Qt5下OpenGL程序的新写法

2015-07-26 06:42 ⁄ 工业·编程 ⁄ 共 5345字 ⁄ 字号小中大 ⁄ 暂无评论

在Qt5中，引入了QOpenGL*系列类，以取代Qt4时代的QGL*系列类。

下面是从Qt5例子中抠出的两种OpenGL程序模板，方便参考。

第一种写法：

#ifndef TRIANGLEWINDOW_H

#define TRIANGLEWINDOW_H

#include <QWindow>

#include <QOpenGLFunctions>

class QPainter;

class QOpenGLContext;

class QOpenGLPaintDevice;

class TriangleWindow : public QWindow, protected QOpenGLFunctions

{

    Q_OBJECT

public:

    explicit TriangleWindow(QWindow *parent = 0);

    ~TriangleWindow();


    virtual void render(QPainter *);

    virtual void render();

    virtual void initialize();


public slots:

    void renderNow();

protected:

    void exposeEvent(QExposeEvent *);

    void resizeEvent(QResizeEvent *);

private:

    bool m_update_pending;

    QOpenGLContext *m_context;

    QOpenGLPaintDevice *m_device;


};

#endif // TRIANGLEWINDOW_H

实现代码如下：

#include "trianglewindow.h"

#include <QCoreApplication>

#include <QPainter>

#include <QOpenGLContext>

#include <QOpenGLPaintDevice>

TriangleWindow::TriangleWindow(QWindow *parent) :

    QWindow(parent)

, m_update_pending(false)

, m_context(0)

, m_device(0)

{

    setSurfaceType(QWindow::OpenGLSurface);

}

TriangleWindow::~TriangleWindow()

{

    delete m_device;

}

void TriangleWindow::render(QPainter *painter)

{

    Q_UNUSED(painter);

}

void TriangleWindow::render()

{

    if (!m_device)

        m_device = new QOpenGLPaintDevice;

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    m_device->setSize(size());

    QPainter painter(m_device);

    render(&painter);

}

void TriangleWindow::initialize()

{

    glClearColor(1, 0, 0, 1);

}

void TriangleWindow::renderNow()

{

    if (!isExposed())

        return;

    m_update_pending = false;

    bool needsInitialize = false;

    if (!m_context) {

        m_context = new QOpenGLContext(this);

        m_context->setFormat(requestedFormat());

        m_context->create();

        needsInitialize = true;

    }

    m_context->makeCurrent(this);

    if (needsInitialize) {

        initializeOpenGLFunctions();

        initialize();

    }

    render();

    m_context->swapBuffers(this);

}

void TriangleWindow::exposeEvent(QExposeEvent *event)

{

    Q_UNUSED(event);

    if (isExposed())

        renderNow();

}

void TriangleWindow::resizeEvent(QResizeEvent *event)

{

    Q_UNUSED(event);

    if (isExposed())

        renderNow();

}

main方法：

#include "trianglewindow.h"

#include <QGuiApplication>

int main(int argc, char **argv)

{

    QGuiApplication app(argc, argv);

    QSurfaceFormat format;

    format.setSamples(4);

    TriangleWindow window;

    window.setFormat(format);

    window.resize(640, 480);

    window.show();

    return app.exec();

}

另一种写法：

#ifndef TRIANGLEWINDOW_H

#define TRIANGLEWINDOW_H

#include <QWindow>

class QOpenGLContext;

class Renderer : public QObject

{

    Q_OBJECT

public:

    explicit Renderer(const QSurfaceFormat &format, Renderer *share = 0, QScreen *screen = 0);

    QSurfaceFormat format() const { return m_format; }

public slots:

    void render(QSurface *surface, const QColor &color, const QSize &viewSize);

private:

    void initialize();

    bool m_initialized;

    QSurfaceFormat m_format;

    QOpenGLContext *m_context;

};

class TriangleWindow : public QWindow

{

    Q_OBJECT

public:

    explicit TriangleWindow(const QSharedPointer<Renderer> &renderer);


signals:

    void needRender(QSurface *surface, const QColor &color, const QSize &viewSize);

private slots:

    void render();

protected:

    void exposeEvent(QExposeEvent *);

private:

    const QSharedPointer<Renderer> m_renderer;

};

#endif // TRIANGLEWINDOW_H

实现文件：

#include "trianglewindow.h"

#include <QOpenGLContext>

Renderer::Renderer(const QSurfaceFormat &format, Renderer *share, QScreen *screen)

    : m_initialized(false)

    , m_format(format)

{

    m_context = new QOpenGLContext(this);

    if (screen)

        m_context->setScreen(screen);

    m_context->setFormat(format);

    if (share)

        m_context->setShareContext(share->m_context);

    m_context->create();

}

TriangleWindow::TriangleWindow(const QSharedPointer<Renderer> &renderer)

    : m_renderer(renderer)

{

    setSurfaceType(QWindow::OpenGLSurface);

    setFlags(Qt::Window | Qt::WindowSystemMenuHint | Qt::WindowTitleHint | Qt::WindowMinMaxButtonsHint | Qt::WindowCloseButtonHint);

    setGeometry(QRect(10, 10, 640, 480));

    setFormat(renderer->format());

    create();

    connect(this, SIGNAL(needRender(QSurface *, const QColor &, const QSize &)),

            renderer.data(), SLOT(render(QSurface *, const QColor &, const QSize &)));

}

void TriangleWindow::exposeEvent(QExposeEvent *)

{

    render();

}

void TriangleWindow::render()

{

    if (isExposed())

        emit needRender(this, QColor(255, 0, 0), size());

}

void Renderer::render(QSurface *surface, const QColor &color, const QSize &viewSize)

{

    if (!m_context->makeCurrent(surface))

        return;

    if (!m_initialized) {

        initialize();

        m_initialized = true;

    }

    glViewport(0, 0, viewSize.width(), viewSize.height());

    glClearColor(color.redF(), color.greenF(), color.blueF(), color.alphaF());

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    m_context->swapBuffers(surface);

}

void Renderer::initialize()

{

    glClearColor(0.1f, 0.1f, 0.2f, 1.0f);

}

main方法：

#include "trianglewindow.h"

#include <QGuiApplication>

int main(int argc, char *argv[])

{

    QGuiApplication app(argc, argv);

    QSurfaceFormat format;

    format.setDepthBufferSize(16);

    format.setSamples(4);

    QSharedPointer<Renderer> renderer(new Renderer(format));

    TriangleWindow *window = new TriangleWindow(renderer);

    window->resize(640, 480);

    window->setVisible(true);

    return app.exec();

}