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, 4 insertions, 3 deletions

diff --git a/src/opengl/qglpaintdevice.cpp b/src/opengl/qglpaintdevice.cpp
index 5aa125f816..e870e45e15 100644
--- a/src/opengl/qglpaintdevice.cpp
+++ b/src/opengl/qglpaintdevice.cpp
@@ -43,6 +43,7 @@
 #include <private/qgl_p.h>
 #include <private/qglpixelbuffer_p.h>
 #include <private/qglframebufferobject_p.h>
+#include <qopenglfunctions.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -90,7 +91,7 @@ void QGLPaintDevice::beginPaint()
 
     if (m_previousFBO != m_thisFBO) {
         ctx->d_ptr->current_fbo = m_thisFBO;
-        glBindFramebuffer(GL_FRAMEBUFFER, m_thisFBO);
+        ctx->contextHandle()->functions()->glBindFramebuffer(GL_FRAMEBUFFER, m_thisFBO);
     }
 
     // Set the default fbo for the context to m_thisFBO so that
@@ -108,7 +109,7 @@ void QGLPaintDevice::ensureActiveTarget()
 
     if (ctx->d_ptr->current_fbo != m_thisFBO) {
         ctx->d_ptr->current_fbo = m_thisFBO;
-        glBindFramebuffer(GL_FRAMEBUFFER, m_thisFBO);
+        ctx->contextHandle()->functions()->glBindFramebuffer(GL_FRAMEBUFFER, m_thisFBO);
     }
 
     ctx->d_ptr->default_fbo = m_thisFBO;
@@ -120,7 +121,7 @@ void QGLPaintDevice::endPaint()
     QGLContext *ctx = context();
     if (m_previousFBO != ctx->d_func()->current_fbo) {
         ctx->d_ptr->current_fbo = m_previousFBO;
-        glBindFramebuffer(GL_FRAMEBUFFER, m_previousFBO);
+        ctx->contextHandle()->functions()->glBindFramebuffer(GL_FRAMEBUFFER, m_previousFBO);
     }
 
     ctx->d_ptr->default_fbo = 0;