qt-everywhere-src-5.15.1/qtbase/examples/opengl/qopenglwindow/background_renderer.h

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#ifndef FRAGMENT_TOY_H
#define FRAGMENT_TOY_H

#include <QObject>
#include <QFile>
#include <QDateTime>
#if QT_CONFIG(filesystemwatcher)
#include <QFileSystemWatcher>
#endif
#include <QOpenGLVertexArrayObject>
#include <QOpenGLBuffer>
#include <QOpenGLShaderProgram>
#include <QOpenGLFunctions>

#include <memory>

class FragmentToy : public QObject, protected QOpenGLFunctions
{
    Q_OBJECT
public:
    explicit FragmentToy(const QString &fragmentSource, QObject *parent = nullptr);
    ~FragmentToy();

    void draw(const QSize &windowSize);

private:
    void fileChanged(const QString &path);
    bool m_recompile_shaders;
#if QT_CONFIG(filesystemwatcher)
    QFileSystemWatcher m_watcher;
#endif
    QString m_fragment_file;
    QDateTime m_fragment_file_last_modified;

    std::unique_ptr<QOpenGLShaderProgram> m_program;
    std::unique_ptr<QOpenGLShader> m_vertex_shader;
    std::unique_ptr<QOpenGLShader> m_fragment_shader;
    QOpenGLVertexArrayObject m_vao;
    QOpenGLBuffer m_vertex_buffer;
    GLuint m_vertex_coord_pos;
};

#endif //FRAGMENT_TOY_H