I thought I have a go myself. This is a fairly brute-force, lazy Saturday morning version. You’ll have to organise the progression and voicings yourself. But if, like me, you are lazy, the rpitch: opt for sample playback works surprisingly well on those samples; for example rpitch -5 will give you a G major chord, with an authentic (guitaristic) voicing.
PD-Pi
[edit]
In fact, using rpitch: you can create several chords, either major or minor, from only one chord. Here, for example is C major to A minor, with the caveat that the A minor voicing is not authentic, it simply shifts the C major voicing down 3 semitones.
with_fx :reverb, mix: 0.6, room: 0.8 do
5.times do
tick
use_sample_defaults amp: 0.3
sample gtr, [4, 9, 15, 5, 10].look
# c3, e3 etc
sleep 0.05
end
sleep 4
5.times do
tick
use_sample_defaults amp: 0.3
sample gtr, [4, 9, 15, 5, 10].look, rpitch: [-3, -4, -3, -3, -4].look
# the 3rd of the chord is now minor
sleep 0.05
end
end