self:numarg(x)
if type(x) == "number" then
self.hmax = math.max(0, math.min(1, x))
end
end
function arpeggio:set_hmod(x)
x = self:numarg(x)
if type(x) == "number" then
self.hmod = math.max(-1, math.min(1, x))
end
end
function arpeggio:set_smin(x)
x = self:numarg(x)
if type(x) == "number" then
self.smin = math.max(-127, math.min(127, x))
end
end
function arpeggio:set_smax(x)
x = self:numarg(x)
if type(x) == "number" then
self.smax = math.max(-127, math.min(127, x))
end
end
function arpeggio:set_smod(x)
x = self:numarg(x)
if type(x) == "number" then
self.smod = math.max(-1, math.min(1, x))
end
end
function arpeggio:set_uniq(x)
x = self:intarg(x)
if type(x) == "number" then
self.uniq = math.max(0, math.min(1, x))
end
end
function arpeggio:set_pref(x)
x = self:numarg(x)
if type(x) == "number" then
self.pref = math.max(-1, math.min(1, x))
end
end
function arpeggio:set_prefmod(x)
x = self:numarg(x)
if type(x) == "number" then
self.prefmod = math.max(-1, math.min(1, x))
end
end
local function update_chord(chord, note, vel)
-- update the chord memory, keeping the notes in ascending order
local n = #chord
if n == 0 then
if vel > 0 then
table.insert(chord, 1, note)
end
return chord
end
for i = 1, n do
if chord[i] == note then
if vel <= 0 then
-- note off: remove note
if i < n then
table.move(chord, i+1, n, i)
end
table.remove(chord)
end
return chord
elseif chord[i] > note then
if vel > 0 then
-- insert note
table.insert(chord, i, note)
end
return chord
end
end
-- if we come here, no note has been inserted or deleted yet
if vel > 0 then
-- note is larger than all present notes in chord, so it needs to be
-- inserted at the end
table.insert(chord, note)
end
return chord
end
-- note input; update the internal chord memory and recompute the pattern
function arpeggio:note(note, vel)
if self.debug&2~=0 then
print(string.format("note = %s", inspect({ note, vel })))
end
if type(note) == "number" and type(vel) == "number" then
if self.latch and next(self.chord) == nil and vel>0 then
-- start new pattern
self.latch = {}
end
update_chord(self.chord, note, vel)
if self.latch and vel>0 then
update_chord(self.latch, note, vel)
end
self.pattern = self:create_pattern(self:get_chord())
self:update_veltracker(self:get_chord(), vel)
end
end
-- this recomputes all indispensability tables
function arpeggio:prepare_meter(meter)
local n = 1
local m = {}
if type(meter) ~= "table" then
-- assume singleton number
meter = { meter }
end
for _,q in ipairs(meter) do
if q ~= math.floor(q) then
error("arpeggio: meter levels must be integer")
return
elseif q < 1 then
error("arpeggio: meter levels must be positive")
return
end
-- factorize each level as Barlow's formula assumes primes
m = tabcat(m, factor(q))
n = n*q
end
self.beats = n
self.last_q = nil
if n > 1 then
self.indisp[1] = indisp(m)
for q = 2, self.n do
local qs = tabcat(m, factor(q))
self.indisp[q] = indisp(qs)
end
else
self.indisp[1] = {0}
for q = 2, self.n do
self.indisp[q] = indisp(q)
end
end
end
-- set a new meter (given either as a singleton number or as a list of
-- numbers) and return the number of pulses
function arpeggio:set_meter(meter)
self:prepare_meter(meter)
return self.beats
end
-- -------------------------------------------------------------------------
-- Ardour interface (this is mostly like barlow_arp)
-- debug level: This only affects the plugin code. 1: print the current beat
-- and other important state information, 3: also print note input, 4: print
-- everything, including note output. Output goes to Ardour's log window.
-- NOTE: To debug the internal state of the arpeggiator object, including
-- pattern changes and note generation, use the arp.debug setting below.
local debug = 0
function dsp_ioconfig ()
return { { midi_in = 1, midi_out = 1, audio_in = -1, audio_out = -1}, }
end
function dsp_options ()
-- NOTE: We need regular_block_length = true in this plugin to get rid of
-- some intricate timing issues with scheduled note-offs for gated notes
-- right at the end of a loop. This sometimes causes hanging notes with
-- automation when transport wraps around to the loop start. It's unclear
-- whether the issue is in Ardour (caused by split cycles with automation)
-- or some unkown bug in the plugin. But the option makes it go away (which
-- seems to indicate that the issue is on the Ardour side).
return { time_info = true, regular_block_length = true }
end
local hrm_scalepoints = { ["0.09 (minor 7th and 3rd)"] = 0.09, ["0.1 (major 2nd and 3rd)"] = 0.1, ["0.17 (4th)"] = 0.17, ["0.21 (5th)"] = 0.21, ["1 (unison, octave)"] = 1 }
local params = {
{ type = "input", name = "bypass", min = 0, max = 1, default = 0, toggled = true, doc = "bypass the arpeggiator, pass through input notes" },
{ type = "input", name = "division", min = 1, max = 7, default = 1, integer = true, doc = "number of subdivisions of the beat" },
{ type = "input", name = "pgm", min = 0, max = 128, default = 0, integer = true, doc = "program change", scalepoints = { default = 0 } },
{ type = "input", name = "latch", min = 0, max = 1, default = 0, toggled = true, doc = "toggle latch mode" },
{ type = "input", name = "up", min = -2, max = 2, default = 1, integer = true, doc = "octave range up" },
{ type = "input", name = "down", min = -2, max = 2, default = -1, integer = true, doc = "octave range down" },
-- Raptor's usual default for the pattern is 0 = random, but 1 = up
-- seems to be a more sensible choice.
{ type = "input", name = "mode", min = 0, max = 5, default = 1, enum = true, doc = "pattern style",
scalepoints =
{ ["0 random"] = 0, ["1 up"] = 1, ["2 down"] = 2, ["3 up-down"] = 3, ["4 down-up"] = 4, ["5 outside-in"] = 5 } },
{ type = "input", name = "raptor", min = 0, max = 1, default = 0, toggled = true, doc = "toggle raptor mode" },
{ type = "input", name = "minvel", min = 0, max = 127, default = 60, integer = true, doc = "minimum velocity" },
{ type = "input", name = "maxvel", min = 0, max = 127, default = 120, integer = true, doc = "maximum velocity" },
{ type = "input", name = "velmod", min = -1, max = 1, default = 1, doc = "automatic velocity modulation according to current pulse strength" },
{ type = "input", name = "gain", min = 0, max = 1, default = 1, doc = "wet/dry mix between input velocity and set values (min/max velocity)" },
-- Pd Raptor allows this to go from 0 to 1000%, but we only support
-- 0-100% here
{ type = "input", name = "gate", min = 0, max = 1, default = 1, doc = "gate as fraction of pulse length", scalepoints = { legato = 0 } },
{ type = "input", name = "gatemod", min = -1, max = 1, default = 0, doc = "automatic gate modulation according to current pulse strength" },
{ type = "input", name = "wmin", min = 0, max = 1, default = 0, doc = "minimum note weight" },
{ type = "input", name = "wmax", min = 0, max = 1, default = 1, doc = "maximum note weight" },
{ type = "input", name = "pmin", min = 0, max = 1, default = 0.3, doc = "minimum note probability" },
{ type = "input", name = "pmax", min = 0, max = 1, default = 1, doc = "maximum note probability" },
{ type = "input", name = "pmod", min = -1, max = 1, default = 0, doc = "automatic note probability modulation according to current pulse strength" },
{ type = "input", name = "hmin", min = 0, max = 1, default = 0, doc = "minimum harmonicity", scalepoints = hrm_scalepoints },
{ type = "input", name = "hmax", min = 0, max = 1, default = 1, doc = "maximum harmonicity", scalepoints = hrm_scalepoints },
{ type = "input", name = "hmod", min = -1, max = 1, default = 0, doc = "automatic harmonicity modulation according to current pulse strength" },
{ type = "input", name = "pref", min = -1, max = 1, default = 1, doc = "harmonic preference" },
{ type = "input", name = "prefmod", min = -1, max = 1, default = 0, doc = "automatic harmonic preference modulation according to current pulse strength" },
{ type = "input", name = "smin", min = -12, max = 12, default = 1, integer = true, doc = "minimum step size" },
{ type = "input", name = "smax", min = -12, max = 12, default = 7, integer = true, doc = "maximum step size" },
{ type = "input", name = "smod", min = -1, max = 1, default = 0, doc = "automatic step size modulation according to current pulse strength" },
{ type = "input", name = "nmax", min = 0, max = 10, default = 1, integer = true, doc = "maximum polyphony (number of simultaneous notes)" },
{ type = "input", name = "nmod", min = -1, max = 1, default = 0, doc = "automatic modulation of the number of notes according to current pulse strength" },
{ type = "input", name = "uniq", min = 0, max = 1, default = 1, toggled = true, doc = "don't repeat notes in consecutive steps" },
{ type = "input", name = "pitchhi", min = -36, max = 36, default = 0, integer = true, doc = "extended pitch range up in semitones (raptor mode)" },
{ type = "input", name = "pitchlo", min = -36, max = 36, default = 0, integer = true, doc = "extended pitch range down in semitones (raptor mode)" },
{ type = "input", name = "pitchtracker", min = 0, max = 3, default = 0, enum = true, doc = "pitch tracker mode, follow input to adjust the pitch range (raptor mode)",
scalepoints =
{ ["0 off"] = 0, ["1 on"] = 1, ["2 treble"] = 2, ["3 bass"] = 3 } },
{ type = "input", name = "inchan", min = 0, max = 16, default = 0, integer = true, doc = "input channel (0 = omni = all channels)", scalepoints = { omni = 0 } },
{ type = "input", name = "outchan", min = 0, max = 16, default = 0, integer = true, doc = "input channel (0 = omni = input channel)", scalepoints = { omni = 0 } },
{ type = "input", name = "loopsize", min = 0, max = 16, default = 4, integer = true, doc = "loop size (number of bars)" },
{ type = "input", name = "loop", min = 0, max = 1, default = 0, toggled = true, doc = "toggle loop mode" },
{ type = "input", name = "mute", min = 0, max = 1, default = 0, toggled = true, doc = "turn the arpeggiator off, suppress all note output" },
}
local n_params = #params
local int_param = map(params, function(x) return x.integer == true or x.enum == true or x.toggled == true end)
function dsp_params ()
return params
end
-- This is basically a collection of presets from the Pd external, with some
-- (very) minor adjustments / bugfixes where I saw fit. The program numbers
-- assume a GM patch set, if your synth isn't GM-compatible then you'll have
-- to adjust them accordingly. NOTE: The tr808 preset assumes a GM-compatible
-- drumkit, so it outputs through MIDI channel 10 by default; other presets
-- leave the output channel as is.
local raptor_presets = {
{ name = "default", params = { bypass = 0, latch = 0, division = 1, pgm = 0, up = 1, down = -1, mode = 1, raptor = 0, minvel = 60, maxvel = 120, velmod = 1, gain = 1, gate = 1, gatemod = 0, wmin = 0, wmax = 1, pmin = 0.3, pmax = 1, pmod = 0, hmin = 0, hmax = 1, hmod = 0, pref = 1, prefmod = 0, smin = 1, smax = 7, smod = 0, nmax = 1, nmod = 0, uniq = 1, pitchhi = 0, pitchlo = 0, pitchtracker = 0, inchan = 0, outchan = 0, loopsize = 4, loop = 0, mute = 0 } },
{ name = "arp", params = { pgm = 26, up = 0, down = -1, mode = 3, raptor = 1, minvel = 105, maxvel = 120, velmod = 1, gain = 0.5, gate = 1, gatemod = 0, wmin = 0, wmax = 1, pmin = 0.9, pmax = 1, pmod = -1, hmin = 0.11, hmax = 1, hmod = 0, pref = 0.8, prefmod = 0, smin = 2, smax = 7, smod = 0, nmax = 1, nmod = 0, uniq = 1, pitchhi = 0, pitchlo = -12, pitchtracker = 2, loopsize = 4 } },
{ name = "bass", params = { pgm = 35, up = 0, down = -1, mode = 3, raptor = 1, minvel = 40, maxvel = 120, velmod = 1, gain = 0.5, gate = 1, gatemod = 0, wmin = 0, wmax = 1, pmin = 0.2, pmax = 1, pmod = 1, hmin = 0.12, hmax = 1, hmod = 0.1, pref = 0.8, prefmod = 0.1, smin = 2, smax = 7, smod = 0, nmax = 1, nmod = 0, uniq = 1, pitchhi = 7, pitchlo = 0, pitchtracker = 3, loopsize = 4 } },
{ name = "piano", params = { pgm = 1, up = 1, down = -1, mode = 0, raptor = 1, minvel = 90, maxvel = 120, velmod = 1, gain = 0.5, gate = 1, gatemod = 0, wmin = 0, wmax = 1, pmin = 0.4, pmax = 1, pmod = 1, hmin = 0.14, hmax = 1, hmod = 0.1, pref = 0.6, prefmod = 0.1, smin = 2, smax = 5, smod = 0, nmax = 2, nmod = 0, uniq = 1, pitchhi = 0, pitchlo = -18, pitchtracker = 2, loopsize = 4 } },
{ name = "raptor", params = { pgm = 5, up = 1, down = -2, mode = 0, raptor = 1, minvel = 60, maxvel = 120, velmod = 1, gain = 0.5, gate = 1, gatemod = 0, wmin = 0, wmax = 1, pmin = 0.4, pmax = 0.9, pmod = 0, hmin = 0.09, hmax = 1, hmod = -1, pref = 1, prefmod = 1, smin = 1, smax = 7, smod = 0, nmax = 3, nmod = -1, uniq = 0, pitchhi = 0, pitchlo = 0, pitchtracker = 0, loopsize = 4 } },
-- some variations of the raptor preset for different instruments
{ name = "raptor-arp", params = { pgm = 26, up = 0, down = -1, mode = 3, raptor = 1, minvel = 105, maxvel = 120, velmod = 1, gain = 0.5, gate = 1, gatemod = 0, wmin = 0, wmax = 1, pmin = 0.4, pmax = 0.9, pmod = 0, hmin = 0.09, hmax = 1, hmod = -1, pref = 1, prefmod = 1, smin = 2, smax = 7, smod = 0, nmax = 1, nmod = 0, uniq = 1, pitchhi = 0, pitchlo = -12, pitchtracker = 2, loopsize = 4 } },
{ name = "raptor-bass", params = { pgm = 35, up = 0, down = -1, mode = 3, raptor = 1, minvel = 40, maxvel = 120, velmod = 1, gain = 0.5, gate = 1, gatemod = 0, wmin = 0, wmax = 1, pmin = 0.4, pmax = 0.9, pmod = 0, hmin = 0.09, hmax = 1, hmod = -1, pref = 1, prefmod = -0.6, smin = 2, smax = 7, smod = 0, nmax = 1, nmod = 0, uniq = 1, pitchhi = 7, pitchlo = -6, pitchtracker = 3, loopsize = 4 } },
{ name = "raptor-piano", params = { pgm = 1, up = 1, down = -1, mode = 0, raptor = 1, minvel = 90, maxvel = 120, velmod = 1, gain = 0.5, gate = 1, gatemod = 0, wmin = 0, wmax = 1, pmin = 0.4, pmax = 0.9, pmod = 0, hmin = 0.09, hmax = 1, hmod = -1, pref = -0.4, prefmod = -0.6, smin = 2, smax = 5, smod = 0, nmax = 2, nmod = 0, uniq = 1, pitchhi = 0, pitchlo = -18, pitchtracker = 2, loopsize = 4 } },
{ name = "raptor-solo", params = { pgm = 25, up = 0, down = -1, mode = 3, raptor = 1, minvel = 40, maxvel = 110, velmod = 0.5, gain = 0.5, gate = 1, gatemod = 0.5, wmin = 0, wmax = 1, pmin = 0.2, pmax = 0.9, pmod = 0.5, hmin = 0.09, hmax = 1, hmod = -1, pref = -0.4, prefmod = 0, smin = 1, smax = 7, smod = 0, nmax = 1, nmod = 0, uniq = 1, pitchhi = 0, pitchlo = 0, pitchtracker = 0, loopsize = 4 } },
{ name = "tr808", params = { pgm = 26, outchan = 10, up = 0, down = 0, mode = 1, raptor = 0, minvel = 60, maxvel = 120, velmod = 1, gain = 0.5, gate = 1, gatemod = 0, wmin = 0, wmax = 1, pmin = 0.3, pmax = 1, pmod = 0, hmin = 0, hmax = 1, hmod = 0, pref = 1, prefmod = 0, smin = 1, smax = 7, smod = 0, nmax = 1, nmod = 0, uniq = 1, pitchhi = 0, pitchlo = 0, pitchtracker = 0, loopsize = 4 } },
{ name = "vibes", params = { pgm = 12, up = 0, down = -1, mode = 3, raptor = 1, minvel = 84, maxvel = 120, velmod = 1, gain = 0.5, gate = 1, gatemod = 0, wmin = 0, wmax = 1, pmin = 0.9, pmax = 1, pmod = -1, hmin = 0.14, hmax = 1, hmod = 0.1, pref = 0.6, prefmod = 0.1, smin = 2, smax = 5, smod = 0, nmax = 2, nmod = 0, uniq = 1, pitchhi = -5, pitchlo = -16, pitchtracker = 2, loopsize = 4 } },
{ name = "weirdmod", params = { pgm = 25, up = 0, down = -1, mode = 5, raptor = 0, minvel = 40, maxvel = 110, velmod = 0.5, gain = 0.5, gate = 1, gatemod = 0.5, wmin = 0, wmax = 1, pmin = 0.2, pmax = 0.9, pmod = 0.5, hmin = 0, hmax = 1, hmod = 0, pref = 1, prefmod = 0, smin = 1, smax = 7, smod = 0, nmax = 1, nmod = 0, uniq = 1, pitchhi = 0, pitchlo = 0, pitchtracker = 0, loopsize = 4 } },
}
function presets()
return raptor_presets
end
-- pertinent state information, to detect changes
local last_rolling -- last transport status, to detect changes
local last_beat -- last beat number
local last_p -- last pulse index from bbt
local last_bypass -- last bypass toggle
local last_mute -- last mute toggle
-- previous param values, to detect changes
local last_param = {}
-- pertinent note information, to handle note input and output
local chan = 0 -- MIDI (input and) output channel
local last_notes -- last notes played
local last_chan -- MIDI channel of the last notes
local off_gate -- off time of last notes (sample time)
local inchan, outchan, pgm = 0, 0, 0
-- create the arpeggiator (default meter)
local last_m = 4 -- last division, to detect changes
local arp = arpeggio:new(4)
-- Debugging output from the arpeggiator object (bitmask):
-- 1 = pattern, 2 = input, 4 = output (e.g., 7 means "all")
-- This is intended for debugging purposes only. it spits out *a lot* of
-- cryptic debug messages in the log window, so it's better to keep this
-- disabled in production code.
--arp.debug = 7
-- param setters
local function arp_set_loopsize(self, x)
-- need to translate beat numbers to steps
self:set_loopsize(x*arp.beats)
end
local param_set = { nil, nil, function (_, x) pgm = x end, arp.set_latch, arp.set_up, arp.set_down, arp.set_mode, arp.set_raptor, arp.set_minvel, arp.set_maxvel, arp.set_velmod, arp.set_gain, arp.set_gate, arp.set_gatemod, arp.set_wmin, arp.set_wmax, arp.set_pmin, arp.set_pmax, arp.set_pmod, arp.set_hmin, arp.set_hmax, arp.set_hmod, arp.set_pref, arp.set_prefmod, arp.set_smin, arp.set_smax, arp.set_smod, arp.set_nmax, arp.set_nmod, arp.set_uniq, arp.set_pitchhi, arp.set_pitchlo, arp.set_pitchtracker, function (_, x) inchan = x end, function (_, x) outchan = x end, arp_set_loopsize, arp.set_loop, nil }
local function get_chan(ch)
if outchan == 0 and inchan > 0 then
ch = inchan-1 -- outchan == inchan > 0 override
elseif outchan > 0 then
ch = outchan-1 -- outchan > 0 override
end
return ch
end
local function check_chan(ch)
return inchan == 0 or ch == inchan-1
end
function dsp_run (_, _, n_samples)
assert (type(midiout) == "table")
assert (type(time) == "table")
assert (type(midiout) == "table")
local ctrl = CtrlPorts:array ()
local subdiv = math.floor(ctrl[2])
local loopsize = math.floor(ctrl[n_params-2])
-- bypass toggle
local bypass = ctrl[1] > 0
-- mute toggle
local mute = ctrl[n_params] > 0
-- rolling state: It seems that we need to check the transport state (as
-- given by Ardour's "transport finite state machine" = TFSM) here, even if
-- the transport is not actually moving yet. Otherwise some input notes may
-- errorneously slip through before playback really starts.
local rolling = Session:transport_state_rolling ()
-- detect param changes (subdiv is caught as a meter change below)
local last_pgm = pgm
local last_inchan = inchan
for i = 1, n_params do
v = ctrl[i]
if int_param[i] then
-- Force integer values. (The GUI enforces this, but fractional
-- values might occur through automation.)
v = math.floor(v)
end
if param_set[i] and v ~= last_param[i] then
last_param[i] = v
param_set[i](arp, v)
end
end
local all_notes_off = false
if bypass ~= last_bypass then
last_bypass = bypass
all_notes_off = true
end
if mute ~= last_mute then
last_mute = mute
all_notes_off = true
end
if last_rolling ~= rolling then
last_rolling = rolling
-- transport change, send all-notes off (we only do this when transport
-- starts rolling, to silence any notes that may have been passed
-- through beforehand; note that Ardour automatically sends
-- all-notes-off to all MIDI channels anyway when transport is stopped)
if rolling then
all_notes_off = true
end
end
if inchan ~= last_inchan and inchan > 0 then
-- input channel has changed, kill off chord memory
arp:panic()
all_notes_off = true
end
local k = 1
if all_notes_off then
--print("all-notes-off", chan)
midiout[k] = { time = 1, data = { 0xb0+chan, 123, 0 } }
k = k+1
end
if pgm ~= last_pgm or get_chan(chan) ~= chan then
-- program or output channel has changed, send the program change
chan = get_chan(chan)
if pgm > 0 then
midiout[k] = { time = 1, data = { 0xc0+chan, pgm-1 } }
k = k+1
end
end
for _,ev in ipairs (midiin) do
local status, num, val = table.unpack(ev.data)
local ch = status & 0xf
status = status & 0xf0
if not rolling or bypass then
-- arpeggiator is just listening, pass through all MIDI data
midiout[k] = ev
k = k+1
elseif status >= 0xb0 then
-- arpeggiator is playing, pass through all MIDI data that's not
-- note-related, i.e., control change, program change, channel
-- pressure, pitch wheel, and system messages
if status == 0xb0 and (num == 123 or num == 64) then
-- Better to skip these CCs (generated by Ardour to prevent
-- hanging notes when relocating the playback position, e.g.,
-- during loop playback). This avoids notes being cut short
-- further down in the signal path. Also, we don't want those
-- messages to proliferate if our MIDI gets sent off to another
-- track. Unfortunately, there's no way to check whether these
-- events are synthetic or user input. So it seems best to just
-- ignore them.
else
midiout[k] = ev
k = k+1
end
end
if status == 0x80 or status == 0x90 and val == 0 then
if check_chan(ch) then
if debug >= 4 then
print("note off", num, val)
end
arp:note(num, 0)
end
elseif status == 0x90 then
if check_chan(ch) then
if debug >= 4 then
print("note on", num, val, "ch", ch)
end
arp:note(num, val)
chan = get_chan(ch)
end
elseif not rolling and status == 0xb0 and num == 123 and ch == chan then
-- This disrupts the arpeggiator during playback, so we only process
-- these messages (generated by Ardour to prevent hanging notes when
-- relocating the playback position) if transport is stopped.
if debug >= 4 then
print("all notes off")
end
arp:panic()
end
end
if rolling and not bypass and not mute then
-- transport is rolling, not bypassed, so the arpeggiator is playing
local function notes_off(ts)
if last_notes then
-- kill the old notes
for _, num in ipairs(last_notes) do
if debug >= 3 then
print("note off", num)
end
midiout[k] = { time = ts, data = { 0x80+last_chan, num, 100 } }
k = k+1
end
last_notes = nil
end
end
if off_gate and last_notes and
off_gate >= time.sample and off_gate < time.sample_end then
-- Gated notes don't normally fall on a beat, so we detect them
-- here. (If the gate time hasn't been set or we miss it, then the
-- note-offs will be taken care of when the next notes get triggered,
-- see below.)
-- sample-accurate "off" time
local ts = off_gate - time.sample + 1
notes_off(ts)
end
-- Check whether a beat is due, so that we trigger the next notes. We
-- want to do this in a sample-accurate manner in order to avoid jitter,
-- check barlow_arp.lua for details.
local denom = time.ts_denominator * subdiv
-- beat numbers at start and end, scaled by base pulses and subdivisions
local b1, b2 = denom/4*time.beat, denom/4*time.beat_end
-- integral part of these
local bf1, bf2 = math.floor(b1), math.floor(b2)
-- sample times at start and end
local s1, s2 = time.sample, time.sample_end
-- current (nominal, i.e., unscaled) beat number, and its sample time
local bt, ts
if last_beat ~= math.floor(time.beat) or bf1 == b1 then
-- next beat is due immediately
bt, ts = time.beat, time.sample
elseif bf2 > bf1 and bf2 ~= b2 then
-- next beat is due some time in this cycle (we're assuming contant
-- tempo here, hence this number may be off in case the tempo is
-- changing very quickly during the cycle -- so don't do that)
local d = math.ceil((b2-bf2)/(b2-b1)*(s2-s1))
assert(d > 0)
bt, ts = time.beat_end, time.sample_end - d
end
if ts then
-- save the last nominal beat so that we can detect sudden changes of
-- the playhead later (e.g., when transport starts rolling, or at the
-- end of a loop when the playhead wraps around to the beginning)
last_beat = math.floor(bt)
-- get the tempo map information
local tm = Temporal.TempoMap.read ()
local pos = Temporal.timepos_t (ts)
local bbt = tm:bbt_at (pos)
local meter = tm:meter_at (pos)
local tempo = tm:tempo_at (pos)
-- current meter (divisions per bar * subdivisions)
local m = meter:divisions_per_bar() * subdiv
-- detect meter changes
if m ~= last_m then
last_m = m
arp:set_meter(m)
-- we also need to update the loop size here
arp_set_loopsize(arp, loopsize)
end
-- calculate a fractional pulse number from the current bbt
local p = bbt.beats-1 + math.max(0, bbt.ticks) / Temporal.ticks_per_beat
-- round to current pulse index
p = math.floor(p * subdiv)
if p == last_p then
-- Avoid triggering the same pulse twice (probably a timing issue
-- which seems to happen when the playback position is relocated,
-- e.g., at the beginning of a loop).
goto skip
end
last_p = p
-- grab some notes from the arpeggiator
arp:set_idx(p) -- in case we've changed position
local notes, vel, gate, w, n = arp:pulse()
-- Make sure that the gate is clamped to the 0-1 range, since we
-- don't support overlapping notes in the current implementation.
gate = math.max(0, math.min(1, gate))
--print(string.format("[%d] notes", p), inspect(notes), vel, gate, w, n)
-- the arpeggiator may return a singleton note, make sure that it's
-- always a list
if type(notes) ~= "table" then
notes = { notes }
end
-- calculate the note-off time in samples, this is used if the gate
-- control is neither 0 nor 1
local gate_ts = ts + math.floor(tm:bbt_duration_at(pos, Temporal.BBT_Offset(0,1,0)):samples() / subdiv * gate)
ts = ts - time.sample + 1
if debug >= 1 then
-- print some debugging information: bbt, fractional beat number,
-- sample offset, current meter, current tempo
print (string.format("%s - %g [%d] - %d/%d - %g bpm", bbt:str(),
math.floor(denom*bt)/denom, ts-1,
meter:divisions_per_bar(), meter:note_value(),
tempo:quarter_notes_per_minute()))
end
-- we take a very small gate value (close to 0) to mean legato
-- instead, in which case notes extend to the next unfiltered note
local legato = gate_ts < time.sample_end
if not legato then
notes_off(ts)
end
if next(notes) ~= nil then
if legato then
notes_off(ts)
end
for i, num in ipairs(notes) do
if debug >= 3 then
print("note on", num, vel)
end
midiout[k] = { time = ts, data = { 0x90+chan, num, vel } }
k = k+1
end
last_notes = notes
last_chan = chan
if gate < 1 and not legato then
-- Set the sample time at which the note-offs are due.
off_gate = gate_ts
else
-- Otherwise don't set the off time in which case the
-- note-offs gets triggered automatically above.
off_gate = nil
end
end
::skip::
end
else
-- transport not rolling or bypass; reset the last beat number
last_beat = nil
end
if debug >= 1 and #midiout > 0 then
-- monitor memory usage of the Lua interpreter
print(string.format("mem: %0.2f KB", collectgarbage("count")))
end
end