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aa050ae0b7
* Replace knobFModel with std::vector * Create QPixmap's on the stack * Assign parent for QGraphicsScene A call to QGraphicsView::setScene does not make the view take ownership of the scene. * Do not allocate QList on the heap * Use static QPixmap's The QPixmap's need to be created within the constructor, and not outside where they are defined, since it can't find them otherwise. I'm not too sure why. * Clear m_vi2->knobFModel in destructor * Use local static QPixmap's * Do not allocate QPixmap with new in AudioFileProcessor * Do not allocate QPixmap with new in Nes * Do not allocate QPixmap with new in Organic * Do not allocate QPixmap with new in SaControlsDialog * Do not allocate QPixmap with new in Vestige * Do not allocate QPixmap with new for FileBrowser * Do not allocate QPixmap with new in MixerLine * Do not allocate QPixmap with new in SendButtonIndicator * Do not allocate QPixmap with new in AutomationClipView * Do not allocate QPixmap with new in MidiClipView * Do not allocate QPixmap with new in AutomationEditor * Do not allocate QPixmap with new in PianoRoll * Do not allocate QPixmap with new in TimeLineWidget * Do not allocate QPixmap with new in EnvelopeAndLfoView * Do not allocate QPixmap with new in PianoView * Do not allocate QPixmap with new in ComboBox * Do not allocate QPixmap with new in Fader * Do not allocate QPixmap with new for LcdWidget * Do not allocate QPixmap with new for LedCheckbox * Use m_ as prefix for members * Use uniform initialization I already started using uniform initialization for the QPixmap changes for some reason, so I'm finishing that up. * Uniform initiaization * And then he realized he was making copies... * Do not call QPixmap copy constructor * Do not call QPixmap copy constructor in SaControlsDialog * Do not make pixmap's static for Lcd's and Led's * Initialize pixmaps in-class * Fix few mistakes and formatting
Spectrum Analyzer plugin
Overview
This plugin consists of three widgets and back-end code to provide them with required data.
The top-level widget is SaControlDialog. It populates configuration widgets (created dynamically) and instantiates spectrum display widgets. Its main back-end class is SaControls, which holds all configuration values.
SaSpectrumView and SaWaterfallView widgets show the result of spectrum analysis. Their main back-end class is SaProcessor, which performs FFT analysis on data received from the Analyzer class, which in turn handles the interface with LMMS.
Threads
The Spectrum Analyzer is involved in three different threads:
- Effect mixer thread: periodically calls
Analyzer::processAudioBuffer()to provide the plugin with more data. This thread is real-time sensitive -- any latency spikes can potentially cause interruptions in the audio stream. For this reason,Analyzer::processAudioBuffer()must finish as fast as possible and must not call any functions that could cause it to be delayed for unpredictable amount of time. A lock-less ring buffer is used to safely feed data to the FFT analysis thread without risking any latency spikes due to a shared mutex being unavailable at the time of writing. - FFT analysis thread: a standalone thread formed by the
SaProcessor::analyze()function. Takes in data from the ring buffer, performs FFT analysis and prepares results for display. This thread is not real-time sensitive but excessive locking is discouraged to maintain good performance. - GUI thread: periodically triggers
paintEvent()of all Qt widgets, includingSaSpectrumViewandSaWaterfallView. While it is not as sensitive to latency spikes as the effect mixer thread, thepaintEvent()s appear to be called sequentially and the execution time of each widget therefore adds to the total time needed to complete one full refresh cycle. This means the maximum frame rate of the Qt GUI will be limited to1 / total_execution_time. Good performance of thepaintEvent()functions should be therefore kept in mind.
Changelog
1.1.2 2019-11-18
- waterfall is no longer cut short when width limit is reached
- various small tweaks based on final review
1.1.1 2019-10-13
- improved interface for accessing SaProcessor private data
- readme file update
- other small improvements based on reviews
1.1.0 2019-08-29
- advanced config: expose hidden constants to user
- advanced config: add support for FFT window overlapping
- waterfall: display at native resolution on high-DPI screens
- waterfall: add cursor and improve label density
- FFT: fix normalization so that 0 dBFS matches full-scale sinewave
- FFT: decouple data acquisition from processing and display
- FFT: separate lock for reallocation (to avoid some needless waiting)
- moved ranges and other constants to a separate file
- debug: better performance measurements
- various performance optimizations
1.0.3 2019-07-25
- rename and tweak amplitude ranges based on feedback
1.0.2 2019-07-12
- variety of small changes based on code review
1.0.1 2019-06-02
- code style changes
- added tool-tips
- use const for unmodified arrays passed to fft_helpers
1.0.0 2019-04-07
- initial release