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50
51#include "fbitem.h"
52#include <QtGui/QOpenGLFramebufferObject>
53#include <QtGui/QOpenGLContext>
54#include <QtGui/QOpenGLFunctions>
55#include <QtCore/QDebug>
56
57#if QT_CONFIG(opengl)
58class FbRenderer : public QQuickFramebufferObject::Renderer
59{
60public:
61 FbRenderer() { }
62
63 // The lifetime of the FBO and this class depends on how QQuickWidget
64 // manages the scenegraph and context when it comes to showing and hiding
65 // the widget. The actual behavior is proven by the debug prints.
66 ~FbRenderer() override {
67 qDebug(msg: "FbRenderer destroyed");
68 }
69
70 void render() override {
71 QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions();
72 f->glClearColor(red: c, green: 0, blue: 0, alpha: 1);
73 f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
74 c += 0.01f * dir;
75 if (c >= 1.0f || c <= 0.0f)
76 dir *= -1;
77 update();
78 }
79
80 QOpenGLFramebufferObject *createFramebufferObject(const QSize &size) override {
81 qDebug() << "Creating FBO" << size;
82 QOpenGLFramebufferObjectFormat format;
83 format.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil);
84 return new QOpenGLFramebufferObject(size, format);
85 }
86
87private:
88 float c = 0;
89 int dir = 1;
90};
91#endif
92
93QQuickFramebufferObject::Renderer *FbItem::createRenderer() const
94{
95#if QT_CONFIG(opengl)
96 return new FbRenderer;
97#else
98 return nullptr;
99#endif
100}
101

source code of qtdeclarative/examples/quick/quickwidgets/quickwidget/fbitem.cpp