BaseVisualMode.cs

			{
				foreach(int tag in s.Tags)
				{
					if(tag == 0) continue;
					if(!sectortags.ContainsKey(tag)) sectortags[tag] = new List<Sector>();
					sectortags[tag].Add(s);
				}

				// ========== Thing vertex slope, vertices with UDMF vertex offsets ==========
				if (s.Sidedefs.Count == 3)
				{
					if (General.Map.UDMF) GetSectorData(s).AddEffectVertexOffset(); //mxd
					List<Thing> slopeceilingthings = new List<Thing>(3);
					List<Thing> slopefloorthings = new List<Thing>(3);

					foreach (Sidedef sd in s.Sidedefs)
					{
						Vertex v = sd.IsFront ? sd.Line.End : sd.Line.Start;

						// Check if a thing is at this vertex
						foreach (VisualBlockEntry block in blockmap.GetBlocks(v.Position))
						{
							foreach (Thing t in block.Things)
							{
								if ((Vector2D)t.Position == v.Position)
								{
									switch (t.Type)
									{
										case 1504: slopefloorthings.Add(t); break;
										case 1505: slopeceilingthings.Add(t); break;
									}
								}
							}
						}
					}

					// Slope any floor vertices?
					if (slopefloorthings.Count > 0)
					{
						SectorData sd = GetSectorData(s);
						sd.AddEffectThingVertexSlope(slopefloorthings, true);
					}

					// Slope any ceiling vertices?
					if (slopeceilingthings.Count > 0)
					{
						SectorData sd = GetSectorData(s);
						sd.AddEffectThingVertexSlope(slopeceilingthings, false);
					}
				}
			}

			// Find interesting things (such as sector slopes)
			// Pass one of slope things, and determine which one are for pass two
			//TODO: unfuck this because UDB decided to overhaul this...
			foreach (Thing t in General.Map.Map.Things)
			{
				// SRB2
				if (t.Type == 750)
				{
					if (!thingtags.ContainsKey(t.Tag)) thingtags[t.Tag] = new List<Thing>();
					thingtags[t.Tag].Add(t);
				}
				continue;

				switch (t.Type)
				{
					// ========== Copy slope ==========
					case 9511:
					case 9510:
						slopethingpass[1].Add(t);
						break;

					// ========== Thing line slope ==========
					case 9501:
					case 9500:
						if (linetags.ContainsKey(t.Args[0]))
						{
							// Only slope each sector once, even when multiple lines of the same sector are tagged. See https://github.com/jewalky/UltimateDoomBuilder/issues/491
							List<Sector> slopedsectors = new List<Sector>();

							foreach (Linedef ld in linetags[t.Args[0]])
							{
								if (ld.Line.GetSideOfLine(t.Position) < 0.0f)
								{
									if (ld.Front != null && !slopedsectors.Contains(ld.Front.Sector))
									{
										GetSectorData(ld.Front.Sector).AddEffectThingLineSlope(t, ld.Front);
										slopedsectors.Add(ld.Front.Sector);
									}
								}
								else if (ld.Back != null && !slopedsectors.Contains(ld.Back.Sector))
								{
									GetSectorData(ld.Back.Sector).AddEffectThingLineSlope(t, ld.Back);
									slopedsectors.Add(ld.Back.Sector);
								}
							}
						}
						break;

					// ========== Thing slope ==========
					case 9503:
					case 9502:
						t.DetermineSector(blockmap);
						if (t.Sector != null)
						{
							SectorData sd = GetSectorData(t.Sector);
							sd.AddEffectThingSlope(t);
						}
						break;
				}
			}

			// Find interesting linedefs (such as line slopes)
			// This also determines which slope lines belong to pass one and pass two. See https://zdoom.org/wiki/Slope
			foreach (Linedef l in General.Map.Map.Linedefs)
			{
				// Builds a cache of linedef ids/tags. Used for slope things. Use linedef tags in UDMF
				if(General.Map.UDMF)
				{
					foreach(int tag in l.Tags)
					{
						if (!linetags.ContainsKey(tag)) linetags[tag] = new List<Linedef>();
						linetags[tag].Add(l);
					}
				}

				//mxd. Rewritten to use action ID instead of number
				if (l.Action == 0 || !General.Map.Config.LinedefActions.ContainsKey(l.Action)) continue;

				switch(General.Map.Config.LinedefActions[l.Action].Id.ToLowerInvariant())
				{
					// ========== Line Set Identification (121) (see https://zdoom.org/wiki/Line_SetIdentification) ==========
					// Builds a cache of linedef ids/tags. Used for slope things. Only used for Hexen format
					case "line_setidentification":
						int tag = l.Args[0] + l.Args[4] * 256;
						if (!linetags.ContainsKey(tag)) linetags[tag] = new List<Linedef>();
						linetags[tag].Add(l);
						break;

					// ========== Plane Align (181) (see http://zdoom.org/wiki/Plane_Align) ==========
					case "plane_align":
						slopelinedefpass[0].Add(l);
						break;

					// ========== Plane Copy (118) (mxd) (see http://zdoom.org/wiki/Plane_Copy) ==========
					case "plane_copy":
						slopelinedefpass[1].Add(l);
						break;

					case "srb2_vertexslope":
					{
						List<Thing> sourcethings = new List<Thing>();
						if (!thingtags.ContainsKey(l.Args[1]) || thingtags[l.Args[1]].Count == 0)
							break;
						foreach (Thing thing in thingtags[l.Args[1]])
						{
							if (sourcethings.Contains(thing))
								continue;
							sourcethings.Add(thing);
							break;
						}
						if (!thingtags.ContainsKey(l.Args[2]) || thingtags[l.Args[2]].Count == 0)
							break;
						foreach (Thing thing in thingtags[l.Args[2]])
						{
							if (sourcethings.Contains(thing))
								continue;
							sourcethings.Add(thing);
							break;
						}
						if (!thingtags.ContainsKey(l.Args[3]) || thingtags[l.Args[3]].Count == 0)
							break;
						foreach (Thing thing in thingtags[l.Args[3]])
						{
							if (sourcethings.Contains(thing))
								continue;
							sourcethings.Add(thing);
							break;
						}
						SectorData sd = GetSectorData((l.Args[0] < 2) ? l.Front.Sector : l.Back.Sector);
						sd.AddEffectSRB2ThingVertexSlope(sourcethings, (l.Args[0] & 1) != 1);
						break;
					}

					// ========== Sector 3D floor (160) (see http://zdoom.org/wiki/Sector_Set3dFloor) ==========
					case "sector_set3dfloor":
						if(l.Front != null)
						{
							//mxd. Added hi-tag/line ID check 
							int sectortag = (General.Map.UDMF || (l.Args[1] & (int)Effect3DFloor.FloorTypes.HiTagIsLineID) != 0) ? l.Args[0] : l.Args[0] + (l.Args[4] << 8);
							if(sectortags.ContainsKey(sectortag)) 
							{
								List<Sector> sectors = sectortags[sectortag];
								foreach(Sector s in sectors) 
								{
									SectorData sd = GetSectorData(s);
									sd.AddEffect3DFloor(l);
								}
							}
						}
						break;

					case "srb2_fofsolid":
					case "srb2_fofwater":
					case "srb2_fofsolidopaque":
					case "srb2_fofcrumbling":
					case "srb2_fofintangible":
					case "srb2_fofbustable":
					case "srb2_foflaser":
					case "srb2_fofcustom":
						if (l.Front != null && sectortags.ContainsKey(l.Args[0]))
						{
							List<Sector> sectors = sectortags[l.Args[0]];
							foreach (Sector s in sectors)
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffect3DFloor(l);
							}
						}
						break;

					case "srb2_foflight":
					case "srb2_foffog":
					case "srb2_fofintangibleinvisible":
						if (l.Front != null && sectortags.ContainsKey(l.Args[0]))
						{
							List<Sector> sectors = sectortags[l.Args[0]];
							foreach (Sector s in sectors)
							{
								SectorData sd = GetSectorData(s);
								//sd.AddEffectBrightnessLevel(l);
								sd.AddEffect3DFloor(l);
							}
						}
						break;

					// ========== Transfer Brightness (50) (see http://zdoom.org/wiki/ExtraFloor_LightOnly) =========
					case "extrafloor_lightonly":
						if(l.Front != null && sectortags.ContainsKey(l.Args[0]))
						{
							List<Sector> sectors = sectortags[l.Args[0]];
							foreach(Sector s in sectors) 
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffectBrightnessLevel(l);
							}
						}
						break;

					// ========== mxd. Transfer Floor Brightness (210) (see http://www.zdoom.org/w/index.php?title=Transfer_FloorLight) =========
					case "transfer_floorlight":
						if(l.Front != null && sectortags.ContainsKey(l.Args[0])) 
						{
							List<Sector> sectors = sectortags[l.Args[0]];
							foreach(Sector s in sectors) 
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffectTransferFloorBrightness(l);
							}
						}
						break;

					// ========== mxd. Transfer Ceiling Brightness (211) (see http://www.zdoom.org/w/index.php?title=Transfer_CeilingLight) =========
					case "transfer_ceilinglight":
						if(l.Front != null && sectortags.ContainsKey(l.Args[0])) 
						{
							List<Sector> sectors = sectortags[l.Args[0]];
							foreach(Sector s in sectors) 
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffectTransferCeilingBrightness(l);
							}
						}
						break;

					// ========== mxd. BOOM: Set Tagged Floor Lighting to Lighting on 1st Sidedef's Sector (213) =========
					case "boom_transfer_floorlight":
						if(l.Front != null && sectortags.ContainsKey(l.Tag))
						{
							List<Sector> sectors = sectortags[l.Tag];
							foreach(Sector s in sectors)
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffectTransferFloorBrightness(l);
							}
						}
						break;

					// ========== mxd. BOOM: Set Tagged Ceiling Lighting to Lighting on 1st Sidedef's Sector (261) =========
					case "boom_transfer_ceilinglight":
						if(l.Front != null && sectortags.ContainsKey(l.Tag))
						{
							List<Sector> sectors = sectortags[l.Tag];
							foreach(Sector s in sectors)
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffectTransferCeilingBrightness(l);
							}
						}
						break;
				}
			}

			// Pass one for linedefs
			foreach (Linedef l in slopelinedefpass[0])
			{
				//mxd. Rewritten to use action ID instead of number
				if (l.Action == 0 || !General.Map.Config.LinedefActions.ContainsKey(l.Action)) continue;

				switch (General.Map.Config.LinedefActions[l.Action].Id.ToLowerInvariant())
				{
					// ========== Plane Align (181) (see http://zdoom.org/wiki/Plane_Align) ==========
					case "plane_align":
						if (((l.Args[0] == 1) || (l.Args[1] == 1)) && (l.Front != null))
						{
							SectorData sd = GetSectorData(l.Front.Sector);
							sd.AddEffectLineSlope(l);
						}
						if (((l.Args[0] == 2) || (l.Args[1] == 2)) && (l.Back != null))
						{
							SectorData sd = GetSectorData(l.Back.Sector);
							sd.AddEffectLineSlope(l);
						}
						break;
				}
			}

			// Pass two of slope things
			//TODO: unfuck this because UDB decided to overhaul this...
			foreach (Thing t in slopethingpass[1])
			{
				switch (t.Type)
				{
					// ========== Copy slope ==========
					case 9511:
					case 9510:
						t.DetermineSector(blockmap);
						if (t.Sector != null)
						{
							SectorData sd = GetSectorData(t.Sector);
							sd.AddEffectCopySlope(t);
						}
						break;
				}
			}
			

			// Pass two for linedefs
			foreach (Linedef l in slopelinedefpass[1])
			{
				if (l.Action == 0 || !General.Map.Config.LinedefActions.ContainsKey(l.Action)) continue;

				switch (General.Map.Config.LinedefActions[l.Action].Id.ToLowerInvariant())
				{
					// ========== Plane Copy (118) (mxd) (see http://zdoom.org/wiki/Plane_Copy) ==========
					case "plane_copy":
						{
							//check the flags...
							bool floorCopyToBack = false;
							bool floorCopyToFront = false;
							bool ceilingCopyToBack = false;
							bool ceilingCopyToFront = false;

							if (l.Args[4] > 0 && l.Args[4] != 3 && l.Args[4] != 12)
							{
								floorCopyToBack = (l.Args[4] & 1) == 1;
								floorCopyToFront = (l.Args[4] & 2) == 2;
								ceilingCopyToBack = (l.Args[4] & 4) == 4;
								ceilingCopyToFront = (l.Args[4] & 8) == 8;
							}

							// Copy slope to front sector
							if (l.Front != null)
							{
								if ((l.Args[0] > 0 || l.Args[1] > 0) || (l.Back != null && (floorCopyToFront || ceilingCopyToFront)))
								{
									SectorData sd = GetSectorData(l.Front.Sector);
									sd.AddEffectPlaneClopySlope(l, true);
								}
							}

							// Copy slope to back sector
							if (l.Back != null)
							{
								if ((l.Args[2] > 0 || l.Args[3] > 0) || (l.Front != null && (floorCopyToBack || ceilingCopyToBack)))
								{
									SectorData sd = GetSectorData(l.Back.Sector);
									sd.AddEffectPlaneClopySlope(l, false);
								}
							}
						}
						break;
				}
			}

			// Visual slope handles
			foreach (KeyValuePair<Sector, List<VisualSlope>> kvp in allslopehandles)
			{
				foreach (VisualSlope handle in kvp.Value)
					if (handle != null && handle.Selected)
						if (handle is BaseVisualSlope)
							RemoveSelectedObject((BaseVisualSlope)handle);

				kvp.Value.Clear();
			}
			usedslopehandles.Clear();
			allslopehandles.Clear();
			sidedefslopehandles.Clear();
			vertexslopehandles.Clear();

			BuildSlopeHandles(General.Map.Map.Sectors.ToList());
		}

		private void BuildSlopeHandles(List<Sector> sectors)
		{
			if (!General.Map.UDMF)
				return;

			foreach (Sector s in sectors)
			{
				if (s.IsDisposed)
					continue;

				SectorData sectordata = GetSectorData(s);
				sectordata.Update();

				// Clear old data
				if (allslopehandles.ContainsKey(s)) allslopehandles.Remove(s);
				if (sidedefslopehandles.ContainsKey(s))	sidedefslopehandles.Remove(s);
				if (vertexslopehandles.ContainsKey(s)) vertexslopehandles.Remove(s);


				// Create visual sidedef slope handles
				foreach (Sidedef sidedef in s.Sidedefs)
				{
					// Create handles for the regular floor and ceiling
					CreateVisualSlopeHandle(sectordata.Floor, sidedef, true);
					CreateVisualSlopeHandle(sectordata.Ceiling, sidedef, false);

					// Create handles for 3D floors
					if (sectordata.ExtraFloors.Count > 0)
					{
						foreach (Effect3DFloor floor in sectordata.ExtraFloors)
						{
							CreateVisualSlopeHandle(floor.Floor, sidedef, false);
							CreateVisualSlopeHandle(floor.Ceiling, sidedef, true);
						}
					}
				}
			}

			// Create visual vertex slope handles
			foreach(Vertex v in General.Map.Map.Vertices)
			{
				if (v.IsDisposed || v.Linedefs.Count == 0)
					continue;

				HashSet<Sector> vertexsectors = new HashSet<Sector>();

				// Find all sectors that have lines connected to this vertex
				foreach(Linedef ld in v.Linedefs)
				{
					if (ld.IsDisposed)
						continue;

					if (ld.Front != null && ld.Front.Sector != null && !ld.Front.Sector.IsDisposed) vertexsectors.Add(ld.Front.Sector);
					if (ld.Back != null && ld.Back.Sector != null && !ld.Back.Sector.IsDisposed) vertexsectors.Add(ld.Back.Sector);
				}

				foreach(Sector s in vertexsectors)
				{
					SectorData sectordata = GetSectorData(s);
					sectordata.Update();

					// Create handles for the regular floor and ceiling
					CreateVisualSlopeHandle(sectordata.Floor, v, s, true);
					CreateVisualSlopeHandle(sectordata.Ceiling, v, s, false);

					// Create handles for 3D floors
					if (sectordata.ExtraFloors.Count > 0)
					{
						foreach (Effect3DFloor floor in sectordata.ExtraFloors)
						{
							CreateVisualSlopeHandle(floor.Floor, v, s, false);
							CreateVisualSlopeHandle(floor.Ceiling, v, s, true);
						}
					}
				}
			}
		}
		
		#endregion

		#region ================== Events

		// Help!
		public override void OnHelp()
		{
			General.ShowHelp("e_visual.html");
		}

		// When entering this mode
		public override void OnEngage()
		{
			//mxd
			useSelectionFromClassicMode = BuilderPlug.Me.SyncSelection ? !General.Interface.ShiftState : General.Interface.ShiftState;
			if(useSelectionFromClassicMode)	UpdateSelectionInfo();

			// Read settings
			cameraflooroffset = General.Map.Config.ReadSetting("cameraflooroffset", cameraflooroffset);
			cameraceilingoffset = General.Map.Config.ReadSetting("cameraceilingoffset", cameraceilingoffset);

            //mxd. Update fog color (otherwise FogBoundaries won't be setup correctly)
            foreach (Sector s in General.Map.Map.Sectors)
                s.UpdateFogColor();

			// biwa. We need a blockmap for the slope things. Can't wait until it's built in base.OnEngage
			// This was the root cause for issue #160
			FillBlockMap();

            // (Re)create special effects
            RebuildElementData();

			// Objects are only selected when they are created, so for objects that are selected we have to make sure
			// that they are created immediately. Otherwise the selection order will not be correct, or the objects
			// will not be selected at all if they are out of the user's camera range when entering visual mode
			// See https://github.com/jewalky/UltimateDoomBuilder/issues/938
			if (useSelectionFromClassicMode)
			{
				foreach (Sector s in General.Map.Map.GetSelectedSectors(true))
				{
					BaseVisualSector bvs = CreateBaseVisualSector(s);
					bvs.Ceiling.PerformAutoSelection();
					bvs.Floor.PerformAutoSelection();
				}

				// Things are automatically selected on creation
				foreach (Thing t in General.Map.Map.GetSelectedThings(true))
					allthings[t] = CreateVisualThing(t);

				// For linedefs it's a bit more complicated...
				foreach (Linedef ld in General.Map.Map.GetSelectedLinedefs(true))
				{
					foreach (Sidedef sd in new Sidedef[] { ld.Front, ld.Back })
					{
						if (sd != null)
						{
							if (!allsectors.ContainsKey(sd.Sector))
								CreateBaseVisualSector(sd.Sector).Rebuild(); // We have to rebuild the sector so that potential 3D floors get created

							VisualSidedefParts vsp = ((BaseVisualSector)allsectors[sd.Sector]).Sides[sd];
							vsp.upper?.PerformAutoSelection();
							vsp.middlesingle?.PerformAutoSelection();
							vsp.middledouble?.PerformAutoSelection();
							vsp.lower?.PerformAutoSelection();

							if (vsp.middle3d != null)
								foreach (VisualMiddle3D vm in vsp.middle3d)
									vm.PerformAutoSelection();

							if (vsp.middleback != null)
								foreach (VisualMiddleBack vm in vsp.middleback)
									vm.PerformAutoSelection();
						}
					}
				}
			}

			//mxd. Update event lines
			renderer.SetEventLines(LinksCollector.GetHelperShapes(General.Map.ThingsFilter.VisibleThings, blockmap));

            // [ZZ] this enables calling of this object from the outside world. Only after properly initialized pls.
            base.OnEngage();
        }

		// When returning to another mode
		public override void OnDisengage()
		{
			base.OnDisengage();

			//mxd
			if(BuilderPlug.Me.SyncSelection ? !General.Interface.ShiftState : General.Interface.ShiftState)
			{
				//clear previously selected stuff
				General.Map.Map.ClearAllSelected();
				
				//refill selection
				List<int> selectedsectorindices = new List<int>();
				List<int> selectedlineindices = new List<int>();
				List<int> selectedvertexindices = new List<int>();

				foreach(IVisualEventReceiver obj in selectedobjects)
				{
					if(obj is BaseVisualThing) 
					{
						((BaseVisualThing)obj).Thing.Selected = true;
					}
					else if(obj is VisualFloor || obj is VisualCeiling) 
					{
						VisualGeometry vg = (VisualGeometry)obj;
						if(vg.Sector != null && vg.Sector.Sector != null && !selectedsectorindices.Contains(vg.Sector.Sector.Index))
						{
							selectedsectorindices.Add(vg.Sector.Sector.Index);
							vg.Sector.Sector.Selected = true;
						}
					}
					else if(obj is VisualLower || obj is VisualUpper || obj is VisualMiddleDouble 
						|| obj is VisualMiddleSingle || obj is VisualMiddle3D) 
					{
						VisualGeometry vg = (VisualGeometry)obj;
						if(vg.Sidedef != null && !selectedlineindices.Contains(vg.Sidedef.Line.Index))
						{
							selectedlineindices.Add(vg.Sidedef.Line.Index);
							vg.Sidedef.Line.Selected = true;
						}
					}
					else if(obj is VisualVertex)
					{
						VisualVertex v = (VisualVertex)obj;
						if(!selectedvertexindices.Contains(v.Vertex.Index))
						{
							selectedvertexindices.Add(v.Vertex.Index);
							v.Vertex.Selected = true;
						}
					}
				}
			}

			General.Map.Map.Update();
		}
		
		// Processing
		public override void OnProcess(long deltatime)
		{
			long pickinterval = PICK_INTERVAL; // biwa
			// Process things?
			base.ProcessThings = (BuilderPlug.Me.ShowVisualThings != 0);
			
			// Setup the move multiplier depending on gravity
			Vector3D movemultiplier = new Vector3D(1.0, 1.0, 1.0);
			if(BuilderPlug.Me.UseGravity) movemultiplier.z = 0.0;
			General.Map.VisualCamera.MoveMultiplier = movemultiplier;
			
			// Apply gravity?
			if(BuilderPlug.Me.UseGravity && (General.Map.VisualCamera.Sector != null))
			{
				SectorData sd = GetSectorData(General.Map.VisualCamera.Sector);
				if(!sd.Updated) sd.Update();

				// Camera below floor level?
				Vector3D feetposition = General.Map.VisualCamera.Position;
				SectorLevel floorlevel = sd.GetFloorBelow(feetposition) ?? sd.Floor;
				double floorheight = floorlevel.plane.GetZ(General.Map.VisualCamera.Position);
				if(General.Map.VisualCamera.Position.z < (floorheight + cameraflooroffset + 0.1))
				{
					// Stay above floor
					gravity = new Vector3D(0.0, 0.0, 0.0);
					General.Map.VisualCamera.Position = new Vector3D(General.Map.VisualCamera.Position.x,
																	 General.Map.VisualCamera.Position.y,
																	 floorheight + cameraflooroffset);
				}
				else
				{
					// Fall down
					gravity.z += GRAVITY * General.Map.VisualCamera.Gravity * deltatime;
					if(gravity.z > 3.0) gravity.z = 3.0;

					// Test if we don't go through a floor
					if((General.Map.VisualCamera.Position.z + gravity.z) < (floorheight + cameraflooroffset + 0.1))
					{
						// Stay above floor
						gravity = new Vector3D(0.0, 0.0, 0.0);
						General.Map.VisualCamera.Position = new Vector3D(General.Map.VisualCamera.Position.x,
																		 General.Map.VisualCamera.Position.y,
																		 floorheight + cameraflooroffset);
					}
					else
					{
						// Apply gravity vector
						General.Map.VisualCamera.Position += gravity;
					}
				}

				// Camera above ceiling?
				feetposition = General.Map.VisualCamera.Position - new Vector3D(0, 0, cameraflooroffset - 7.0);
				SectorLevel ceillevel = sd.GetCeilingAbove(feetposition) ?? sd.Ceiling;
				double ceilheight = ceillevel.plane.GetZ(General.Map.VisualCamera.Position);
				if(General.Map.VisualCamera.Position.z > (ceilheight - cameraceilingoffset - 0.01))
				{
					// Stay below ceiling
					General.Map.VisualCamera.Position = new Vector3D(General.Map.VisualCamera.Position.x,
																	 General.Map.VisualCamera.Position.y,
																	 ceilheight - cameraceilingoffset);
				}
			}
			else
			{
				gravity = new Vector3D(0.0, 0.0, 0.0);
			}
			
			// Do processing
			base.OnProcess(deltatime);

			// Process visible geometry
			foreach(IVisualEventReceiver g in visiblegeometry)
			{
				g.OnProcess(deltatime);
			}

			// biwa. Use a lower pick interval for paint selection, to make it more reliable
			if (paintselectpressed)
				pickinterval = PICK_INTERVAL_PAINT_SELECT;
			
			// Time to pick a new target?
			if(Clock.CurrentTime > (lastpicktime + pickinterval))
			{
				PickTargetUnlocked();
				lastpicktime = Clock.CurrentTime;
			}
			
			// The mouse is always in motion
			MouseEventArgs args = new MouseEventArgs(General.Interface.MouseButtons, 0, 0, 0, 0);
			OnMouseMove(args);
		}

		//mxd
		public override void OnClockReset()
		{
			base.OnClockReset();
			lastpicktime = 0;
		}

		// This draws a frame
		public override void OnRedrawDisplay()
		{
			renderer.SetClassicLightingColorMap(General.Map.Data.MainColorMap);

			// Start drawing
			if(renderer.Start())
			{
				// Use fog!
				renderer.SetFogMode(true);

				// Set target for highlighting
				renderer.ShowSelection = General.Settings.GZOldHighlightMode || General.Settings.UseHighlight; //mxd

				if(General.Settings.UseHighlight)
					renderer.SetHighlightedObject(target.picked);
				
				// Begin with geometry
				renderer.StartGeometry();

				// Render all visible sectors
				foreach(VisualGeometry g in visiblegeometry)
					renderer.AddSectorGeometry(g);

				if(BuilderPlug.Me.ShowVisualThings != 0)
				{
					// Render things in cages?
					renderer.DrawThingCages = ((BuilderPlug.Me.ShowVisualThings & 2) != 0);
					
					// Render all visible things
					foreach(VisualThing t in visiblethings)
						renderer.AddThingGeometry(t);
				}

				//mxd
				if(General.Map.UDMF && General.Map.Config.VertexHeightSupport && General.Settings.GZShowVisualVertices && vertices.Count > 0) 
				{
					List<VisualVertex> verts = new List<VisualVertex>();

					foreach(KeyValuePair<Vertex, VisualVertexPair> pair in vertices)
						verts.AddRange(pair.Value.Vertices);

					renderer.SetVisualVertices(verts);
				}

				renderer.SetVisualSlopeHandles(usedslopehandles);

				// Done rendering geometry
				renderer.FinishGeometry();
				
				// Render crosshair
				renderer.RenderCrosshair();
				
				// Present!
				renderer.Finish();
			}
		}
		
		// After resources were reloaded
		protected override void ResourcesReloaded()
		{
			base.ResourcesReloaded();
			RebuildElementData();
			UpdateChangedObjects(); //mxd
			PickTarget();
		}
		
		// This usually happens when geometry is changed by undo, redo, cut or paste actions
		// and uses the marks to check what needs to be reloaded.
		protected override void ResourcesReloadedPartial()
		{
			// Let the core do this (it will just dispose the sectors that were changed)
			base.ResourcesReloadedPartial();

			if (General.Map.UndoRedo.GeometryChanged)
			{
				// The base doesn't know anything about slobe handles, so we have to clear them up ourself
				if (General.Map.UDMF)
				{
					List<Sector> removedsectors = new List<Sector>();

					// Get the sectors that were disposed...
					foreach(Sector s in allslopehandles.Keys)
					{
						if (s.IsDisposed)
							removedsectors.Add(s);
					}

					// ... so that we can remove their slope handles
					foreach(Sector s in removedsectors)
					{
						allslopehandles[s].Clear();
						allslopehandles.Remove(s);

						sidedefslopehandles[s].Clear();
						sidedefslopehandles.Remove(s);

						vertexslopehandles[s].Clear();
						vertexslopehandles.Remove(s);
					}

					// Rebuild slope handles for the changed sectors
					BuildSlopeHandles(General.Map.Map.GetMarkedSectors(true));
				}
			}
			else
			{
				bool sectorsmarked = false;

				// Neighbour sectors must be updated as well
				foreach (Sector s in General.Map.Map.Sectors)
				{
					if(s.Marked)
					{
						sectorsmarked = true;
						foreach(Sidedef sd in s.Sidedefs)
						{
							sd.Marked = true;
							if(sd.Other != null) sd.Other.Marked = true;
						}
					}
				}
				
				// Go for all sidedefs to update
				foreach(Sidedef sd in General.Map.Map.Sidedefs)
				{
					if(sd.Marked && VisualSectorExists(sd.Sector))
					{
						BaseVisualSector vs = (BaseVisualSector)GetVisualSector(sd.Sector);
						VisualSidedefParts parts = vs.GetSidedefParts(sd);
						parts.SetupAllParts();
					}
				}
				
				// Go for all sectors to update
				foreach(Sector s in General.Map.Map.Sectors)
				{
					if(s.Marked)
					{
						SectorData sd = GetSectorDataEx(s);
						if(sd != null)
						{
							sd.Reset(false); //mxd (changed Reset implementation)

							// UpdateSectorGeometry for associated sectors (sd.UpdateAlso) as well!
							foreach(KeyValuePair<Sector, bool> us in sd.UpdateAlso)
							{
								if(VisualSectorExists(us.Key))
								{
									BaseVisualSector vs = (BaseVisualSector)GetVisualSector(us.Key);
									vs.UpdateSectorGeometry(us.Value);
								}
							}
						}
						
						// And update for this sector ofcourse
						if(VisualSectorExists(s))
						{
							BaseVisualSector vs = (BaseVisualSector)GetVisualSector(s);
							vs.UpdateSectorGeometry(false);
						}
					}
				}
				
				if(!sectorsmarked)
				{
					// No sectors or geometry changed. So we only have
					// to update things when they have changed.
					HashSet<Thing> toremove = new HashSet<Thing>(); //mxd
					foreach(KeyValuePair<Thing, VisualThing> vt in allthings)
					{
						if((vt.Value != null) && vt.Key.Marked)
						{
							if(vt.Key.IsDisposed) toremove.Add(vt.Key); //mxd. Disposed things will cause problems
							else ((BaseVisualThing)vt.Value).Rebuild();
						}
					}

					//mxd. Remove disposed things
					foreach(Thing t in toremove)
					{
						if(allthings[t] != null) allthings[t].Dispose();
						allthings.Remove(t);
					}
				}
				else
				{
					// Things depend on the sector they are in and because we can't
					// easily determine which ones changed, we dispose all things
					foreach(KeyValuePair<Thing, VisualThing> vt in allthings)
						if(vt.Value != null) vt.Value.Dispose();
					
					// Apply new lists
					allthings = new Dictionary<Thing, VisualThing>(allthings.Count);
				}
				
				// Clear visibility collections
				visiblesectors.Clear();
				visibleblocks.Clear();
				visiblegeometry.Clear();
				visiblethings.Clear();
				
				// Make new blockmap
				if(sectorsmarked || General.Map.UndoRedo.PopulationChanged || General.Map.IsChanged)
					FillBlockMap();
				
				RebuildElementData();
				UpdateChangedObjects();
				
				// Visibility culling (this re-creates the needed resources)
				DoCulling();
			}
			
			// Determine what we're aiming at now
			PickTarget();
		}
		
		// Mouse moves
		public override void OnMouseMove(MouseEventArgs e)
		{
			base.OnMouseMove(e);
			IVisualEventReceiver o = GetTargetEventReceiver(true);
			o.OnMouseMove(e);

			//mxd. Show hints!
			if(o.GetType() != lasthighlighttype) 
			{
				if(General.Interface.ActiveDockerTabName == "Help") 
				{
					if(o is BaseVisualGeometrySidedef) 
					{
						General.Hints.ShowHints(this.GetType(), "sidedefs");
					}
					else if(o is BaseVisualGeometrySector) 
					{
						General.Hints.ShowHints(this.GetType(), "sectors");
					}
					else if(o is BaseVisualThing) 
					{
						General.Hints.ShowHints(this.GetType(), "things");
					}
					else if(o is BaseVisualVertex) 
					{
						General.Hints.ShowHints(this.GetType(), "vertices");
					}
					else 
					{
						General.Hints.ShowHints(this.GetType(), HintsManager.GENERAL);
					}
				}

				lasthighlighttype = o.GetType();
			}

			// biwa
			if (o is NullVisualEventReceiver)
				highlighted = null;
			else if (o is VisualGeometry)
				highlighted = (VisualGeometry)o;
			else if (o is VisualThing)
				highlighted = (VisualThing)o;
		}
		
		// Undo performed
		public override void OnUndoEnd()
		{
			base.OnUndoEnd();