Merged DRTVWR-546 into SL-16329

27 files changed, 219 insertions, 177 deletions

diff --git a/indra/llcommon/workqueue.h b/indra/llcommon/workqueue.h
index b88aef989a..5ec790da79 100644
--- a/indra/llcommon/workqueue.h
+++ b/indra/llcommon/workqueue.h
@@ -94,6 +94,12 @@ namespace LL
         void postEvery(const std::chrono::duration<Rep, Period>& interval,
                        CALLABLE&& callable);
 
+        template <typename CALLABLE>
+        bool tryPost(CALLABLE&& callable)
+        {
+            return mQueue.tryPush(TimedWork(TimePoint::clock::now(), std::move(callable)));
+        }
+
         /*------------------------- handshake API --------------------------*/
 
         /**
diff --git a/indra/llinventory/llsettingssky.cpp b/indra/llinventory/llsettingssky.cpp
index 23f9c8e9d7..0ada97ad3f 100644
--- a/indra/llinventory/llsettingssky.cpp
+++ b/indra/llinventory/llsettingssky.cpp
@@ -1214,9 +1214,9 @@ LLColor3 LLSettingsSky::getLightTransmittanceFast( const LLColor3& total_density
 
 // performs soft scale clip and gamma correction ala the shader implementation
 // scales colors down to 0 - 1 range preserving relative ratios
-LLColor3 LLSettingsSky::gammaCorrect(const LLColor3& in) const
+LLColor3 LLSettingsSky::gammaCorrect(const LLColor3& in,const F32 &gamma) const
 {
-    F32 gamma = getGamma();
+    //F32 gamma = getGamma(); // SL-16127: Use cached gamma from atmospheric vars
 
     LLColor3 v(in);
     // scale down to 0 to 1 range preserving relative ratio (aka homegenize)
diff --git a/indra/llinventory/llsettingssky.h b/indra/llinventory/llsettingssky.h
index 77d9d8e87c..fa9326f006 100644
--- a/indra/llinventory/llsettingssky.h
+++ b/indra/llinventory/llsettingssky.h
@@ -254,7 +254,7 @@ public:
     LLColor3 getLightTransmittance(F32 distance) const;
     LLColor3 getLightTransmittanceFast(const LLColor3& total_density, const F32 density_multiplier, const F32 distance) const;
     LLColor3 getTotalDensity() const;
-    LLColor3 gammaCorrect(const LLColor3& in) const;
+    LLColor3 gammaCorrect(const LLColor3& in,const F32 &gamma) const;
 
     LLColor3 getBlueDensity() const;
     LLColor3 getBlueHorizon() const;
diff --git a/indra/llrender/llimagegl.cpp b/indra/llrender/llimagegl.cpp
index 09b1c71f02..cbc5392882 100644
--- a/indra/llrender/llimagegl.cpp
+++ b/indra/llrender/llimagegl.cpp
@@ -2288,7 +2288,10 @@ bool LLImageGLThread::postCallback(const std::function<void()>& callback)
 {
     try
     {
-        mCallbackQueue.post(callback);
+        if (!mCallbackQueue.tryPost(callback))
+        {
+            mPendingCallbackQ.push(callback);
+        }
     }
     catch (LLThreadSafeQueueInterrupt e)
     {
@@ -2304,6 +2307,18 @@ void LLImageGLThread::executeCallbacks()
     LL_PROFILE_ZONE_SCOPED;
     //executed from main thread
     mCallbackQueue.runPending();
+
+    while (!mPendingCallbackQ.empty())
+    {
+        if (mCallbackQueue.tryPost(mPendingCallbackQ.front()))
+        {
+            mPendingCallbackQ.pop();
+        }
+        else
+        {
+            break;
+        }
+    }
 }
 
 void LLImageGLThread::run()
diff --git a/indra/llrender/llimagegl.h b/indra/llrender/llimagegl.h
index 95b60bd0bd..8264e4a5f2 100644
--- a/indra/llrender/llimagegl.h
+++ b/indra/llrender/llimagegl.h
@@ -332,6 +332,8 @@ public:
     void* mContext;
     LLAtomicBool mFinished;
 
+    std::queue<std::function<void()>> mPendingCallbackQ;
+
     static LLImageGLThread* sInstance;
 };
 
diff --git a/indra/llwindow/llwindow.cpp b/indra/llwindow/llwindow.cpp
index 67ef98d7b3..f4678a70c5 100644
--- a/indra/llwindow/llwindow.cpp
+++ b/indra/llwindow/llwindow.cpp
@@ -403,7 +403,7 @@ LLWindow* LLWindowManager::createWindow(
 	const std::string& title, const std::string& name, S32 x, S32 y, S32 width, S32 height, U32 flags,
 	BOOL fullscreen, 
 	BOOL clearBg,
-	BOOL disable_vsync,
+	BOOL enable_vsync,
 	BOOL use_gl,
 	BOOL ignore_pixel_depth,
 	U32 fsaa_samples)
@@ -415,26 +415,26 @@ LLWindow* LLWindowManager::createWindow(
 #if LL_MESA_HEADLESS
 		new_window = new LLWindowMesaHeadless(callbacks,
 			title, name, x, y, width, height, flags, 
-			fullscreen, clearBg, disable_vsync, use_gl, ignore_pixel_depth);
+			fullscreen, clearBg, enable_vsync, use_gl, ignore_pixel_depth);
 #elif LL_SDL
 		new_window = new LLWindowSDL(callbacks,
 			title, x, y, width, height, flags, 
-			fullscreen, clearBg, disable_vsync, use_gl, ignore_pixel_depth, fsaa_samples);
+			fullscreen, clearBg, enable_vsync, use_gl, ignore_pixel_depth, fsaa_samples);
 #elif LL_WINDOWS
 		new_window = new LLWindowWin32(callbacks,
 			title, name, x, y, width, height, flags, 
-			fullscreen, clearBg, disable_vsync, use_gl, ignore_pixel_depth, fsaa_samples);
+			fullscreen, clearBg, enable_vsync, use_gl, ignore_pixel_depth, fsaa_samples);
 #elif LL_DARWIN
 		new_window = new LLWindowMacOSX(callbacks,
 			title, name, x, y, width, height, flags, 
-			fullscreen, clearBg, disable_vsync, use_gl, ignore_pixel_depth, fsaa_samples);
+			fullscreen, clearBg, enable_vsync, use_gl, ignore_pixel_depth, fsaa_samples);
 #endif
 	}
 	else
 	{
 		new_window = new LLWindowHeadless(callbacks,
 			title, name, x, y, width, height, flags, 
-			fullscreen, clearBg, disable_vsync, use_gl, ignore_pixel_depth);
+			fullscreen, clearBg, enable_vsync, use_gl, ignore_pixel_depth);
 	}
 
 	if (FALSE == new_window->isValid())
diff --git a/indra/llwindow/llwindow.h b/indra/llwindow/llwindow.h
index b76d313011..43d81e4d59 100644
--- a/indra/llwindow/llwindow.h
+++ b/indra/llwindow/llwindow.h
@@ -77,7 +77,7 @@ public:
 	BOOL setSize(LLCoordScreen size);
 	BOOL setSize(LLCoordWindow size);
 	virtual void setMinSize(U32 min_width, U32 min_height, bool enforce_immediately = true);
-	virtual BOOL switchContext(BOOL fullscreen, const LLCoordScreen &size, BOOL disable_vsync, const LLCoordScreen * const posp = NULL) = 0;
+	virtual BOOL switchContext(BOOL fullscreen, const LLCoordScreen &size, BOOL enable_vsync, const LLCoordScreen * const posp = NULL) = 0;
 
     //create a new GL context that shares a namespace with this Window's main GL context and make it current on the current thread
     // returns a pointer to be handed back to destroySharedConext/makeContextCurrent
@@ -92,6 +92,7 @@ public:
     virtual BOOL setCursorPosition(LLCoordWindow position) = 0;
 	virtual BOOL getCursorPosition(LLCoordWindow *position) = 0;
 #if LL_WINDOWS
+    virtual void toggleVSync(bool enable_vsync) = 0;
     virtual BOOL getCursorDelta(LLCoordCommon* delta) = 0;
 #endif
 	virtual void showCursor() = 0;
@@ -295,7 +296,7 @@ public:
 		U32 flags = 0,
 		BOOL fullscreen = FALSE,
 		BOOL clearBg = FALSE,
-		BOOL disable_vsync = TRUE,
+		BOOL enable_vsync = FALSE,
 		BOOL use_gl = TRUE,
 		BOOL ignore_pixel_depth = FALSE,
 		U32 fsaa_samples = 0);
diff --git a/indra/llwindow/llwindowheadless.cpp b/indra/llwindow/llwindowheadless.cpp
index 70f473281b..c3738af6ca 100644
--- a/indra/llwindow/llwindowheadless.cpp
+++ b/indra/llwindow/llwindowheadless.cpp
@@ -35,7 +35,7 @@
 //
 LLWindowHeadless::LLWindowHeadless(LLWindowCallbacks* callbacks, const std::string& title, const std::string& name, S32 x, S32 y, S32 width, S32 height,
 							 U32 flags,  BOOL fullscreen, BOOL clear_background,
-							 BOOL disable_vsync, BOOL use_gl, BOOL ignore_pixel_depth)
+							 BOOL enable_vsync, BOOL use_gl, BOOL ignore_pixel_depth)
 	: LLWindow(callbacks, fullscreen, flags)
 {
 	// Initialize a headless keyboard.
diff --git a/indra/llwindow/llwindowheadless.h b/indra/llwindow/llwindowheadless.h
index f8ba9bbed4..78c5e4bae4 100644
--- a/indra/llwindow/llwindowheadless.h
+++ b/indra/llwindow/llwindowheadless.h
@@ -48,13 +48,14 @@ public:
 	/*virtual*/ BOOL setPosition(LLCoordScreen position) {return FALSE;};
 	/*virtual*/ BOOL setSizeImpl(LLCoordScreen size) {return FALSE;};
 	/*virtual*/ BOOL setSizeImpl(LLCoordWindow size) {return FALSE;};
-	/*virtual*/ BOOL switchContext(BOOL fullscreen, const LLCoordScreen &size, BOOL disable_vsync, const LLCoordScreen * const posp = NULL) {return FALSE;};
+	/*virtual*/ BOOL switchContext(BOOL fullscreen, const LLCoordScreen &size, BOOL enable_vsync, const LLCoordScreen * const posp = NULL) {return FALSE;};
     void* createSharedContext()  { return nullptr; }
     void makeContextCurrent(void*)  {}
     void destroySharedContext(void*)  {}
 	/*virtual*/ BOOL setCursorPosition(LLCoordWindow position) {return FALSE;};
 	/*virtual*/ BOOL getCursorPosition(LLCoordWindow *position) {return FALSE;};
 #if LL_WINDOWS
+    /*virtual*/ virtual void toggleVSync(bool enable_vsync) { }
     /*virtual*/ BOOL getCursorDelta(LLCoordCommon* delta) { return FALSE; }
 #endif
 	/*virtual*/ void showCursor() {};
@@ -103,7 +104,7 @@ public:
 		S32 x, S32 y, 
 		S32 width, S32 height,
 		U32 flags,  BOOL fullscreen, BOOL clear_background,
-		BOOL disable_vsync, BOOL use_gl, BOOL ignore_pixel_depth);
+		BOOL enable_vsync, BOOL use_gl, BOOL ignore_pixel_depth);
 	virtual ~LLWindowHeadless();
 
 private:
diff --git a/indra/llwindow/llwindowmacosx.cpp b/indra/llwindow/llwindowmacosx.cpp
index 23830dd24e..a74fa78388 100644
--- a/indra/llwindow/llwindowmacosx.cpp
+++ b/indra/llwindow/llwindowmacosx.cpp
@@ -111,7 +111,7 @@ LLWindowMacOSX::LLWindowMacOSX(LLWindowCallbacks* callbacks,
 							   const std::string& title, const std::string& name, S32 x, S32 y, S32 width,
 							   S32 height, U32 flags,
 							   BOOL fullscreen, BOOL clearBg,
-							   BOOL disable_vsync, BOOL use_gl,
+							   BOOL enable_vsync, BOOL use_gl,
 							   BOOL ignore_pixel_depth,
 							   U32 fsaa_samples)
 	: LLWindow(NULL, fullscreen, flags)
@@ -165,7 +165,7 @@ LLWindowMacOSX::LLWindowMacOSX(LLWindowCallbacks* callbacks,
 	// Stash an object pointer for OSMessageBox()
 	gWindowImplementation = this;
 	// Create the GL context and set it up for windowed or fullscreen, as appropriate.
-	if(createContext(x, y, width, height, 32, fullscreen, disable_vsync))
+	if(createContext(x, y, width, height, 32, fullscreen, enable_vsync))
 	{
 		if(mWindow != NULL)
 		{
@@ -610,7 +610,7 @@ void LLWindowMacOSX::getMouseDeltas(float* delta)
 	delta[1] = mCursorLastEventDeltaY;
 }
 
-BOOL LLWindowMacOSX::createContext(int x, int y, int width, int height, int bits, BOOL fullscreen, BOOL disable_vsync)
+BOOL LLWindowMacOSX::createContext(int x, int y, int width, int height, int bits, BOOL fullscreen, BOOL enable_vsync)
 {
 	BOOL			glNeedsInit = FALSE;
 
@@ -625,7 +625,7 @@ BOOL LLWindowMacOSX::createContext(int x, int y, int width, int height, int bits
 	{
 		// Our OpenGL view is already defined within SecondLife.xib.
 		// Get the view instead.
-		mGLView = createOpenGLView(mWindow, mFSAASamples, !disable_vsync);
+		mGLView = createOpenGLView(mWindow, mFSAASamples, enable_vsync);
 		mContext = getCGLContextObj(mGLView);
 		
 		// Since we just created the context, it needs to be set up.
@@ -653,7 +653,7 @@ BOOL LLWindowMacOSX::createContext(int x, int y, int width, int height, int bits
 
 	// Disable vertical sync for swap
 	GLint frames_per_swap = 0;
-	if (disable_vsync)
+	if (!enable_vsync)
 	{
 		frames_per_swap = 0;
 	}
@@ -689,7 +689,7 @@ BOOL LLWindowMacOSX::createContext(int x, int y, int width, int height, int bits
 
 // We only support OS X 10.7's fullscreen app mode which is literally a full screen window that fills a virtual desktop.
 // This makes this method obsolete.
-BOOL LLWindowMacOSX::switchContext(BOOL fullscreen, const LLCoordScreen &size, BOOL disable_vsync, const LLCoordScreen * const posp)
+BOOL LLWindowMacOSX::switchContext(BOOL fullscreen, const LLCoordScreen &size, BOOL enable_vsync, const LLCoordScreen * const posp)
 {
 	return FALSE;
 }
diff --git a/indra/llwindow/llwindowmacosx.h b/indra/llwindow/llwindowmacosx.h
index ede2b453d5..18fa86930f 100644
--- a/indra/llwindow/llwindowmacosx.h
+++ b/indra/llwindow/llwindowmacosx.h
@@ -60,7 +60,7 @@ public:
 	BOOL setPosition(LLCoordScreen position) override;
 	BOOL setSizeImpl(LLCoordScreen size) override;
 	BOOL setSizeImpl(LLCoordWindow size) override;
-	BOOL switchContext(BOOL fullscreen, const LLCoordScreen &size, BOOL disable_vsync, const LLCoordScreen * const posp = NULL) override;
+	BOOL switchContext(BOOL fullscreen, const LLCoordScreen &size, BOOL enable_vsync, const LLCoordScreen * const posp = NULL) override;
 	BOOL setCursorPosition(LLCoordWindow position) override;
 	BOOL getCursorPosition(LLCoordWindow *position) override;
 	void showCursor() override;
@@ -143,7 +143,7 @@ public:
 protected:
 	LLWindowMacOSX(LLWindowCallbacks* callbacks,
 		const std::string& title, const std::string& name, int x, int y, int width, int height, U32 flags,
-		BOOL fullscreen, BOOL clearBg, BOOL disable_vsync, BOOL use_gl,
+		BOOL fullscreen, BOOL clearBg, BOOL enable_vsync, BOOL use_gl,
 		BOOL ignore_pixel_depth,
 		U32 fsaa_samples);
 		~LLWindowMacOSX();
@@ -176,7 +176,7 @@ protected:
 	//
 
 	// create or re-create the GL context/window.  Called from the constructor and switchContext().
-	BOOL createContext(int x, int y, int width, int height, int bits, BOOL fullscreen, BOOL disable_vsync);
+	BOOL createContext(int x, int y, int width, int height, int bits, BOOL fullscreen, BOOL enable_vsync);
 	void destroyContext();
 	void setupFailure(const std::string& text, const std::string& caption, U32 type);
 	void adjustCursorDecouple(bool warpingMouse = false);
diff --git a/indra/llwindow/llwindowwin32.cpp b/indra/llwindow/llwindowwin32.cpp
index 70cf839510..e52624d66a 100644
--- a/indra/llwindow/llwindowwin32.cpp
+++ b/indra/llwindow/llwindowwin32.cpp
@@ -473,7 +473,7 @@ LLWindowWin32::LLWindowWin32(LLWindowCallbacks* callbacks,
 							 const std::string& title, const std::string& name, S32 x, S32 y, S32 width,
 							 S32 height, U32 flags, 
 							 BOOL fullscreen, BOOL clearBg,
-							 BOOL disable_vsync, BOOL use_gl,
+							 BOOL enable_vsync, BOOL use_gl,
 							 BOOL ignore_pixel_depth,
 							 U32 fsaa_samples)
 	: LLWindow(callbacks, fullscreen, flags)
@@ -800,7 +800,7 @@ LLWindowWin32::LLWindowWin32(LLWindowCallbacks* callbacks,
 	LLCoordScreen windowPos(x,y);
 	LLCoordScreen windowSize(window_rect.right - window_rect.left,
 							 window_rect.bottom - window_rect.top);
-	if (!switchContext(mFullscreen, windowSize, disable_vsync, &windowPos))
+	if (!switchContext(mFullscreen, windowSize, enable_vsync, &windowPos))
 	{
 		return;
 	}
@@ -1126,7 +1126,7 @@ BOOL LLWindowWin32::setSizeImpl(const LLCoordWindow size)
 }
 
 // changing fullscreen resolution
-BOOL LLWindowWin32::switchContext(BOOL fullscreen, const LLCoordScreen& size, BOOL disable_vsync, const LLCoordScreen* const posp)
+BOOL LLWindowWin32::switchContext(BOOL fullscreen, const LLCoordScreen& size, BOOL enable_vsync, const LLCoordScreen* const posp)
 {
     //called from main thread
     GLuint	pixel_format;
@@ -1802,16 +1802,7 @@ const	S32   max_format  = (S32)num_formats - 1;
 	}
 	
 	// Disable vertical sync for swap
-	if (disable_vsync && wglSwapIntervalEXT)
-	{
-		LL_DEBUGS("Window") << "Disabling vertical sync" << LL_ENDL;
-		wglSwapIntervalEXT(0);
-	}
-	else
-	{
-		LL_DEBUGS("Window") << "Keeping vertical sync" << LL_ENDL;
-        wglSwapIntervalEXT(1);
-	}
+    toggleVSync(enable_vsync);
 
 	SetWindowLongPtr(mWindowHandle, GWLP_USERDATA, (LONG_PTR)this);
 
@@ -1906,6 +1897,20 @@ void LLWindowWin32::destroySharedContext(void* contextPtr)
     wglDeleteContext((HGLRC)contextPtr);
 }
 
+void LLWindowWin32::toggleVSync(bool enable_vsync)
+{
+    if (!enable_vsync && wglSwapIntervalEXT)
+    {
+        LL_INFOS("Window") << "Disabling vertical sync" << LL_ENDL;
+        wglSwapIntervalEXT(0);
+    }
+    else
+    {
+        LL_INFOS("Window") << "Enabling vertical sync" << LL_ENDL;
+        wglSwapIntervalEXT(1);
+    }
+}
+
 void LLWindowWin32::moveWindow( const LLCoordScreen& position, const LLCoordScreen& size )
 {
 	if( mIsMouseClipping )
@@ -2203,6 +2208,17 @@ void LLWindowWin32::gatherInput()
     }
 
     {
+        LL_PROFILE_ZONE_NAMED("gi - PeekMessage");
+        S32 msg_count = 0;
+        while ((msg_count < MAX_MESSAGE_PER_UPDATE) && PeekMessage(&msg, NULL, WM_USER, WM_USER, PM_REMOVE))
+        {
+            TranslateMessage(&msg);
+            DispatchMessage(&msg);
+            msg_count++;
+        }
+    }
+
+    {
         LL_PROFILE_ZONE_NAMED("gi - function queue");
         //process any pending functions
         std::function<void()> curFunc;
diff --git a/indra/llwindow/llwindowwin32.h b/indra/llwindow/llwindowwin32.h
index 7a9a30ccea..d082080807 100644
--- a/indra/llwindow/llwindowwin32.h
+++ b/indra/llwindow/llwindowwin32.h
@@ -93,11 +93,12 @@ public:
 	/*virtual*/ BOOL setPosition(LLCoordScreen position);
 	/*virtual*/ BOOL setSizeImpl(LLCoordScreen size);
 	/*virtual*/ BOOL setSizeImpl(LLCoordWindow size);
-	/*virtual*/ BOOL switchContext(BOOL fullscreen, const LLCoordScreen &size, BOOL disable_vsync, const LLCoordScreen * const posp = NULL);
+	/*virtual*/ BOOL switchContext(BOOL fullscreen, const LLCoordScreen &size, BOOL enable_vsync, const LLCoordScreen * const posp = NULL);
     /*virtual*/ void setTitle(const std::string title);
     void* createSharedContext() override;
     void makeContextCurrent(void* context) override;
     void destroySharedContext(void* context) override;
+    /*virtual*/ void toggleVSync(bool enable_vsync);
 	/*virtual*/ BOOL setCursorPosition(LLCoordWindow position);
 	/*virtual*/ BOOL getCursorPosition(LLCoordWindow *position);
     /*virtual*/ BOOL getCursorDelta(LLCoordCommon* delta);
@@ -164,7 +165,7 @@ public:
 protected:
 	LLWindowWin32(LLWindowCallbacks* callbacks,
 		const std::string& title, const std::string& name, int x, int y, int width, int height, U32 flags, 
-		BOOL fullscreen, BOOL clearBg, BOOL disable_vsync, BOOL use_gl,
+		BOOL fullscreen, BOOL clearBg, BOOL enable_vsync, BOOL use_gl,
 		BOOL ignore_pixel_depth, U32 fsaa_samples);
 	~LLWindowWin32();
 
diff --git a/indra/newview/app_settings/settings.xml b/indra/newview/app_settings/settings.xml
index 291f0f7d95..f15b5d0981 100644
--- a/indra/newview/app_settings/settings.xml
+++ b/indra/newview/app_settings/settings.xml
@@ -3352,16 +3352,16 @@
       <key>Value</key>
       <integer>0</integer>
     </map>
-    <key>DisableVerticalSync</key>
+    <key>RenderVSyncEnable</key>
     <map>
       <key>Comment</key>
-      <string>Update frames as fast as possible (FALSE = update frames between display scans).  Requires restart.</string>
+      <string>Update frames between display scans (FALSE = Update frames as fast as possible).</string>
       <key>Persist</key>
       <integer>1</integer>
       <key>Type</key>
       <string>Boolean</string>
       <key>Value</key>
-      <integer>0</integer>
+      <integer>1</integer>
     </map>
     <key>EnableGroupChatPopups</key>
     <map>
diff --git a/indra/newview/lldrawpoolwater.cpp b/indra/newview/lldrawpoolwater.cpp
index aa426cd785..5f9e623b4c 100644
--- a/indra/newview/lldrawpoolwater.cpp
+++ b/indra/newview/lldrawpoolwater.cpp
@@ -337,7 +337,8 @@ void LLDrawPoolWater::render(S32 pass)
 // for low end hardware
 void LLDrawPoolWater::renderOpaqueLegacyWater()
 {
-	LLVOSky *voskyp = gSky.mVOSkyp;
+    LL_PROFILE_ZONE_SCOPED;
+    LLVOSky *voskyp = gSky.mVOSkyp;
 
 	LLGLSLShader* shader = NULL;
 	if (LLGLSLShader::sNoFixedFunction)
@@ -444,6 +445,7 @@ void LLDrawPoolWater::renderOpaqueLegacyWater()
 
 void LLDrawPoolWater::renderReflection(LLFace* face)
 {
+    LL_PROFILE_ZONE_SCOPED;
 	LLVOSky *voskyp = gSky.mVOSkyp;
 
 	if (!voskyp)
@@ -472,6 +474,7 @@ void LLDrawPoolWater::renderReflection(LLFace* face)
 
 void LLDrawPoolWater::shade2(bool edge, LLGLSLShader* shader, const LLColor3& light_diffuse, const LLVector3& light_dir, F32 light_exp)
 {
+    LL_PROFILE_ZONE_SCOPED;
     F32  water_height  = LLEnvironment::instance().getWaterHeight(); 
     F32  camera_height = LLViewerCamera::getInstance()->getOrigin().mV[2];
     F32  eyedepth      = camera_height - water_height;
@@ -680,7 +683,8 @@ void LLDrawPoolWater::shade2(bool edge, LLGLSLShader* shader, const LLColor3& li
 
 void LLDrawPoolWater::shade()
 {
-	if (!deferred_render)
+    LL_PROFILE_ZONE_SCOPED;
+    if (!deferred_render)
 	{
 		gGL.setColorMask(true, true);
 	}
diff --git a/indra/newview/lllegacyatmospherics.cpp b/indra/newview/lllegacyatmospherics.cpp
index 9eda254b25..238e9fe0e1 100644
--- a/indra/newview/lllegacyatmospherics.cpp
+++ b/indra/newview/lllegacyatmospherics.cpp
@@ -202,14 +202,8 @@ void LLAtmospherics::init()
 	mInitialized = true;
 }
 
-LLColor4 LLAtmospherics::calcSkyColorInDir(AtmosphericsVars& vars, const LLVector3 &dir, bool isShiny)
-{
-    LLSettingsSky::ptr_t psky = LLEnvironment::instance().getCurrentSky();
-    return calcSkyColorInDir(psky, vars, dir, isShiny);
-}
-
 // This cubemap is used as "environmentMap" in indra/newview/app_settings/shaders/class2/deferred/softenLightF.glsl
-LLColor4 LLAtmospherics::calcSkyColorInDir(const LLSettingsSky::ptr_t &psky, AtmosphericsVars& vars, const LLVector3 &dir, bool isShiny)
+LLColor4 LLAtmospherics::calcSkyColorInDir(const LLSettingsSky::ptr_t &psky, AtmosphericsVars& vars, const LLVector3 &dir, bool isShiny, bool low_end)
 {
 	const F32 sky_saturation = 0.25f;
 	const F32 land_saturation = 0.1f;
@@ -227,7 +221,7 @@ LLColor4 LLAtmospherics::calcSkyColorInDir(const LLSettingsSky::ptr_t &psky, Atm
 		}
 		F32 greyscale_sat = brightness * (1.0f - land_saturation);
 		desat_fog = desat_fog * land_saturation + smear(greyscale_sat);
-		if (!gPipeline.canUseWindLightShaders())
+		if (low_end)
 		{
 			col = LLColor4(desat_fog, 0.f);
 		}
@@ -258,8 +252,7 @@ LLColor4 LLAtmospherics::calcSkyColorInDir(const LLSettingsSky::ptr_t &psky, Atm
 		return LLColor4(sky_color, 0.0f);
 	}
 
-	bool low_end = !gPipeline.canUseWindLightShaders();
-	LLColor3 sky_color = low_end ? vars.hazeColor * 2.0f : psky->gammaCorrect(vars.hazeColor * 2.0f);
+	LLColor3 sky_color = low_end ? vars.hazeColor * 2.0f : psky->gammaCorrect(vars.hazeColor * 2.0f, vars.gamma);
 
 	return LLColor4(sky_color, 0.0f);
 }
@@ -437,12 +430,16 @@ void LLAtmospherics::updateFog(const F32 distance, const LLVector3& tosun_in)
 
     LLSettingsSky::ptr_t psky = LLEnvironment::instance().getCurrentSky();
 
+    // NOTE: This is very similar to LLVOSky::cacheEnvironment()
+    // Differences:
+    //     vars.sun_norm
+    //     vars.sunlight
     // invariants across whole sky tex process...
-    vars.blue_density = psky->getBlueDensity();    
+    vars.blue_density = psky->getBlueDensity();
     vars.blue_horizon = psky->getBlueHorizon();
     vars.haze_density = psky->getHazeDensity();
     vars.haze_horizon = psky->getHazeHorizon();
-    vars.density_multiplier = psky->getDensityMultiplier();    
+    vars.density_multiplier = psky->getDensityMultiplier();
     vars.distance_multiplier = psky->getDistanceMultiplier();
     vars.max_y = psky->getMaxY();
     vars.sun_norm = LLEnvironment::instance().getSunDirectionCFR();
@@ -457,9 +454,9 @@ void LLAtmospherics::updateFog(const F32 distance, const LLVector3& tosun_in)
     vars.total_density = psky->getTotalDensity();
     vars.gamma = psky->getGamma();
 
-	res_color[0] = calcSkyColorInDir(vars, tosun);
-	res_color[1] = calcSkyColorInDir(vars, perp_tosun);
-	res_color[2] = calcSkyColorInDir(vars, tosun_45);
+    res_color[0] = calcSkyColorInDir(psky, vars, tosun);
+    res_color[1] = calcSkyColorInDir(psky, vars, perp_tosun);
+    res_color[2] = calcSkyColorInDir(psky, vars, tosun_45);
 
 	sky_fog_color = color_norm(res_color[0] + res_color[1] + res_color[2]);
 
diff --git a/indra/newview/lllegacyatmospherics.h b/indra/newview/lllegacyatmospherics.h
index 03c8efb91a..d48f3040c3 100644
--- a/indra/newview/lllegacyatmospherics.h
+++ b/indra/newview/lllegacyatmospherics.h
@@ -257,13 +257,11 @@ public:
     void setCloudDensity(F32 cloud_density)          { mCloudDensity = cloud_density; }
     void setWind ( const LLVector3& wind )           { mWind = wind.length(); }
 
-    LLColor4 calcSkyColorInDir(AtmosphericsVars& vars, const LLVector3& dir, bool isShiny = false);
-    LLColor4 calcSkyColorInDir(const LLSettingsSky::ptr_t &psky, AtmosphericsVars& vars, const LLVector3& dir, bool isShiny = false);
+    LLColor4 calcSkyColorInDir(const LLSettingsSky::ptr_t &psky, AtmosphericsVars& vars, const LLVector3& dir, bool isShiny = false, const bool low_end = false);
 
-protected:    
+protected:
 
     void     calcSkyColorWLVert(const LLSettingsSky::ptr_t &psky, LLVector3 & Pn, AtmosphericsVars& vars);
-    LLColor3 getHazeColor(LLSettingsSky::ptr_t psky, AtmosphericsVars& vars, F32 costheta, F32 cloud_shadow);
 
     LLHaze              mHaze;
     F32                 mHazeConcentration;
diff --git a/indra/newview/llsettingsvo.cpp b/indra/newview/llsettingsvo.cpp
index 6a88a8ef2c..0c59de5ea0 100644
--- a/indra/newview/llsettingsvo.cpp
+++ b/indra/newview/llsettingsvo.cpp
@@ -666,6 +666,7 @@ void LLSettingsVOSky::updateSettings()
 
 void LLSettingsVOSky::applySpecial(void *ptarget, bool force)
 {
+    LL_PROFILE_ZONE_SCOPED
     LLVector4 light_direction = LLEnvironment::instance().getClampedLightNorm();
 
     LLShaderUniforms* shader = &((LLShaderUniforms*)ptarget)[LLGLSLShader::SG_DEFAULT];
@@ -908,6 +909,8 @@ LLSD LLSettingsVOWater::convertToLegacy(const LLSettingsWater::ptr_t &pwater)
 //-------------------------------------------------------------------------
 void LLSettingsVOWater::applySpecial(void *ptarget, bool force)
 {
+    LL_PROFILE_ZONE_SCOPED
+
     LLEnvironment& env = LLEnvironment::instance();
 
     auto group = LLGLSLShader::SG_WATER;
diff --git a/indra/newview/llviewercontrol.cpp b/indra/newview/llviewercontrol.cpp
index 76dc9a6790..3e7459ee8a 100644
--- a/indra/newview/llviewercontrol.cpp
+++ b/indra/newview/llviewercontrol.cpp
@@ -241,6 +241,12 @@ static bool handleAnisotropicChanged(const LLSD& newvalue)
 	return true;
 }
 
+static bool handleVSyncChanged(const LLSD& newvalue)
+{
+    gViewerWindow->getWindow()->toggleVSync(newvalue.asBoolean());
+    return true;
+}
+
 static bool handleVolumeLODChanged(const LLSD& newvalue)
 {
 	LLVOVolume::sLODFactor = llclamp((F32) newvalue.asReal(), 0.01f, MAX_LOD_FACTOR);
@@ -665,6 +671,7 @@ void settings_setup_listeners()
 	gSavedSettings.getControl("RenderAutoMaskAlphaNonDeferred")->getSignal()->connect(boost::bind(&handleResetVertexBuffersChanged, _2));
 	gSavedSettings.getControl("RenderObjectBump")->getSignal()->connect(boost::bind(&handleRenderBumpChanged, _2));
 	gSavedSettings.getControl("RenderMaxVBOSize")->getSignal()->connect(boost::bind(&handleResetVertexBuffersChanged, _2));
+    gSavedSettings.getControl("RenderVSyncEnable")->getSignal()->connect(boost::bind(&handleVSyncChanged, _2));
 	gSavedSettings.getControl("RenderDeferredNoise")->getSignal()->connect(boost::bind(&handleReleaseGLBufferChanged, _2));
 	gSavedSettings.getControl("RenderDebugGL")->getSignal()->connect(boost::bind(&handleRenderDebugGLChanged, _2));
 	gSavedSettings.getControl("RenderDebugPipeline")->getSignal()->connect(boost::bind(&handleRenderDebugPipelineChanged, _2));
diff --git a/indra/newview/llviewerwindow.cpp b/indra/newview/llviewerwindow.cpp
index 7dc7b33938..a35ad55cf7 100644
--- a/indra/newview/llviewerwindow.cpp
+++ b/indra/newview/llviewerwindow.cpp
@@ -1903,7 +1903,7 @@ LLViewerWindow::LLViewerWindow(const Params& p)
 		p.title, p.name, p.x, p.y, p.width, p.height, 0,
 		p.fullscreen, 
 		gHeadlessClient,
-		gSavedSettings.getBOOL("DisableVerticalSync"),
+		gSavedSettings.getBOOL("RenderVSyncEnable"),
 		!gHeadlessClient,
 		p.ignore_pixel_depth,
 		gSavedSettings.getBOOL("RenderDeferred") ? 0 : gSavedSettings.getU32("RenderFSAASamples")); //don't use window level anti-aliasing if FBOs are enabled
@@ -5569,7 +5569,7 @@ void LLViewerWindow::restartDisplay(BOOL show_progress_bar)
 	}
 }
 
-BOOL LLViewerWindow::changeDisplaySettings(LLCoordScreen size, BOOL disable_vsync, BOOL show_progress_bar)
+BOOL LLViewerWindow::changeDisplaySettings(LLCoordScreen size, BOOL enable_vsync, BOOL show_progress_bar)
 {
 	//BOOL was_maximized = gSavedSettings.getBOOL("WindowMaximized");
 
diff --git a/indra/newview/llviewerwindow.h b/indra/newview/llviewerwindow.h
index 8a6df613dc..93194b1884 100644
--- a/indra/newview/llviewerwindow.h
+++ b/indra/newview/llviewerwindow.h
@@ -424,7 +424,7 @@ public:
 	void			requestResolutionUpdate();
 	void			checkSettings();
 	void			restartDisplay(BOOL show_progress_bar);
-	BOOL			changeDisplaySettings(LLCoordScreen size, BOOL disable_vsync, BOOL show_progress_bar);
+	BOOL			changeDisplaySettings(LLCoordScreen size, BOOL enable_vsync, BOOL show_progress_bar);
 	BOOL			getIgnoreDestroyWindow() { return mIgnoreActivate; }
 	F32				getWorldViewAspectRatio() const;
 	const LLVector2& getDisplayScale() const { return mDisplayScale; }
diff --git a/indra/newview/llvosky.cpp b/indra/newview/llvosky.cpp
index 1e546861b9..72ec8390a4 100644
--- a/indra/newview/llvosky.cpp
+++ b/indra/newview/llvosky.cpp
@@ -64,7 +64,7 @@ namespace
     const S32 NUM_TILES_X = 8;
     const S32 NUM_TILES_Y = 4;
     const S32 NUM_TILES = NUM_TILES_X * NUM_TILES_Y;
-    const S32 NUM_CUBEMAP_FACES = 6; // See sResolution for face dimensions
+    const S32 NUM_CUBEMAP_FACES = 6; // See SKYTEX_RESOLUTION for face dimensions
     const S32 TOTAL_TILES = NUM_CUBEMAP_FACES * NUM_TILES;
     const S32 MAX_TILES = TOTAL_TILES + 1;
 
@@ -87,8 +87,6 @@ namespace
 		SkyTex
 ***************************************/
 
-S32 LLSkyTex::sComponents = 4;
-S32 LLSkyTex::sResolution = 64;
 S32 LLSkyTex::sCurrent = 0;
 
 
@@ -102,14 +100,14 @@ LLSkyTex::LLSkyTex() :
 void LLSkyTex::init(bool isShiny)
 {
     mIsShiny = isShiny;
-	mSkyData = new LLColor4[sResolution * sResolution];
-	mSkyDirs = new LLVector3[sResolution * sResolution];
+	mSkyData = new LLColor4[SKYTEX_RESOLUTION * SKYTEX_RESOLUTION];
+	mSkyDirs = new LLVector3[SKYTEX_RESOLUTION * SKYTEX_RESOLUTION];
 
 	for (S32 i = 0; i < 2; ++i)
 	{
 		mTexture[i] = LLViewerTextureManager::getLocalTexture(FALSE);
 		mTexture[i]->setAddressMode(LLTexUnit::TAM_CLAMP);
-		mImageRaw[i] = new LLImageRaw(sResolution, sResolution, sComponents);
+		mImageRaw[i] = new LLImageRaw(SKYTEX_RESOLUTION, SKYTEX_RESOLUTION, SKYTEX_COMPONENTS);
 
 		initEmpty(i);
 	}
@@ -141,7 +139,7 @@ LLSkyTex::~LLSkyTex()
 
 S32 LLSkyTex::getResolution()
 {
-    return sResolution;
+    return SKYTEX_RESOLUTION;
 }
 
 S32 LLSkyTex::getCurrent()
@@ -169,12 +167,12 @@ S32 LLSkyTex::getWhich(const BOOL curr)
 void LLSkyTex::initEmpty(const S32 tex)
 {
 	U8* data = mImageRaw[tex]->getData();
-	for (S32 i = 0; i < sResolution; ++i)
+	for (S32 i = 0; i < SKYTEX_RESOLUTION; ++i)
 	{
-		for (S32 j = 0; j < sResolution; ++j)
+		for (S32 j = 0; j < SKYTEX_RESOLUTION; ++j)
 		{
-			const S32 basic_offset = (i * sResolution + j);
-			S32 offset = basic_offset * sComponents;
+			const S32 basic_offset = (i * SKYTEX_RESOLUTION + j);
+			S32 offset = basic_offset * SKYTEX_COMPONENTS;
 			data[offset] = 0;
 			data[offset+1] = 0;
 			data[offset+2] = 0;
@@ -190,12 +188,12 @@ void LLSkyTex::initEmpty(const S32 tex)
 void LLSkyTex::create()
 {
 	U8* data = mImageRaw[sCurrent]->getData();
-	for (S32 i = 0; i < sResolution; ++i)
+	for (S32 i = 0; i < SKYTEX_RESOLUTION; ++i)
 	{
-		for (S32 j = 0; j < sResolution; ++j)
+		for (S32 j = 0; j < SKYTEX_RESOLUTION; ++j)
 		{
-			const S32 basic_offset = (i * sResolution + j);
-			S32 offset = basic_offset * sComponents;
+			const S32 basic_offset = (i * SKYTEX_RESOLUTION + j);
+			S32 offset = basic_offset * SKYTEX_COMPONENTS;
 			U32* pix = (U32*)(data + offset);
 			LLColor4U temp = LLColor4U(mSkyData[basic_offset]);
 			*pix = temp.asRGBA();
@@ -392,10 +390,8 @@ const LLVector3* LLHeavenBody::corners() const
 		Sky
 ***************************************/
 
-
-S32 LLVOSky::sResolution = LLSkyTex::getResolution();
-S32 LLVOSky::sTileResX = sResolution/NUM_TILES_X;
-S32 LLVOSky::sTileResY = sResolution/NUM_TILES_Y;
+const S32 SKYTEX_TILE_RES_X = SKYTEX_RESOLUTION / NUM_TILES_X;
+const S32 SKYTEX_TILE_RES_Y = SKYTEX_RESOLUTION / NUM_TILES_Y;
 
 LLVOSky::LLVOSky(const LLUUID &id, const LLPCode pcode, LLViewerRegion *regionp)
 :	LLStaticViewerObject(id, pcode, regionp, TRUE),
@@ -490,6 +486,7 @@ void LLVOSky::init()
 
 void LLVOSky::cacheEnvironment(LLSettingsSky::ptr_t psky,AtmosphericsVars& atmosphericsVars)
 {
+    // NOTE: Also see: LLAtmospherics::updateFog()
     // invariants across whole sky tex process...
     atmosphericsVars.blue_density = psky->getBlueDensity();
     atmosphericsVars.blue_horizon = psky->getBlueHorizon();
@@ -598,8 +595,8 @@ void LLVOSky::initSkyTextureDirs(const S32 side, const S32 tile)
 	S32 tile_x = tile % NUM_TILES_X;
 	S32 tile_y = tile / NUM_TILES_X;
 
-	S32 tile_x_pos = tile_x * sTileResX;
-	S32 tile_y_pos = tile_y * sTileResY;
+	S32 tile_x_pos = tile_x * SKYTEX_TILE_RES_X;
+	S32 tile_y_pos = tile_y * SKYTEX_TILE_RES_Y;
 
 	F32 coeff[3] = {0, 0, 0};
 	const S32 curr_coef = side >> 1; // 0/1 = Z axis, 2/3 = Y, 4/5 = X
@@ -609,11 +606,11 @@ void LLVOSky::initSkyTextureDirs(const S32 side, const S32 tile)
 
 	coeff[curr_coef] = (F32)side_dir;
 
-	F32 inv_res = 1.f/sResolution;
+	F32 inv_res = 1.f/SKYTEX_RESOLUTION;
 	S32 x, y;
-	for (y = tile_y_pos; y < (tile_y_pos + sTileResY); ++y)
+	for (y = tile_y_pos; y < (tile_y_pos + SKYTEX_TILE_RES_Y); ++y)
 	{
-		for (x = tile_x_pos; x < (tile_x_pos + sTileResX); ++x)
+		for (x = tile_x_pos; x < (tile_x_pos + SKYTEX_TILE_RES_X); ++x)
 		{
 			coeff[x_coef] = F32((x<<1) + 1) * inv_res - 1.f;
 			coeff[y_coef] = F32((y<<1) + 1) * inv_res - 1.f;
@@ -625,21 +622,23 @@ void LLVOSky::initSkyTextureDirs(const S32 side, const S32 tile)
 	}
 }
 
-void LLVOSky::createSkyTexture(LLSettingsSky::ptr_t psky, AtmosphericsVars& vars, const S32 side, const S32 tile)
+void LLVOSky::createSkyTexture(const LLSettingsSky::ptr_t &psky, AtmosphericsVars& vars, const S32 side, const S32 tile)
 {
+    const bool low_end = !gPipeline.canUseWindLightShaders();
+
 	S32 tile_x = tile % NUM_TILES_X;
 	S32 tile_y = tile / NUM_TILES_X;
 
-	S32 tile_x_pos = tile_x * sTileResX;
-	S32 tile_y_pos = tile_y * sTileResY;
+	S32 tile_x_pos = tile_x * SKYTEX_TILE_RES_X;
+	S32 tile_y_pos = tile_y * SKYTEX_TILE_RES_Y;
 
 	S32 x, y;
-	for (y = tile_y_pos; y < (tile_y_pos + sTileResY); ++y)
+	for (y = tile_y_pos; y < (tile_y_pos + SKYTEX_TILE_RES_Y); ++y)
 	{
-		for (x = tile_x_pos; x < (tile_x_pos + sTileResX); ++x)
+		for (x = tile_x_pos; x < (tile_x_pos + SKYTEX_TILE_RES_X); ++x)
 		{
-			mSkyTex  [side].setPixel(m_legacyAtmospherics.calcSkyColorInDir(psky, vars, mSkyTex  [side].getDir(x, y), false), x, y);
-			mShinyTex[side].setPixel(m_legacyAtmospherics.calcSkyColorInDir(psky, vars, mShinyTex[side].getDir(x, y), true ), x, y);
+			mSkyTex  [side].setPixel(m_legacyAtmospherics.calcSkyColorInDir(psky, vars, mSkyTex  [side].getDir(x, y), false, low_end), x, y);
+			mShinyTex[side].setPixel(m_legacyAtmospherics.calcSkyColorInDir(psky, vars, mShinyTex[side].getDir(x, y), true , low_end), x, y);
 		}
 	}
 }
diff --git a/indra/newview/llvosky.h b/indra/newview/llvosky.h
index 793dcf4cbf..5941ab6e3b 100644
--- a/indra/newview/llvosky.h
+++ b/indra/newview/llvosky.h
@@ -43,6 +43,9 @@ const F32 HEAVENLY_BODY_DIST	= HORIZON_DIST - 20.f;
 const F32 HEAVENLY_BODY_FACTOR	= 0.1f;
 const F32 HEAVENLY_BODY_SCALE	= HEAVENLY_BODY_DIST * HEAVENLY_BODY_FACTOR;
 
+const F32 SKYTEX_COMPONENTS = 4;
+const F32 SKYTEX_RESOLUTION = 64;
+
 class LLFace;
 class LLHaze;
 
@@ -50,8 +53,6 @@ class LLSkyTex
 {
 	friend class LLVOSky;
 private:
-	static S32		sResolution;
-	static S32		sComponents;
 	LLPointer<LLViewerTexture> mTexture[2];
 	LLPointer<LLImageRaw> mImageRaw[2];
 	LLColor4		*mSkyData;
@@ -82,25 +83,25 @@ protected:
 
 	void setDir(const LLVector3 &dir, const S32 i, const S32 j)
 	{
-		S32 offset = i * sResolution + j;
+		S32 offset = i * SKYTEX_RESOLUTION + j;
 		mSkyDirs[offset] = dir;
 	}
 
 	const LLVector3 &getDir(const S32 i, const S32 j) const
 	{
-		S32 offset = i * sResolution + j;
+		S32 offset = i * SKYTEX_RESOLUTION + j;
 		return mSkyDirs[offset];
 	}
 
 	void setPixel(const LLColor4 &col, const S32 i, const S32 j)
 	{
-		S32 offset = i * sResolution + j;
+		S32 offset = i * SKYTEX_RESOLUTION + j;
 		mSkyData[offset] = col;
 	}
 
 	void setPixel(const LLColor4U &col, const S32 i, const S32 j)
 	{
-		S32 offset = (i * sResolution + j) * sComponents;
+		S32 offset = (i * SKYTEX_RESOLUTION + j) * SKYTEX_COMPONENTS;
 		U32* pix = (U32*) &(mImageRaw[sCurrent]->getData()[offset]);
 		*pix = col.asRGBA();
 	}
@@ -108,7 +109,7 @@ protected:
 	LLColor4U getPixel(const S32 i, const S32 j)
 	{
 		LLColor4U col;
-		S32 offset = (i * sResolution + j) * sComponents;
+		S32 offset = (i * SKYTEX_RESOLUTION + j) * SKYTEX_COMPONENTS;
 		U32* pix = (U32*) &(mImageRaw[sCurrent]->getData()[offset]);
 		col.fromRGBA( *pix );
 		return col;
@@ -300,7 +301,7 @@ protected:
 	void updateDirections(LLSettingsSky::ptr_t psky);
 
 	void initSkyTextureDirs(const S32 side, const S32 tile);
-	void createSkyTexture(LLSettingsSky::ptr_t psky, AtmosphericsVars& vars, const S32 side, const S32 tile);
+	void createSkyTexture(const LLSettingsSky::ptr_t &psky, AtmosphericsVars& vars, const S32 side, const S32 tile);
 
 	LLPointer<LLViewerFetchedTexture> mSunTexturep[2];
 	LLPointer<LLViewerFetchedTexture> mMoonTexturep[2];
diff --git a/indra/newview/llvowlsky.cpp b/indra/newview/llvowlsky.cpp
index 5a8126fa38..d1f584cbca 100644
--- a/indra/newview/llvowlsky.cpp
+++ b/indra/newview/llvowlsky.cpp
@@ -36,8 +36,8 @@
 #include "llenvironment.h"
 #include "llsettingssky.h"
 
-static const U32 MIN_SKY_DETAIL = 8;
-static const U32 MAX_SKY_DETAIL = 180;
+constexpr U32 MIN_SKY_DETAIL = 8;
+constexpr U32 MAX_SKY_DETAIL = 180;
 
 inline U32 LLVOWLSky::getNumStacks(void)
 {
@@ -97,13 +97,14 @@ LLDrawable * LLVOWLSky::createDrawable(LLPipeline * pipeline)
 	return mDrawable;
 }
 
-inline F32 LLVOWLSky::calcPhi(U32 i)
+// a tiny helper function for controlling the sky dome tesselation.
+inline F32 calcPhi(const U32 &i, const F32 &reciprocal_num_stacks)
 {
     // Calc: PI/8 * 1-((1-t^4)*(1-t^4))  { 0<t<1 }
     // Demos: \pi/8*\left(1-((1-x^{4})*(1-x^{4}))\right)\ \left\{0<x\le1\right\}
 
 	// i should range from [0..SKY_STACKS] so t will range from [0.f .. 1.f]
-	F32 t = float(i) / float(getNumStacks());
+	F32 t = float(i) * reciprocal_num_stacks; //SL-16127: remove: / float(getNumStacks());
 
 	// ^4 the parameter of the tesselation to bias things toward 0 (the dome's apex)
 	t *= t;
@@ -187,6 +188,8 @@ BOOL LLVOWLSky::updateGeometry(LLDrawable * drawable)
     }
 
 	{
+        const F32 dome_radius = LLEnvironment::instance().getCurrentSky()->getDomeRadius();
+
 		const U32 max_buffer_bytes = gSavedSettings.getS32("RenderMaxVBOSize")*1024;
 		const U32 data_mask = LLDrawPoolWLSky::SKY_VERTEX_DATA_MASK;
 		const U32 max_verts = max_buffer_bytes / LLVertexBuffer::calcVertexSize(data_mask);
@@ -202,12 +205,14 @@ BOOL LLVOWLSky::updateGeometry(LLDrawable * drawable)
 		// round up to a whole number of segments
 		const U32 strips_segments = (total_stacks+stacks_per_seg-1) / stacks_per_seg;
 
-		LL_INFOS() << "WL Skydome strips in " << strips_segments << " batches." << LL_ENDL;
-
 		mStripsVerts.resize(strips_segments, NULL);
 
+#if RELEASE_SHOW_DEBUG
+		LL_INFOS() << "WL Skydome strips in " << strips_segments << " batches." << LL_ENDL;
+
 		LLTimer timer;
 		timer.start();
+#endif
 
 		for (U32 i = 0; i < strips_segments ;++i)
 		{
@@ -232,34 +237,42 @@ BOOL LLVOWLSky::updateGeometry(LLDrawable * drawable)
 			const U32 num_indices_this_seg = 1+num_stacks_this_seg*(2+2*verts_per_stack);
 			llassert(num_indices_this_seg * sizeof(U16) <= max_buffer_bytes);
 
-			if (!segment->allocateBuffer(num_verts_this_seg, num_indices_this_seg, TRUE))
+			bool allocated = segment->allocateBuffer(num_verts_this_seg, num_indices_this_seg, TRUE);
+#if RELEASE_SHOW_WARNS
+			if( !allocated )
 			{
 				LL_WARNS() << "Failed to allocate Vertex Buffer on update to "
 					<< num_verts_this_seg << " vertices and "
 					<< num_indices_this_seg << " indices" << LL_ENDL;
 			}
+#else
+			(void) allocated;
+#endif
 
 			// lock the buffer
 			BOOL success = segment->getVertexStrider(vertices)
 				&& segment->getTexCoord0Strider(texCoords)
 				&& segment->getIndexStrider(indices);
 
-			if(!success) 
+#if RELEASE_SHOW_DEBUG
+			if(!success)
 			{
 				LL_ERRS() << "Failed updating WindLight sky geometry." << LL_ENDL;
 			}
-
-            U32 vertex_count = 0;
-            U32 index_count  = 0;
+#else
+			(void) success;
+#endif
 
 			// fill it
-			buildStripsBuffer(begin_stack, end_stack, vertex_count, index_count, vertices, texCoords, indices);
+			buildStripsBuffer(begin_stack, end_stack, vertices, texCoords, indices, dome_radius, verts_per_stack, total_stacks);
 
 			// and unlock the buffer
 			segment->flush();
 		}
 	
+#if RELEASE_SHOW_DEBUG
 		LL_INFOS() << "completed in " << llformat("%.2f", timer.getElapsedTimeF32().value()) << "seconds" << LL_ENDL;
+#endif
 	}
 
 	updateStarColors();
@@ -364,23 +377,16 @@ void LLVOWLSky::initStars()
 
 void LLVOWLSky::buildStripsBuffer(U32 begin_stack,
                                   U32 end_stack,
-                                  U32& vertex_count,
-                                  U32& index_count,
-								  LLStrider<LLVector3> & vertices,
-								  LLStrider<LLVector2> & texCoords,
-								  LLStrider<U16> & indices)
+                                  LLStrider<LLVector3> & vertices,
+                                  LLStrider<LLVector2> & texCoords,
+                                  LLStrider<U16> & indices,
+                                  const F32 dome_radius,
+                                  const U32& num_slices,
+                                  const U32& num_stacks)
 {
-    const F32 RADIUS = LLEnvironment::instance().getCurrentSky()->getDomeRadius();
-
-	U32 i, j, num_slices, num_stacks;
+	U32 i, j;
 	F32 phi0, theta, x0, y0, z0;
-
-	// paranoia checking for SL-55986/SL-55833
-	U32 count_verts = 0;
-	U32 count_indices = 0;
-
-	num_slices = getNumSlices();
-	num_stacks = getNumStacks();
+	const F32 reciprocal_num_stacks = 1.f / num_stacks;
 
 	llassert(end_stack <= num_stacks);
 
@@ -391,7 +397,7 @@ void LLVOWLSky::buildStripsBuffer(U32 begin_stack,
     for(i = begin_stack + 1; i <= end_stack+1; ++i) 
 #endif
 	{
-		phi0 = calcPhi(i);
+		phi0 = calcPhi(i, reciprocal_num_stacks);
 
 		for(j = 0; j < num_slices; ++j)
 		{
@@ -404,24 +410,22 @@ void LLVOWLSky::buildStripsBuffer(U32 begin_stack,
 			z0 = sin(phi0) * sin(theta);
 
 #if NEW_TESS
-            *vertices++ = LLVector3(x0 * RADIUS, y0 * RADIUS, z0 * RADIUS);
+            *vertices++ = LLVector3(x0 * dome_radius, y0 * dome_radius, z0 * dome_radius);
 #else
             if (i == num_stacks-2)
 			{
-				*vertices++ = LLVector3(x0*RADIUS, y0*RADIUS-1024.f*2.f, z0*RADIUS);
+				*vertices++ = LLVector3(x0*dome_radius, y0*dome_radius-1024.f*2.f, z0*dome_radius);
 			}
 			else if (i == num_stacks-1)
 			{
-				*vertices++ = LLVector3(0, y0*RADIUS-1024.f*2.f, 0);
+				*vertices++ = LLVector3(0, y0*dome_radius-1024.f*2.f, 0);
 			}
 			else
 			{
-				*vertices++		= LLVector3(x0 * RADIUS, y0 * RADIUS, z0 * RADIUS);
+				*vertices++		= LLVector3(x0 * dome_radius, y0 * dome_radius, z0 * dome_radius);
 			}
 #endif
 
-			++count_verts;
-
 			// generate planar uv coordinates
 			// note: x and z are transposed in order for things to animate
 			// correctly in the global coordinate system where +x is east and
@@ -432,12 +436,11 @@ void LLVOWLSky::buildStripsBuffer(U32 begin_stack,
 
 	//build triangle strip...
 	*indices++ = 0 ;
-	count_indices++ ;
+
 	S32 k = 0 ;
 	for(i = 1; i <= end_stack - begin_stack; ++i) 
 	{
 		*indices++ = i * num_slices + k ;
-		count_indices++ ;
 
 		k = (k+1) % num_slices ;
 		for(j = 0; j < num_slices ; ++j) 
@@ -445,8 +448,6 @@ void LLVOWLSky::buildStripsBuffer(U32 begin_stack,
 			*indices++ = (i-1) * num_slices + k ;
 			*indices++ = i * num_slices + k ;
 
-			count_indices += 2 ;
-
 			k = (k+1) % num_slices ;
 		}
 
@@ -456,11 +457,7 @@ void LLVOWLSky::buildStripsBuffer(U32 begin_stack,
 		}
 
 		*indices++ = i * num_slices + k ;
-		count_indices++ ;
 	}
-
-    vertex_count = count_verts;
-    index_count = count_indices;
 }
 
 void LLVOWLSky::updateStarColors()
diff --git a/indra/newview/llvowlsky.h b/indra/newview/llvowlsky.h
index 2b7ebe75dd..3853dd2c70 100644
--- a/indra/newview/llvowlsky.h
+++ b/indra/newview/llvowlsky.h
@@ -55,8 +55,6 @@ public:
 	void restoreGL();
 
 private:
-	// a tiny helper function for controlling the sky dome tesselation.
-	static F32 calcPhi(U32 i);
 
 	// helper function for initializing the stars.
 	void initStars();
@@ -66,11 +64,12 @@ private:
 	// begin_stack is the first stack to be included, end_stack is the first
 	// stack not to be included.
 	static void buildStripsBuffer(U32 begin_stack, U32 end_stack,
-                                  U32& vertex_count,
-                                  U32& index_count,
-								  LLStrider<LLVector3> & vertices,
-								  LLStrider<LLVector2> & texCoords,
-								  LLStrider<U16> & indices);
+                                  LLStrider<LLVector3> & vertices,
+                                  LLStrider<LLVector2> & texCoords,
+                                  LLStrider<U16> & indices,
+                                  const F32 RADIUS,
+                                  const U32& num_slices,
+                                  const U32& num_stacks);
 
 	// helper function for updating the stars colors.
 	void updateStarColors();
diff --git a/indra/newview/pipeline.cpp b/indra/newview/pipeline.cpp
index 6ed6e20b03..71a438302a 100644
--- a/indra/newview/pipeline.cpp
+++ b/indra/newview/pipeline.cpp
@@ -1231,7 +1231,8 @@ void LLPipeline::releaseShadowTargets()
 
 void LLPipeline::createGLBuffers()
 {
-	stop_glerror();
+    LL_PROFILE_ZONE_SCOPED;
+    stop_glerror();
 	assertInitialized();
 
 	updateRenderDeferred();
@@ -1384,7 +1385,7 @@ void LLPipeline::restoreGL()
 			if (part)
 			{
 				part->restoreGL();
-			}
+		}
 		}
 	}
 }
@@ -2428,8 +2429,7 @@ void LLPipeline::updateCull(LLCamera& camera, LLCullResult& result, S32 water_cl
 		LLVOCachePartition* vo_part = region->getVOCachePartition();
 		if(vo_part)
 		{
-			bool do_occlusion_cull = can_use_occlusion && use_occlusion && !gUseWireframe && 0 > water_clip /* && !gViewerWindow->getProgressView()->getVisible()*/;
-            do_occlusion_cull &= !sReflectionRender;
+            bool do_occlusion_cull = can_use_occlusion && use_occlusion && !gUseWireframe; // && 0 > water_clip
 			vo_part->cull(camera, do_occlusion_cull);
 		}
 	}
@@ -2629,7 +2629,8 @@ void LLPipeline::doOcclusion(LLCamera& camera, LLRenderTarget& source, LLRenderT
 
 void LLPipeline::doOcclusion(LLCamera& camera)
 {
-	if (LLPipeline::sUseOcclusion > 1 && !LLSpatialPartition::sTeleportRequested && 
+    LL_PROFILE_ZONE_SCOPED;
+    if (LLPipeline::sUseOcclusion > 1 && !LLSpatialPartition::sTeleportRequested &&
 		(sCull->hasOcclusionGroups() || LLVOCachePartition::sNeedsOcclusionCheck))
 	{
 		LLVertexBuffer::unbind();
@@ -3422,7 +3423,8 @@ void LLPipeline::stateSort(LLSpatialGroup* group, LLCamera& camera)
 
 void LLPipeline::stateSort(LLSpatialBridge* bridge, LLCamera& camera, BOOL fov_changed)
 {
-	if (bridge->getSpatialGroup()->changeLOD() || fov_changed)
+    LL_PROFILE_ZONE_SCOPED;
+    if (bridge->getSpatialGroup()->changeLOD() || fov_changed)
 	{
 		bool force_update = false;
 		bridge->updateDistance(camera, force_update);
@@ -3431,7 +3433,8 @@ void LLPipeline::stateSort(LLSpatialBridge* bridge, LLCamera& camera, BOOL fov_c
 
 void LLPipeline::stateSort(LLDrawable* drawablep, LLCamera& camera)
 {
-	if (!drawablep
+    LL_PROFILE_ZONE_SCOPED;
+    if (!drawablep
 		|| drawablep->isDead() 
 		|| !hasRenderType(drawablep->getRenderType()))
 	{
@@ -4708,7 +4711,8 @@ void LLPipeline::renderGeomPostDeferred(LLCamera& camera, bool do_occlusion)
 
 void LLPipeline::renderGeomShadow(LLCamera& camera)
 {
-	U32 cur_type = 0;
+    LL_PROFILE_ZONE_SCOPED;
+    U32 cur_type = 0;
 	
 	LLGLEnable cull(GL_CULL_FACE);
 
@@ -8384,15 +8388,13 @@ LLVector4 pow4fsrgb(LLVector4 v, F32 f)
 	return v;
 }
 
-static LLTrace::BlockTimerStatHandle FTM_DEFERRED_LIGHTING("Deferred Lighting");
-
 void LLPipeline::renderDeferredLighting(LLRenderTarget *screen_target)
 {
+    LL_PROFILE_ZONE_SCOPED;
     if (!sCull)
     {
         return;
     }
-    LL_RECORD_BLOCK_TIME(FTM_DEFERRED_LIGHTING);
 
     LLRenderTarget *deferred_target       = &mDeferredScreen;
     LLRenderTarget *deferred_depth_target = &mDeferredDepth;
@@ -9200,6 +9202,7 @@ inline float sgn(float a)
 
 void LLPipeline::generateWaterReflection(LLCamera& camera_in)
 {
+    LL_PROFILE_ZONE_SCOPED;
     if (LLPipeline::sWaterReflections && assertInitialized() && LLDrawPoolWater::sNeedsReflectionUpdate)
     {
         bool skip_avatar_update = false;
@@ -9254,11 +9257,6 @@ void LLPipeline::generateWaterReflection(LLCamera& camera_in)
             water_clip = -1;
         }
 
-        S32 occlusion = LLPipeline::sUseOcclusion;
-
-        //disable occlusion culling for reflection map for now
-        LLPipeline::sUseOcclusion = 0;
-
         if (!camera_is_underwater)
         {
             //generate planar reflection map
@@ -9374,8 +9372,6 @@ void LLPipeline::generateWaterReflection(LLCamera& camera_in)
             set_current_modelview(saved_modelview);
         }
 
-        //LLPipeline::sUseOcclusion = occlusion;
-
         camera.setOrigin(camera_in.getOrigin());
         //render distortion map
         static bool last_update = true;
@@ -9470,7 +9466,6 @@ void LLPipeline::generateWaterReflection(LLCamera& camera_in)
 
         gPipeline.popRenderTypeMask();
 
-        LLPipeline::sUseOcclusion     = occlusion;
         LLPipeline::sUnderWaterRender = false;
         LLPipeline::sReflectionRender = false;
 
diff --git a/indra/newview/skins/default/xui/en/floater_preferences_graphics_advanced.xml b/indra/newview/skins/default/xui/en/floater_preferences_graphics_advanced.xml
index 7786ba8a1c..cba75e8ea7 100644
--- a/indra/newview/skins/default/xui/en/floater_preferences_graphics_advanced.xml
+++ b/indra/newview/skins/default/xui/en/floater_preferences_graphics_advanced.xml
@@ -334,15 +334,15 @@
     width="256" />
 
   <check_box
-    control_name="RenderVBOEnable"
+    control_name="RenderVSyncEnable"
     height="16"
     initial_value="true"
-    label="Enable OpenGL Vertex Buffer Objects"
+    label="Enable VSync"
     layout="topleft"
     left="30"
     top_delta="16"
-    name="vbo"
-    tool_tip="Enabling this on modern hardware gives a performance gain.  However, older hardware often has poor implementations of VBOs and you may get crashes when this is enabled."
+    name="vsync"
+    tool_tip="Synchronizes the frame rate to the refresh rate of the monitor, which results in smooth performance."
     width="315" />
 
   <check_box