Revert "Replace deprecated QGLWidget with QOpenGLWidget"

This reverts commit 2f7adf19d0.

celestia.pro

@@ -12,6 +12,7 @@ DEFINES += GIT_COMMIT=\\\"$$GIT_COMMIT\\\"
 QMAKE_CXXFLAGS += -std=c++11
 
 QT += widgets
+QT += opengl
 
 contains(DEFINES, TEST_MODEL) {
     QT += testlib

src/celestia/qt/qtappwin.cpp

@@ -40,7 +40,6 @@
 #include <QDesktopWidget>
 #include <QInputDialog>
 #include <QUrl>
-#include <QSurfaceFormat>
 #include <vector>
 #include <string>
 #include <cassert>
@@ -274,17 +273,24 @@ void CelestiaAppWindow::init(const QString& qConfigFileName,
 
     // Enable antialiasing if requested in the config file.
     // TODO: Make this settable via the GUI
-    QSurfaceFormat glformat = QSurfaceFormat::defaultFormat();
+    QGLFormat glformat = QGLFormat::defaultFormat();
     if (m_appCore->getConfig()->aaSamples > 1)
     {
-        glformat.setRenderableType(QSurfaceFormat::OpenGL);
+        glformat.setSampleBuffers(true);
         glformat.setSamples(m_appCore->getConfig()->aaSamples);
-        QSurfaceFormat::setDefaultFormat(glformat);
+        QGLFormat::setDefaultFormat(glformat);
     }
 
     glWidget = new CelestiaGlWidget(nullptr, "Celestia", m_appCore);
     glWidget->makeCurrent();
 
+    GLenum glewErr = glewInit();
+    if (glewErr != GLEW_OK)
+    {
+        QMessageBox::critical(0, "Celestia",
+                              QString(_("Celestia was unable to initialize OpenGL extensions (error %1). Graphics quality will be reduced.")).arg(glewErr));
+    }
+
     m_appCore->setCursorHandler(glWidget);
     m_appCore->setContextMenuCallback(ContextMenu);
     MainWindowInstance = this; // TODO: Fix context menu callback
@@ -635,7 +641,7 @@ void CelestiaAppWindow::saveBookmarks()
 void CelestiaAppWindow::celestia_tick()
 {
     m_appCore->tick();
-    glWidget->update();
+    glWidget->updateGL();
 }
 
 
@@ -673,7 +679,7 @@ void CelestiaAppWindow::slotGrabImage()
         QFileInfo saveAsFile(saveAsName);
 
         //glWidget->repaint();
-        QImage grabbedImage = glWidget->grabFramebuffer();
+        QImage grabbedImage = glWidget->grabFrameBuffer();
         grabbedImage.save(saveAsName);
 
         settings.setValue("GrabImageDir", saveAsFile.absolutePath());
@@ -784,7 +790,7 @@ void CelestiaAppWindow::slotCaptureVideo()
 void CelestiaAppWindow::slotCopyImage()
 {
     //glWidget->repaint();
-    QImage grabbedImage = glWidget->grabFramebuffer();
+    QImage grabbedImage = glWidget->grabFrameBuffer();
     QApplication::clipboard()->setImage(grabbedImage);
     m_appCore->flash(QString(_("Captured screen shot to clipboard")).toStdString());
 }
@@ -1009,7 +1015,7 @@ void CelestiaAppWindow::slotAddBookmark()
     appState.captureState(m_appCore);
 
     // Capture the current frame buffer to use as a bookmark icon.
-    QImage grabbedImage = glWidget->grabFramebuffer();
+    QImage grabbedImage = glWidget->grabFrameBuffer();
     int width = grabbedImage.width();
     int height = grabbedImage.height();
 

src/celestia/qt/qtglwidget.cpp

@@ -23,7 +23,6 @@
 #include <QPaintDevice>
 #include <QMouseEvent>
 #include <QSettings>
-#include <QMessageBox>
 
 #ifndef DEBUG
 #  define G_DISABLE_ASSERT
@@ -62,7 +61,7 @@ const unsigned int DEFAULT_TEXTURE_RESOLUTION = medres;
 
 
 CelestiaGlWidget::CelestiaGlWidget(QWidget* parent, const char* /* name */, CelestiaCore* core) :
-    QOpenGLWidget(parent)
+    QGLWidget(parent)
 {
     setFocusPolicy(Qt::ClickFocus);
 
@@ -113,16 +112,6 @@ static GLContext::GLRenderPath getBestAvailableRenderPath(const GLContext& /*glc
 
 void CelestiaGlWidget::initializeGL()
 {
-    GLenum glewErr = glewInit();
-
-    if (glewErr != GLEW_OK)
-    {
-        QString errMsg;
-        errMsg = QString(_("GLEW Error: %1\n")).arg(reinterpret_cast<const char*>(glewGetErrorString(glewErr)));
-        QMessageBox::critical(0, "Celestia", errMsg);
-        exit(1); // We need OpenGL 2.1 at least
-    }
-
     if (!appCore->initRenderer())
     {
         // cerr << "Failed to initialize renderer.\n";

src/celestia/qt/qtglwidget.h

@@ -16,7 +16,7 @@
 
 #include <GL/glew.h>
 
-#include <QOpenGLWidget>
+#include <QGLWidget>
 
 #include "celestia/celestiacore.h"
 #include "celengine/simulation.h"
@@ -28,7 +28,7 @@
   *@author Christophe Teyssier
   */
 
-class CelestiaGlWidget : public QOpenGLWidget, public CelestiaCore::CursorHandler
+class CelestiaGlWidget : public QGLWidget, public CelestiaCore::CursorHandler
 {
     Q_OBJECT