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CLK/OSBindings/Qt/scantargetwidget.cpp

78 lines
2.5 KiB
C++

#include "scantargetwidget.h"
#include <QDebug>
#include <QOpenGLContext>
#include <QTimer>
#include "../../ClockReceiver/TimeTypes.hpp"
ScanTargetWidget::ScanTargetWidget(QWidget *parent) : QOpenGLWidget(parent) {}
ScanTargetWidget::~ScanTargetWidget() {}
void ScanTargetWidget::initializeGL() {
// Retain the default background colour.
const QColor backgroundColour = palette().color(QWidget::backgroundRole());
glClearColor(backgroundColour.redF(), backgroundColour.greenF(), backgroundColour.blueF(), 1.0);
// Follow each swapped frame with an additional update.
connect(this, &QOpenGLWidget::frameSwapped, this, &ScanTargetWidget::vsync);
}
void ScanTargetWidget::paintGL() {
glClear(GL_COLOR_BUFFER_BIT);
// Gmynastics ahoy: if a producer has been specified or previously connected then:
//
// (i) if it's a new producer, generate a new scan target and pass it on;
// (ii) in any case, check whether the underlyiung framebuffer has changed; and
// (iii) draw.
//
// The slightly convoluted scan target forwarding arrangement works around an issue
// with QOpenGLWidget under macOS, which I did not fully diagnose, in which creating
// a scan target in ::initializeGL did not work (and no other arrangement really works
// with regard to starting up).
if(isConnected || producer) {
if(producer) {
isConnected = true;
framebuffer = defaultFramebufferObject();
scanTarget = std::make_unique<Outputs::Display::OpenGL::ScanTarget>(framebuffer);
producer->set_scan_target(scanTarget.get());
producer = nullptr;
}
// Qt reserves the right to change the framebuffer object due to window resizes or if setParent is called;
// therefore check whether it has changed.
const auto newFramebuffer = defaultFramebufferObject();
if(framebuffer != newFramebuffer) {
framebuffer = newFramebuffer;
scanTarget->set_target_framebuffer(framebuffer);
}
vsyncPredictor.begin_redraw();
scanTarget->update(width(), height());
scanTarget->draw(width(), height());
vsyncPredictor.end_redraw();
}
}
void ScanTargetWidget::vsync() {
vsyncPredictor.announce_vsync();
const auto time_now = Time::nanos_now();
const auto delay_time = ((vsyncPredictor.suggested_draw_time() - time_now) / 1'000'000) - 5; // TODO: the extra 5 is a random guess.
if(delay_time > 0) {
QTimer::singleShot(delay_time, this, SLOT(repaint()));
} else {
repaint();
}
}
void ScanTargetWidget::resizeGL(int w, int h) {
glViewport(0, 0, w, h);
}
void ScanTargetWidget::setScanProducer(MachineTypes::ScanProducer *producer) {
this->producer = producer;
repaint();
}