Added explicit threading API to QtOpenGL.

Since QtOpenGL/QGLContext is implemented in terms of
QtGui/QOpenGLContext which has stricter requirements about how it's
supposed to be used, we need to apply these requirements to QGLContext
as well.

This change adds QGLContext::moveToThread(QThread *) and documents it as
a necessity for making a context current on another thread.

Also introduces QGLPixelbuffer::context() to access the QGLContext of a
pixelbuffer, and made QGLWidget::context() return a non-const
QGLContext, since there's no good reason why it shouldn't, and it leads
to less const_cast clutter.

We could have introduced a backdoor in QOpenGLContext instead, making it
loosen its requirements, but that would have made it harder / impossible
to fully support threaded OpenGL in all the platforms.

Task-number: QTBUG-22560
Change-Id: Ibb6f65f342e7c963e80cc42ab5664c5f1cab30b0
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/opengl/qgl.h b/src/opengl/qgl.h
index ab2fd8d203..1d21b42cd5 100644
--- a/src/opengl/qgl.h
+++ b/src/opengl/qgl.h
@@ -281,6 +281,8 @@ public:
     QGLFormat requestedFormat() const;
     void setFormat(const QGLFormat& format);
 
+    void moveToThread(QThread *thread);
+
     virtual void makeCurrent();
     virtual void doneCurrent();
 
@@ -413,7 +415,7 @@ public:
     QGLFormat format() const;
     void setFormat(const QGLFormat& format);
 
-    const QGLContext* context() const;
+    QGLContext* context() const;
     void setContext(QGLContext* context, const QGLContext* shareContext = 0,
                     bool deleteOldContext = true);