Added osg::SyncSwapBuffersCallback to include/osg/GraphicsContext and support for enabling it to include/osg/DisplaySettings, and to the Viewer/CompositeViewer::realize() methods.

To enable the sync of swap buffers set the env var OSG_SYNC_SWAP_BUFFERS to ON or 1, to switch off set to OFF or 0.

One can also use the --sync command line option for application that pass on command line options to the osg::DisplaySettings::instance().


git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14456 16af8721-9629-0410-8352-f15c8da7e697

src/osg/DisplaySettings.cpp

@@ -218,6 +218,7 @@ void DisplaySettings::setDefaults()
     _glContextProfileMask = 0;
 
     _swapMethod = SWAP_DEFAULT;
+    _syncSwapBuffers = 0;
 
     _keystoneHint = false;
 
@@ -630,6 +631,23 @@ void DisplaySettings::readEnvironmentalVariables()
 
     }
 
+    if ((ptr = getenv("OSG_SYNC_SWAP_BUFFERS")) != 0)
+    {
+        if (strcmp(ptr,"OFF")==0)
+        {
+            _syncSwapBuffers = 0;
+        }
+        else
+        if (strcmp(ptr,"ON")==0)
+        {
+            _syncSwapBuffers = 1;
+        }
+        else
+        {
+            _syncSwapBuffers = atoi(ptr);
+        }
+    }
+
     if( (ptr = getenv("OSG_KEYSTONE")) != 0)
     {
         if (strcmp(ptr,"OFF")==0)
@@ -715,6 +733,7 @@ void DisplaySettings::readCommandLine(ArgumentParser& arguments)
         arguments.getApplicationUsage()->addCommandLineOption("--keystone-on","Set the keystone hint to true to tell the viewer to do keystone correction.");
         arguments.getApplicationUsage()->addCommandLineOption("--keystone-off","Set the keystone hint to false.");
         arguments.getApplicationUsage()->addCommandLineOption("--menubar-behavior <behavior>","Set the menubar behavior (AUTO_HIDE | FORCE_HIDE | FORCE_SHOW)");
+        arguments.getApplicationUsage()->addCommandLineOption("--sync","Enable sync of swap buffers");
     }
 
     std::string str;
@@ -769,6 +788,11 @@ void DisplaySettings::readCommandLine(ArgumentParser& arguments)
         _numMultiSamples = atoi(str.c_str());
     }
 
+    while(arguments.read("--sync"))
+    {
+        _syncSwapBuffers = 1;
+    }
+
     if (arguments.read("--keystone",str))
     {
         _keystoneHint = true;

src/osg/GraphicsContext.cpp

@@ -23,6 +23,7 @@
 #include <osg/Drawable>
 #include <osg/FragmentProgram>
 #include <osg/VertexProgram>
+#include <osg/GLExtensions>
 
 #include <OpenThreads/ReentrantMutex>
 
@@ -975,3 +976,60 @@ void GraphicsContext::resizedImplementation(int x, int y, int width, int height)
     _traits->width = width;
     _traits->height = height;
 }
+
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// SyncSwapBuffersCallback
+//
+SyncSwapBuffersCallback::SyncSwapBuffersCallback():
+    _extensionInitialized(false),
+    _glFenceSync(0),
+    _glIsSync(0),
+    _glDeleteSync(0),
+    _glClientWaitSync(0),
+    _glWaitSync(0),
+    _glGetInteger64v(0),
+    _glGetSynciv(0),
+    _previousSync(0)
+{
+        OSG_NOTICE<<"Created Swap callback."<<std::endl;
+}
+
+void SyncSwapBuffersCallback::setUpExtensions()
+{
+    _extensionInitialized = true;
+    osg::setGLExtensionFuncPtr(_glFenceSync, "glFenceSync");
+    osg::setGLExtensionFuncPtr(_glIsSync, "glIsSync");
+    osg::setGLExtensionFuncPtr(_glDeleteSync, "glDeleteSync");
+    osg::setGLExtensionFuncPtr(_glClientWaitSync, "glClientWaitSync");
+    osg::setGLExtensionFuncPtr(_glWaitSync, "glWaitSync");
+    osg::setGLExtensionFuncPtr(_glGetInteger64v, "glGetInteger64v");
+    osg::setGLExtensionFuncPtr(_glGetSynciv, "glGetSynciv");
+}
+
+void SyncSwapBuffersCallback::swapBuffersImplementation(osg::GraphicsContext* gc)
+{
+    // OSG_NOTICE<<"Before swap - place to do swap ready sync"<<std::endl;
+    gc->swapBuffersImplementation();
+    //glFinish();
+
+    if (!_extensionInitialized) setUpExtensions();
+
+    if (_glClientWaitSync)
+    {
+        if (_previousSync)
+        {
+            unsigned int num_seconds = 1;
+            GLuint64 timeout = num_seconds * ((GLuint64)1000 * 1000 * 1000);
+            _glClientWaitSync(_previousSync, 0, timeout);
+
+            _glDeleteSync(_previousSync);
+        }
+
+        _previousSync = _glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
+    }
+    //gc->getState()->checkGLErrors("after glWaitSync");
+
+    //OSG_NOTICE<<"After swap"<<std::endl;
+}

src/osgViewer/CompositeViewer.cpp

@@ -601,6 +601,8 @@ void CompositeViewer::realize()
     {
         osg::GraphicsContext* gc = *citr;
 
+        if (ds->getSyncSwapBuffers()) gc->setSwapCallback(new osg::SyncSwapBuffersCallback);
+
         // set the pool sizes, 0 the default will result in no GL object pools.
         gc->getState()->setMaxTexturePoolSize(maxTexturePoolSize);
         gc->getState()->setMaxBufferObjectPoolSize(maxBufferObjectPoolSize);

src/osgViewer/Viewer.cpp

@@ -544,6 +544,8 @@ void Viewer::realize()
     {
         osg::GraphicsContext* gc = *citr;
 
+        if (ds->getSyncSwapBuffers()) gc->setSwapCallback(new osg::SyncSwapBuffersCallback);
+
         // set the pool sizes, 0 the default will result in no GL object pools.
         gc->getState()->setMaxTexturePoolSize(maxTexturePoolSize);
         gc->getState()->setMaxBufferObjectPoolSize(maxBufferObjectPoolSize);