opengl init

headers/OutputWidget.h

@@ -6,7 +6,7 @@
 #include <QOpenGLFunctions>
 #include <QOpenGLWidget>
 
-class OutputWidget : public QOpenGLWidget, protected QOpenGLFunctions {
+class OutputWidget : public QOpenGLWidget, public QOpenGLFunctions {
 	Q_OBJECT
 private:
 	void initializeGL() override;

src/MainWindow.cpp

@@ -8,6 +8,7 @@ MainWindow::MainWindow() {
 }
 
 void MainWindow::buildUI() {
+	resize(700, 700);
 
 	auto sizeSlider = new QSlider(Qt::Horizontal);
 	sizeSlider->setRange(100, 800);

src/OutputWidget.cpp

@@ -1,8 +1,16 @@
 
+#include <iostream>
 #include "../headers/OutputWidget.h"
 
 void OutputWidget::initializeGL() {
-
+	initializeOpenGLFunctions();
+	std::cout << "Initialize GL" << std::endl;
+	auto format = this->format();
+	std::cout << "OpenGL version: " <<
+		format.majorVersion() << "." << format.minorVersion()
+	<< std::endl;
+
+	::glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
 }
 
 void OutputWidget::paintGL() {