seq.lsp

一个音频的可执行程序。可以导入MP3/WAV格式的文件后

;; seq.lsp -- sequence control constructs for Nyquist

;; get-srates -- this either returns the sample rate of a sound or a
;;   vector of sample rates of a vector of sounds
;;
(defun get-srates (sounds)
  (cond ((arrayp sounds)
         (let ((result (make-array (length sounds))))
           (dotimes (i (length sounds))
                    (setf (aref result i) (snd-srate (aref sounds i))))
           result))
        (t
         (snd-srate sounds))))

; These are complex macros that implement sequences of various types.
; The complexity is due to the fact that a behavior within a sequence
; can reference the environment, e.g. (let ((p 60)) (seq (osc p) (osc p)))
; is an example where p must be in the environment of each member of
; the sequence.  Since the execution of the sequence elements are delayed,
; the environment must be captured and then used later.  In XLISP, the
; EVAL function does not execute in the current environment, so a special
; EVAL, EVALHOOK must be used to evaluate with an environment.  Another
; feature of XLISP (see evalenv.lsp) is used to capture the environment
; when the seq is first evaluated, so that the environment can be used
; later.  Finally, it is also necessary to save the current transformation
; environment until later.

(defmacro seq (&rest list)
  (cond ((null list)
         (snd-zero (warp-time *WARP*) *sound-srate*))
        ((null (cdr list))
         (car list))
        ((null (cddr list))
         ; (format t "SEQ with 2 behaviors: ~A~%" list)
         `(let* ((first%sound ,(car list))
                (s%rate (get-srates first%sound)))
            (cond ((arrayp first%sound)
                   (snd-multiseq (prog1 first%sound (setf first%sound nil))
                     #'(lambda (t0)
                        (format t "MULTISEQ's 2nd behavior: ~A~%" ',(cadr list))
                        (with%environment ',(nyq:the-environment)
;			    (display "MULTISEQ 1" t0)
                            (at-abs t0
                                (force-srates s%rate ,(cadr list)))))))
                  (t
                   ; allow gc of first%sound:
                   (snd-seq (prog1 first%sound (setf first%sound nil))
                     #'(lambda (t0) 
;                        (format t "SEQ's 2nd behavior: ~A~%" ',(cadr list))
                        (with%environment ',(nyq:the-environment)
                            (at-abs t0
                                (force-srate s%rate ,(cadr list))))))))))

        (t
         `(let* ((nyq%environment (nyq:the-environment))
                 (first%sound ,(car list))
                 (s%rate (get-srates first%sound))
                 (seq%environment (getenv)))
            (cond ((arrayp first%sound)
;		   (print "calling snd-multiseq")
                   (snd-multiseq (prog1 first%sound (setf first%sound nil))
                     #'(lambda (t0)
                        (multiseq-iterate ,(cdr list)))))
                  (t 
;		   (print "calling snd-seq")
                   ; allow gc of first%sound:
                   (snd-seq (prog1 first%sound (setf first%sound nil))
                     #'(lambda (t0)
                        (seq-iterate ,(cdr list))))))))))

(defun envdepth (e) (length (car e)))

(defmacro myosd (pitch)
  `(let () (format t "myosc env depth is ~A~%" 
                   (envdepth (getenv))) (osc ,pitch)))

(defmacro seq-iterate (behavior-list)
  (cond ((null (cdr behavior-list))
         `(eval-seq-behavior ,(car behavior-list)))
        (t
         `(snd-seq (eval-seq-behavior ,(car behavior-list))
                   (evalhook '#'(lambda (t0) 
                                  ; (format t "lambda depth ~A~%" (envdepth (getenv)))
                                  (seq-iterate ,(cdr behavior-list)))
                             nil nil seq%environment)))))

(defmacro multiseq-iterate (behavior-list)
  (cond ((null (cdr behavior-list))
         `(eval-multiseq-behavior ,(car behavior-list)))
        (t
         `(snd-multiseq (eval-multiseq-behavior ,(car behavior-list))
                   (evalhook '#'(lambda (t0) 
                                  ; (format t "lambda depth ~A~%" (envdepth (getenv)))
                                  (multiseq-iterate ,(cdr behavior-list)))
                             nil nil seq%environment)))))

(defmacro eval-seq-behavior (beh)
  `(with%environment nyq%environment 
                     (at-abs t0
                             (force-srate s%rate ,beh))))

(defmacro eval-multiseq-behavior (beh)
  `(with%environment nyq%environment 
;			    (display "MULTISEQ 2" t0)
                     (at-abs t0
                             (force-srates s%rate ,beh))))

(defmacro with%environment (env &rest expr)
  `(progv ',*environment-variables* ,env ,@expr))



(defmacro seqrep (pair sound)
  `(let ((,(car pair) 0)
         (loop%count ,(cadr pair))
         (nyq%environment (nyq:the-environment))
         seqrep%closure first%sound s%rate)
     ; note: s%rate will tell whether we want a single or multichannel
     ; sound, and what the sample rates should be.
     (cond ((not (integerp loop%count))
            (error "bad argument type" loop%count))
           (t
            (setf seqrep%closure #'(lambda (t0)
;	      (display "SEQREP" loop%count ,(car pair))
              (cond ((< ,(car pair) loop%count)
                     (setf first%sound 
                           (with%environment nyq%environment
                                             (at-abs t0 ,sound)))
                     ; (display "seqrep" s%rate nyq%environment ,(car pair)
                     ;          loop%count)
                     (if s%rate
                       (setf first%sound (force-srates s%rate first%sound))
                       (setf s%rate (get-srates first%sound)))
                     (setf ,(car pair) (1+ ,(car pair)))
                     ; note the following test is AFTER the counter increment
                     (cond ((= ,(car pair) loop%count)
;                            (display "seqrep: computed the last sound at"
;                               ,(car pair) loop%count
;                               (local-to-global 0))
                            first%sound) ;last sound
                           ((arrayp s%rate)
;                            (display "seqrep: calling snd-multiseq at"
;                             ,(car pair) loop%count (local-to-global 0) 
;                             (snd-t0 (aref first%sound 0)))
                            (snd-multiseq (prog1 first%sound
                                                 (setf first%sound nil))
                                          seqrep%closure))
                           (t
;                            (display "seqrep: calling snd-seq at"
;                             ,(car pair) loop%count (local-to-global 0) 
;                             (snd-t0 first%sound))
                            (snd-seq (prog1 first%sound
                                            (setf first%sound nil))
                                     seqrep%closure))))
                    (t (snd-zero (warp-time *WARP*) *sound-srate*)))))
            (funcall seqrep%closure (local-to-global 0))))))


;; (timed-seq '((time1 stretch1 expr1) (time2 stretch2 expr2) ...))
;; a timed-seq takes a list of events as shown above
;; it sums the behaviors, similar to 
;;     (sim (at time1 (stretch stretch1 expr1)) ...)
;; but the implementation avoids starting all expressions at once
;; 
;; Notes: (1) the times must be in increasing order
;;   (2) EVAL is used on each event, so events cannot refer to parameters
;;        or local variables
;;
(defun timed-seq (score)
  ; check to insure that times are strictly increasing and >= 0 and stretches are >= 0
  (let ((start-time 0) error-msg)
    (dolist (event score)
      (cond ((< (car event) start-time)
             (error (format nil "Out-of-order time in TIMED-SEQ: ~A" event)))
            ((< (cadr event) 0)
             (error (format nil "Negative stretch factor in TIMED-SEQ: ~A" event)))
            (t
             (setf start-time (car event)))))
    (cond ((null score) (s-rest 0))
          (t
           (at (caar score)
               (seqrep (i (length score))
                 (cond ((cdr score)
                        (let (event)
                          (prog1
                            (set-logical-stop
                              (stretch (cadar score)
                              (setf event (eval (caddar score))))
                            (- (caadr score) (caar score)))
;                           (display "timed-seq" (caddar score) (local-to-global 0))
                            (setf score (cdr score)))))
                         (t
                          (stretch (cadar score) (eval (caddar score)))))))))))