feedc0de/oscilloscope
1
0
Fork 0
Code Issues Pull Requests 1 Actions Packages Projects Releases Wiki Activity

Uses alpha channel to draw lines, uses Qt::FlatCap style, uses QPainter::Antialiasing

Browse Source
This commit is contained in:
Gitea
2019-09-22 18:58:45 +02:00
parent 2b9b1cf9a4
commit 86dccd467e
2 changed files with 39 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

55
osciwidget.cpp
View File

@@ -17,11 +17,11 @@ qint32 framesForDuration(qint64 duration){
OsciWidget::OsciWidget(QWidget *parent) OsciWidget::OsciWidget(QWidget *parent)
: QOpenGLWidget{parent} : QOpenGLWidget{parent}
, m_bufferOffset{m_buffer.begin()} , m_bufferOffset{m_buffer.begin()}
, m_lastTime{0} , m_lastBufferUpdate{0}
, m_redrawTimerId(startTimer(1000/m_fps, Qt::PreciseTimer)) , m_redrawTimerId(startTimer(1000/m_fps, Qt::PreciseTimer))
{ {
m_statsTimer.start(); m_statsTimer.start();
m_bufferTimer.start(); m_globalTimer.start();
} }
int OsciWidget::lightspeed() const int OsciWidget::lightspeed() const
@@ -62,17 +62,18 @@ void OsciWidget::renderSamples(const SamplePair *begin, const SamplePair *end)
auto offset = std::distance(m_buffer.begin(), m_bufferOffset); auto offset = std::distance(m_buffer.begin(), m_bufferOffset);
if(m_bufferTimer.elapsed()-m_lastTime > 5000) if(m_globalTimer.elapsed()-m_lastBufferUpdate > 5000)
{ {
//qDebug() << "deleting: " << m_bufferOffset - m_buffer.begin() << m_buffer.size(); //qDebug() << "deleting: " << m_bufferOffset - m_buffer.begin() << m_buffer.size();
// Delete drawn frames // Delete drawn frames
//m_buffer.erase(m_buffer.begin(), m_bufferOffset); //m_buffer.erase(m_buffer.begin(), m_bufferOffset);
// TODO improve by drawing remaining(undrawn) buffer instead // TODO improve by drawing remaining(undrawn) buffer instead
drawBuffer(m_bufferOffset, m_buffer.end(), QColor(0, 255, 0));
m_buffer.clear(); m_buffer.clear();
offset = 0; offset = 0;
m_lastTime = m_bufferTimer.elapsed(); m_lastBufferUpdate = m_globalTimer.elapsed();
} }
//qDebug () << " inserting " << std::distance(begin, end); //qDebug () << " inserting " << std::distance(begin, end);
m_buffer.insert(m_buffer.end(), begin, end); m_buffer.insert(m_buffer.end(), begin, end);
@@ -88,7 +89,7 @@ void OsciWidget::paintEvent(QPaintEvent *event)
m_frameCounter++; m_frameCounter++;
if (m_statsTimer.hasExpired(1000)) if (m_statsTimer.hasExpired(1000))
{ {
emit statusUpdate(QString("%0FPS (%1 callbacks, %2 samples, %3 avg per callback, bufferSize %4, elapsed %5)").arg(m_frameCounter).arg(m_callbacksCounter).arg(m_samplesCounter).arg(m_callbacksCounter>0?m_samplesCounter/m_callbacksCounter:0).arg(m_buffer.size()).arg(m_bufferTimer.elapsed())); emit statusUpdate(QString("%0FPS (%1 callbacks, %2 samples, %3 avg per callback, bufferSize %4, elapsed %5)").arg(m_frameCounter).arg(m_callbacksCounter).arg(m_samplesCounter).arg(m_callbacksCounter>0?m_samplesCounter/m_callbacksCounter:0).arg(m_buffer.size()).arg(m_globalTimer.elapsed()));
m_frameCounter = 0; m_frameCounter = 0;
m_callbacksCounter = 0; m_callbacksCounter = 0;
m_samplesCounter = 0; m_samplesCounter = 0;
@@ -103,28 +104,32 @@ void OsciWidget::darkenFrame()
{ {
QPainter painter(&m_pixmap); QPainter painter(&m_pixmap);
painter.setCompositionMode(QPainter::CompositionMode_Multiply);
painter.setPen({});
//auto afterglowColor = 255 * pow(m_decayTime, 1.0/m_fps); //auto afterglowColor = 255 * pow(m_decayTime, 1.0/m_fps);
auto afterglowColor = static_cast<int>(255 * pow(exp(-1), 1000.0/m_decayTime/m_fps)); auto afterglowFactor = pow(exp(-1), 1000.0/m_decayTime/m_fps);
qDebug() << afterglowColor; auto afterglowColor = static_cast<int>(255*afterglowFactor);
//qDebug() << afterglowFactor;
//QColor blendColor;
//black.setAlpha(afterglowColor);
painter.setCompositionMode(QPainter::CompositionMode_Multiply);
painter.setBrush(QColor(afterglowColor, afterglowColor, afterglowColor)); painter.setBrush(QColor(afterglowColor, afterglowColor, afterglowColor));
painter.drawRect(m_pixmap.rect()); painter.drawRect(m_pixmap.rect());
//m_pixmap.fill(Qt::black); //m_pixmap.fill(Qt::black);
} }
void OsciWidget::drawBuffer(SampleBuffer::iterator &bufferPos, const SampleBuffer::iterator &end) void OsciWidget::drawBuffer(SampleBuffer::iterator &bufferPos, const SampleBuffer::iterator &end, QColor color)
{ {
QPainter painter(&m_pixmap); QPainter painter(&m_pixmap);
painter.setRenderHint(QPainter::Antialiasing);
painter.translate(m_pixmap.width()/2, m_pixmap.height()/2); painter.translate(m_pixmap.width()/2, m_pixmap.height()/2);
painter.scale(m_factor * m_pixmap.width() / 2.0, m_factor * m_pixmap.height() / 2.0); painter.scale(m_factor * m_pixmap.width() / 2.0, m_factor * m_pixmap.height() / 2.0);
QPen pen; QPen pen;
pen.setCosmetic(true); // let pen be scale invariant pen.setCosmetic(true); // let pen be scale invariant
pen.setWidth(2); pen.setWidth(2);
pen.setColor(QColor(0, 255, 0)); // This prevents most of the overlapping when drawing lines from and to the same points
painter.setPen(pen); pen.setCapStyle(Qt::FlatCap);
for (;bufferPos < end; ++bufferPos) for (;bufferPos < end; ++bufferPos)
{ {
@@ -137,14 +142,26 @@ void OsciWidget::drawBuffer(SampleBuffer::iterator &bufferPos, const SampleBuffe
const QLineF line(m_lastPoint, p); const QLineF line(m_lastPoint, p);
auto beamOpacity = std::min(1.0, 1. / ((line.length() * m_lightspeed) + 1)); auto beamBrightness = std::min(1.0, 1. / ((line.length() * m_lightspeed) + 1));
// time from bufferPos to end in ms
double time = 1000.0 * std::distance(bufferPos, end) / 44100.0; double time = 1000.0 * std::distance(bufferPos, end) / 44100.0;
auto beamDecay = exp(-time/m_decayTime);
painter.setOpacity(beamDecay*beamOpacity); auto beamDecay = exp(-time/m_decayTime);
// HACK: gamma rolloff the brightness to make it look better (make configurable?)
auto beamVisibility = pow(beamBrightness, 2.0)*beamDecay;
QColor drawColor(color);
drawColor.setAlphaF(beamVisibility);
//QColor drawColor(color.red()*beamVisibility, color.green()*beamVisibility, color.blue()*beamVisibility);
pen.setColor(drawColor);
painter.setPen(pen);
//painter.setOpacity(beamVisibility);
painter.drawLine(m_lastPoint, p); painter.drawLine(m_lastPoint, p);
//painter.drawLine(m_lastPoint, m_lastPoint);
//painter.setPen(pen);
//painter.drawPoint(m_lastPoint);
m_lastPoint = p; m_lastPoint = p;
} }
@@ -166,14 +183,14 @@ void OsciWidget::updateDrawBuffer()
resizeDrawBuffer(); resizeDrawBuffer();
darkenFrame(); darkenFrame();
// persistance time is the time it needs to decay to 1/e ~ 36,7% // decay time is the time it needs to decay to 1/e ~ 36,7%
auto duration = 1000*(m_bufferTimer.elapsed()-m_lastTime); auto duration = 1000*(m_globalTimer.elapsed()-m_lastBufferUpdate);
size_t framesOffset = framesForDuration(duration); size_t framesOffset = framesForDuration(duration);
//qDebug() << framesOffset << m_buffer.size()-framesOffset << m_bufferOffset - m_buffer.begin(); //qDebug() << framesOffset << m_buffer.size()-framesOffset << m_bufferOffset - m_buffer.begin();
auto bufferEnd = m_buffer.begin() + std::min(framesOffset, m_buffer.size()); auto bufferEnd = m_buffer.begin() + std::min(framesOffset, m_buffer.size());
drawBuffer(m_bufferOffset, bufferEnd); drawBuffer(m_bufferOffset, bufferEnd, QColor(0, 255, 0));
} }
void OsciWidget::timerEvent(QTimerEvent *event) void OsciWidget::timerEvent(QTimerEvent *event)

6
osciwidget.h
View File

@@ -54,13 +54,13 @@ private:
int m_frameCounter{0}, m_callbacksCounter{0}, m_samplesCounter{0}; int m_frameCounter{0}, m_callbacksCounter{0}, m_samplesCounter{0};
QElapsedTimer m_statsTimer; QElapsedTimer m_statsTimer;
QElapsedTimer m_bufferTimer; QElapsedTimer m_globalTimer;
qint64 m_lastTime; qint64 m_lastBufferUpdate;
int m_redrawTimerId; int m_redrawTimerId;
QPointF m_lastPoint; QPointF m_lastPoint;
QPixmap m_pixmap; QPixmap m_pixmap;
void darkenFrame(); void darkenFrame();
void drawBuffer(SampleBuffer::iterator &bufferPos, const SampleBuffer::iterator &end); void drawBuffer(SampleBuffer::iterator &bufferPos, const SampleBuffer::iterator &end, QColor color);
void resizeDrawBuffer(); void resizeDrawBuffer();
}; };