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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
//! [0]
class MyGLWidget : public QOpenGLWidget
{
public:
MyGLWidget(QWidget *parent) : QOpenGLWidget(parent) { }
protected:
void initializeGL() override
{
// Set up the rendering context, load shaders and other resources, etc.:
QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions();
f->glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
...
}
void resizeGL(int w, int h) override
{
// Update projection matrix and other size related settings:
m_projection.setToIdentity();
m_projection.perspective(45.0f, w / float(h), 0.01f, 100.0f);
...
}
void paintGL() override
{
// Draw the scene:
QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions();
f->glClear(GL_COLOR_BUFFER_BIT);
...
}
};
//! [0]
//! [1]
class MyGLWidget : public QOpenGLWidget, protected QOpenGLFunctions
{
...
void initializeGL() override
{
initializeOpenGLFunctions();
glClearColor(...);
...
}
...
};
//! [1]
//! [2]
QOpenGLWidget *widget = new QOpenGLWidget(parent);
QSurfaceFormat format;
format.setDepthBufferSize(24);
format.setStencilBufferSize(8);
format.setVersion(3, 2);
format.setProfile(QSurfaceFormat::CoreProfile);
widget->setFormat(format); // must be called before the widget or its parent window gets shown
//! [2]
//! [3]
...
void paintGL() override
{
QOpenGLFunctions_3_2_Core *f = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_2_Core>();
...
f->glDrawArraysInstanced(...);
...
}
...
//! [3]
//! [4]
class MyGLWidget : public QOpenGLWidget
{
...
private:
QOpenGLVertexArrayObject m_vao;
QOpenGLBuffer m_vbo;
QOpenGLShaderProgram *m_program;
QOpenGLShader *m_shader;
QOpenGLTexture *m_texture;
};
MyGLWidget::MyGLWidget()
: m_program(0), m_shader(0), m_texture(0)
{
// No OpenGL resource initialization is done here.
}
MyGLWidget::~MyGLWidget()
{
// Make sure the context is current and then explicitly
// destroy all underlying OpenGL resources.
makeCurrent();
delete m_texture;
delete m_shader;
delete m_program;
m_vbo.destroy();
m_vao.destroy();
doneCurrent();
}
void MyGLWidget::initializeGL()
{
m_vao.create();
if (m_vao.isCreated())
m_vao.bind();
m_vbo.create();
m_vbo.bind();
m_vbo.allocate(...);
m_texture = new QOpenGLTexture(QImage(...));
m_shader = new QOpenGLShader(...);
m_program = new QOpenGLShaderProgram(...);
...
}
//! [4]
//! [5]
MyGLWidget::~MyGLWidget()
{
cleanup();
}
void MyGLWidget::initializeGL()
{
...
connect(context(), &QOpenGLContext::aboutToBeDestroyed, this, &MyGLWidget::cleanup);
}
void MyGLWidget::cleanup()
{
makeCurrent();
delete m_texture;
m_texture = 0;
...
doneCurrent();
disconnect(context(), &QOpenGLContext::aboutToBeDestroyed, this, &MyGLWidget::cleanup);
}
//! [5]
//! [6]
int main(int argc, char **argv)
{
QApplication app(argc, argv);
QSurfaceFormat format;
format.setDepthBufferSize(24);
format.setStencilBufferSize(8);
format.setVersion(3, 2);
format.setProfile(QSurfaceFormat::CoreProfile);
QSurfaceFormat::setDefaultFormat(format);
MyWidget widget;
widget.show();
return app.exec();
}
//! [6]
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