Long live Qt!

1 files changed, 132 insertions, 0 deletions

diff --git a/doc/src/snippets/code/src_opengl_qgl.cpp b/doc/src/snippets/code/src_opengl_qgl.cpp
new file mode 100644
index 0000000..15b0005
--- /dev/null
+++ b/doc/src/snippets/code/src_opengl_qgl.cpp
@@ -0,0 +1,132 @@
+//! [0]
+QGLFormat fmt;
+fmt.setAlpha(true);
+fmt.setStereo(true);
+QGLFormat::setDefaultFormat(fmt);
+//! [0]
+
+
+//! [1]
+QGLFormat fmt;
+fmt.setDoubleBuffer(false);                 // single buffer
+fmt.setDirectRendering(false);              // software rendering
+MyGLWidget* myWidget = new MyGLWidget(fmt, ...);
+//! [1]
+
+
+//! [2]
+QGLFormat fmt;
+fmt.setOverlay(true);
+fmt.setStereo(true);
+MyGLWidget* myWidget = new MyGLWidget(fmt, ...);
+if (!myWidget->format().stereo()) {
+    // ok, goggles off
+    if (!myWidget->format().hasOverlay()) {
+        qFatal("Cool hardware required");
+    }
+}
+//! [2]
+
+
+//! [3]
+// The rendering in MyGLWidget depends on using
+// stencil buffer and alpha channel
+MyGLWidget::MyGLWidget(QWidget* parent)
+    : QGLWidget(QGLFormat(QGL::StencilBuffer | QGL::AlphaChannel), parent)
+{
+    if (!format().stencil())
+        qWarning("Could not get stencil buffer; results will be suboptimal");
+    if (!format().alpha())
+        qWarning("Could not get alpha channel; results will be suboptimal");
+    ...
+}
+//! [3]
+
+
+//! [4]
+QApplication a(argc, argv);
+QGLFormat f;
+f.setDoubleBuffer(false);
+QGLFormat::setDefaultFormat(f);
+//! [4]
+
+
+//! [5]
+QGLFormat f = QGLFormat::defaultOverlayFormat();
+f.setDoubleBuffer(true);
+QGLFormat::setDefaultOverlayFormat(f);
+//! [5]
+
+
+//! [6]
+// ...continued from above
+MyGLWidget* myWidget = new MyGLWidget(QGLFormat(QGL::HasOverlay), ...);
+if (myWidget->format().hasOverlay()) {
+    // Yes, we got an overlay, let's check _its_ format:
+    QGLContext* olContext = myWidget->overlayContext();
+    if (olContext->format().doubleBuffer())
+        ; // yes, we got a double buffered overlay
+    else
+        ; // no, only single buffered overlays are available
+}
+//! [6]
+
+
+//! [7]
+QGLContext *cx;
+//  ...
+QGLFormat f;
+f.setStereo(true);
+cx->setFormat(f);
+if (!cx->create())
+    exit(); // no OpenGL support, or cannot render on the specified paintdevice
+if (!cx->format().stereo())
+    exit(); // could not create stereo context
+//! [7]
+
+
+//! [8]
+class MyGLDrawer : public QGLWidget
+{
+    Q_OBJECT        // must include this if you use Qt signals/slots
+
+public:
+    MyGLDrawer(QWidget *parent)
+        : QGLWidget(parent) {}
+
+protected:
+
+    void initializeGL()
+    {
+        // Set up the rendering context, define display lists etc.:
+        ...
+        glClearColor(0.0, 0.0, 0.0, 0.0);
+        glEnable(GL_DEPTH_TEST);
+        ...
+    }
+
+    void resizeGL(int w, int h)
+    {
+        // setup viewport, projection etc.:
+        glViewport(0, 0, (GLint)w, (GLint)h);
+        ...
+        glFrustum(...);
+        ...
+    }
+
+    void paintGL()
+    {
+        // draw the scene:
+        ...
+        glRotatef(...);
+        glMaterialfv(...);
+        glBegin(GL_QUADS);
+        glVertex3f(...);
+        glVertex3f(...);
+        ...
+        glEnd();
+        ...
+    }
+
+};
+//! [8]