diff --git a/ClassicalSharp/Entities/PhysicsEntity.cs b/ClassicalSharp/Entities/PhysicsEntity.cs
index 119c7156e..dfe1761cf 100644
--- a/ClassicalSharp/Entities/PhysicsEntity.cs
+++ b/ClassicalSharp/Entities/PhysicsEntity.cs
@@ -5,7 +5,7 @@ using OpenTK;
 namespace ClassicalSharp {
 	
 	/// <summary> Entity that performs collision detection. </summary>
-	public abstract class PhysicsEntity : Entity {
+	public abstract partial class PhysicsEntity : Entity {
 		
 		public PhysicsEntity( Game game ) : base( game ) {
 		}
@@ -24,33 +24,19 @@ namespace ClassicalSharp {
 		
 		bool GetBoundingBox( byte block, int x, int y, int z, ref BoundingBox box ) {
 			if( info.CollideType[block] != BlockCollideType.Solid ) return false;
-			
-			box.Min = new Vector3( x, y, z ) + info.MinBB[block];
-			box.Max = new Vector3( x, y, z ) + info.MaxBB[block];
+			Add( x, y, z, ref info.MinBB[block], ref box.Min );
+			Add( x, y, z, ref info.MaxBB[block], ref box.Max );
 			return true;
 		}
 		
-		struct State {
-			public BoundingBox BlockBB;
-			public byte Block;
-			public float tSquared;
-			
-			public State( BoundingBox bb, byte block, float tSquared ) {
-				BlockBB = bb;
-				Block = block;
-				this.tSquared = tSquared;
-			}
+		static void Add( int x, int y, int z, ref Vector3 offset, ref Vector3 target ) {
+			target.X = x + offset.X;
+			target.Y = y + offset.Y;
+			target.Z = z + offset.Z;
 		}
 		
-		// TODO: test for corner cases, and refactor this.
-		static State[] stateCache = new State[0];
-		class StateComparer : IComparer<State> {
-			public int Compare( State x, State y ) {
-				return x.tSquared.CompareTo( y.tSquared );
-			}
-		}
 		
-		static StateComparer comparer = new StateComparer();
+		// TODO: test for corner cases, and refactor this.	
 		protected void MoveAndWallSlide() {
 			if( Velocity == Vector3.Zero )
 				return;
@@ -101,7 +87,7 @@ namespace ClassicalSharp {
 				CalcTime( ref vel, ref entityBB, ref blockBB, out tx, out ty, out tz );
 				if( tx > 1 || ty > 1 || tz > 1 ) continue;
 				float tSquared = tx * tx + ty * ty + tz * tz;
-				stateCache[count++] = new State( blockBB, blockId, tSquared );
+				stateCache[count++] = new State( x, y, z, blockId, tSquared );
 			}
 		}
 		
@@ -109,12 +95,17 @@ namespace ClassicalSharp {
 		                                ref BoundingBox entityBB, ref BoundingBox entityExtentBB ) {
 			bool wasOn = onGround;
 			onGround = false;
-			Array.Sort( stateCache, 0, count, comparer );
+			if( count > 0 )
+				QuickSort( stateCache, 0, count - 1 );
 			collideX = false; collideY = false; collideZ = false;
+			BoundingBox blockBB = default(BoundingBox);
 
 			for( int i = 0; i < count; i++ ) {
 				State state = stateCache[i];
-				BoundingBox blockBB = state.BlockBB;
+				Vector3 blockPos = new Vector3( state.X >> 3, state.Y >> 3, state.Z >> 3 );
+				int block = (state.X & 0x7) | (state.Y & 0x7) << 3 | (state.Z & 0x7) << 6;
+				blockBB.Min = blockPos + info.MinBB[block];
+				blockBB.Max = blockPos + info.MaxBB[block];
 				if( !entityExtentBB.Intersects( blockBB ) ) continue;
 				
 				float tx = 0, ty = 0, tz = 0;
@@ -287,5 +278,48 @@ namespace ClassicalSharp {
 			if( entityBB.YIntersects( blockBB ) ) ty = 0;
 			if( entityBB.ZIntersects( blockBB ) ) tz = 0;
 		}
+		
+		
+		struct State {
+			public int X, Y, Z;
+			public float tSquared;
+			
+			public State( int x, int y, int z, byte block, float tSquared ) {
+				X = x << 3; Y = y << 3; Z = z << 3;
+				X |= (block & 0x07);
+				Y |= (block & 0x38) >> 3;
+				Z |= (block & 0xC0) >> 6;
+				this.tSquared = tSquared;
+			}
+		}
+		static State[] stateCache = new State[0];
+		
+		static void QuickSort( State[] keys, int left, int right ) {
+			while( left < right ) {
+				int i = left, j = right;		
+				float pivot = keys[(i + j) / 2].tSquared;
+				// partition the list
+				while( i <= j ) {
+					while( pivot > keys[i].tSquared ) i++;
+					while( pivot < keys[j].tSquared ) j--;
+					
+					if( i <= j ) {
+						State key = keys[i]; keys[i] = keys[j]; keys[j] = key;
+						i++; j--;
+					}					
+				}
+				
+				// recurse into the smaller subset
+				if( j - left <= right - i ) {
+					if( left < j )
+						QuickSort( keys, left, j );
+					left = i;
+				} else {
+					if( i < right )
+						QuickSort( keys, i, right );
+					right = j;
+				}
+			}
+		}
 	}
 }
\ No newline at end of file
diff --git a/ClassicalSharp/Rendering/MapRenderer.Rendering.cs b/ClassicalSharp/Rendering/MapRenderer.Rendering.cs
index 0689d2775..b4dc04a20 100644
--- a/ClassicalSharp/Rendering/MapRenderer.Rendering.cs
+++ b/ClassicalSharp/Rendering/MapRenderer.Rendering.cs
@@ -4,10 +4,62 @@ using OpenTK;
 
 namespace ClassicalSharp {
 	
-	// TODO: optimise chunk rendering
-	//  --> reduce iterations: liquid and sprite pass only need 1 row
 	public partial class MapRenderer : IDisposable {
 		
+		// Render solid and fully transparent to fill depth buffer.
+		// These blocks are treated as having an alpha value of either none or full.
+		void RenderNormal() {
+			int[] texIds = game.TerrainAtlas1D.TexIds;
+			api.SetBatchFormat( VertexFormat.Pos3fTex2fCol4b );
+			api.Texturing = true;
+			api.AlphaTest = true;
+			
+			for( int batch = 0; batch < _1DUsed; batch++ ) {
+				if( pendingNormal[batch] || usedNormal[batch] ) {
+					api.BindTexture( texIds[batch] );
+					RenderNormalBatch( batch );
+					pendingNormal[batch] = false;
+				}
+			}
+			api.AlphaTest = false;
+			api.Texturing = false;
+			DebugPickedPos();
+		}
+		
+		// Render translucent(liquid) blocks. These 'blend' into other blocks.
+		void RenderTranslucent() {
+			Block block = game.LocalPlayer.BlockAtHead;
+			drawAllFaces = block == Block.Water || block == Block.StillWater;
+			// First fill depth buffer
+			int[] texIds = game.TerrainAtlas1D.TexIds;
+			api.SetBatchFormat( VertexFormat.Pos3fTex2fCol4b );
+			api.Texturing = false;
+			api.AlphaBlending = false;
+			api.ColourWrite = false;
+			for( int batch = 0; batch < _1DUsed; batch++ ) {
+				if( pendingTranslucent[batch] || usedTranslucent[batch] ) {
+					RenderTranslucentBatchDepthPass( batch );
+					pendingTranslucent[batch] = false;
+				}
+			}
+			
+			// Then actually draw the transluscent blocks
+			api.AlphaBlending = true;
+			api.Texturing = true;
+			api.ColourWrite = true;
+			api.DepthWrite = false; // we already calculated depth values in depth pass
+			
+			for( int batch = 0; batch < _1DUsed; batch++ ) {
+				if( !usedTranslucent[batch] ) continue;
+				api.BindTexture( texIds[batch] );
+				RenderTranslucentBatch( batch );
+			}
+			api.DepthWrite = true;
+			api.AlphaTest = false;
+			api.AlphaBlending = false;
+			api.Texturing = false;
+		}
+		
 		const DrawMode mode = DrawMode.Triangles;
 		const int maxVertex = 65536;
 		const int maxIndices = maxVertex / 4 * 6;
diff --git a/ClassicalSharp/Rendering/MapRenderer.Sorting.cs b/ClassicalSharp/Rendering/MapRenderer.Sorting.cs
index eb3b23b98..e05a5e8e7 100644
--- a/ClassicalSharp/Rendering/MapRenderer.Sorting.cs
+++ b/ClassicalSharp/Rendering/MapRenderer.Sorting.cs
@@ -21,8 +21,7 @@ namespace ClassicalSharp {
 			}
 			// NOTE: Over 5x faster compared to normal comparison of IComparer<ChunkInfo>.Compare
 			if( distances.Length > 1 )
-				//FastSorter<ChunkInfo>.QuickSort( distances, chunks, 0, chunks.Length - 1 );
-				Array.Sort( distances, chunks, 0, chunks.Length - 1 );
+				QuickSort( distances, chunks, 0, chunks.Length - 1 );
 			
 			Vector3I pPos = newChunkPos;
 			for( int i = 0; i < chunks.Length; i++ ) {
@@ -41,19 +40,11 @@ namespace ClassicalSharp {
 			}
 			RecalcBooleans( false );
 			//SimpleOcclusionCulling();
-		}		
-	}
-
-	static class FastSorter<T> {
-		
-		static void Swap( int[] keys, T[] values, int a, int b ) {
-			int key = keys[a]; keys[a] = keys[b]; keys[b] = key;		
-			T value = values[a]; values[a] = values[b]; values[b] = value;
 		}
 		
-		public static void QuickSort( int[] keys, T[] values, int left, int right ) {
+		static void QuickSort( int[] keys, ChunkInfo[] values, int left, int right ) {
 			while( left < right ) {
-				int i = left, j = right;		
+				int i = left, j = right;
 				int pivot = keys[(i + j) / 2];
 				// partition the list
 				while( i <= j ) {
@@ -61,9 +52,10 @@ namespace ClassicalSharp {
 					while( pivot < keys[j] ) j--;
 					
 					if( i <= j ) {
-						Swap( keys, values, i, j );
+						int key = keys[i]; keys[i] = keys[j]; keys[j] = key;
+						ChunkInfo value = values[i]; values[i] = values[j]; values[j] = value;
 						i++; j--;
-					}					
+					}
 				}
 				
 				// recurse into the smaller subset
diff --git a/ClassicalSharp/Rendering/MapRenderer.cs b/ClassicalSharp/Rendering/MapRenderer.cs
index aee107016..b52b4d080 100644
--- a/ClassicalSharp/Rendering/MapRenderer.cs
+++ b/ClassicalSharp/Rendering/MapRenderer.cs
@@ -55,6 +55,7 @@ namespace ClassicalSharp {
 			game.MapEvents.OnNewMapLoaded += OnNewMapLoaded;
 			game.MapEvents.EnvVariableChanged += EnvVariableChanged;
 			game.Events.BlockDefinitionChanged += BlockDefinitionChanged;
+			game.Events.ViewDistanceChanged += ViewDistanceChanged;
 		}
 		
 		public void Dispose() {
@@ -66,6 +67,7 @@ namespace ClassicalSharp {
 			game.MapEvents.OnNewMapLoaded -= OnNewMapLoaded;
 			game.MapEvents.EnvVariableChanged -= EnvVariableChanged;
 			game.MapEvents.BlockDefinitionChanged -= BlockDefinitionChanged;
+			game.Events.ViewDistanceChanged -= ViewDistanceChanged;
 			builder.Dispose();
 		}
 		
@@ -111,6 +113,12 @@ namespace ClassicalSharp {
 			builder.OnNewMap();
 		}
 		
+		void ViewDistanceChanged( object sender, EventArgs e ) {
+			lastCamPos = new Vector3( float.MaxValue );
+			lastYaw = float.MaxValue;
+			lastPitch = float.MaxValue;
+		}
+		
 		void RecalcBooleans( bool sizeChanged ) {
 			if( sizeChanged ) {
 				usedTranslucent = new bool[_1DUsed];
@@ -246,12 +254,30 @@ namespace ClassicalSharp {
 		int chunksTarget = 4;
 		const double targetTime = (1.0 / 30) + 0.01;
 		void UpdateChunks( double deltaTime ) {
-			int chunksUpdatedThisFrame = 0;
+			int chunkUpdates = 0;
 			int viewDist = game.ViewDistance < 16 ? 16 : game.ViewDistance;
 			int adjViewDistSqr = (viewDist + 24) * (viewDist + 24);
 			chunksTarget += deltaTime < targetTime ? 1 : -1; // build more chunks if 30 FPS or over, otherwise slowdown.
 			Utils.Clamp( ref chunksTarget, 4, 12 );
 			
+			LocalPlayer p = game.LocalPlayer;
+			Vector3 cameraPos = game.CurrentCameraPos;
+			bool samePos = cameraPos == lastCamPos && p.HeadYawDegrees == lastYaw
+				&& p.PitchDegrees == lastPitch;
+			if( samePos )
+				UpdateChunksStill( deltaTime, ref chunkUpdates, adjViewDistSqr );
+			else
+				UpdateChunksAndVisibility( deltaTime, ref chunkUpdates, adjViewDistSqr );
+			
+			lastCamPos = cameraPos;
+			lastYaw = p.HeadYawDegrees; lastPitch = p.PitchDegrees;
+			if( !samePos || chunkUpdates != 0 )
+				RecalcBooleans( false );
+		}
+		Vector3 lastCamPos;
+		float lastYaw, lastPitch;
+		
+		void UpdateChunksAndVisibility( double deltaTime, ref int chunkUpdats, int adjViewDistSqr ) {
 			for( int i = 0; i < chunks.Length; i++ ) {
 				ChunkInfo info = chunks[i];
 				if( info.Empty ) continue;
@@ -259,84 +285,40 @@ namespace ClassicalSharp {
 				bool inRange = distSqr <= adjViewDistSqr;
 				
 				if( info.NormalParts == null && info.TranslucentParts == null ) {
-					if( inRange && chunksUpdatedThisFrame < chunksTarget ) {
-						game.ChunkUpdates++;
-						builder.GetDrawInfo( info.CentreX - 8, info.CentreY - 8, info.CentreZ - 8,
-						                    ref info.NormalParts, ref info.TranslucentParts, ref info.OcclusionFlags );
-						
-						if( info.NormalParts == null && info.TranslucentParts == null )
-							info.Empty = true;
-						chunksUpdatedThisFrame++;
-					}
+					if( inRange && chunkUpdats < chunksTarget )
+						BuildChunk( info, ref chunkUpdats );
 				}
 				info.Visible = inRange &&
 					game.Culling.SphereInFrustum( info.CentreX, info.CentreY, info.CentreZ, 14 ); // 14 ~ sqrt(3 * 8^2)
 			}
-			
-			LocalPlayer p = game.LocalPlayer;
-			Vector3 cameraPos = game.CurrentCameraPos;
-			if( chunksUpdatedThisFrame == 0 && cameraPos == lastCamPos 
-			   && p.HeadYawDegrees == lastYaw && p.PitchDegrees == lastPitch ) return;
-			
-			lastCamPos = cameraPos;
-			lastYaw = p.HeadYawDegrees; lastPitch = p.PitchDegrees;
-			RecalcBooleans( false );
-		}
-		Vector3 lastCamPos;
-		float lastYaw, lastPitch;
-		
-		// Render solid and fully transparent to fill depth buffer.
-		// These blocks are treated as having an alpha value of either none or full.
-		void RenderNormal() {
-			int[] texIds = game.TerrainAtlas1D.TexIds;
-			api.SetBatchFormat( VertexFormat.Pos3fTex2fCol4b );
-			api.Texturing = true;
-			api.AlphaTest = true;
-			
-			for( int batch = 0; batch < _1DUsed; batch++ ) {
-				if( pendingNormal[batch] || usedNormal[batch] ) {
-					api.BindTexture( texIds[batch] );
-					RenderNormalBatch( batch );
-					pendingNormal[batch] = false;
-				}
-			}
-			api.AlphaTest = false;
-			api.Texturing = false;
-			DebugPickedPos();
 		}
 		
-		// Render translucent(liquid) blocks. These 'blend' into other blocks.
-		void RenderTranslucent() {
-			Block block = game.LocalPlayer.BlockAtHead;
-			drawAllFaces = block == Block.Water || block == Block.StillWater;
-			// First fill depth buffer
-			int[] texIds = game.TerrainAtlas1D.TexIds;
-			api.SetBatchFormat( VertexFormat.Pos3fTex2fCol4b );
-			api.Texturing = false;
-			api.AlphaBlending = false;
-			api.ColourWrite = false;
-			for( int batch = 0; batch < _1DUsed; batch++ ) {
-				if( pendingTranslucent[batch] || usedTranslucent[batch] ) {
-					RenderTranslucentBatchDepthPass( batch );
-					pendingTranslucent[batch] = false;
-				}
+		void UpdateChunksStill( double deltaTime, ref int chunkUpdates, int adjViewDistSqr ) {
+			for( int i = 0; i < chunks.Length; i++ ) {
+				ChunkInfo info = chunks[i];
+				if( info.Empty ) continue;
+				int distSqr = distances[i];
+				bool inRange = distSqr <= adjViewDistSqr;
+				
+				if( info.NormalParts == null && info.TranslucentParts == null ) {
+					if( inRange && chunkUpdates < chunksTarget ) {
+						BuildChunk( info, ref chunkUpdates );
+						// only need to update the visibility of chunks in range.
+						info.Visible = inRange &&
+							game.Culling.SphereInFrustum( info.CentreX, info.CentreY, info.CentreZ, 14 ); // 14 ~ sqrt(3 * 8^2)
+					}
+				}		
 			}
+		}
+		
+		void BuildChunk( ChunkInfo info, ref int chunkUpdates ) {
+			game.ChunkUpdates++;
+			builder.GetDrawInfo( info.CentreX - 8, info.CentreY - 8, info.CentreZ - 8,
+			                    ref info.NormalParts, ref info.TranslucentParts, ref info.OcclusionFlags );
 			
-			// Then actually draw the transluscent blocks
-			api.AlphaBlending = true;
-			api.Texturing = true;
-			api.ColourWrite = true;
-			api.DepthWrite = false; // we already calculated depth values in depth pass
-			
-			for( int batch = 0; batch < _1DUsed; batch++ ) {
-				if( !usedTranslucent[batch] ) continue;
-				api.BindTexture( texIds[batch] );
-				RenderTranslucentBatch( batch );
-			}
-			api.DepthWrite = true;
-			api.AlphaTest = false;
-			api.AlphaBlending = false;
-			api.Texturing = false;
+			if( info.NormalParts == null && info.TranslucentParts == null )
+				info.Empty = true;
+			chunkUpdates++;
 		}
 	}
 }
\ No newline at end of file