Add ScreenBounds method to IRender interface.

This method is expected to return Rectangles that cover
the region where Renderables returned by Render may exist.

OpenRA.Game/Traits/Player/FrozenActorLayer.cs

@@ -302,6 +302,12 @@ namespace OpenRA.Traits
 				.SelectMany(ff => ff.Render(wr));
 		}
 
+		public IEnumerable<Rectangle> ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			// Player-actor render traits don't require screen bounds
+			yield break;
+		}
+
 		public FrozenActor FromID(uint id)
 		{
 			FrozenActor fa;

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -96,7 +96,11 @@ namespace OpenRA.Traits
 	public interface ITick { void Tick(Actor self); }
 	[RequireExplicitImplementation]
 	public interface ITickRender { void TickRender(WorldRenderer wr, Actor self); }
-	public interface IRender { IEnumerable<IRenderable> Render(Actor self, WorldRenderer wr); }
+	public interface IRender
+	{
+		IEnumerable<IRenderable> Render(Actor self, WorldRenderer wr);
+		IEnumerable<Rectangle> ScreenBounds(Actor self, WorldRenderer wr);
+	}
 
 	public interface IAutoSelectionSizeInfo : ITraitInfoInterface { }
 	public interface IAutoSelectionSize { int2 SelectionSize(Actor self); }

OpenRA.Mods.Cnc/Traits/Render/WithCargo.cs

@@ -10,6 +10,7 @@
 #endregion
 
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common;
@@ -98,6 +99,14 @@ namespace OpenRA.Mods.Cnc.Traits.Render
 			}
 		}
 
+		IEnumerable<Rectangle> IRender.ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			var pos = self.CenterPosition;
+			foreach (var p in previews.Values.SelectMany(p => p))
+				foreach (var b in p.ScreenBounds(wr, pos))
+					yield return b;
+		}
+
 		void INotifyPassengerEntered.OnPassengerEntered(Actor self, Actor passenger)
 		{
 			if (info.DisplayTypes.Contains(passenger.Trait<Passenger>().Info.CargoType))

OpenRA.Mods.Common/Traits/Attack/AttackGarrisoned.cs

@@ -11,6 +11,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Traits.Render;
@@ -189,7 +190,7 @@ namespace OpenRA.Mods.Common.Traits
 			}
 		}
 
-		public IEnumerable<IRenderable> Render(Actor self, WorldRenderer wr)
+		IEnumerable<IRenderable> IRender.Render(Actor self, WorldRenderer wr)
 		{
 			var pal = wr.Palette(Info.MuzzlePalette);
 
@@ -199,6 +200,12 @@ namespace OpenRA.Mods.Common.Traits
 					yield return r;
 		}
 
+		IEnumerable<Rectangle> IRender.ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			// Muzzle flashes don't contribute to actor bounds
+			yield break;
+		}
+
 		protected override void Tick(Actor self)
 		{
 			base.Tick(self);

OpenRA.Mods.Common/Traits/Buildings/Bridge.cs

@@ -11,6 +11,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using OpenRA.Effects;
 using OpenRA.GameRules;
@@ -216,6 +217,25 @@ namespace OpenRA.Mods.Common.Traits
 			return renderables[template];
 		}
 
+		public IEnumerable<Rectangle> ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			foreach (var kv in footprint)
+			{
+				var xy = wr.ScreenPxPosition(wr.World.Map.CenterOfCell(kv.Key));
+				var size = wr.Theater.TileSprite(new TerrainTile(template, kv.Value)).Bounds.Size;
+
+				// Add an extra pixel padding to avoid issues with odd-sized sprites
+				var halfWidth = size.Width / 2 + 1;
+				var halfHeight = size.Height / 2 + 1;
+
+				yield return Rectangle.FromLTRB(
+					xy.X - halfWidth,
+					xy.Y - halfHeight,
+					xy.X + halfWidth,
+					xy.Y + halfHeight);
+			}
+		}
+
 		void KillUnitsOnBridge()
 		{
 			foreach (var c in footprint.Keys)

OpenRA.Mods.Common/Traits/Carryall.cs

@@ -192,6 +192,17 @@ namespace OpenRA.Mods.Common.Traits
 			}
 		}
 
+		IEnumerable<Rectangle> IRender.ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			if (carryablePreview == null)
+				yield break;
+
+			var pos = self.CenterPosition;
+			foreach (var p in carryablePreview)
+				foreach (var b in p.ScreenBounds(wr, pos))
+					yield return b;
+		}
+
 		IEnumerable<IOrderTargeter> IIssueOrder.Orders
 		{
 			get

OpenRA.Mods.Common/Traits/Contrail.cs

@@ -71,6 +71,12 @@ namespace OpenRA.Mods.Common.Traits
 			return new IRenderable[] { trail };
 		}
 
+		IEnumerable<Rectangle> IRender.ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			// Contrails don't contribute to actor bounds
+			yield break;
+		}
+
 		void INotifyAddedToWorld.AddedToWorld(Actor self)
 		{
 			trail = new ContrailRenderable(self.World, color, info.TrailWidth, info.TrailLength, 0, info.ZOffset);

OpenRA.Mods.Common/Traits/Render/CustomTerrainDebugOverlay.cs

@@ -75,5 +75,11 @@ namespace OpenRA.Mods.Common.Traits
 				yield return new TextRenderable(font, center, 0, info.Color, info.Type);
 			}
 		}
+
+		IEnumerable<Rectangle> IRender.ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			// World-actor render traits don't require screen bounds
+			yield break;
+		}
 	}
 }

OpenRA.Mods.Common/Traits/Render/RenderNameTag.cs

@@ -54,5 +54,11 @@ namespace OpenRA.Mods.Common.Traits.Render
 
 			return new IRenderable[] { new TextRenderable(font, effectPos, 0, color, name) };
 		}
+
+		IEnumerable<Rectangle> IRender.ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			// Name tags don't contribute to actor bounds
+			yield break;
+		}
 	}
 }

OpenRA.Mods.Common/Traits/Render/RenderSprites.cs

@@ -11,6 +11,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Graphics;
@@ -181,6 +182,13 @@ namespace OpenRA.Mods.Common.Traits.Render
 			}
 		}
 
+		public virtual IEnumerable<Rectangle> ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			foreach (var a in anims)
+				if (a.IsVisible)
+					yield return a.Animation.ScreenBounds(self, wr, info.Scale);
+		}
+
 		void ITick.Tick(Actor self)
 		{
 			Tick(self);

OpenRA.Mods.Common/Traits/Render/RenderVoxels.cs

@@ -11,6 +11,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Graphics;
@@ -91,7 +92,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 		public void OnOwnerChanged(Actor self, Player oldOwner, Player newOwner) { initializePalettes = true; }
 
 		protected PaletteReference colorPalette, normalsPalette, shadowPalette;
-		public IEnumerable<IRenderable> Render(Actor self, WorldRenderer wr)
+		IEnumerable<IRenderable> IRender.Render(Actor self, WorldRenderer wr)
 		{
 			if (initializePalettes)
 			{
@@ -108,6 +109,14 @@ namespace OpenRA.Mods.Common.Traits.Render
 				colorPalette, normalsPalette, shadowPalette) };
 		}
 
+		IEnumerable<Rectangle> IRender.ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			var pos = self.CenterPosition;
+			foreach (var c in components)
+				if (c.IsVisible)
+					yield return c.ScreenBounds(pos, wr, info.Scale);
+		}
+
 		public string Image { get { return info.Image ?? self.Info.Name; } }
 		public void Add(ModelAnimation v) { components.Add(v); }
 		public void Remove(ModelAnimation v) { components.Remove(v); }

OpenRA.Mods.Common/Traits/Render/WithMuzzleOverlay.cs

@@ -11,6 +11,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Traits;
@@ -86,7 +87,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 
 		void INotifyAttack.PreparingAttack(Actor self, Target target, Armament a, Barrel barrel) { }
 
-		public IEnumerable<IRenderable> Render(Actor self, WorldRenderer wr)
+		IEnumerable<IRenderable> IRender.Render(Actor self, WorldRenderer wr)
 		{
 			foreach (var arm in armaments)
 			{
@@ -103,6 +104,12 @@ namespace OpenRA.Mods.Common.Traits.Render
 			}
 		}
 
+		IEnumerable<Rectangle> IRender.ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			// Muzzle flashes don't contribute to actor bounds
+			yield break;
+		}
+
 		void ITick.Tick(Actor self)
 		{
 			foreach (var a in anims.Values)

OpenRA.Mods.Common/Traits/Render/WithParachute.cs

@@ -11,6 +11,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Graphics;
@@ -154,7 +155,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 				shadow.Tick();
 		}
 
-		public IEnumerable<IRenderable> Render(Actor self, WorldRenderer wr)
+		IEnumerable<IRenderable> IRender.Render(Actor self, WorldRenderer wr)
 		{
 			if (info.ShadowImage == null)
 				return Enumerable.Empty<IRenderable>();
@@ -170,5 +171,21 @@ namespace OpenRA.Mods.Common.Traits.Render
 			var palette = wr.Palette(info.ShadowPalette);
 			return new IRenderable[] { new SpriteRenderable(shadow.Image, pos, info.ShadowOffset, info.ShadowZOffset, palette, 1, true) };
 		}
+
+		IEnumerable<Rectangle> IRender.ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			if (info.ShadowImage == null)
+				return Enumerable.Empty<Rectangle>();
+
+			if (IsTraitDisabled || self.IsDead || !self.IsInWorld)
+				return Enumerable.Empty<Rectangle>();
+
+			if (self.World.FogObscures(self))
+				return Enumerable.Empty<Rectangle>();
+
+			var dat = self.World.Map.DistanceAboveTerrain(self.CenterPosition);
+			var pos = self.CenterPosition - new WVec(0, 0, dat.Length);
+			return new Rectangle[] { shadow.ScreenBounds(wr, pos, info.ShadowOffset, 1) };
+		}
 	}
 }

OpenRA.Mods.Common/Traits/Render/WithTextDecoration.cs

@@ -75,6 +75,12 @@ namespace OpenRA.Mods.Common.Traits.Render
 			return !Info.RequiresSelection ? RenderInner(self, wr) : SpriteRenderable.None;
 		}
 
+		IEnumerable<Rectangle> IRender.ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			// Text decorations don't contribute to actor bounds
+			yield break;
+		}
+
 		IEnumerable<IRenderable> IRenderAboveShroudWhenSelected.RenderAboveShroud(Actor self, WorldRenderer wr)
 		{
 			return Info.RequiresSelection ? RenderInner(self, wr) : SpriteRenderable.None;

OpenRA.Mods.Common/Traits/World/EditorActorLayer.cs

@@ -98,6 +98,12 @@ namespace OpenRA.Mods.Common.Traits
 				.SelectMany(p => p.Render());
 		}
 
+		IEnumerable<Rectangle> IRender.ScreenBounds(Actor self, WorldRenderer wr)
+		{
+			// World-actor render traits don't require screen bounds
+			yield break;
+		}
+
 		public EditorActorPreview Add(ActorReference reference) { return Add(NextActorName(), reference); }
 
 		EditorActorPreview Add(string id, ActorReference reference, bool initialSetup = false)