+#include <epoxy/gl.h>
+#include <QGLWidget>
+#include <string>
+#include <vector>
+
+#include "mixer.h"
+#include "qgl.h"
+#include "qobjectdefs.h"
+
+class QMouseEvent;
+class QWidget;
+
+// Note: We use the older QGLWidget instead of QOpenGLWidget as it is
+// much faster (does not go through a separate offscreen rendering step).
+//
+// TODO: Consider if QOpenGLWindow could do what we want.
+class GLWidget : public QGLWidget