Made xcb plugin work when the GLX extension is not present.

Change-Id: I9285d7524586ff404206c088019ece33335137d9
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

config.tests/qpa/xcb-glx/xcb-glx.cpp

@@ -0,0 +1,57 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the config.tests of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <xcb/xcb.h>
+#include <xcb/glx.h>
+
+int main(int, char **)
+{
+    int primaryScreen = 0;
+
+    xcb_connection_t *connection = xcb_connect("", &primaryScreen);
+    xcb_generic_error_t *error = 0;
+    xcb_glx_query_version_cookie_t xglx_query_cookie = xcb_glx_query_version(connection,
+                                                                             XCB_GLX_MAJOR_VERSION,
+                                                                             XCB_GLX_MINOR_VERSION);
+    xcb_glx_query_version_reply(connection, xglx_query_cookie, &error);
+
+    return 0;
+}

config.tests/qpa/xcb-glx/xcb-glx.pro

@@ -0,0 +1,5 @@
+SOURCES = xcb-glx.cpp
+CONFIG -= qt
+
+LIBS += -lxcb -lxcb-glx
+

configure

@@ -801,6 +801,7 @@ CFG_XINPUT2=auto
 CFG_XINPUT=runtime
 CFG_XKB=auto
 CFG_XCB=auto
+CFG_XCB_GLX=no
 CFG_XCB_LIMITED=yes
 CFG_EGLFS=auto
 CFG_DIRECTFB=auto
@@ -4790,6 +4791,11 @@ if [ "$CFG_XCB" != "no" ]; then
             QT_CONFIG="$QT_CONFIG xcb-render"
         fi
 
+        if compileTest qpa/xcb-glx "xcb-glx" $QMAKE_CFLAGS_XCB $QMAKE_LIBS_XCB; then
+            CFG_XCB_GLX=yes
+            QT_CONFIG="$QT_CONFIG xcb-glx"
+        fi
+
         if compileTest qpa/xcb-poll-for-queued-event "xcb-poll-for-queued-event" $QMAKE_CFLAGS_XCB $QMAKE_LIBS_XCB; then
             CFG_XCB_LIMITED=no
             QT_CONFIG="$QT_CONFIG xcb-poll-for-queued-event"

src/plugins/platforms/xcb/README

@@ -1,14 +1,14 @@
 Requires libxcb >= 1.5.
 
 Required packages:
-libxcb1 libxcb1-dev libx11-xcb1 libx11-xcb-dev libxcb-keysyms1 libxcb-keysyms1-dev libxcb-image0 libxcb-image0-dev libxcb-shm0 libxcb-shm0-dev libxcb-icccm1 libxcb-icccm1-dev libxcb-sync0 libxcb-sync0-dev libxcb-render-util0 libxcb-render-util0-dev libxcb-xfixes0-dev libxrender-dev libxcb-shape0-dev libxcb-randr0-dev
+libxcb1 libxcb1-dev libx11-xcb1 libx11-xcb-dev libxcb-keysyms1 libxcb-keysyms1-dev libxcb-image0 libxcb-image0-dev libxcb-shm0 libxcb-shm0-dev libxcb-icccm1 libxcb-icccm1-dev libxcb-sync0 libxcb-sync0-dev libxcb-render-util0 libxcb-render-util0-dev libxcb-xfixes0-dev libxrender-dev libxcb-shape0-dev libxcb-randr0-dev libxcb-glx0-dev
 
 On Ubuntu 11.10 icccm1 is replaced by icccm4 and xcb-render-util is not available:
-libxcb1 libxcb1-dev libx11-xcb1 libx11-xcb-dev libxcb-keysyms1 libxcb-keysyms1-dev libxcb-image0 libxcb-image0-dev libxcb-shm0 libxcb-shm0-dev libxcb-icccm4 libxcb-icccm4-dev libxcb-sync0 libxcb-sync0-dev libxcb-xfixes0-dev libxrender-dev libxcb-shape0-dev libxcb-randr0-dev
+libxcb1 libxcb1-dev libx11-xcb1 libx11-xcb-dev libxcb-keysyms1 libxcb-keysyms1-dev libxcb-image0 libxcb-image0-dev libxcb-shm0 libxcb-shm0-dev libxcb-icccm4 libxcb-icccm4-dev libxcb-sync0 libxcb-sync0-dev libxcb-xfixes0-dev libxrender-dev libxcb-shape0-dev libxcb-randr0-dev libxcb-glx0-dev
 The packages for xcb-render-util can be installed manually from http://packages.ubuntu.com/natty/libxcb-render-util0 and http://packages.ubuntu.com/natty/libxcb-render-util0-dev
 
 On Ubuntu 12.04 icccm1 is replaced by icccm4 and xcb-render-util can be installed automatically:
-libxcb1 libxcb1-dev libx11-xcb1 libx11-xcb-dev libxcb-keysyms1 libxcb-keysyms1-dev libxcb-image0 libxcb-image0-dev libxcb-shm0 libxcb-shm0-dev libxcb-icccm4 libxcb-icccm4-dev libxcb-sync0 libxcb-sync0-dev libxcb-xfixes0-dev libxrender-dev libxcb-shape0-dev libxcb-randr0-dev libxcb-render-util0 libxcb-render-util0-dev
+libxcb1 libxcb1-dev libx11-xcb1 libx11-xcb-dev libxcb-keysyms1 libxcb-keysyms1-dev libxcb-image0 libxcb-image0-dev libxcb-shm0 libxcb-shm0-dev libxcb-icccm4 libxcb-icccm4-dev libxcb-sync0 libxcb-sync0-dev libxcb-xfixes0-dev libxrender-dev libxcb-shape0-dev libxcb-randr0-dev libxcb-render-util0 libxcb-render-util0-dev libxcb-glx0-dev
 
 
 On Fedora, the following packages are required:

src/plugins/platforms/xcb/qxcbconnection.cpp

@@ -72,6 +72,10 @@
 #include <xcb/render.h>
 #endif
 
+#if defined(XCB_HAS_XCB_GLX)
+#include <xcb/glx.h>
+#endif
+
 #ifdef XCB_USE_EGL //don't pull in eglext prototypes
 #include <EGL/egl.h>
 #endif
@@ -263,6 +267,7 @@ QXcbConnection::QXcbConnection(QXcbNativeInterface *nativeInterface, const char
 #endif
     , xfixes_first_event(0)
     , xrandr_first_event(0)
+    , has_glx_extension(false)
     , has_shape_extension(false)
     , has_randr_extension(false)
     , has_input_shape(false)
@@ -320,6 +325,7 @@ QXcbConnection::QXcbConnection(QXcbNativeInterface *nativeInterface, const char
                       0, 0, 1, 1, 0, XCB_WINDOW_CLASS_INPUT_ONLY,
                       m_screens.at(0)->screen()->root_visual, 0, 0);
 
+    initializeGLX();
     initializeXFixes();
     initializeXRender();
     m_xi2Enabled = false;
@@ -1312,6 +1318,33 @@ void QXcbConnection::initializeXRender()
 #endif
 }
 
+void QXcbConnection::initializeGLX()
+{
+#ifdef XCB_HAS_XCB_GLX
+    const xcb_query_extension_reply_t *reply = xcb_get_extension_data(m_connection, &xcb_glx_id);
+    if (!reply || !reply->present)
+        return;
+
+    has_glx_extension = true;
+
+    xcb_generic_error_t *error = 0;
+    xcb_glx_query_version_cookie_t xglx_query_cookie = xcb_glx_query_version(m_connection,
+                                                                             XCB_GLX_MAJOR_VERSION,
+                                                                             XCB_GLX_MINOR_VERSION);
+    xcb_glx_query_version_reply_t *xglx_query = xcb_glx_query_version_reply(m_connection,
+                                                                            xglx_query_cookie, &error);
+    if (!xglx_query || error) {
+        qWarning("QXcbConnection: Failed to initialize GLX");
+        free(error);
+        has_glx_extension = false;
+    }
+    free(xglx_query);
+#else
+    // no way to check, assume GLX is present
+    has_glx_extension = true;
+#endif
+}
+
 void QXcbConnection::initializeXRandr()
 {
     const xcb_query_extension_reply_t *reply = xcb_get_extension_data(m_connection, &xcb_randr_id);

src/plugins/platforms/xcb/qxcbconnection.h

@@ -374,6 +374,7 @@ public:
     inline xcb_timestamp_t time() const { return m_time; }
     inline void setTime(xcb_timestamp_t t) { if (t > m_time) m_time = t; }
 
+    bool hasGLX() const { return has_glx_extension; }
     bool hasXFixes() const { return xfixes_first_event > 0; }
     bool hasXShape() const { return has_shape_extension; }
     bool hasXRandr() const { return has_randr_extension; }
@@ -387,6 +388,7 @@ private slots:
 private:
     void initializeAllAtoms();
     void sendConnectionEvent(QXcbAtom::Atom atom, uint id = 0);
+    void initializeGLX();
     void initializeXFixes();
     void initializeXRender();
     void initializeXRandr();
@@ -507,6 +509,7 @@ private:
     uint32_t xfixes_first_event;
     uint32_t xrandr_first_event;
 
+    bool has_glx_extension;
     bool has_shape_extension;
     bool has_randr_extension;
     bool has_input_shape;

src/plugins/platforms/xcb/qxcbintegration.cpp

@@ -192,9 +192,11 @@ QPlatformOpenGLContext *QXcbIntegration::createPlatformOpenGLContext(QOpenGLCont
         screen->connection()->egl_display(), screen->connection());
 #elif defined(XCB_USE_DRI2)
     return new QDri2Context(context->format(), context->shareHandle());
-#endif
+#else
+    Q_UNUSED(screen);
     qWarning("QXcbIntegration: Cannot create platform OpenGL context, none of GLX, EGL, or DRI2 are enabled");
     return 0;
+#endif
 }
 #endif
 
@@ -207,7 +209,13 @@ bool QXcbIntegration::hasCapability(QPlatformIntegration::Capability cap) const
 {
     switch (cap) {
     case ThreadedPixmaps: return true;
+#if defined(XCB_USE_GLX)
+    case OpenGL: return m_connections.at(0)->hasGLX();
+#elif defined(XCB_USE_EGL) || defined(XCB_USE_DRI2)
     case OpenGL: return true;
+#else
+    case OpenGL: return false;
+#endif
     case ThreadedOpenGL: return false;
     case WindowMasks: return true;
     default: return QPlatformIntegration::hasCapability(cap);

src/plugins/platforms/xcb/qxcbwindow.cpp

@@ -233,9 +233,7 @@ void QXcbWindow::create()
     m_format = window()->requestedFormat();
 
 #if (defined(XCB_USE_GLX) || defined(XCB_USE_EGL)) && defined(XCB_USE_XLIB)
-    if (QGuiApplicationPrivate::platformIntegration()->hasCapability(QPlatformIntegration::OpenGL)
+    if (QGuiApplicationPrivate::platformIntegration()->hasCapability(QPlatformIntegration::OpenGL)) {
-        || m_format.hasAlpha())
-    {
 #if defined(XCB_USE_GLX)
         XVisualInfo *visualInfo = qglx_findVisualInfo(DISPLAY_FROM_XCB(m_screen), m_screen->screenNumber(), &m_format);
         if (!visualInfo && window()->surfaceType() == QSurface::OpenGLSurface)

src/plugins/platforms/xcb/xcb.pro

@@ -98,6 +98,10 @@ contains(DEFINES, XCB_USE_DRI2) {
         HEADERS += qglxintegration.h
         SOURCES += qglxintegration.cpp
         LIBS += $$QMAKE_LIBS_DYNLOAD
+        contains(QT_CONFIG, xcb-glx) {
+            DEFINES += XCB_HAS_XCB_GLX
+            LIBS += -lxcb-glx
+        }
     }
 }