From c2a322e48f8a01ca6506d5be925a68145a70f29e Mon Sep 17 00:00:00 2001
From: Matthew Budd <mjbudd77@gmail.com>
Date: Fri, 14 Aug 2020 20:42:54 -0400
Subject: [PATCH] Updated GTK GUI GLX window / context setup to better match
 glx code from  snes9x GTK backend.

---
 src/drivers/sdl/glxwin.cpp | 80 +++++++++++++++++++++++++++++++++++---
 1 file changed, 74 insertions(+), 6 deletions(-)

diff --git a/src/drivers/sdl/glxwin.cpp b/src/drivers/sdl/glxwin.cpp
index 228f5d25..8576144b 100644
--- a/src/drivers/sdl/glxwin.cpp
+++ b/src/drivers/sdl/glxwin.cpp
@@ -89,8 +89,14 @@ static void getAttrbList( GLint *buf )
    int i=0;
 
 	buf[i] = GLX_RGBA; i++;
-	buf[i] = GLX_DEPTH_SIZE; i++;
-	buf[i] = 24; i++;
+	//buf[i] = GLX_DEPTH_SIZE; i++;
+	//buf[i] = 24; i++;
+	buf[i] = GLX_RED_SIZE; i++;
+	buf[i] = 8; i++;
+	buf[i] = GLX_GREEN_SIZE; i++;
+	buf[i] = 8; i++;
+	buf[i] = GLX_BLUE_SIZE; i++;
+	buf[i] = 8; i++;
 
 	if ( double_buffer_ena )
 	{
@@ -392,6 +398,7 @@ int  spawn_glxwin( int flags )
 //************************************************************************
 int  init_gtk3_GLXContext( int flags )
 {
+	int screenNumber;
 	GLint  att[32];
 
 	XWindowAttributes xattrb;
@@ -410,12 +417,20 @@ int  init_gtk3_GLXContext( int flags )
 		printf("Error: Failed to obtain gdkWindow Handle for evbox widget\n");
 		return -1;
 	}
+	if (!GDK_IS_X11_WINDOW (gdkWin))
+	{
+		printf("Error: GDK Window is not of X11 Type\n");
+		return -1;
+	}
+	GdkDisplay *gdk_display = gdk_window_get_display (gdkWin);
+	GdkScreen *gdk_screen   = gdk_window_get_screen (gdkWin);
+   screenNumber = gdk_x11_screen_get_screen_number (gdk_screen);
+	dpy = GDK_DISPLAY_XDISPLAY( gdk_display );
+
 	win = GDK_WINDOW_XID( gdkWin );
 
 	root = GDK_ROOT_WINDOW();
 
-	dpy = gdk_x11_get_default_xdisplay();
-
 	if ( dpy == NULL )
 	{
 		printf("Error: Failed to obtain X Display Handle for evbox widget\n");
@@ -431,16 +446,64 @@ int  init_gtk3_GLXContext( int flags )
 	//printf("XWinSize: (%i x %i) \n", xattrb.width, xattrb.height );
 	//printf("XWinDepth: %i \n", xattrb.depth );
 	//printf("XWinVisual: %p \n", xattrb.visual );
+	printf("XScreenNumber: %i \n", screenNumber );
 
-	vi = glXChooseVisual(dpy, 0, att);
+	vi = glXChooseVisual(dpy, screenNumber, att);
 
 	if (vi == NULL) 
 	{
 		printf("\n\tno appropriate visual found\n\n");
 	   exit(0);
 	} 
-	else {
+	else 
+	{
+		int val;
 		printf("\n\tvisual %p selected\n", (void *)vi->visualid); /* %p creates hexadecimal output like in glxinfo */
+
+		if ( glXGetConfig( dpy, vi, GLX_RGBA, &val ) == 0 )
+		{
+			printf("GLX_RGBA: %i \n", val );
+		}
+		if ( glXGetConfig( dpy, vi, GLX_USE_GL, &val ) == 0 )
+		{
+			printf("GLX_USE_GL: %i \n", val );
+		}
+		if ( glXGetConfig( dpy, vi, GLX_LEVEL, &val ) == 0 )
+		{
+			printf("GLX_LEVEL: %i \n", val );
+		}
+		if ( glXGetConfig( dpy, vi, GLX_BUFFER_SIZE, &val ) == 0 )
+		{
+			printf("GLX_BUFFER_SIZE: %i \n", val );
+		}
+		if ( glXGetConfig( dpy, vi, GLX_DOUBLEBUFFER, &val ) == 0 )
+		{
+			printf("GLX_DOUBLEBUFFER: %i \n", val );
+		}
+		if ( glXGetConfig( dpy, vi, GLX_RED_SIZE, &val ) == 0 )
+		{
+			printf("GLX_RED_SIZE: %i \n", val );
+		}
+		if ( glXGetConfig( dpy, vi, GLX_GREEN_SIZE, &val ) == 0 )
+		{
+			printf("GLX_GREEN_SIZE: %i \n", val );
+		}
+		if ( glXGetConfig( dpy, vi, GLX_BLUE_SIZE, &val ) == 0 )
+		{
+			printf("GLX_BLUE_SIZE: %i \n", val );
+		}
+		if ( glXGetConfig( dpy, vi, GLX_ALPHA_SIZE, &val ) == 0 )
+		{
+			printf("GLX_ALPHA_SIZE: %i \n", val );
+		}
+		if ( glXGetConfig( dpy, vi, GLX_DEPTH_SIZE, &val ) == 0 )
+		{
+			printf("GLX_DEPTH_SIZE: %i \n", val );
+		}
+		if ( glXGetConfig( dpy, vi, GLX_STENCIL_SIZE, &val ) == 0 )
+		{
+			printf("GLX_STENCIL_SIZE: %i \n", val );
+		}
 	}
 
 	if ( glc == NULL )
@@ -454,6 +517,11 @@ int  init_gtk3_GLXContext( int flags )
 	}
 	XFree(vi); vi = NULL;
 
+	if ( glc == NULL )
+	{
+		return -1;
+	}
+	
 	glXMakeCurrent(dpy, win, glc);
 
 	genTextures( flags & GLXWIN_PIXEL_LINEAR_FILTER ? 1 : 0 );