OpenGL: Allow querying OpenGL extensions via the QOpenGLContext

Change-Id: Ia88470554bbfd2a56738dadfcafafe42a990382d
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

src/gui/kernel/qopenglcontext.cpp

@@ -49,6 +49,7 @@
 #include <QtCore/QThread>
 
 #include <QtGui/private/qguiapplication_p.h>
+#include <QtGui/private/qopengl_p.h>
 #include <QtGui/private/qwindow_p.h>
 #include <QtGui/QScreen>
 
@@ -401,6 +402,37 @@ QOpenGLFunctions *QOpenGLContext::functions() const
     return d->functions;
 }
 
+/*!
+    Returns the set of OpenGL extensions supported by this context.
+
+    The context or a sharing context must be current.
+
+    \sa hasExtension()
+*/
+QSet<QByteArray> QOpenGLContext::extensions() const
+{
+    Q_D(const QOpenGLContext);
+    if (d->extensionNames.isEmpty()) {
+        QOpenGLExtensionMatcher matcher;
+        d->extensionNames = matcher.extensions();
+    }
+
+    return d->extensionNames;
+}
+
+/*!
+    Returns true if this OpenGL context supports the specified OpenGL
+    \a extension, false otherwise.
+
+    The context or a sharing context must be current.
+
+    \sa extensions()
+*/
+bool QOpenGLContext::hasExtension(const QByteArray &extension) const
+{
+    return extensions().contains(extension);
+}
+
 /*!
     Call this to get the default framebuffer object for the current surface.
 

src/gui/kernel/qopenglcontext.h

@@ -129,6 +129,9 @@ public:
 
     QOpenGLFunctions *functions() const;
 
+    QSet<QByteArray> extensions() const;
+    bool hasExtension(const QByteArray &extension) const;
+
 Q_SIGNALS:
     void aboutToBeDestroyed();
 

src/gui/kernel/qopenglcontext_p.h

@@ -49,7 +49,9 @@
 #include <private/qobject_p.h>
 #include <qmutex.h>
 
+#include <QtCore/QByteArray>
 #include <QtCore/QHash>
+#include <QtCore/QSet>
 
 QT_BEGIN_HEADER
 
@@ -212,6 +214,7 @@ public:
     QScreen *screen;
     QSurface *surface;
     QOpenGLFunctions *functions;
+    mutable QSet<QByteArray> extensionNames;
 
     GLuint current_fbo;
     GLint max_texture_size;