Port of SNOW-643 : Water flicker at high altitude. This doesn't fix the low altitude flicker though (STORM-306)

28 files changed, 448 insertions, 159 deletions

diff --git a/indra/llrender/llgl.cpp b/indra/llrender/llgl.cpp
index c0edd92bc1..096e8e07ab 100644
--- a/indra/llrender/llgl.cpp
+++ b/indra/llrender/llgl.cpp
@@ -610,41 +610,46 @@ void LLGLManager::shutdownGL()
 void LLGLManager::initExtensions()
 {
 #if LL_MESA_HEADLESS
-# if GL_ARB_multitexture
+# ifdef GL_ARB_multitexture
 	mHasMultitexture = TRUE;
 # else
 	mHasMultitexture = FALSE;
 # endif
-# if GL_ARB_texture_env_combine
+# ifdef GL_ARB_texture_env_combine
 	mHasARBEnvCombine = TRUE;	
 # else
 	mHasARBEnvCombine = FALSE;
 # endif
-# if GL_ARB_texture_compression
+# ifdef GL_ARB_texture_compression
 	mHasCompressedTextures = TRUE;
 # else
 	mHasCompressedTextures = FALSE;
 # endif
-# if GL_ARB_vertex_buffer_object
+# ifdef GL_ARB_vertex_buffer_object
 	mHasVertexBufferObject = TRUE;
 # else
 	mHasVertexBufferObject = FALSE;
 # endif
-# if GL_EXT_framebuffer_object
+# ifdef GL_EXT_framebuffer_object
 	mHasFramebufferObject = TRUE;
 # else
 	mHasFramebufferObject = FALSE;
 # endif
-# if GL_EXT_framebuffer_multisample
+# ifdef GL_EXT_framebuffer_multisample
 	mHasFramebufferMultisample = TRUE;
 # else
 	mHasFramebufferMultisample = FALSE;
 # endif
-# if GL_ARB_draw_buffers
+# ifdef GL_ARB_draw_buffers
 	mHasDrawBuffers = TRUE;
 #else
 	mHasDrawBuffers = FALSE;
 # endif
+# if defined(GL_NV_depth_clamp) || defined(GL_ARB_depth_clamp)
+	mHasDepthClamp = TRUE;
+#else
+	mHasDepthClamp = FALSE;
+#endif
 # if GL_EXT_blend_func_separate
 	mHasBlendFuncSeparate = TRUE;
 #else
@@ -671,6 +676,7 @@ void LLGLManager::initExtensions()
 	mHasCompressedTextures = glh_init_extensions("GL_ARB_texture_compression");
 	mHasOcclusionQuery = ExtensionExists("GL_ARB_occlusion_query", gGLHExts.mSysExts);
 	mHasVertexBufferObject = ExtensionExists("GL_ARB_vertex_buffer_object", gGLHExts.mSysExts);
+	mHasDepthClamp = ExtensionExists("GL_ARB_depth_clamp", gGLHExts.mSysExts) || ExtensionExists("GL_NV_depth_clamp", gGLHExts.mSysExts);
 	// mask out FBO support when packed_depth_stencil isn't there 'cause we need it for LLRenderTarget -Brad
 	mHasFramebufferObject = ExtensionExists("GL_EXT_framebuffer_object", gGLHExts.mSysExts)
 		&& ExtensionExists("GL_EXT_packed_depth_stencil", gGLHExts.mSysExts);
@@ -694,6 +700,7 @@ void LLGLManager::initExtensions()
 	if (getenv("LL_GL_NOEXT"))
 	{
 		//mHasMultitexture = FALSE; // NEEDED!
+		mHasDepthClamp = FALSE;
 		mHasARBEnvCombine = FALSE;
 		mHasCompressedTextures = FALSE;
 		mHasVertexBufferObject = FALSE;
@@ -755,6 +762,7 @@ void LLGLManager::initExtensions()
 		if (strchr(blacklist,'s')) mHasFramebufferMultisample = FALSE;
 		if (strchr(blacklist,'t')) mHasTextureRectangle = FALSE;
 		if (strchr(blacklist,'u')) mHasBlendFuncSeparate = FALSE;//S
+		if (strchr(blacklist,'v')) mHasDepthClamp = FALSE;
 		
 	}
 #endif // LL_LINUX || LL_SOLARIS
@@ -2037,7 +2045,7 @@ void LLGLDepthTest::checkState()
 	}
 }
 
-LLGLClampToFarClip::LLGLClampToFarClip(glh::matrix4f P)
+LLGLSquashToFarClip::LLGLSquashToFarClip(glh::matrix4f P)
 {
 	for (U32 i = 0; i < 4; i++)
 	{
@@ -2050,7 +2058,7 @@ LLGLClampToFarClip::LLGLClampToFarClip(glh::matrix4f P)
 	glMatrixMode(GL_MODELVIEW);
 }
 
-LLGLClampToFarClip::~LLGLClampToFarClip()
+LLGLSquashToFarClip::~LLGLSquashToFarClip()
 {
 	glMatrixMode(GL_PROJECTION);
 	glPopMatrix();
diff --git a/indra/llrender/llgl.h b/indra/llrender/llgl.h
index 5e8965c06a..b0decc1499 100644
--- a/indra/llrender/llgl.h
+++ b/indra/llrender/llgl.h
@@ -92,6 +92,7 @@ public:
 	BOOL mHasOcclusionQuery;
 	BOOL mHasPointParameters;
 	BOOL mHasDrawBuffers;
+	BOOL mHasDepthClamp;
 	BOOL mHasTextureRectangle;
 
 	// Other extensions.
@@ -315,11 +316,11 @@ private:
   leaves this class.
   Does not stack.
 */
-class LLGLClampToFarClip
+class LLGLSquashToFarClip
 {
 public:
-	LLGLClampToFarClip(glh::matrix4f projection);
-	~LLGLClampToFarClip();
+	LLGLSquashToFarClip(glh::matrix4f projection);
+	~LLGLSquashToFarClip();
 };
 
 /*
diff --git a/indra/llrender/llglheaders.h b/indra/llrender/llglheaders.h
index 5a34b46d0c..576969b81a 100644
--- a/indra/llrender/llglheaders.h
+++ b/indra/llrender/llglheaders.h
@@ -829,5 +829,15 @@ extern void glGetBufferPointervARB (GLenum, GLenum, GLvoid* *);
 
 #endif // LL_MESA / LL_WINDOWS / LL_DARWIN
 
+// Even when GL_ARB_depth_clamp is available in the driver, the (correct)
+// headers, and therefore GL_DEPTH_CLAMP might not be defined.
+// In that case GL_DEPTH_CLAMP_NV should be defined, but why not just
+// use the known numeric.
+//
+// To avoid #ifdef's in the code. Just define this here.
+#ifndef GL_DEPTH_CLAMP
+// Probably (still) called GL_DEPTH_CLAMP_NV.
+#define GL_DEPTH_CLAMP 0x864F
+#endif
 
 #endif // LL_LLGLHEADERS_H
diff --git a/indra/newview/lldrawable.cpp b/indra/newview/lldrawable.cpp
index 583bb54160..8106fada11 100644
--- a/indra/newview/lldrawable.cpp
+++ b/indra/newview/lldrawable.cpp
@@ -358,6 +358,7 @@ void LLDrawable::makeActive()
 	{
 		U32 pcode = mVObjp->getPCode();
 		if (pcode == LLViewerObject::LL_VO_WATER ||
+			pcode == LLViewerObject::LL_VO_VOID_WATER ||
 			pcode == LLViewerObject::LL_VO_SURFACE_PATCH ||
 			pcode == LLViewerObject::LL_VO_PART_GROUP ||
 			pcode == LLViewerObject::LL_VO_HUD_PART_GROUP ||
diff --git a/indra/newview/lldrawpool.cpp b/indra/newview/lldrawpool.cpp
index cb651f9d3a..ba576ff97f 100644
--- a/indra/newview/lldrawpool.cpp
+++ b/indra/newview/lldrawpool.cpp
@@ -89,6 +89,7 @@ LLDrawPool *LLDrawPool::createPool(const U32 type, LLViewerTexture *tex0)
 	case POOL_SKY:
 		poolp = new LLDrawPoolSky();
 		break;
+	case POOL_VOIDWATER:
 	case POOL_WATER:
 		poolp = new LLDrawPoolWater();
 		break;
diff --git a/indra/newview/lldrawpool.h b/indra/newview/lldrawpool.h
index 221f81ec25..e394aeaaf1 100644
--- a/indra/newview/lldrawpool.h
+++ b/indra/newview/lldrawpool.h
@@ -57,6 +57,7 @@ public:
 		POOL_BUMP,
 		POOL_INVISIBLE, // see below *
 		POOL_AVATAR,
+		POOL_VOIDWATER,
 		POOL_WATER,
 		POOL_GLOW,
 		POOL_ALPHA,
diff --git a/indra/newview/lldrawpoolground.cpp b/indra/newview/lldrawpoolground.cpp
index e950fbfa82..b4dc0c26a6 100644
--- a/indra/newview/lldrawpoolground.cpp
+++ b/indra/newview/lldrawpoolground.cpp
@@ -68,7 +68,7 @@ void LLDrawPoolGround::render(S32 pass)
 
 	LLGLDepthTest gls_depth(GL_TRUE, GL_FALSE);
 
-	LLGLClampToFarClip far_clip(glh_get_current_projection());
+	LLGLSquashToFarClip far_clip(glh_get_current_projection());
 
 	F32 water_height = gAgent.getRegion()->getWaterHeight();
 	glPushMatrix();
diff --git a/indra/newview/lldrawpoolsky.cpp b/indra/newview/lldrawpoolsky.cpp
index d811ab8c54..9eb45a952c 100644
--- a/indra/newview/lldrawpoolsky.cpp
+++ b/indra/newview/lldrawpoolsky.cpp
@@ -97,7 +97,7 @@ void LLDrawPoolSky::render(S32 pass)
 
 	LLGLDepthTest gls_depth(GL_TRUE, GL_FALSE);
 
-	LLGLClampToFarClip far_clip(glh_get_current_projection());
+	LLGLSquashToFarClip far_clip(glh_get_current_projection());
 
 	LLGLEnable fog_enable( (mVertexShaderLevel < 1 && LLViewerCamera::getInstance()->cameraUnderWater()) ? GL_FOG : 0);
 
diff --git a/indra/newview/lldrawpoolwater.cpp b/indra/newview/lldrawpoolwater.cpp
index ce1b899d55..6126908231 100644
--- a/indra/newview/lldrawpoolwater.cpp
+++ b/indra/newview/lldrawpoolwater.cpp
@@ -532,6 +532,7 @@ void LLDrawPoolWater::shade()
 	glColor4fv(water_color.mV);
 
 	{
+		LLGLEnable depth_clamp(gGLManager.mHasDepthClamp ? GL_DEPTH_CLAMP : 0);
 		LLGLDisable cullface(GL_CULL_FACE);
 		for (std::vector<LLFace*>::iterator iter = mDrawFace.begin();
 			iter != mDrawFace.end(); iter++)
@@ -548,30 +549,19 @@ void LLDrawPoolWater::shade()
 
 			sNeedsReflectionUpdate = TRUE;
 			
-			if (water->getUseTexture())
+			if (water->getUseTexture() || !water->getIsEdgePatch())
 			{
 				sNeedsDistortionUpdate = TRUE;
 				face->renderIndexed();
 			}
+			else if (gGLManager.mHasDepthClamp || deferred_render)
+			{
+				face->renderIndexed();
+			}
 			else
-			{ //smash background faces to far clip plane
-				if (water->getIsEdgePatch())
-				{
-					if (deferred_render)
-					{
-						face->renderIndexed();
-					}
-					else
-					{
-						LLGLClampToFarClip far_clip(glh_get_current_projection());
-						face->renderIndexed();
-					}
-				}
-				else
-				{
-					sNeedsDistortionUpdate = TRUE;
-					face->renderIndexed();
-				}
+			{
+				LLGLSquashToFarClip far_clip(glh_get_current_projection());
+				face->renderIndexed();
 			}
 		}
 	}
diff --git a/indra/newview/lldrawpoolwlsky.cpp b/indra/newview/lldrawpoolwlsky.cpp
index 41a299151e..eaa6aa7e37 100644
--- a/indra/newview/lldrawpoolwlsky.cpp
+++ b/indra/newview/lldrawpoolwlsky.cpp
@@ -260,7 +260,7 @@ void LLDrawPoolWLSky::render(S32 pass)
 	LLGLDepthTest depth(GL_TRUE, GL_FALSE);
 	LLGLDisable clip(GL_CLIP_PLANE0);
 
-	LLGLClampToFarClip far_clip(glh_get_current_projection());
+	LLGLSquashToFarClip far_clip(glh_get_current_projection());
 
 	renderSkyHaze(camHeightLocal);
 
diff --git a/indra/newview/llfloatergodtools.cpp b/indra/newview/llfloatergodtools.cpp
index f95112a8ab..087e4abe7e 100644
--- a/indra/newview/llfloatergodtools.cpp
+++ b/indra/newview/llfloatergodtools.cpp
@@ -210,13 +210,6 @@ void LLFloaterGodTools::processRegionInfo(LLMessageSystem* msg)
 	llassert(msg);
 	if (!msg) return;
 
-	LLHost host = msg->getSender();
-	if (host != gAgent.getRegionHost())
-	{
-		// update is for a different region than the one we're in
-		return;
-	}
-
 	//const S32 SIM_NAME_BUF = 256;
 	U32 region_flags;
 	U8 sim_access;
@@ -234,6 +227,8 @@ void LLFloaterGodTools::processRegionInfo(LLMessageSystem* msg)
 	S32 redirect_grid_y;
 	LLUUID cache_id;
 
+	LLHost host = msg->getSender();
+
 	msg->getStringFast(_PREHASH_RegionInfo, _PREHASH_SimName, sim_name);
 	msg->getU32Fast(_PREHASH_RegionInfo, _PREHASH_EstateID, estate_id);
 	msg->getU32Fast(_PREHASH_RegionInfo, _PREHASH_ParentEstateID, parent_estate_id);
@@ -243,6 +238,15 @@ void LLFloaterGodTools::processRegionInfo(LLMessageSystem* msg)
 	msg->getF32Fast(_PREHASH_RegionInfo, _PREHASH_ObjectBonusFactor, object_bonus_factor);
 	msg->getF32Fast(_PREHASH_RegionInfo, _PREHASH_BillableFactor, billable_factor);
 	msg->getF32Fast(_PREHASH_RegionInfo, _PREHASH_WaterHeight, water_height);
+
+	if (host != gAgent.getRegionHost())
+	{
+		// Update is for a different region than the one we're in.
+		// Just check for a waterheight change.
+		LLWorld::getInstance()->waterHeightRegionInfo(sim_name, water_height);
+		return;
+	}
+
 	msg->getF32Fast(_PREHASH_RegionInfo, _PREHASH_TerrainRaiseLimit, terrain_raise_limit);
 	msg->getF32Fast(_PREHASH_RegionInfo, _PREHASH_TerrainLowerLimit, terrain_lower_limit);
 	msg->getS32Fast(_PREHASH_RegionInfo, _PREHASH_PricePerMeter, price_per_meter);
diff --git a/indra/newview/llspatialpartition.cpp b/indra/newview/llspatialpartition.cpp
index fb984a7c62..960e72ee42 100644
--- a/indra/newview/llspatialpartition.cpp
+++ b/indra/newview/llspatialpartition.cpp
@@ -1555,7 +1555,9 @@ void LLSpatialGroup::doOcclusion(LLCamera* camera)
 {
 	if (mSpatialPartition->isOcclusionEnabled() && LLPipeline::sUseOcclusion > 1)
 	{
-		if (earlyFail(camera, this))
+		// Don't cull hole/edge water, unless we have the GL_ARB_depth_clamp extension
+		if ((mSpatialPartition->mDrawableType == LLDrawPool::POOL_VOIDWATER && !gGLManager.mHasDepthClamp) ||
+			earlyFail(camera, this))
 		{
 			setOcclusionState(LLSpatialGroup::DISCARD_QUERY);
 			assert_states_valid(this);
@@ -1576,7 +1578,18 @@ void LLSpatialGroup::doOcclusion(LLCamera* camera)
 				{
 					buildOcclusion();
 				}
-
+				
+				// Depth clamp all water to avoid it being culled as a result of being
+				// behind the far clip plane, and in the case of edge water to avoid
+				// it being culled while still visible.
+				bool const use_depth_clamp = gGLManager.mHasDepthClamp &&
+											(mSpatialPartition->mDrawableType == LLDrawPool::POOL_WATER ||
+											mSpatialPartition->mDrawableType == LLDrawPool::POOL_VOIDWATER);
+				if (use_depth_clamp)
+				{
+					glEnable(GL_DEPTH_CLAMP);
+				}
+				
 				glBeginQueryARB(GL_SAMPLES_PASSED_ARB, mOcclusionQuery[LLViewerCamera::sCurCameraID]);					
 				glVertexPointer(3, GL_FLOAT, 0, mOcclusionVerts);
 				if (camera->getOrigin().isExactlyZero())
@@ -1592,6 +1605,11 @@ void LLSpatialGroup::doOcclusion(LLCamera* camera)
 								GL_UNSIGNED_BYTE, get_box_fan_indices(camera, mBounds[0]));
 				}
 				glEndQueryARB(GL_SAMPLES_PASSED_ARB);
+				
+				if (use_depth_clamp)
+				{
+					glDisable(GL_DEPTH_CLAMP);
+				}
 			}
 
 			setOcclusionState(LLSpatialGroup::QUERY_PENDING);
@@ -2591,9 +2609,10 @@ void renderBoundingBox(LLDrawable* drawable, BOOL set_color = TRUE)
 						gGL.color4f(0.5f,0.5f,0.5f,1.0f);
 						break;
 				case LLViewerObject::LL_VO_PART_GROUP:
-			case LLViewerObject::LL_VO_HUD_PART_GROUP:
+				case LLViewerObject::LL_VO_HUD_PART_GROUP:
 						gGL.color4f(0,0,1,1);
 						break;
+				case LLViewerObject::LL_VO_VOID_WATER:
 				case LLViewerObject::LL_VO_WATER:
 						gGL.color4f(0,0.5f,1,1);
 						break;
diff --git a/indra/newview/llspatialpartition.h b/indra/newview/llspatialpartition.h
index 1a25f3f85d..2b9cf6c630 100644
--- a/indra/newview/llspatialpartition.h
+++ b/indra/newview/llspatialpartition.h
@@ -551,6 +551,13 @@ public:
 	virtual void addGeometryCount(LLSpatialGroup* group, U32 &vertex_count, U32& index_count) { }
 };
 
+//spatial partition for hole and edge water (implemented in LLVOWater.cpp)
+class LLVoidWaterPartition : public LLWaterPartition
+{
+public:
+	LLVoidWaterPartition();
+};
+
 //spatial partition for terrain (impelmented in LLVOSurfacePatch.cpp)
 class LLTerrainPartition : public LLSpatialPartition
 {
diff --git a/indra/newview/llsurface.cpp b/indra/newview/llsurface.cpp
index af4d9fa7b9..6fc8153b77 100644
--- a/indra/newview/llsurface.cpp
+++ b/indra/newview/llsurface.cpp
@@ -1162,8 +1162,13 @@ void LLSurface::setWaterHeight(F32 height)
 	if (!mWaterObjp.isNull())
 	{
 		LLVector3 water_pos_region = mWaterObjp->getPositionRegion();
+		bool changed = water_pos_region.mV[VZ] != height;
 		water_pos_region.mV[VZ] = height;
 		mWaterObjp->setPositionRegion(water_pos_region);
+		if (changed)
+		{
+			LLWorld::getInstance()->updateWaterObjects();
+		}
 	}
 	else
 	{
diff --git a/indra/newview/llviewerdisplay.cpp b/indra/newview/llviewerdisplay.cpp
index 916cbe2267..10c5a27aa7 100644
--- a/indra/newview/llviewerdisplay.cpp
+++ b/indra/newview/llviewerdisplay.cpp
@@ -573,7 +573,8 @@ void display(BOOL rebuild, F32 zoom_factor, int subfield, BOOL for_snapshot)
 
 		S32 water_clip = 0;
 		if ((LLViewerShaderMgr::instance()->getVertexShaderLevel(LLViewerShaderMgr::SHADER_ENVIRONMENT) > 1) &&
-			 gPipeline.hasRenderType(LLPipeline::RENDER_TYPE_WATER))
+			 (gPipeline.hasRenderType(LLPipeline::RENDER_TYPE_WATER) || 
+			  gPipeline.hasRenderType(LLPipeline::RENDER_TYPE_VOIDWATER)))
 		{
 			if (LLViewerCamera::getInstance()->cameraUnderWater())
 			{
diff --git a/indra/newview/llviewerobject.cpp b/indra/newview/llviewerobject.cpp
index 741a9e6ec4..4ef1853095 100644
--- a/indra/newview/llviewerobject.cpp
+++ b/indra/newview/llviewerobject.cpp
@@ -167,8 +167,10 @@ LLViewerObject *LLViewerObject::createObject(const LLUUID &id, const LLPCode pco
 	  res = new LLVOSurfacePatch(id, pcode, regionp); break;
 	case LL_VO_SKY:
 	  res = new LLVOSky(id, pcode, regionp); break;
+	case LL_VO_VOID_WATER:
+		res = new LLVOVoidWater(id, pcode, regionp); break;
 	case LL_VO_WATER:
-	  res = new LLVOWater(id, pcode, regionp); break;
+		res = new LLVOWater(id, pcode, regionp); break;
 	case LL_VO_GROUND:
 	  res = new LLVOGround(id, pcode, regionp); break;
 	case LL_VO_PART_GROUP:
diff --git a/indra/newview/llviewerobject.h b/indra/newview/llviewerobject.h
index bcc2cb164f..10683618cc 100644
--- a/indra/newview/llviewerobject.h
+++ b/indra/newview/llviewerobject.h
@@ -131,7 +131,7 @@ public:
 
 	typedef const child_list_t const_child_list_t;
 
-	LLViewerObject(const LLUUID &id, const LLPCode type, LLViewerRegion *regionp, BOOL is_global = FALSE);
+	LLViewerObject(const LLUUID &id, const LLPCode pcode, LLViewerRegion *regionp, BOOL is_global = FALSE);
 	MEM_TYPE_NEW(LLMemType::MTYPE_OBJECT);
 
 	virtual void markDead();				// Mark this object as dead, and clean up its references
@@ -518,14 +518,14 @@ public:
 	{
 		LL_VO_CLOUDS =				LL_PCODE_APP | 0x20,
 		LL_VO_SURFACE_PATCH =		LL_PCODE_APP | 0x30,
-		//LL_VO_STARS =				LL_PCODE_APP | 0x40,
+		LL_VO_WL_SKY =				LL_PCODE_APP | 0x40,
 		LL_VO_SQUARE_TORUS =		LL_PCODE_APP | 0x50,
 		LL_VO_SKY =					LL_PCODE_APP | 0x60,
-		LL_VO_WATER =				LL_PCODE_APP | 0x70,
-		LL_VO_GROUND =				LL_PCODE_APP | 0x80,
-		LL_VO_PART_GROUP =			LL_PCODE_APP | 0x90,
-		LL_VO_TRIANGLE_TORUS =		LL_PCODE_APP | 0xa0,
-		LL_VO_WL_SKY =				LL_PCODE_APP | 0xb0, // should this be moved to 0x40?
+		LL_VO_VOID_WATER =			LL_PCODE_APP | 0x70,
+		LL_VO_WATER =				LL_PCODE_APP | 0x80,
+		LL_VO_GROUND =				LL_PCODE_APP | 0x90,
+		LL_VO_PART_GROUP =			LL_PCODE_APP | 0xa0,
+		LL_VO_TRIANGLE_TORUS =		LL_PCODE_APP | 0xb0,
 		LL_VO_HUD_PART_GROUP =		LL_PCODE_APP | 0xc0,
 	} EVOType;
 
@@ -717,8 +717,8 @@ public:
 class LLAlphaObject : public LLViewerObject
 {
 public:
-	LLAlphaObject(const LLUUID &id, const LLPCode type, LLViewerRegion *regionp)
-	: LLViewerObject(id,type,regionp) 
+	LLAlphaObject(const LLUUID &id, const LLPCode pcode, LLViewerRegion *regionp)
+	: LLViewerObject(id,pcode,regionp) 
 	{ mDepth = 0.f; }
 
 	virtual F32 getPartSize(S32 idx);
@@ -735,8 +735,8 @@ public:
 class LLStaticViewerObject : public LLViewerObject
 {
 public:
-	LLStaticViewerObject(const LLUUID& id, const LLPCode type, LLViewerRegion* regionp, BOOL is_global = FALSE)
-		: LLViewerObject(id,type,regionp, is_global)
+	LLStaticViewerObject(const LLUUID& id, const LLPCode pcode, LLViewerRegion* regionp, BOOL is_global = FALSE)
+		: LLViewerObject(id,pcode,regionp, is_global)
 	{ }
 
 	virtual void updateDrawable(BOOL force_damped);
diff --git a/indra/newview/llviewerregion.cpp b/indra/newview/llviewerregion.cpp
index 98f16757b2..74e9b9f4a2 100644
--- a/indra/newview/llviewerregion.cpp
+++ b/indra/newview/llviewerregion.cpp
@@ -261,6 +261,7 @@ LLViewerRegion::LLViewerRegion(const U64 &handle,
 	//MUST MATCH declaration of eObjectPartitions
 	mObjectPartition.push_back(new LLHUDPartition());		//PARTITION_HUD
 	mObjectPartition.push_back(new LLTerrainPartition());	//PARTITION_TERRAIN
+	mObjectPartition.push_back(new LLVoidWaterPartition());	//PARTITION_VOIDWATER
 	mObjectPartition.push_back(new LLWaterPartition());		//PARTITION_WATER
 	mObjectPartition.push_back(new LLTreePartition());		//PARTITION_TREE
 	mObjectPartition.push_back(new LLParticlePartition());	//PARTITION_PARTICLE
diff --git a/indra/newview/llviewerregion.h b/indra/newview/llviewerregion.h
index 038c831e59..bf3948bef1 100644
--- a/indra/newview/llviewerregion.h
+++ b/indra/newview/llviewerregion.h
@@ -73,6 +73,7 @@ public:
 	{
 		PARTITION_HUD=0,
 		PARTITION_TERRAIN,
+		PARTITION_VOIDWATER,
 		PARTITION_WATER,
 		PARTITION_TREE,
 		PARTITION_PARTICLE,
diff --git a/indra/newview/llviewershadermgr.cpp b/indra/newview/llviewershadermgr.cpp
index d078c15316..c1abead36e 100644
--- a/indra/newview/llviewershadermgr.cpp
+++ b/indra/newview/llviewershadermgr.cpp
@@ -335,8 +335,8 @@ void LLViewerShaderMgr::setShaders()
 	}
 	else
 	{
-			LLPipeline::sRenderGlow = 
-			LLPipeline::sWaterReflections = FALSE;
+		LLPipeline::sRenderGlow = FALSE;
+		LLPipeline::sWaterReflections = FALSE;
 	}
 	
 	//hack to reset buffers that change behavior with shaders
diff --git a/indra/newview/llviewerwindow.cpp b/indra/newview/llviewerwindow.cpp
index 43d18c6d83..66b8d7cd69 100644
--- a/indra/newview/llviewerwindow.cpp
+++ b/indra/newview/llviewerwindow.cpp
@@ -1406,6 +1406,11 @@ LLViewerWindow::LLViewerWindow(
 		gSavedSettings.setBOOL("ProbeHardwareOnStartup", FALSE);
 	}
 
+	if (!gGLManager.mHasDepthClamp)
+	{
+		LL_INFOS("RenderInit") << "Missing feature GL_ARB_depth_clamp. Void water might disappear in rare cases." << LL_ENDL;
+	}
+	
 	// If we crashed while initializng GL stuff last time, disable certain features
 	if (gSavedSettings.getBOOL("RenderInitError"))
 	{
diff --git a/indra/newview/llvosurfacepatch.cpp b/indra/newview/llvosurfacepatch.cpp
index eba600b50a..2eb4398488 100644
--- a/indra/newview/llvosurfacepatch.cpp
+++ b/indra/newview/llvosurfacepatch.cpp
@@ -80,7 +80,7 @@ public:
 //============================================================================
 
 LLVOSurfacePatch::LLVOSurfacePatch(const LLUUID &id, const LLPCode pcode, LLViewerRegion *regionp)
-	:	LLStaticViewerObject(id, LL_VO_SURFACE_PATCH, regionp),
+	:	LLStaticViewerObject(id, pcode, regionp),
 		mDirtiedPatch(FALSE),
 		mPool(NULL),
 		mBaseComp(0),
diff --git a/indra/newview/llvowater.cpp b/indra/newview/llvowater.cpp
index 598938b710..9280eb8fa4 100644
--- a/indra/newview/llvowater.cpp
+++ b/indra/newview/llvowater.cpp
@@ -61,7 +61,8 @@ const F32 WAVE_STEP_INV	= (1. / WAVE_STEP);
 
 
 LLVOWater::LLVOWater(const LLUUID &id, const LLPCode pcode, LLViewerRegion *regionp)
-:	LLStaticViewerObject(id, LL_VO_WATER, regionp)
+:	LLStaticViewerObject(id, pcode, regionp),
+	mRenderType(LLPipeline::RENDER_TYPE_WATER)
 {
 	// Terrain must draw during selection passes so it can block objects behind it.
 	mbCanSelect = FALSE;
@@ -114,7 +115,7 @@ LLDrawable *LLVOWater::createDrawable(LLPipeline *pipeline)
 {
 	pipeline->allocDrawable(this);
 	mDrawable->setLit(FALSE);
-	mDrawable->setRenderType(LLPipeline::RENDER_TYPE_WATER);
+	mDrawable->setRenderType(mRenderType);
 
 	LLDrawPoolWater *pool = (LLDrawPoolWater*) gPipeline.getPool(LLDrawPool::POOL_WATER);
 
@@ -268,6 +269,11 @@ U32 LLVOWater::getPartitionType() const
 	return LLViewerRegion::PARTITION_WATER; 
 }
 
+U32 LLVOVoidWater::getPartitionType() const
+{
+	return LLViewerRegion::PARTITION_VOIDWATER;
+}
+
 LLWaterPartition::LLWaterPartition()
 : LLSpatialPartition(0, FALSE, 0)
 {
@@ -275,3 +281,9 @@ LLWaterPartition::LLWaterPartition()
 	mDrawableType = LLPipeline::RENDER_TYPE_WATER;
 	mPartitionType = LLViewerRegion::PARTITION_WATER;
 }
+
+LLVoidWaterPartition::LLVoidWaterPartition()
+{
+	mDrawableType = LLPipeline::RENDER_TYPE_VOIDWATER;
+	mPartitionType = LLViewerRegion::PARTITION_VOIDWATER;
+}
diff --git a/indra/newview/llvowater.h b/indra/newview/llvowater.h
index beefc3f17f..cb9584cabf 100644
--- a/indra/newview/llvowater.h
+++ b/indra/newview/llvowater.h
@@ -29,6 +29,7 @@
 
 #include "llviewerobject.h"
 #include "llviewertexture.h"
+#include "pipeline.h"
 #include "v2math.h"
 
 const U32 N_RES	= 16; //32			// number of subdivisions of wave tile
@@ -77,6 +78,19 @@ public:
 protected:
 	BOOL mUseTexture;
 	BOOL mIsEdgePatch;
+	S32  mRenderType; 
 };
 
+class LLVOVoidWater : public LLVOWater
+{
+public:
+	LLVOVoidWater(LLUUID const& id, LLPCode pcode, LLViewerRegion* regionp) : LLVOWater(id, pcode, regionp)
+	{
+		mRenderType = LLPipeline::RENDER_TYPE_VOIDWATER;
+	}
+
+	/*virtual*/ U32 getPartitionType() const;
+};
+
+
 #endif // LL_VOSURFACEPATCH_H
diff --git a/indra/newview/llworld.cpp b/indra/newview/llworld.cpp
index 5760d04a08..8731c9e1a7 100644
--- a/indra/newview/llworld.cpp
+++ b/indra/newview/llworld.cpp
@@ -55,6 +55,11 @@
 #include "pipeline.h"
 #include "llappviewer.h"		// for do_disconnect()
 
+#include <deque>
+#include <queue>
+#include <map>
+#include <cstring>
+
 //
 // Globals
 //
@@ -834,10 +839,69 @@ F32 LLWorld::getLandFarClip() const
 
 void LLWorld::setLandFarClip(const F32 far_clip)
 {
+	static S32 const rwidth = (S32)REGION_WIDTH_U32;
+	S32 const n1 = (llceil(mLandFarClip) - 1) / rwidth;
+	S32 const n2 = (llceil(far_clip) - 1) / rwidth;
+	bool need_water_objects_update = n1 != n2;
+
 	mLandFarClip = far_clip;
+
+	if (need_water_objects_update)
+	{
+		updateWaterObjects();
+	}
 }
 
+// Some region that we're connected to, but not the one we're in, gave us
+// a (possibly) new water height. Update it in our local copy.
+void LLWorld::waterHeightRegionInfo(std::string const& sim_name, F32 water_height)
+{
+	for (region_list_t::iterator iter = mRegionList.begin(); iter != mRegionList.end(); ++iter)
+	{
+		if ((*iter)->getName() == sim_name)
+		{
+			(*iter)->setWaterHeight(water_height);
+			break;
+		}
+	}
+}
 
+// There are three types of water objects:
+// Region water objects: the water in a region.
+// Hole water objects: water in the void but within current draw distance.
+// Edge water objects: the water outside the draw distance, up till the horizon.
+//
+// For example:
+//
+// -----------------------horizon-------------------------
+// |                 |                 |                 |
+// |  Edge Water     |                 |                 |
+// |                 |                 |                 |
+// |                 |                 |                 |
+// |                 |                 |                 |
+// |                 |                 |                 |
+// |                 |      rwidth     |                 |
+// |                 |     <----->     |                 |
+// -------------------------------------------------------
+// |                 |Hole |other|     |                 |
+// |                 |Water|reg. |     |                 |
+// |                 |-----------------|                 |
+// |                 |other|cur. |<--> |                 |
+// |                 |reg. | reg.|  \__|_ draw distance  |
+// |                 |-----------------|                 |
+// |                 |     |     |<--->|                 |
+// |                 |     |     |  \__|_ range          |
+// -------------------------------------------------------
+// |                 |<----width------>|<--horizon ext.->|
+// |                 |                 |                 |
+// |                 |                 |                 |
+// |                 |                 |                 |
+// |                 |                 |                 |
+// |                 |                 |                 |
+// |                 |                 |                 |
+// |                 |                 |                 |
+// -------------------------------------------------------
+//
 void LLWorld::updateWaterObjects()
 {
 	if (!gAgent.getRegion())
@@ -850,128 +914,265 @@ void LLWorld::updateWaterObjects()
 		return;
 	}
 
-	// First, determine the min and max "box" of water objects
-	S32 min_x = 0;
-	S32 min_y = 0;
-	S32 max_x = 0;
-	S32 max_y = 0;
+	// Region width in meters.
+	S32 const rwidth = (S32)REGION_WIDTH_U32;
+
+	// The distance we might see into the void
+	// when standing on the edge of a region, in meters.
+	S32 const draw_distance = llceil(mLandFarClip);
+
+	// We can only have "holes" in the water (where there no region) if we
+	// can have existing regions around it. Taking into account that this
+	// code is only executed when we enter a region, and not when we walk
+	// around in it, we (only) need to take into account regions that fall
+	// within the draw_distance.
+	//
+	// Set 'range' to draw_distance, rounded up to the nearest multiple of rwidth.
+	S32 const nsims = (draw_distance + rwidth - 1) / rwidth;
+	S32 const range = nsims * rwidth;
+
+	// Get South-West corner of current region.
+	LLViewerRegion const* regionp = gAgent.getRegion();
 	U32 region_x, region_y;
-
-	S32 rwidth = 256;
-
-	// We only want to fill in water for stuff that's near us, say, within 256 or 512m
-	S32 range = LLViewerCamera::getInstance()->getFar() > 256.f ? 512 : 256;
-
-	LLViewerRegion* regionp = gAgent.getRegion();
 	from_region_handle(regionp->getHandle(), &region_x, &region_y);
 
-	min_x = (S32)region_x - range;
-	min_y = (S32)region_y - range;
-	max_x = (S32)region_x + range;
-	max_y = (S32)region_y + range;
+	// The min. and max. coordinates of the South-West corners of the Hole water objects.
+	S32 const min_x = (S32)region_x - range;
+	S32 const min_y = (S32)region_y - range;
+	S32 const max_x = (S32)region_x + range;
+	S32 const max_y = (S32)region_y + range;
+
+	// Attempt to determine a sensible water height for all the
+	// Hole Water objects.
+	//
+	// It make little sense to try to guess what the best water
+	// height should be when that isn't completely obvious: if it's
+	// impossible to satisfy every region's water height without
+	// getting a jump in the water height.
+	//
+	// In order to keep the reasoning simple, we assume something
+	// logical as a group of connected regions, where the coastline
+	// is at the outer edge. Anything more complex that would "break"
+	// under such an assumption would probably break anyway (would
+	// depend on terrain editing and existing mega prims, say, if
+	// anything would make sense at all).
+	//
+	// So, what we do is find all connected regions within the
+	// draw distance that border void, and then pick the lowest
+	// water height of those (coast) regions.
+	S32 const n = 2 * nsims + 1;
+	S32 const origin = nsims + nsims * n;
+	std::vector<F32> water_heights(n * n);
+	std::vector<U8> checked(n * n, 0);		// index = nx + ny * n + origin;
+	U8 const region_bit = 1;
+	U8 const hole_bit = 2;
+	U8 const bordering_hole_bit = 4;
+	U8 const bordering_edge_bit = 8;
+	// Use the legacy waterheight for the Edge water in the case
+	// that we don't find any Hole water at all.
+	F32 water_height = DEFAULT_WATER_HEIGHT;
+	int max_count = 0;
+	LL_DEBUGS("WaterHeight") << "Current region: " << regionp->getName() << "; water height: " << regionp->getWaterHeight() << " m." << LL_ENDL;
+	std::map<S32, int> water_height_counts;
+	typedef std::queue<std::pair<S32, S32>, std::deque<std::pair<S32, S32> > > nxny_pairs_type;
+	nxny_pairs_type nxny_pairs;
+	nxny_pairs.push(nxny_pairs_type::value_type(0, 0));
+	water_heights[origin] = regionp->getWaterHeight();
+	checked[origin] = region_bit;
+	// For debugging purposes.
+	int number_of_connected_regions = 1;
+	int uninitialized_regions = 0;
+	int bordering_hole = 0;
+	int bordering_edge = 0;
+	while(!nxny_pairs.empty())
+	{
+		S32 const nx = nxny_pairs.front().first;
+		S32 const ny = nxny_pairs.front().second;
+		LL_DEBUGS("WaterHeight") << "nx,ny = " << nx << "," << ny << LL_ENDL;
+		S32 const index = nx + ny * n + origin;
+		nxny_pairs.pop();
+		for (S32 dir = 0; dir < 4; ++dir)
+		{
+			S32 const cnx = nx + gDirAxes[dir][0];
+			S32 const cny = ny + gDirAxes[dir][1];
+			LL_DEBUGS("WaterHeight") << "dir = " << dir << "; cnx,cny = " << cnx << "," << cny << LL_ENDL;
+			S32 const cindex = cnx + cny * n + origin;
+			bool is_hole = false;
+			bool is_edge = false;
+			LLViewerRegion* new_region_found = NULL;
+			if (cnx < -nsims || cnx > nsims ||
+			    cny < -nsims || cny > nsims)
+			{
+				LL_DEBUGS("WaterHeight") << "  Edge Water!" << LL_ENDL;
+				// Bumped into Edge water object.
+				is_edge = true;
+			}
+			else if (checked[cindex])
+			{
+				LL_DEBUGS("WaterHeight") << "  Already checked before!" << LL_ENDL;
+				// Already checked.
+				is_hole = (checked[cindex] & hole_bit);
+			}
+			else
+			{
+				S32 x = (S32)region_x + cnx * rwidth;
+				S32 y = (S32)region_y + cny * rwidth;
+				U64 region_handle = to_region_handle(x, y);
+				new_region_found = getRegionFromHandle(region_handle);
+				is_hole = !new_region_found;
+				checked[cindex] = is_hole ? hole_bit : region_bit;
+			}
+			if (is_hole)
+			{
+				// This was a region that borders at least one 'hole'.
+				// Count the found coastline.
+				F32 new_water_height = water_heights[index];
+				LL_DEBUGS("WaterHeight") << "  This is void; counting coastline with water height of " << new_water_height << LL_ENDL;
+				S32 new_water_height_cm = llround(new_water_height * 100);
+				int count = (water_height_counts[new_water_height_cm] += 1);
+				// Just use the lowest water height: this is mainly about the horizon water,
+				// and whatever we do, we don't want it to be possible to look under the water
+				// when looking in the distance: it is better to make a step downwards in water
+				// height when going away from the avie than a step upwards. However, since
+				// everyone is used to DEFAULT_WATER_HEIGHT, don't allow a single region
+				// to drag the water level below DEFAULT_WATER_HEIGHT on it's own.
+				if (bordering_hole == 0 ||			// First time we get here.
+				    (new_water_height >= DEFAULT_WATER_HEIGHT &&
+					 new_water_height < water_height) ||
+				    (new_water_height < DEFAULT_WATER_HEIGHT &&
+					 count > max_count)
+				   )
+				{
+					water_height = new_water_height;
+				}
+				if (count > max_count)
+				{
+					max_count = count;
+				}
+				if (!(checked[index] & bordering_hole_bit))
+				{
+					checked[index] |= bordering_hole_bit;
+					++bordering_hole;
+				}
+			}
+			else if (is_edge && !(checked[index] & bordering_edge_bit))
+			{
+				checked[index] |= bordering_edge_bit;
+				++bordering_edge;
+			}
+			if (!new_region_found)
+			{
+				// Dead end, there is no region here.
+				continue;
+			}
+			// Found a new connected region.
+			++number_of_connected_regions;
+			if (new_region_found->getName().empty())
+			{
+				// Uninitialized LLViewerRegion, don't use it's water height.
+				LL_DEBUGS("WaterHeight") << "  Uninitialized region." << LL_ENDL;
+				++uninitialized_regions;
+				continue;
+			}
+			nxny_pairs.push(nxny_pairs_type::value_type(cnx, cny));
+			water_heights[cindex] = new_region_found->getWaterHeight();
+			LL_DEBUGS("WaterHeight") << "  Found a new region (name: " << new_region_found->getName() << "; water height: " << water_heights[cindex] << " m)!" << LL_ENDL;
+		}
+	}
+	llinfos << "Number of connected regions: " << number_of_connected_regions << " (" << uninitialized_regions <<
+		" uninitialized); number of regions bordering Hole water: " << bordering_hole <<
+		"; number of regions bordering Edge water: " << bordering_edge << llendl;
+	llinfos << "Coastline count (height, count): ";
+	bool first = true;
+	for (std::map<S32, int>::iterator iter = water_height_counts.begin(); iter != water_height_counts.end(); ++iter)
+	{
+		if (!first) llcont << ", ";
+		llcont << "(" << (iter->first / 100.f) << ", " << iter->second << ")";
+		first = false;
+	}
+	llcont << llendl;
+	llinfos << "Water height used for Hole and Edge water objects: " << water_height << llendl;
 
-	F32 height = 0.f;
-	
-	for (region_list_t::iterator iter = mRegionList.begin();
-		 iter != mRegionList.end(); ++iter)
+	// Update all Region water objects.
+	for (region_list_t::iterator iter = mRegionList.begin(); iter != mRegionList.end(); ++iter)
 	{
 		LLViewerRegion* regionp = *iter;
 		LLVOWater* waterp = regionp->getLand().getWaterObj();
-		height += regionp->getWaterHeight();
 		if (waterp)
 		{
 			gObjectList.updateActive(waterp);
 		}
 	}
 
+	// Clean up all existing Hole water objects.
 	for (std::list<LLVOWater*>::iterator iter = mHoleWaterObjects.begin();
-		 iter != mHoleWaterObjects.end(); ++ iter)
+		 iter != mHoleWaterObjects.end(); ++iter)
 	{
 		LLVOWater* waterp = *iter;
 		gObjectList.killObject(waterp);
 	}
 	mHoleWaterObjects.clear();
 
-	// Now, get a list of the holes
-	S32 x, y;
-	for (x = min_x; x <= max_x; x += rwidth)
+	// Let the Edge and Hole water boxes be 1024 meter high so that they
+	// are never too small to be drawn (A LL_VO_*_WATER box has water
+	// rendered on it's bottom surface only), and put their bottom at
+	// the current regions water height.
+	F32 const box_height = 1024;
+	F32 const water_center_z = water_height + box_height / 2;
+
+	// Create new Hole water objects within 'range' where there is no region.
+	for (S32 x = min_x; x <= max_x; x += rwidth)
 	{
-		for (y = min_y; y <= max_y; y += rwidth)
+		for (S32 y = min_y; y <= max_y; y += rwidth)
 		{
 			U64 region_handle = to_region_handle(x, y);
 			if (!getRegionFromHandle(region_handle))
 			{
-				LLVOWater* waterp = (LLVOWater *)gObjectList.createObjectViewer(LLViewerObject::LL_VO_WATER, gAgent.getRegion());
+				LLVOWater* waterp = (LLVOWater*)gObjectList.createObjectViewer(LLViewerObject::LL_VO_VOID_WATER, gAgent.getRegion());
 				waterp->setUseTexture(FALSE);
-				waterp->setPositionGlobal(LLVector3d(x + rwidth/2,
-													 y + rwidth/2,
-													 256.f+DEFAULT_WATER_HEIGHT));
-				waterp->setScale(LLVector3((F32)rwidth, (F32)rwidth, 512.f));
+				waterp->setPositionGlobal(LLVector3d(x + rwidth / 2, y + rwidth / 2, water_center_z));
+				waterp->setScale(LLVector3((F32)rwidth, (F32)rwidth, box_height));
 				gPipeline.createObject(waterp);
 				mHoleWaterObjects.push_back(waterp);
 			}
 		}
 	}
 
-	// Update edge water objects
-	S32 wx, wy;
-	S32 center_x, center_y;
-	wx = (max_x - min_x) + rwidth;
-	wy = (max_y - min_y) + rwidth;
-	center_x = min_x + (wx >> 1);
-	center_y = min_y + (wy >> 1);
-
-	S32 add_boundary[4] = {
-		512 - (max_x - region_x),
-		512 - (max_y - region_y),
-		512 - (region_x - min_x),
-		512 - (region_y - min_y) };
+	// Center of the region.
+	S32 const center_x = region_x + rwidth / 2;
+	S32 const center_y = region_y + rwidth / 2;
+	// Width of the area with Hole water objects.
+	S32 const width = rwidth + 2 * range;
+	S32 const horizon_extend = 2048 + 512 - range;	// Legacy value.
+	// The overlap is needed to get rid of sky pixels being visible between the
+	// Edge and Hole water object at greater distances (due to floating point
+	// round off errors).
+	S32 const edge_hole_overlap = 1;		// Twice the actual overlap.
 		
-	S32 dir;
-	for (dir = 0; dir < 8; dir++)
+	for (S32 dir = 0; dir < 8; ++dir)
 	{
-		S32 dim[2] = { 0 };
-		switch (gDirAxes[dir][0])
-		{
-		case -1: dim[0] = add_boundary[2]; break;
-		case  0: dim[0] = wx; break;
-		default: dim[0] = add_boundary[0]; break;
-		}
-		switch (gDirAxes[dir][1])
-		{
-		case -1: dim[1] = add_boundary[3]; break;
-		case  0: dim[1] = wy; break;
-		default: dim[1] = add_boundary[1]; break;
-		}
+		// Size of the Edge water objects.
+		S32 const dim_x = (gDirAxes[dir][0] == 0) ? width : (horizon_extend + edge_hole_overlap);
+		S32 const dim_y = (gDirAxes[dir][1] == 0) ? width : (horizon_extend + edge_hole_overlap);
+		// And their position.
+		S32 const water_center_x = center_x + (width + horizon_extend) / 2 * gDirAxes[dir][0];
+		S32 const water_center_y = center_y + (width + horizon_extend) / 2 * gDirAxes[dir][1];
 
-		// Resize and reshape the water objects
-		const S32 water_center_x = center_x + llround((wx + dim[0]) * 0.5f * gDirAxes[dir][0]);
-		const S32 water_center_y = center_y + llround((wy + dim[1]) * 0.5f * gDirAxes[dir][1]);
-		
 		LLVOWater* waterp = mEdgeWaterObjects[dir];
 		if (!waterp || waterp->isDead())
 		{
 			// The edge water objects can be dead because they're attached to the region that the
 			// agent was in when they were originally created.
-			mEdgeWaterObjects[dir] = (LLVOWater *)gObjectList.createObjectViewer(LLViewerObject::LL_VO_WATER,
-																				 gAgent.getRegion());
+			mEdgeWaterObjects[dir] = (LLVOWater *)gObjectList.createObjectViewer(LLViewerObject::LL_VO_VOID_WATER, gAgent.getRegion());
 			waterp = mEdgeWaterObjects[dir];
 			waterp->setUseTexture(FALSE);
-			waterp->setIsEdgePatch(TRUE);
+			waterp->setIsEdgePatch(TRUE);		// Mark that this is edge water and not hole water.
 			gPipeline.createObject(waterp);
 		}
 
 		waterp->setRegion(gAgent.getRegion());
-		LLVector3d water_pos(water_center_x, water_center_y, 
-			DEFAULT_WATER_HEIGHT+256.f);
-		LLVector3 water_scale((F32) dim[0], (F32) dim[1], 512.f);
-
-		//stretch out to horizon
-		water_scale.mV[0] += fabsf(2048.f * gDirAxes[dir][0]);
-		water_scale.mV[1] += fabsf(2048.f * gDirAxes[dir][1]);
-
-		water_pos.mdV[0] += 1024.f * gDirAxes[dir][0];
-		water_pos.mdV[1] += 1024.f * gDirAxes[dir][1];
+		LLVector3d water_pos(water_center_x, water_center_y, water_center_z);
+		LLVector3 water_scale((F32) dim_x, (F32) dim_y, box_height);
 
 		waterp->setPositionGlobal(water_pos);
 		waterp->setScale(water_scale);
diff --git a/indra/newview/llworld.h b/indra/newview/llworld.h
index 4465fde210..c60dc8dc29 100644
--- a/indra/newview/llworld.h
+++ b/indra/newview/llworld.h
@@ -137,6 +137,7 @@ public:
 
 	LLViewerTexture *getDefaultWaterTexture();
 	void updateWaterObjects();
+	void waterHeightRegionInfo(std::string const& sim_name, F32 water_height);
 	void shiftRegions(const LLVector3& offset);
 
 	void setSpaceTimeUSec(const U64 space_time_usec);
diff --git a/indra/newview/pipeline.cpp b/indra/newview/pipeline.cpp
index 1ee3b84b5e..272682710c 100644
--- a/indra/newview/pipeline.cpp
+++ b/indra/newview/pipeline.cpp
@@ -628,14 +628,14 @@ void LLPipeline::allocateScreenBuffer(U32 resX, U32 resY)
 //static
 void LLPipeline::updateRenderDeferred()
 {
-	BOOL deferred = (gSavedSettings.getBOOL("RenderDeferred") && 
-		LLRenderTarget::sUseFBO &&
-			 LLFeatureManager::getInstance()->isFeatureAvailable("RenderDeferred") &&
-		gSavedSettings.getBOOL("VertexShaderEnable") && 
-		gSavedSettings.getBOOL("RenderAvatarVP") &&
-			 (gSavedSettings.getBOOL("WindLightUseAtmosShaders")) ? TRUE : FALSE) &&
-		!gUseWireframe;
-	
+	BOOL deferred = ((gSavedSettings.getBOOL("RenderDeferred") && 
+					 LLRenderTarget::sUseFBO &&
+					 LLFeatureManager::getInstance()->isFeatureAvailable("RenderDeferred") &&
+					 gSavedSettings.getBOOL("VertexShaderEnable") && 
+					 gSavedSettings.getBOOL("RenderAvatarVP") &&
+					 gSavedSettings.getBOOL("WindLightUseAtmosShaders")) ? TRUE : FALSE) &&
+					!gUseWireframe;
+
 	sRenderDeferred = deferred;			
 }
 
@@ -1632,20 +1632,14 @@ void LLPipeline::updateCull(LLCamera& camera, LLCullResult& result, S32 water_cl
 
 	camera.disableUserClipPlane();
 
-	if (gSky.mVOSkyp.notNull() && gSky.mVOSkyp->mDrawable.notNull())
+	if (hasRenderType(LLPipeline::RENDER_TYPE_SKY) && 
+		gSky.mVOSkyp.notNull() && 
+		gSky.mVOSkyp->mDrawable.notNull())
 	{
-		// Hack for sky - always visible.
-		if (hasRenderType(LLPipeline::RENDER_TYPE_SKY)) 
-		{
-			gSky.mVOSkyp->mDrawable->setVisible(camera);
-			sCull->pushDrawable(gSky.mVOSkyp->mDrawable);
-			gSky.updateCull();
-			stop_glerror();
-		}
-	}
-	else
-	{
-		llinfos << "No sky drawable!" << llendl;
+		gSky.mVOSkyp->mDrawable->setVisible(camera);
+		sCull->pushDrawable(gSky.mVOSkyp->mDrawable);
+		gSky.updateCull();
+		stop_glerror();
 	}
 
 	if (hasRenderType(LLPipeline::RENDER_TYPE_GROUND) && 
@@ -2214,6 +2208,7 @@ void LLPipeline::stateSort(LLCamera& camera, LLCullResult &result)
 					  LLPipeline::RENDER_TYPE_TERRAIN,
 					  LLPipeline::RENDER_TYPE_TREE,
 					  LLPipeline::RENDER_TYPE_SKY,
+					  LLPipeline::RENDER_TYPE_VOIDWATER,
 					  LLPipeline::RENDER_TYPE_WATER,
 					  LLPipeline::END_RENDER_TYPES))
 	{
@@ -5005,6 +5000,10 @@ void LLPipeline::setLight(LLDrawable *drawablep, BOOL is_light)
 void LLPipeline::toggleRenderType(U32 type)
 {
 	gPipeline.mRenderTypeEnabled[type] = !gPipeline.mRenderTypeEnabled[type];
+	if (type == LLPipeline::RENDER_TYPE_WATER)
+	{
+		gPipeline.mRenderTypeEnabled[LLPipeline::RENDER_TYPE_VOIDWATER] = !gPipeline.mRenderTypeEnabled[LLPipeline::RENDER_TYPE_VOIDWATER];
+	}
 }
 
 //static
@@ -7331,6 +7330,7 @@ void LLPipeline::generateWaterReflection(LLCamera& camera_in)
 				gPipeline.pushRenderTypeMask();
 
 				clearRenderTypeMask(LLPipeline::RENDER_TYPE_WATER,
+									LLPipeline::RENDER_TYPE_VOIDWATER,
 									LLPipeline::RENDER_TYPE_GROUND,
 									LLPipeline::RENDER_TYPE_SKY,
 									LLPipeline::RENDER_TYPE_CLOUDS,
@@ -7383,6 +7383,7 @@ void LLPipeline::generateWaterReflection(LLCamera& camera_in)
 		{
 			camera.setFar(camera_in.getFar());
 			clearRenderTypeMask(LLPipeline::RENDER_TYPE_WATER,
+								LLPipeline::RENDER_TYPE_VOIDWATER,
 								LLPipeline::RENDER_TYPE_GROUND,
 								END_RENDER_TYPES);	
 			stop_glerror();
@@ -7899,6 +7900,7 @@ void LLPipeline::generateGI(LLCamera& camera, LLVector3& lightDir, std::vector<L
 								 LLPipeline::RENDER_TYPE_TREE, 
 								 LLPipeline::RENDER_TYPE_TERRAIN,
 								 LLPipeline::RENDER_TYPE_WATER,
+								 LLPipeline::RENDER_TYPE_VOIDWATER,
 								 LLPipeline::RENDER_TYPE_PASS_ALPHA_SHADOW,
 								 LLPipeline::RENDER_TYPE_AVATAR,
 								 LLPipeline::RENDER_TYPE_PASS_SIMPLE,
@@ -8082,6 +8084,7 @@ void LLPipeline::generateSunShadow(LLCamera& camera)
 					LLPipeline::RENDER_TYPE_TREE, 
 					LLPipeline::RENDER_TYPE_TERRAIN,
 					LLPipeline::RENDER_TYPE_WATER,
+					LLPipeline::RENDER_TYPE_VOIDWATER,
 					LLPipeline::RENDER_TYPE_PASS_ALPHA_SHADOW,
 					LLPipeline::RENDER_TYPE_PASS_SIMPLE,
 					LLPipeline::RENDER_TYPE_PASS_BUMP,
diff --git a/indra/newview/pipeline.h b/indra/newview/pipeline.h
index fe0683d29f..74e1cf6d7e 100644
--- a/indra/newview/pipeline.h
+++ b/indra/newview/pipeline.h
@@ -358,6 +358,7 @@ public:
 		RENDER_TYPE_AVATAR						= LLDrawPool::POOL_AVATAR,
 		RENDER_TYPE_TREE						= LLDrawPool::POOL_TREE,
 		RENDER_TYPE_INVISIBLE					= LLDrawPool::POOL_INVISIBLE,
+		RENDER_TYPE_VOIDWATER					= LLDrawPool::POOL_VOIDWATER,
 		RENDER_TYPE_WATER						= LLDrawPool::POOL_WATER,
  		RENDER_TYPE_ALPHA						= LLDrawPool::POOL_ALPHA,
 		RENDER_TYPE_GLOW						= LLDrawPool::POOL_GLOW,