Fix crash while initializing OpenGL context

GL was crashing with a BadAlloc, this seems to be related to the Intel
graphics drivers when using indirect rendering. Using a direct rendering
context fixes the problem, however we can at least attempt both way if
one or the other fails.

diff --git a/src/gtkgl.c b/src/gtkgl.c
index 6a62e86a377dc910e6f72854e4b7d0a98d4daac0..af2c62bac5f888263fee7a61ee90e9189f50f2ad 100644 (file)
--- a/src/gtkgl.c
+++ b/src/gtkgl.c
@@ -56,6 +56,26 @@ void gtk_gl_disable(GtkWidget *widget)
 #elif defined(SYS_X11)
 #include <GL/glx.h>
 #include <gdk/gdkx.h>
+static gboolean gtk_gl_errors;
+static int gtk_gl_handler(Display *xdisplay, XErrorEvent *xerror)
+{
+       gtk_gl_errors = TRUE;
+       return 0;
+}
+static GLXContext gtk_gl_create_context(Display *xdisplay, XVisualInfo *xvinfo,
+               GLXContext shared, Bool direct)
+{
+       gtk_gl_errors = FALSE;
+       XSync(xdisplay, False);
+       void *handler = XSetErrorHandler(gtk_gl_handler);
+       GLXContext context = glXCreateContext(xdisplay, xvinfo, shared, direct);
+       XSync(xdisplay, False);
+       XSetErrorHandler(handler);
+
+       if (gtk_gl_errors)
+               return 0;
+       return context;
+}
 void gtk_gl_enable(GtkWidget *widget)
 {
        g_debug("GtkGl: enable");
@@ -72,10 +92,20 @@ void gtk_gl_enable(GtkWidget *widget)
                         GLX_DOUBLEBUFFER,
                         GLX_DEPTH_SIZE,  1,
                         None};
+
        XVisualInfo *xvinfo  = glXChooseVisual(xdisplay, nscreen, attribs);
        if (!xvinfo)
                g_error("GtkGl: enable - unable to get valid OpenGL Visual");
-       GLXContext   context = glXCreateContext(xdisplay, xvinfo, NULL, True);
+       GLXContext context = 0;
+       if (!context)
+               context = gtk_gl_create_context(xdisplay, xvinfo, NULL, True);
+       if (!context)
+               context = gtk_gl_create_context(xdisplay, xvinfo, NULL, False);
+       if (!context)
+               g_error("Unable to create OpenGL context,"
+                       "possible graphics driver problem?");
+       g_debug("GtkGl: direct rendering = %d\n", glXIsDirect(xdisplay, context));
+
        g_object_set_data(G_OBJECT(widget), "glcontext", context);
 
        /* Fix up colormap */