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50
51#include "glwidget.h"
52#include "helper.h"
53
54#include <QPainter>
55#include <QTimer>
56
57//! [0]
58GLWidget::GLWidget(Helper *helper, QWidget *parent)
59 : QOpenGLWidget(parent), helper(helper)
60{
61 elapsed = 0;
62 setFixedSize(w: 200, h: 200);
63 setAutoFillBackground(false);
64}
65//! [0]
66
67//! [1]
68void GLWidget::animate()
69{
70 elapsed = (elapsed + qobject_cast<QTimer*>(object: sender())->interval()) % 1000;
71 update();
72}
73//! [1]
74
75//! [2]
76void GLWidget::paintEvent(QPaintEvent *event)
77{
78 QPainter painter;
79 painter.begin(this);
80 painter.setRenderHint(hint: QPainter::Antialiasing);
81 helper->paint(painter: &painter, event, elapsed);
82 painter.end();
83}
84//! [2]
85

source code of qtbase/examples/opengl/2dpainting/glwidget.cpp