From 67d27a20a0b0722ec2f211f1a9454a038f0db01e Mon Sep 17 00:00:00 2001
From: vsv <vitaly.smetannikov@opencascade.com>
Date: Mon, 14 Apr 2014 10:50:57 +0400
Subject: [PATCH] Use visual Id on Linux

---
 src/XGUI/XGUI_Main.cpp | 73 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/src/XGUI/XGUI_Main.cpp b/src/XGUI/XGUI_Main.cpp
index f851637d6..26f8d58fd 100644
--- a/src/XGUI/XGUI_Main.cpp
+++ b/src/XGUI/XGUI_Main.cpp
@@ -2,9 +2,82 @@
 #include <QApplication>
 #include <QTranslator>
 
+#ifndef WIN32
+
+#include <X11/Xlib.h>
+#include <GL/glx.h>
+
+/*!
+  \brief Open the default X display and returns pointer to it.
+         This method is available on Linux only.
+  \return Pointer to X display.
+  \sa getVisual()
+*/
+void* getDisplay()
+{
+  static Display* pDisplay = NULL;
+  if ( !pDisplay )
+    pDisplay = XOpenDisplay( NULL );
+  return pDisplay;
+}
+
+/*!
+  \brief Returns pointer to X visual suitable for 3D rendering.
+         This method is available on Linux only.
+  \return Pointer to X visual.
+  \sa getDisplay()
+*/
+Qt::HANDLE getVisual()
+{
+  Qt::HANDLE res = (Qt::HANDLE)NULL;
+
+  Display* pDisplay = (Display*)getDisplay();
+  if ( !pDisplay )
+    return res;
+
+  int errorBase;
+  int eventBase;
+
+  // Make sure OpenGL's GLX extension supported
+  if( !glXQueryExtension( pDisplay, &errorBase, &eventBase ) ){
+    qCritical( "Could not find glx extension" );
+    return res;
+  }
+
+  // Find an appropriate visual
+
+  int doubleBufferVisual[]  = {
+    GLX_RGBA,           // Needs to support OpenGL
+    GLX_DEPTH_SIZE, 16, // Needs to support a 16 bit depth buffer
+    GLX_DOUBLEBUFFER,   // Needs to support double-buffering
+    None                // end of list
+  };
+
+  // Try for the double-bufferd visual first
+  XVisualInfo *visualInfo = NULL;
+  visualInfo = glXChooseVisual( pDisplay, DefaultScreen(pDisplay), doubleBufferVisual );
+
+  if( visualInfo == NULL ){
+    qCritical( "Could not find matching glx visual" );
+    return res;
+  }
+
+  qDebug() << "Picked visual 0x" << hex << XVisualIDFromVisual( visualInfo->visual );
+  res = (Qt::HANDLE)( visualInfo->visual );
+ 
+  return res;
+}
+#endif // WIN32
+
+
+
 int main(int argc, char *argv[])
 {
+#ifndef WIN32
+  QApplication app(getDisplay(), argc, argv, getVisual());
+#else
   QApplication app(argc, argv);
+#endif
 
   // Install translator
   QTranslator aTranslator;
-- 
2.39.2