97 lines
3.9 KiB
Common Lisp
97 lines
3.9 KiB
Common Lisp
(in-package #:asteroid)
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;;; Spectrum Analyzer - Parenscript Implementation
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;;; Generates JavaScript for real-time audio visualization
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(defun generate-spectrum-analyzer-js ()
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"Generate JavaScript code for the spectrum analyzer using Parenscript"
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(ps:ps
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(defvar *audio-context* nil)
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(defvar *analyser* nil)
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(defvar *canvas* nil)
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(defvar *canvas-ctx* nil)
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(defvar *animation-id* nil)
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(defun init-spectrum-analyzer ()
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"Initialize the spectrum analyzer"
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(let ((audio-element (chain document (get-element-by-id "live-audio")))
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(canvas-element (chain document (get-element-by-id "spectrum-canvas"))))
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(when (and audio-element canvas-element)
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;; Create Audio Context
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(setf *audio-context* (new (or (@ window -audio-context)
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(@ window -webkit-audio-context))))
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;; Create Analyser Node
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(setf *analyser* (chain *audio-context* (create-analyser)))
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(setf (@ *analyser* fft-size) 256)
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(setf (@ *analyser* smoothing-time-constant) 0.8)
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;; Connect audio source to analyser
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(let ((source (chain *audio-context* (create-media-element-source audio-element))))
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(chain source (connect *analyser*))
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(chain *analyser* (connect (@ *audio-context* destination))))
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;; Setup canvas
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(setf *canvas* canvas-element)
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(setf *canvas-ctx* (chain *canvas* (get-context "2d")))
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;; Start visualization
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(draw-spectrum))))
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(defun draw-spectrum ()
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"Draw the spectrum analyzer visualization"
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(setf *animation-id* (request-animation-frame draw-spectrum))
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(let* ((buffer-length (@ *analyser* frequency-bin-count))
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(data-array (new (-uint8-array buffer-length)))
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(width (@ *canvas* width))
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(height (@ *canvas* height))
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(bar-width (/ width buffer-length))
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(bar-height 0)
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(x 0))
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(chain *analyser* (get-byte-frequency-data data-array))
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;; Clear canvas with fade effect
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(setf (@ *canvas-ctx* fill-style) "rgba(0, 0, 0, 0.2)")
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(chain *canvas-ctx* (fill-rect 0 0 width height))
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;; Draw bars
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(dotimes (i buffer-length)
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(setf bar-height (/ (* (aref data-array i) height) 256))
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;; Create gradient for each bar
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(let ((gradient (chain *canvas-ctx*
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(create-linear-gradient 0 (- height bar-height) 0 height))))
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(chain gradient (add-color-stop 0 "#00ff00"))
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(chain gradient (add-color-stop 0.5 "#00aa00"))
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(chain gradient (add-color-stop 1 "#005500"))
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(setf (@ *canvas-ctx* fill-style) gradient)
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(chain *canvas-ctx* (fill-rect x (- height bar-height) bar-width bar-height))
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(incf x bar-width)))))
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(defun stop-spectrum-analyzer ()
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"Stop the spectrum analyzer"
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(when *animation-id*
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(cancel-animation-frame *animation-id*)
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(setf *animation-id* nil)))
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;; Initialize when audio starts playing
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(chain document (add-event-listener "DOMContentLoaded"
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(lambda ()
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(let ((audio-element (chain document (get-element-by-id "live-audio"))))
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(when audio-element
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(chain audio-element (add-event-listener "play" init-spectrum-analyzer))
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(chain audio-element (add-event-listener "pause" stop-spectrum-analyzer)))))))))
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(defun write-spectrum-analyzer-js ()
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"Write the generated JavaScript to a file"
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(with-open-file (stream (asdf:system-relative-pathname :asteroid "static/js/spectrum-analyzer.js")
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:direction :output
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:if-exists :supersede
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:if-does-not-exist :create)
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(write-string (generate-spectrum-analyzer-js) stream)))
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