4 files changed, 97 insertions, 6 deletions

diff --git a/src/plugins/platforms/xcb/qglxintegration.cpp b/src/plugins/platforms/xcb/qglxintegration.cpp
index 23bec15b48..5e2731430d 100644
--- a/src/plugins/platforms/xcb/qglxintegration.cpp
+++ b/src/plugins/platforms/xcb/qglxintegration.cpp
@@ -50,6 +50,7 @@
 #include <GL/glx.h>
 
 #include <QtGui/QOpenGLContext>
+#include <QtGui/QOffscreenSurface>
 
 #include "qglxintegration.h"
 #include <QtPlatformSupport/private/qglxconvenience_p.h>
@@ -270,6 +271,7 @@ QGLXContext::QGLXContext(QXcbScreen *screen, const QSurfaceFormat &format, QPlat
     , m_screen(screen)
     , m_context(0)
     , m_format(format)
+    , m_isPBufferCurrent(false)
 {
     m_shareContext = 0;
     if (share)
@@ -390,19 +392,35 @@ bool QGLXContext::makeCurrent(QPlatformSurface *surface)
 {
     Q_ASSERT(surface->surface()->surfaceType() == QSurface::OpenGLSurface);
 
-    GLXDrawable glxDrawable = static_cast<QXcbWindow *>(surface)->xcb_window();
-
-    return glXMakeCurrent(DISPLAY_FROM_XCB(m_screen), glxDrawable, m_context);
+    QSurface::SurfaceClass surfaceClass = surface->surface()->surfaceClass();
+    if (surfaceClass == QSurface::Window) {
+        m_isPBufferCurrent = false;
+        QXcbWindow *window = static_cast<QXcbWindow *>(surface);
+        return glXMakeCurrent(DISPLAY_FROM_XCB(m_screen), window->xcb_window(), m_context);
+    } else if (surfaceClass == QSurface::Offscreen) {
+        m_isPBufferCurrent = true;
+        QGLXPbuffer *pbuffer = static_cast<QGLXPbuffer *>(surface);
+        return glXMakeContextCurrent(DISPLAY_FROM_XCB(m_screen), pbuffer->pbuffer(), pbuffer->pbuffer(), m_context);
+    }
+    return false;
 }
 
 void QGLXContext::doneCurrent()
 {
-    glXMakeCurrent(DISPLAY_FROM_XCB(m_screen), 0, 0);
+    if (m_isPBufferCurrent)
+        glXMakeContextCurrent(DISPLAY_FROM_XCB(m_screen), 0, 0, 0);
+    else
+        glXMakeCurrent(DISPLAY_FROM_XCB(m_screen), 0, 0);
+    m_isPBufferCurrent = false;
 }
 
 void QGLXContext::swapBuffers(QPlatformSurface *surface)
 {
-    GLXDrawable glxDrawable = static_cast<QXcbWindow *>(surface)->xcb_window();
+    GLXDrawable glxDrawable = 0;
+    if (surface->surface()->surfaceClass() == QSurface::Offscreen)
+        glxDrawable = static_cast<QGLXPbuffer *>(surface)->pbuffer();
+    else
+        glxDrawable = static_cast<QXcbWindow *>(surface)->xcb_window();
     glXSwapBuffers(DISPLAY_FROM_XCB(m_screen), glxDrawable);
 }
 
@@ -454,4 +472,36 @@ bool QGLXContext::isValid() const
     return m_context != 0;
 }
 
+
+QGLXPbuffer::QGLXPbuffer(QOffscreenSurface *offscreenSurface)
+    : QPlatformOffscreenSurface(offscreenSurface)
+    , m_format(offscreenSurface->requestedFormat())
+    , m_screen(static_cast<QXcbScreen *>(offscreenSurface->screen()->handle()))
+    , m_pbuffer(0)
+{
+    GLXFBConfig config = qglx_findConfig(DISPLAY_FROM_XCB(m_screen), m_screen->screenNumber(), m_format);
+
+    if (config) {
+        const int attributes[] = {
+            GLX_PBUFFER_WIDTH, offscreenSurface->size().width(),
+            GLX_PBUFFER_HEIGHT, offscreenSurface->size().height(),
+            GLX_LARGEST_PBUFFER, False,
+            GLX_PRESERVED_CONTENTS, False,
+            GLX_NONE
+        };
+
+        m_pbuffer = glXCreatePbuffer(DISPLAY_FROM_XCB(m_screen), config, attributes);
+
+        if (m_pbuffer)
+            m_format = qglx_surfaceFormatFromGLXFBConfig(DISPLAY_FROM_XCB(m_screen), config);
+    }
+}
+
+QGLXPbuffer::~QGLXPbuffer()
+{
+    if (m_pbuffer)
+        glXDestroyPbuffer(DISPLAY_FROM_XCB(m_screen), m_pbuffer);
+}
+
+
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/xcb/qglxintegration.h b/src/plugins/platforms/xcb/qglxintegration.h
index 78e9985334..d10b1d441b 100644
--- a/src/plugins/platforms/xcb/qglxintegration.h
+++ b/src/plugins/platforms/xcb/qglxintegration.h
@@ -46,6 +46,7 @@
 #include "qxcbscreen.h"
 
 #include <qpa/qplatformopenglcontext.h>
+#include <qpa/qplatformoffscreensurface.h>
 #include <QtGui/QSurfaceFormat>
 
 #include <QtCore/QMutex>
@@ -89,6 +90,25 @@ private:
     GLXContext m_context;
     GLXContext m_shareContext;
     QSurfaceFormat m_format;
+    bool m_isPBufferCurrent;
+};
+
+
+class QGLXPbuffer : public QPlatformOffscreenSurface
+{
+public:
+    explicit QGLXPbuffer(QOffscreenSurface *offscreenSurface);
+    ~QGLXPbuffer();
+
+    QSurfaceFormat format() const { return m_format; }
+    bool isValid() const { return m_pbuffer != 0; }
+
+    GLXPbuffer pbuffer() const { return m_pbuffer; }
+
+private:
+    QSurfaceFormat m_format;
+    QXcbScreen *m_screen;
+    GLXPbuffer m_pbuffer;
 };
 
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/xcb/qxcbintegration.cpp b/src/plugins/platforms/xcb/qxcbintegration.cpp
index 1840dd1ce5..d0b0ab8d02 100644
--- a/src/plugins/platforms/xcb/qxcbintegration.cpp
+++ b/src/plugins/platforms/xcb/qxcbintegration.cpp
@@ -78,10 +78,12 @@
 #elif defined(XCB_USE_EGL)
 #include "qxcbeglsurface.h"
 #include <QtPlatformSupport/private/qeglplatformcontext_p.h>
+#include <QtPlatformSupport/private/qeglpbuffer_p.h>
 #endif
 
 #include <QtGui/QOpenGLContext>
 #include <QtGui/QScreen>
+#include <QtGui/QOffscreenSurface>
 #ifndef QT_NO_ACCESSIBILITY
 #include <qpa/qplatformaccessibility.h>
 #ifndef QT_NO_ACCESSIBILITY_ATSPI_BRIDGE
@@ -168,7 +170,10 @@ public:
 
     EGLSurface eglSurfaceForPlatformSurface(QPlatformSurface *surface)
     {
-        return static_cast<QXcbWindow *>(surface)->eglSurface()->surface();
+        if (surface->surface()->surfaceClass() == QSurface::Window)
+            return static_cast<QXcbWindow *>(surface)->eglSurface()->surface();
+        else
+            return static_cast<QEGLPbuffer *>(surface)->pbuffer();
     }
 
 private:
@@ -205,6 +210,20 @@ QPlatformBackingStore *QXcbIntegration::createPlatformBackingStore(QWindow *wind
     return new QXcbBackingStore(window);
 }
 
+QPlatformOffscreenSurface *QXcbIntegration::createPlatformOffscreenSurface(QOffscreenSurface *surface) const
+{
+#if defined(XCB_USE_GLX)
+    return new QGLXPbuffer(surface);
+#elif defined(XCB_USE_EGL)
+    QXcbScreen *screen = static_cast<QXcbScreen *>(surface->screen()->handle());
+    return new QEGLPbuffer(screen->connection()->egl_display(), surface->requestedFormat(), surface);
+#else
+    Q_UNUSED(surface);
+    qWarning("QXcbIntegration: Cannot create platform offscreen surface, neither GLX nor EGL are enabled");
+    return 0;
+#endif
+}
+
 bool QXcbIntegration::hasCapability(QPlatformIntegration::Capability cap) const
 {
     switch (cap) {
diff --git a/src/plugins/platforms/xcb/qxcbintegration.h b/src/plugins/platforms/xcb/qxcbintegration.h
index cd6c2fd73c..13b3b115ca 100644
--- a/src/plugins/platforms/xcb/qxcbintegration.h
+++ b/src/plugins/platforms/xcb/qxcbintegration.h
@@ -68,6 +68,8 @@ public:
 #endif
     QPlatformBackingStore *createPlatformBackingStore(QWindow *window) const;
 
+    QPlatformOffscreenSurface *createPlatformOffscreenSurface(QOffscreenSurface *surface) const;
+
     bool hasCapability(Capability cap) const;
     QAbstractEventDispatcher *guiThreadEventDispatcher() const;