From 0f2959ce6904157afff6c316f1d380de1ae44386 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Fri, 21 Dec 2007 13:32:13 +0000
Subject: [PATCH] From Jeremy Moles, "Here is a implementation of
 setScreeResolution and setScreenRefreshRate for systems support Xrandr. The
 include CMakeFile makes this optional, and turns it OFF by default, in which
 case any person trying to use these functions under Linux will be instructed
 to build osgViewer w/ Xrandr support. "

---
 src/osgViewer/CMakeLists.txt        |  12 +++-
 src/osgViewer/GraphicsWindowX11.cpp | 107 +++++++++++++++++++++++++++-
 2 files changed, 117 insertions(+), 2 deletions(-)

diff --git a/src/osgViewer/CMakeLists.txt b/src/osgViewer/CMakeLists.txt
index cbe3cff34..1228cbcc8 100644
--- a/src/osgViewer/CMakeLists.txt
+++ b/src/osgViewer/CMakeLists.txt
@@ -62,17 +62,27 @@ ELSE(WIN32)
         )
 
     ELSE(APPLE)
-    
         # X11 for everybody else
+        OPTION(OSGVIEWER_USE_XRANDR "Set to ON to enable Xrandr support for GraphicsWindowX11." OFF)
+
         SET(LIB_PUBLIC_HEADERS ${LIB_PUBLIC_HEADERS}
             ${HEADER_PATH}/api/X11/GraphicsWindowX11
             ${HEADER_PATH}/api/X11/PixelBufferX11
+            ${XRANDR_INCLUDE_DIRS}
         )
         SET(LIB_COMMON_FILES ${LIB_COMMON_FILES} 
             GraphicsWindowX11.cpp 
             PixelBufferX11.cpp
         )
         
+        IF(OSGVIEWER_USE_XRANDR)
+            INCLUDE(FindPkgConfig)
+            PKG_CHECK_MODULES(XRANDR REQUIRED xrandr)
+            ADD_DEFINITIONS(-DOSGVIEWER_USE_XRANDR)
+            SET(LIB_PUBLIC_HEADERS ${LIB_PUBLIC_HEADERS} ${XRANDR_INCLUDE_DIRS})
+        LINK_LIBRARIES(Xrandr)
+        ENDIF(OSGVIEWER_USE_XRANDR)
+
     ENDIF(APPLE)
 
 ENDIF(WIN32)
diff --git a/src/osgViewer/GraphicsWindowX11.cpp b/src/osgViewer/GraphicsWindowX11.cpp
index 3f3e0e0d0..b499044ee 100644
--- a/src/osgViewer/GraphicsWindowX11.cpp
+++ b/src/osgViewer/GraphicsWindowX11.cpp
@@ -30,6 +30,10 @@
 
 #include <X11/Xmd.h>        /* For CARD16 */
 
+#ifdef OSGVIEWER_USE_XRANDR
+#include <X11/extensions/Xrandr.h>
+#endif
+
 #include <unistd.h>
 
 using namespace osgViewer;
@@ -1293,9 +1297,90 @@ int X11ErrorHandling(Display* display, XErrorEvent* event)
 
 }
 
-struct X11WindowingSystemInterface : public osg::GraphicsContext::WindowingSystemInterface
+class X11WindowingSystemInterface : public osg::GraphicsContext::WindowingSystemInterface
 {
+#ifdef OSGVIEWER_USE_XRANDR
+    // TODO: Investigate whether or not Robert thinks we should store/restore the original
+    // resolution in the destructor; I'm not sure the other ones do this, and it may be the
+    // responsibility of the user.
+    bool _setScreen(const osg::GraphicsContext::ScreenIdentifier& si, unsigned int width, unsigned height, double rate) {
+        Display* display = XOpenDisplay(si.displayName().c_str());
+        
+        if(display)
+        {
+            XRRScreenConfiguration* sc = XRRGetScreenInfo(display, RootWindow(display, si.screenNum));
 
+            if(!sc)
+            {
+                osg::notify(osg::NOTICE) << "Unable to create XRRScreenConfiguration on display \"" << XDisplayName(si.displayName().c_str()) << "\"."<<std::endl;
+                return false;
+            }
+
+            int      numScreens = 0;
+            int      numRates   = 0;
+            Rotation currentRot = 0;
+            bool     okay       = false;
+
+            XRRConfigRotations(sc, &currentRot);
+            
+            // If the width or height are zero, use our defaults.
+            if(!width || !height)
+            {
+                getScreenResolution(si, width, height);
+            }
+
+            // If this somehow fails, okay will still be false, no iteration will take place below,
+            // and the sc pointer will still be freed later on.
+            XRRScreenSize* ss = XRRConfigSizes(sc, &numScreens);
+
+            for(int i = 0; i < numScreens; i++)
+            {
+                if(ss[i].width == static_cast<int>(width) && ss[i].height == static_cast<int>(height))
+                {
+                    short* rates     = XRRConfigRates(sc, i, &numRates);
+                    bool   rateFound = false;
+                    
+                    // Search for our rate in the list of acceptable rates given to us by Xrandr.
+                    // If it's not found, rateFound will still be false and the call will never
+                    // be made to XRRSetScreenConfigAndRate since the rate will be invalid.
+                    for(int r = 0; r < numRates; r++)
+                    {
+                        if(rates[r] == static_cast<short>(rate))
+                        {
+                            rateFound = true;
+                            break;
+                        }
+                    }
+
+                    if(rate > 0.0f && !rateFound)
+                    {
+                        osg::notify(osg::NOTICE) << "Unable to find valid refresh rate " << rate << " on display \"" << XDisplayName(si.displayName().c_str()) << "\"."<<std::endl;
+                    }
+                    else if(XRRSetScreenConfigAndRate(display, sc, DefaultRootWindow(display), i, currentRot, static_cast<short>(rate), CurrentTime) != RRSetConfigSuccess)
+                    {
+                        osg::notify(osg::NOTICE) << "Unable to set resolution to " << width << "x" << height << " on display \"" << XDisplayName(si.displayName().c_str()) << "\"."<<std::endl;
+                    }
+                    else
+                    {
+                        okay = true;
+                        break;
+                    }
+                }
+            }
+    
+            XRRFreeScreenConfigInfo(sc);
+    
+            return okay;
+        }
+        else
+        {
+            osg::notify(osg::NOTICE) << "Unable to open display \"" << XDisplayName(si.displayName().c_str()) << "\"."<<std::endl;
+            return false;
+        }
+    }
+#endif
+
+public:
     X11WindowingSystemInterface()
     {
         osg::notify(osg::INFO)<<"X11WindowingSystemInterface()"<<std::endl;
@@ -1361,6 +1446,26 @@ struct X11WindowingSystemInterface : public osg::GraphicsContext::WindowingSyste
         }
     }
 
+    virtual bool setScreenResolution(const osg::GraphicsContext::ScreenIdentifier& si, unsigned int width, unsigned int height)
+    {
+#ifdef OSGVIEWER_USE_XRANDR
+        return _setScreen(si, width, height, 0.0f);
+#else
+        osg::notify(osg::NOTICE) << "You must build osgViewer with Xrandr 1.2 or higher for setScreenResolution support!" << std::endl;
+        return false;
+#endif
+    }
+
+    virtual bool setScreenRefreshRate(const osg::GraphicsContext::ScreenIdentifier& si, double rate)
+    {
+#ifdef OSGVIEWER_USE_XRANDR
+        return _setScreen(si, 0, 0, rate);
+#else
+        osg::notify(osg::NOTICE) << "You must build osgViewer with Xrandr 1.2 or higher for setScreenRefreshRate support!" << std::endl;
+        return false;
+#endif
+    }
+
     virtual osg::GraphicsContext* createGraphicsContext(osg::GraphicsContext::Traits* traits)
     {
         if (traits->pbuffer)