Fall back on glXChooseVisual() if glXChooseFBConfig() doesn't work.

Some older drivers don't fully support glXChooseFBConfig(). As a bonus,
fix some memory leaks here and there.

Task-number: QTBUG-21880
Change-Id: Ie306dee27f616927a6aa55fd71601569b828afcc
Reviewed-by: Uli Schlachter <psychon@znc.in>
Reviewed-by: Jørgen Lind <jorgen.lind@nokia.com>

2 files changed, 30 insertions, 19 deletions

diff --git a/src/plugins/platforms/xlib/qglxintegration.cpp b/src/plugins/platforms/xlib/qglxintegration.cpp
index 875e166672..80ea371eab 100644
--- a/src/plugins/platforms/xlib/qglxintegration.cpp
+++ b/src/plugins/platforms/xlib/qglxintegration.cpp
@@ -70,9 +70,19 @@ QGLXContext::QGLXContext(QXlibScreen *screen, const QSurfaceFormat &format, QPla
     if (share)
         shareGlxContext = static_cast<const QGLXContext*>(share)->glxContext();
 
-    GLXFBConfig config = qglx_findConfig(screen->display()->nativeDisplay(),screen->xScreenNumber(),format);
-    m_context = glXCreateNewContext(screen->display()->nativeDisplay(),config,GLX_RGBA_TYPE,shareGlxContext,TRUE);
-    m_windowFormat = qglx_surfaceFormatFromGLXFBConfig(screen->display()->nativeDisplay(),config,m_context);
+    Display *xDisplay = screen->display()->nativeDisplay();
+
+    GLXFBConfig config = qglx_findConfig(xDisplay,screen->xScreenNumber(),format);
+    if (config) {
+        m_context = glXCreateNewContext(xDisplay,config,GLX_RGBA_TYPE,shareGlxContext,TRUE);
+        m_windowFormat = qglx_surfaceFormatFromGLXFBConfig(xDisplay,config,m_context);
+    } else {
+        XVisualInfo *visualInfo = qglx_findVisualInfo(xDisplay, screen->xScreenNumber(), format);
+        if (!visualInfo)
+            qFatal("Could not initialize GLX");
+        m_context = glXCreateContext(xDisplay, visualInfo, shareGlxContext, true);
+        XFree(visualInfo);
+    }
 
 #ifdef MYX11_DEBUG
     qDebug() << "QGLXGLContext::create context" << m_context;
diff --git a/src/plugins/platforms/xlib/qxlibwindow.cpp b/src/plugins/platforms/xlib/qxlibwindow.cpp
index d5724d6050..6c9081c9ca 100644
--- a/src/plugins/platforms/xlib/qxlibwindow.cpp
+++ b/src/plugins/platforms/xlib/qxlibwindow.cpp
@@ -87,6 +87,8 @@ QXlibWindow::QXlibWindow(QWindow *window)
 #if !defined(QT_OPENGL_ES_2)
         XVisualInfo *visualInfo = qglx_findVisualInfo(mScreen->display()->nativeDisplay(), mScreen->xScreenNumber(),
                                                       window->format());
+        if (!visualInfo)
+            qFatal("Could not initialize GLX");
 #else
         QPlatformWindowFormat windowFormat = correctColorBuffers(window->platformWindowFormat());
 
@@ -101,23 +103,22 @@ QXlibWindow::QXlibWindow(QWindow *window)
         XVisualInfo *visualInfo;
         int matchingCount = 0;
         visualInfo = XGetVisualInfo(mScreen->display()->nativeDisplay(), VisualIDMask, &visualInfoTemplate, &matchingCount);
+        if (!visualInfo)
+            qFatal("Could not initialize EGL");
 #endif //!defined(QT_OPENGL_ES_2)
-        if (visualInfo) {
-            mDepth = visualInfo->depth;
-            mFormat = (mDepth == 32) ? QImage::Format_ARGB32_Premultiplied : QImage::Format_RGB32;
-            mVisual = visualInfo->visual;
-            Colormap cmap = XCreateColormap(mScreen->display()->nativeDisplay(), mScreen->rootWindow(), visualInfo->visual, AllocNone);
-
-            XSetWindowAttributes a;
-            a.background_pixel = WhitePixel(mScreen->display()->nativeDisplay(), mScreen->xScreenNumber());
-            a.border_pixel = BlackPixel(mScreen->display()->nativeDisplay(), mScreen->xScreenNumber());
-            a.colormap = cmap;
-            x_window = XCreateWindow(mScreen->display()->nativeDisplay(), mScreen->rootWindow(),x, y, w, h,
-                                     0, visualInfo->depth, InputOutput, visualInfo->visual,
-                                     CWBackPixel|CWBorderPixel|CWColormap, &a);
-        } else {
-            qFatal("no window!");
-        }
+        mDepth = visualInfo->depth;
+        mFormat = (mDepth == 32) ? QImage::Format_ARGB32_Premultiplied : QImage::Format_RGB32;
+        mVisual = visualInfo->visual;
+        Colormap cmap = XCreateColormap(mScreen->display()->nativeDisplay(), mScreen->rootWindow(), visualInfo->visual, AllocNone);
+
+        XSetWindowAttributes a;
+        a.background_pixel = WhitePixel(mScreen->display()->nativeDisplay(), mScreen->xScreenNumber());
+        a.border_pixel = BlackPixel(mScreen->display()->nativeDisplay(), mScreen->xScreenNumber());
+        a.colormap = cmap;
+        x_window = XCreateWindow(mScreen->display()->nativeDisplay(), mScreen->rootWindow(),x, y, w, h,
+                                 0, visualInfo->depth, InputOutput, visualInfo->visual,
+                                 CWBackPixel|CWBorderPixel|CWColormap, &a);
+        XFree(visualInfo);
     } else
 #endif //!defined(QT_NO_OPENGL)
     {