Cache and interpolate resolutions when drawing sample waveforms

include/AutomationEditor.h

@@ -36,6 +36,7 @@
 #include "JournallingObject.h"
 #include "MidiClip.h"
 #include "SampleClip.h"
+#include "SampleWaveform.h"
 #include "TimePos.h"
 #include "lmms_basics.h"
 
@@ -233,6 +234,7 @@ protected slots:
 
 	MidiClip* m_ghostNotes = nullptr;
 	QPointer<SampleClip> m_ghostSample = nullptr; // QPointer to set to nullptr on deletion
+	SampleWaveform m_waveform;
 	bool m_renderSample = false;
 
 	void centerTopBottomScroll();

include/SampleClipView.h

@@ -26,6 +26,7 @@
 #define LMMS_GUI_SAMPLE_CLIP_VIEW_H
 
 #include "ClipView.h"
+#include "SampleWaveform.h"
 
 namespace lmms
 {
@@ -63,6 +64,7 @@ public slots:
 
 private:
 	SampleClip * m_clip;
+	SampleWaveform m_waveform;
 	QPixmap m_paintPixmap;
 	bool splitClip( const TimePos pos ) override;
 } ;

include/SampleWaveform.h

@@ -26,23 +26,30 @@
 #define LMMS_GUI_SAMPLE_WAVEFORM_H
 
 #include <QPainter>
+#include <optional>
 
-#include "Sample.h"
+#include "SampleFrame.h"
 #include "lmms_export.h"
 
 namespace lmms::gui {
 class LMMS_EXPORT SampleWaveform
 {
 public:
-	struct Parameters
-	{
-		const SampleFrame* buffer;
-		size_t size;
-		float amplification;
-		bool reversed;
-	};
+	SampleWaveform() = default;
+	SampleWaveform(const SampleFrame* buffer, size_t size);
 
-	static void visualize(Parameters parameters, QPainter& painter, const QRect& rect);
+	void generate();
+	void visualize(QPainter& painter, const QRect& rect,
+		float amplification = 1.0f, bool reversed = false,
+		std::optional<size_t> from = std::nullopt,
+		std::optional<size_t> to = std::nullopt);
+	void reset(const SampleFrame* buffer, size_t size);
+
+private:
+	const SampleFrame* m_buffer = nullptr;
+	size_t m_size = 0;
+	std::unordered_map<int, std::vector<float>> m_min;
+	std::unordered_map<int, std::vector<float>> m_max;
 };
 } // namespace lmms::gui
 

plugins/AudioFileProcessor/AudioFileProcessorView.cpp

@@ -210,6 +210,7 @@ void AudioFileProcessorView::dropEvent(QDropEvent* de)
 	}
 
 	m_waveView->updateSampleRange();
+	m_waveView->updateWaveform();
 	Engine::getSong()->setModified();
 	de->accept();
 }
@@ -263,6 +264,7 @@ void AudioFileProcessorView::openAudioFile()
 	castModel<AudioFileProcessor>()->setAudioFile(af);
 	Engine::getSong()->setModified();
 	m_waveView->updateSampleRange();
+	m_waveView->updateWaveform();
 }
 
 void AudioFileProcessorView::modelChanged()

plugins/AudioFileProcessor/AudioFileProcessorWaveView.cpp

@@ -26,6 +26,7 @@
 
 #include "ConfigManager.h"
 #include "FontHelper.h"
+#include "Sample.h"
 #include "SampleWaveform.h"
 
 #include <QPainter>
@@ -50,6 +51,11 @@ void AudioFileProcessorWaveView::updateSampleRange()
 	}
 }
 
+void AudioFileProcessorWaveView::updateWaveform()
+{
+	m_waveform.reset(m_sample->data(), m_sample->sampleSize());
+}
+
 void AudioFileProcessorWaveView::setTo(int to)
 {
 	m_to = std::min(to, static_cast<int>(m_sample->sampleSize()));
@@ -89,6 +95,7 @@ AudioFileProcessorWaveView::AudioFileProcessorWaveView(QWidget* parent, int w, i
 	configureKnobRelationsAndWaveViews();
 
 	updateSampleRange();
+	updateWaveform();
 
 	m_graph.fill(Qt::transparent);
 	update();
@@ -339,12 +346,8 @@ void AudioFileProcessorWaveView::updateGraph()
 	QPainter p(&m_graph);
 	p.setPen(QColor(255, 255, 255));
 
-	const auto dataOffset = m_reversed ? m_sample->sampleSize() - m_to : m_from;
-
 	const auto rect = QRect{0, 0, m_graph.width(), m_graph.height()};
-	const auto waveform = SampleWaveform::Parameters{
-		m_sample->data() + dataOffset, static_cast<size_t>(range()), m_sample->amplification(), m_sample->reversed()};
-	SampleWaveform::visualize(waveform, p, rect);
+	m_waveform.visualize(p, rect, m_sample->amplification(), m_sample->reversed(), m_from, m_to);
 }
 
 void AudioFileProcessorWaveView::zoom(const bool out)

plugins/AudioFileProcessor/AudioFileProcessorWaveView.h

@@ -27,6 +27,7 @@
 
 
 #include "Knob.h"
+#include "SampleWaveform.h"
 
 
 namespace lmms
@@ -126,6 +127,7 @@ public slots:
 	} ;
 
 	Sample const* m_sample;
+	SampleWaveform m_waveform;
 	QPixmap m_graph;
 	int m_from;
 	int m_to;
@@ -153,6 +155,7 @@ public slots:
 
 
 	void updateSampleRange();
+	void updateWaveform();
 private:
 	void setTo(int to);
 	void setFrom(int from);

plugins/SlicerT/SlicerTWaveform.cpp

@@ -85,6 +85,7 @@ SlicerTWaveform::SlicerTWaveform(int totalWidth, int totalHeight, SlicerT* instr
 
 	connect(instrument, &SlicerT::isPlaying, this, &SlicerTWaveform::isPlaying);
 	connect(instrument, &SlicerT::dataChanged, this, &SlicerTWaveform::updateUI);
+	connect(instrument, &SlicerT::dataChanged, this, &SlicerTWaveform::updateWaveform);
 
 	m_emptySampleIcon = m_emptySampleIcon.createMaskFromColor(QColor(255, 255, 255), Qt::MaskMode::MaskOutColor);
 
@@ -115,10 +116,8 @@ void SlicerTWaveform::drawSeekerWaveform()
 	brush.setPen(s_waveformColor);
 
 	const auto& sample = m_slicerTParent->m_originalSample;
-	const auto waveform
-		= SampleWaveform::Parameters{sample.data(), sample.sampleSize(), sample.amplification(), sample.reversed()};
 	const auto rect = QRect(0, 0, m_seekerWaveform.width(), m_seekerWaveform.height());
-	SampleWaveform::visualize(waveform, brush, rect);
+	m_waveform.visualize(brush, rect, sample.amplification(), sample.reversed());
 
 	// increase brightness in inner color
 	QBitmap innerMask = m_seekerWaveform.createMaskFromColor(s_waveformMaskColor, Qt::MaskMode::MaskOutColor);
@@ -173,11 +172,9 @@ void SlicerTWaveform::drawEditorWaveform()
 	brush.setPen(s_waveformColor);
 	float zoomOffset = (m_editorHeight - m_zoomLevel * m_editorHeight) / 2;
 
-	const auto& sample = m_slicerTParent->m_originalSample;
-	const auto waveform = SampleWaveform::Parameters{
-		sample.data() + startFrame, endFrame - startFrame, sample.amplification(), sample.reversed()};
 	const auto rect = QRect(0, zoomOffset, m_editorWidth, m_zoomLevel * m_editorHeight);
-	SampleWaveform::visualize(waveform, brush, rect);
+	const auto& sample = m_slicerTParent->m_originalSample;
+	m_waveform.visualize(brush, rect, sample.amplification(), sample.reversed(), startFrame, endFrame);
 
 	// increase brightness in inner color
 	QBitmap innerMask = m_editorWaveform.createMaskFromColor(s_waveformMaskColor, Qt::MaskMode::MaskOutColor);
@@ -275,6 +272,12 @@ void SlicerTWaveform::updateUI()
 	update();
 }
 
+void SlicerTWaveform::updateWaveform()
+{
+	const auto& sample = m_slicerTParent->m_originalSample;
+	m_waveform.reset(sample.data(), sample.sampleSize());
+}
+
 // updates the closest object and changes the cursor respectivly
 void SlicerTWaveform::updateClosest(QMouseEvent* me)
 {

plugins/SlicerT/SlicerTWaveform.h

@@ -31,6 +31,7 @@
 #include <QInputDialog>
 #include <QMouseEvent>
 #include <QPainter>
+#include "SampleWaveform.h"
 
 namespace lmms {
 
@@ -44,6 +45,7 @@ class SlicerTWaveform : public QWidget
 
 public slots:
 	void updateUI();
+	void updateWaveform();
 	void isPlaying(float current, float start, float end);
 
 public:
@@ -112,6 +114,9 @@ public slots:
 	SlicerT* m_slicerTParent;
 
 	QElapsedTimer m_updateTimer;
+
+	SampleWaveform m_waveform;
+
 	void drawSeekerWaveform();
 	void drawSeeker();
 	void drawEditorWaveform();

src/gui/SampleWaveform.cpp

@@ -23,73 +23,93 @@
  */
 
 #include "SampleWaveform.h"
+#include "interpolation.h"
 
 namespace lmms::gui {
 
-void SampleWaveform::visualize(Parameters parameters, QPainter& painter, const QRect& rect)
+SampleWaveform::SampleWaveform(const SampleFrame* buffer, size_t size)
+	: m_buffer(buffer)
+	, m_size(size)
 {
-	const int x = rect.x();
-	const int height = rect.height();
-	const int width = rect.width();
-	const int centerY = rect.center().y();
+}
 
-	const int halfHeight = height / 2;
+void SampleWaveform::generate()
+{
+	if (!m_buffer || m_size == 0) { return; }
 
-	const auto color = painter.pen().color();
-	const auto rmsColor = color.lighter(123);
+	m_min.clear();
+	m_max.clear();
 
-	const float framesPerPixel = std::max(1.0f, static_cast<float>(parameters.size) / width);
+	const auto maxLevel = static_cast<int>(std::log2(m_size));
+	for (auto level = 1; level <= maxLevel; ++level)
+	{
+		const auto downsampledSize = m_size / static_cast<int>(std::exp2(level));
+		m_min[level].resize(downsampledSize);
+		m_max[level].resize(downsampledSize);
+
+		if (level == 1)
+		{
+			for (auto i = std::size_t{0}; i < downsampledSize; ++i)
+			{
+				static auto peakComp = [](const SampleFrame& a, const SampleFrame& b) { return a.average() < b.average(); };
+				m_min[level][i] = std::min_element(&m_buffer[i * 2], &m_buffer[i * 2 + 2], peakComp)->average();
+				m_max[level][i] = std::max_element(&m_buffer[i * 2], &m_buffer[i * 2 + 2], peakComp)->average();
+			}
+		}
+		else
+		{
+			for (auto i = std::size_t{0}; i < downsampledSize; ++i)
+			{
+				m_min[level][i] = *std::min_element(&m_min[level - 1][i * 2], &m_min[level - 1][i * 2 + 2]);
+				m_max[level][i] = *std::max_element(&m_max[level - 1][i * 2], &m_max[level - 1][i * 2 + 2]);
+			}
+		}
+	}
+}
 
-	constexpr float maxFramesPerPixel = 512.0f;
-	const float resolution = std::max(1.0f, framesPerPixel / maxFramesPerPixel);
-	const float framesPerResolution = framesPerPixel / resolution;
+void SampleWaveform::visualize(QPainter& painter, const QRect& rect, float amplification, bool reversed,
+	std::optional<size_t> from, std::optional<size_t> to)
+{
+	if (!m_buffer || m_size == 0) { return; }
 
-	size_t numPixels = std::min(parameters.size, static_cast<size_t>(width));
-	auto min = std::vector<float>(numPixels, 1);
-	auto max = std::vector<float>(numPixels, -1);
-	auto squared = std::vector<float>(numPixels, 0);
+	const auto sampleBegin = from.value_or(0);
+	const auto sampleEnd = to.value_or(m_size);
+	const auto samplesPerPixel = std::max(1, static_cast<int>(sampleEnd - sampleBegin) / rect.width());
 
-	const size_t maxFrames = static_cast<size_t>(numPixels * framesPerPixel);
+	const auto downsampledLevelLow = static_cast<int>(std::log2(samplesPerPixel));
+	const auto downsampledLevelHigh = static_cast<int>(std::ceil(std::log2(samplesPerPixel)));
 
-	auto pixelIndex = std::size_t{0};
+	const auto downsampledFactorLow = static_cast<int>(std::exp2(downsampledLevelLow));
+	const auto downsampledFactorHigh = static_cast<int>(std::exp2(downsampledLevelHigh));
 
-	for (auto i = std::size_t{0}; i < maxFrames; i += static_cast<std::size_t>(resolution))
-	{
-		pixelIndex = i / framesPerPixel;
-		const auto frameIndex = !parameters.reversed ? i : maxFrames - i;
+	const auto ratio = downsampledFactorHigh == downsampledFactorLow
+		? 1.0f
+		: static_cast<float>(samplesPerPixel - downsampledFactorLow) / (downsampledFactorHigh - downsampledFactorLow);
 
-		const auto& frame = parameters.buffer[frameIndex];
-		const auto value = frame.average();
+	const auto centerY = rect.center().y();
+	const auto centerHeight = rect.height() / 2.0f;
 
-		if (value > max[pixelIndex]) { max[pixelIndex] = value; }
-		if (value < min[pixelIndex]) { min[pixelIndex] = value; }
+	for (auto i = 0; i < rect.width(); ++i)
+	{	
+		const auto index = static_cast<float>(i * samplesPerPixel);
+		const auto lowIndex = static_cast<int>(std::floor(index / downsampledFactorLow));
+		const auto highIndex = static_cast<int>(std::ceil(index / downsampledFactorHigh));
 
-		squared[pixelIndex] += value * value;
-	}
-
-	if (pixelIndex < numPixels)
-	{
-		numPixels = pixelIndex;
-	}
-
-	for (auto i = std::size_t{0}; i < numPixels; i++)
-	{
-		const int lineY1 = centerY - max[i] * halfHeight * parameters.amplification;
-		const int lineY2 = centerY - min[i] * halfHeight * parameters.amplification;
-		const int lineX = static_cast<int>(i) + x;
-		painter.drawLine(lineX, lineY1, lineX, lineY2);
-
-		const float rms = std::sqrt(squared[i] / framesPerResolution);
-		const float maxRMS = std::clamp(rms, min[i], max[i]);
-		const float minRMS = std::clamp(-rms, min[i], max[i]);
+		const auto minPeak = linearInterpolate(m_min[downsampledLevelLow][lowIndex], m_min[downsampledLevelHigh][highIndex], ratio);
+		const auto maxPeak = linearInterpolate(m_max[downsampledLevelLow][lowIndex], m_max[downsampledLevelHigh][highIndex], ratio);
 
-		const int rmsLineY1 = centerY - maxRMS * halfHeight * parameters.amplification;
-		const int rmsLineY2 = centerY - minRMS * halfHeight * parameters.amplification;
-
-		painter.setPen(rmsColor);
-		painter.drawLine(lineX, rmsLineY1, lineX, rmsLineY2);
-		painter.setPen(color);
+		const auto lineMin = centerY - minPeak * centerHeight * amplification;
+		const auto lineMax = centerY - maxPeak * centerHeight * amplification;
+		const auto lineX = rect.x() + (reversed ? rect.width() - i : i);
+		painter.drawLine(lineX, lineMax, lineX, lineMin);
 	}
 }
 
+void SampleWaveform::reset(const SampleFrame* buffer, size_t size)
+{
+	m_buffer = buffer;
+	m_size = size;
+	generate();
+}
+
 } // namespace lmms::gui

src/gui/clips/SampleClipView.cpp

@@ -61,6 +61,8 @@ SampleClipView::SampleClipView( SampleClip * _clip, TrackView * _tv ) :
 void SampleClipView::updateSample()
 {
 	update();
+	m_waveform.reset(m_clip->m_sample.data(), m_clip->m_sample.sampleSize());
+
 	// set tooltip to filename so that user can see what sample this
 	// sample-clip contains
 	setToolTip(
@@ -272,9 +274,8 @@ void SampleClipView::paintEvent( QPaintEvent * pe )
 	QRect r = QRect( offset, spacing,
 			qMax( static_cast<int>( m_clip->sampleLength() * ppb / ticksPerBar ), 1 ), rect().bottom() - 2 * spacing );
 
-	const auto& sample = m_clip->m_sample;
-	const auto waveform = SampleWaveform::Parameters{sample.data(), sample.sampleSize(), sample.amplification(), sample.reversed()};
-	SampleWaveform::visualize(waveform, p, r);
+	const auto& sample = m_clip->sample();
+	m_waveform.visualize(p, r, sample.amplification(), sample.reversed());
 
 	QString name = PathUtil::cleanName(m_clip->m_sample.sampleFile());
 	paintTextLabel(name, p);