Opusmodus 1.3.24902

– New function:

• POLYGON-RHYTHM – Generates a symmetrical polygon to a given n-gon.

– Update:
LENGTH-WEIGHT – :swallow keyword added.
LENGTH-REST-SERIES – omn-form and :swallow keyword added.
LENGTH-TO-REST – omn-form and :swallow keyword added.

– Documents:
Howto Score/Rhythm/Polygon Rhythm.opmo 

Note: 

Select 'Check for Updates...' from Opusmodus app menu to get the latest version.

POLYGON-RHYTHM

This function returns a symmetrical polygon to a given n-gon (sides number) with circle points (denominator) and a given staring point.

In this example we use 3-gon in a 16 point circle with the starting point 0:

(polygon-rhythm 3 16 0)
=> (1/16 -1/16 -1/16 -1/16 1/16 -1/16 -1/16 -1/16
    -1/16 -1/16 -1/16 -1/16 1/16 -1/16 -1/16 -1/16)

Same as above with :legato t added:

(polygon-rhythm 3 16 0 :legato t)
=> (1/4 1/2 1/4)

The 3-gon in a 16 point circle with the starting point 0 will produce 7 symmetrical 3-gon’s:

Example with start point 5:

(polygon-rhythm 3 16 5)
=> (-1/16 -1/16 -1/16 -1/16 -1/16 1/16 -1/16 -1/16
    -1/16 -1/16 -1/16 1/16 -1/16 -1/16 -1/16 1/16)

(circle-rhythm-plot (polygon-rhythm 3 16 5) :points 16)

Examples:

In the following example we create 8 bars of a ‘Drum Set’ rhythm.

First we assign the ‘GM Percussion’ names to variables:

(setf bd (read-map *gm-percussion* 'acoustic-bass-drum))
(setf sd (read-map *gm-percussion* 'Acoustic-Snare))
(setf ht (read-map *gm-percussion* 'High-Tom))
(setf hh (read-map *gm-percussion* 'Open-Hi-hat))

Next we create 4 polygon rhythms:

(setf bd-gon (polygon-rhythm 3 16 0 :pitch bd :seed 5))
(setf sd-gon (polygon-rhythm 2 16 1 :pitch sd :seed 45))
(setf ht-gon (polygon-rhythm 2 16 5 :pitch ht :seed 45))
(setf hh-gon (polygon-rhythm 5 16 2 :pitch hh :seed 5))

With the CIRCLE-RHYTHM-PLOT function you can visualise how the rhythms are working together:

(circle-rhythm-plot (list bd-gon sd-gon ht-gon hh-gon) :points 16)

Let’s hear the result above, using PS function and ‘GM Instrument Set’ with a 8 times loop:

(ps 'gm
    :ds-bd (list (gen-eval 8 'bd-gon))
    :ds-sd (list (gen-eval 8 'sd-gon))
    :ds-ht (list (gen-eval 8 'ht-gon))
    :ds-hh (list (gen-eval 8 'hh-gon))
    :tempo 120)

Same as above but without a seed value:

(ps 'gm
    :ds-bd (list (gen-eval 8 '(polygon-rhythm 3 16 0 :pitch bd)))
    :ds-sd (list (gen-eval 8 '(polygon-rhythm 2 16 1 :pitch sd)))
    :ds-ht (list (gen-eval 8 '(polygon-rhythm 2 16 5 :pitch ht)))
    :ds-hh (list (gen-eval 8 '(polygon-rhythm 5 16 2 :pitch hh)))
    :tempo 120)

In the next example we add a few more percussion instruments.

The '? start symbol means the start point is selected at random: 0 to 15.

(progn
  (setf bd (read-map *gm-percussion* 'Acoustic-Bass-Drum))
  (setf sd (read-map *gm-percussion* 'Acoustic-Snare))
  (setf ht (read-map *gm-percussion* 'High-Tom))
  (setf hh (read-map *gm-percussion* 'Open-Hi-hat))
  (setf lb (read-map *gm-percussion* 'Low-Bongo))
  (setf hb (read-map *gm-percussion* 'High-Bongo))
  (setf mhc (read-map *gm-percussion* 'Mute-Hi-Conga))
  (setf lc (read-map *gm-percussion* 'Low-Conga))
  
  (ps 'gm
      :ds-bd (list (gen-eval 16 '(polygon-rhythm 3 16 0 :pitch bd)))
      :ds-sd (list (gen-eval 16 '(polygon-rhythm 2 16 1 :pitch sd)))
      :ds-ht (list (gen-eval 16 '(polygon-rhythm 2 16 5 :pitch ht)))
      :ds-hh (list (gen-eval 16 '(polygon-rhythm 5 16 2 :pitch hh)))
      :rhy (list (gen-eval 16 '(polygon-rhythm 5 16 '? :pitch lb))
                 (gen-eval 16 '(polygon-rhythm 4 16 '? :pitch hb))
                 (gen-eval 16 '(polygon-rhythm 7 16 '? :pitch mhc))
                 (gen-eval 16 '(polygon-rhythm 7 16 '? :pitch lc)))
      :tempo 120)
  )