Mercurial > hg > amuse
changeset 322:51389b0db7fe
Constructor for diatonic pitch intervals
Ignore-this: 2a9c7d2c4972b19a2b88ee3a7d25c032
darcs-hash:20100607105724-13bc2-c8c542edf11defdacc53ff53320413e251c472c5.gz
| author | Thomas Praetzlich <io901tp@gold.ac.uk> |
|---|---|
| date | Mon, 07 Jun 2010 11:57:24 +0100 |
| parents | 376357c84189 |
| children | 4b4fb8859e82 |
| files | base/constructors.lisp base/package.lisp |
| diffstat | 2 files changed, 15 insertions(+), 0 deletions(-) [+] |
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--- a/base/constructors.lisp Mon Jun 07 11:54:00 2010 +0100 +++ b/base/constructors.lisp Mon Jun 07 11:57:24 2010 +0100 @@ -58,6 +58,20 @@ (defun make-mips-pitch-interval (cspan mspan) (make-instance 'diatonic-pitch-interval :span (list cspan mspan))) +(defun make-diatonic-pitch-interval (interval accidentals) + "Returns a diatonic pitch interval given a number for the interval which corresponds to a major/perfect diatonic interval (unison=1,second=2,third=3, ...), if accidentals=0. If accidental>0 (<0), the interval is modified by |accidentals| sharps (flats). The sign of the given interval number determines whether the interval is raising or falling" +(let* + ((direction (signum interval)) ; -1:falling interval, +1:raising interval , 0: undefined interval + (octave (floor (/ (abs interval) 8))) ; determines the ocatve of the interval + (ref-pitch (make-diatonic-pitch #\C 0 0)) ; use reference pitch for the calculation later + (pitch-name ; calculate pitch from interval according to reference pitch + (elt "CDEFGAB" (mod (1- (abs interval)) 7))) + (diatonic-interval (pitch- (make-diatonic-pitch pitch-name accidentals octave) ref-pitch))) ; calculate interval + (cond ((> direction 0) diatonic-interval) ; raising interval + ((< direction 0) (pitch- (make-instance 'amuse:diatonic-pitch-interval :span '(0 0)) diatonic-interval)) ; falling interval + ((= direction 0) (error 'invalid-argument :function 'make-diatonic-pitch-interval + :argument "inverval = 0" ))))) ; the constructor is not defined if interval = 0 + ;; Events (defun make-chromatic-pitched-event (pitch-number onset duration)
--- a/base/package.lisp Mon Jun 07 11:54:00 2010 +0100 +++ b/base/package.lisp Mon Jun 07 11:57:24 2010 +0100 @@ -129,6 +129,7 @@ #:make-standard-anchored-period #:make-chromatic-pitch #:make-diatonic-pitch + #:make-diatonic-pitch-interval #:make-chromatic-pitch-interval #:make-chromatic-pitched-event #:make-standard-time-signature