Modernize the OpenGL examples

Change them to use QOpenGLWidget and QOpenGLTexture.
Advocate also the usage of VBOs.

Hopeless examples, that rely on the fixed pipeline and will
not compile or work in ES and dynamic builds, are moved to
a "legacy" directory. The documentation pages for these are
removed. This long due change avoids the confusion newcomers
experience when trying to get started with Qt 5 and OpenGL.

hellowindow's behavior is changed to open a single window only
by default. The old default behavior, that opened three windows
on platforms that supported both MultipleWindows & ThreadedOpenGL,
can be requested by passing --multiple. --single is removed since it
is the default now. This plays much nicer with drivers that have
issues with threading.

In addition, say hello to hellogl2.

This is the old hellogl example updated to use QOpenGLWidget and
OpenGL 2. It also has a mainwindow with multiple (un)dockable widgets
containing the OpenGL widgets. This helps testing the behavior when
the top-level of the QOpenGLWidget changes and provides a very
important example of how to do proper resource management in this case.
(must use aboutToBeDestroyed() of the context, since the context goes
away and is replaced by a new one on every dock/undock)

As a bonus, the logo is now real 3D, no more orthographic nonsense.

Launch with --multisample to request 4x MSAA.

Launch with --coreprofile to request 3.2 Core. In this particular example
the shaders are present in both versions and there is a VAO so the application
is functional with core profile contexts.

Change-Id: Id780a80cb0708ef164cc172450ed74050f065596
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>

1 files changed, 2 insertions, 14 deletions

diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 1ca9f83501..10ba8ac2ee 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -219,8 +219,6 @@ QGLSignalProxy *QGLSignalProxy::instance()
     \value NoDeprecatedFunctions    Disables the use of deprecated functionality for OpenGL 3.x
                                     contexts. A context with deprecated functionality disabled is
                                     called a forward compatible context in the OpenGL specification.
-
-    \sa {Sample Buffers Example}
 */
 
 /*****************************************************************************
@@ -3276,8 +3274,7 @@ uint QGLContext::colorIndex(const QColor&) const
     The returned QColor object will generally work as expected only
     when passed as the argument to QGLWidget::qglColor() or
     QGLWidget::qglClearColor(). Under certain circumstances it can
-    also be used to draw transparent graphics with a QPainter. See the
-    examples/opengl/overlay_x11 example for details.
+    also be used to draw transparent graphics with a QPainter.
 */
 QColor QGLContext::overlayTransparentColor() const
 {
@@ -3717,10 +3714,6 @@ void QGLContext::doneCurrent()
     \li Call QPainter::end() to finish painting.
     \endlist
 
-    Overpainting 2D content on top of 3D content takes a little more effort.
-    One approach to doing this is shown in the
-    \l{Overpainting Example}{Overpainting} example.
-
     \section1 Threading
 
     As of Qt version 4.8, support for doing threaded GL rendering has
@@ -3814,8 +3807,7 @@ void QGLContext::doneCurrent()
     \e{OpenGL is a trademark of Silicon Graphics, Inc. in the United States and other
     countries.}
 
-    \sa QOpenGLWidget, QGLPixelBuffer, {Hello GL Example}, {2D Painting Example}, {Overpainting Example},
-        {Grabber Example}
+    \sa QOpenGLWidget, QGLPixelBuffer
 */
 
 /*!
@@ -4776,8 +4768,6 @@ static void qt_gl_draw_text(QPainter *p, int x, int y, const QString &str,
    \note This function can only be used inside a
    QPainter::beginNativePainting()/QPainter::endNativePainting() block
    if a painter is active on the QGLWidget.
-
-   \l{Overpainting Example}{Overpaint} with QPainter::drawText() instead.
 */
 
 void QGLWidget::renderText(int x, int y, const QString &str, const QFont &font)
@@ -4868,8 +4858,6 @@ void QGLWidget::renderText(int x, int y, const QString &str, const QFont &font)
     \note This function can only be used inside a
     QPainter::beginNativePainting()/QPainter::endNativePainting() block
     if a painter is active on the QGLWidget.
-
-    \l{Overpainting Example}{Overpaint} with QPainter::drawText() instead.
 */
 void QGLWidget::renderText(double x, double y, double z, const QString &str, const QFont &font)
 {