Merge pull request #51 from pqftgs/x11_multiple_monitors

Properly support multiple monitors on Linux.

Re-adds Xinerama code for multi-monitor support on Linux. It was previously removed from Blender for having little use. However, it's fairly important for full-screen games.

This makes full-screen windows render on one monitor, rather than halfway down the middle.
Fixes this problem: https://dl.dropboxusercontent.com/u/19279604/temp/arrgghh.png

Author: DCubix

CMakeLists.txt

@@ -269,6 +269,7 @@ endif()
 
 if(WITH_X11)
 	option(WITH_X11_XINPUT    "Enable X11 Xinput (tablet support and unicode input)"  ON)
+	option(WITH_X11_XINERAMA  "Enable multi-monitor support"                          ON)
 	option(WITH_X11_XF86VMODE "Enable X11 video mode switching"                       ON)
 endif()
 
@@ -706,6 +707,7 @@ endif()
 if(WITH_GHOST_SDL OR WITH_HEADLESS)
 	set(WITH_X11           OFF)
 	set(WITH_X11_XINPUT    OFF)
+	set(WITH_X11_XINERAMA  OFF)
 	set(WITH_X11_XF86VMODE OFF)
 	set(WITH_GHOST_XDND    OFF)
 	set(WITH_INPUT_IME     OFF)
@@ -838,6 +840,14 @@ if(WITH_X11)
 		endif()
 	endif()
 
+	if(WITH_X11_XINERAMA)
+		if(X11_Xinerama_LIB)
+			list(APPEND PLATFORM_LINKLIBS ${X11_Xinerama_LIB})
+		else()
+			set(WITH_X11_XINERAMA OFF)
+		endif()
+	endif()
+
 	if(WITH_X11_XF86VMODE)
 		# XXX, why dont cmake make this available?
 		find_library(X11_Xxf86vmode_LIB Xxf86vm   ${X11_LIB_SEARCH_PATH})
@@ -3048,6 +3058,7 @@ if(FIRST_RUN)
 	info_cfg_option(WITH_INSTALL_PORTABLE)
 	info_cfg_option(WITH_X11_XF86VMODE)
 	info_cfg_option(WITH_X11_XINPUT)
+	info_cfg_option(WITH_X11_XINERAMA)
 	info_cfg_option(WITH_MEM_JEMALLOC)
 	info_cfg_option(WITH_MEM_VALGRIND)
 	info_cfg_option(WITH_SYSTEM_GLEW)

intern/ghost/CMakeLists.txt

@@ -242,6 +242,13 @@ elseif(WITH_X11)
 		)
 	endif()
 
+	if(WITH_X11_XINERAMA)
+		add_definitions(-DWITH_X11_XINERAMA)
+		list(APPEND INC_SYS
+			${X11_Xinerama_INCLUDE_PATH}
+		)
+	endif()
+
 	add_definitions(-DWITH_X11)
 
 elseif(WIN32)

intern/ghost/intern/GHOST_SystemX11.cpp

@@ -55,6 +55,10 @@
 #  include "GHOST_DropTargetX11.h"
 #endif
 
+#ifdef WITH_X11_XINERAMA
+#  include "X11/extensions/Xinerama.h"
+#endif
+
 #include "GHOST_Debug.h"
 
 #ifdef WITH_XF86KEYSYM
@@ -249,9 +253,47 @@ getMainDisplayDimensions(
 		GHOST_TUns32& height) const
 {
 	if (m_display) {
-		/* note, for this to work as documented,
-		 * we would need to use Xinerama check r54370 for code that did this,
-		 * we've since removed since its not worth the extra dep - campbell */
+
+#ifdef WITH_X11_XINERAMA
+		GHOST_TInt32 m_x = 1, m_y = 1;
+		getCursorPosition(m_x, m_y);
+
+		/* NOTE, no way to select a primary monitor, uses the first */
+		bool success = false;
+		int dummy1, dummy2;
+		if (XineramaQueryExtension(m_display, &dummy1, &dummy2)) {
+			if (XineramaIsActive(m_display)) {
+				int heads = 0;
+				XineramaScreenInfo *p = XineramaQueryScreens(m_display, &heads);
+				/* with a single head, all dimensions is fine */
+				if (heads > 1) {
+					int i;
+					for (i = 0; i < heads; i++) {
+						if ((m_x >= p[i].x_org) && (m_x <= p[i].x_org + p[i].width) &&
+						    (m_y >= p[i].y_org) && (m_y <= p[i].y_org + p[i].height))
+						{
+							width = p[i].width;
+							height = p[i].height;
+							break;
+						}
+					}
+					/* highly unlikely! */
+					if (i == heads) {
+						width = p[0].width;
+						height = p[0].height;
+					}
+					success = true;
+				}
+				XFree(p);
+			}
+		}
+
+		if (success) {
+			return;
+		}
+#endif
+
+		/* fallback to all */
 		getAllDisplayDimensions(width, height);
 	}
 }