Allow Animation to generate its own Renderables.

OpenRA.Game/Graphics/Animation.cs

@@ -9,6 +9,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 
 namespace OpenRA.Graphics
 {
@@ -44,6 +45,16 @@ namespace OpenRA.Graphics
 			}
 		}
 
+		public IEnumerable<IRenderable> Render(WPos pos, int zOffset, PaletteReference palette, float scale)
+		{
+			yield return new SpriteRenderable(Image, pos, zOffset, palette, scale);
+		}
+
+		public IEnumerable<IRenderable> Render(WPos pos, PaletteReference palette)
+		{
+			return Render(pos, 0, palette, 1f);
+		}
+
 		public void Play(string sequenceName)
 		{
 			PlayThen(sequenceName, null);

OpenRA.Game/Graphics/AnimationWithOffset.cs

@@ -9,6 +9,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using OpenRA.Traits;
 
 namespace OpenRA.Graphics
@@ -34,19 +35,14 @@ namespace OpenRA.Graphics
 			this.ZOffset = zOffset;
 		}
 
-		public IRenderable Image(Actor self, WorldRenderer wr, PaletteReference pal)
-		{
-			return Image(self, wr, pal, 1f);
-		}
-
-		public IRenderable Image(Actor self, WorldRenderer wr, PaletteReference pal, float scale)
+		public IEnumerable<IRenderable> Render(Actor self, WorldRenderer wr, PaletteReference pal, float scale)
 		{
 			var p = self.CenterPosition;
 			if (OffsetFunc != null)
 				p += OffsetFunc();
 
 			var z = (ZOffset != null) ? ZOffset(p) : 0;
-			return new SpriteRenderable(Animation.Image, p, z, pal, scale);
+			return Animation.Render(p, z, pal, scale);
 		}
 
 		public static implicit operator AnimationWithOffset(Animation a)

OpenRA.Game/Graphics/Renderable.cs

@@ -10,6 +10,7 @@
 
 using System.Collections.Generic;
 using System.Drawing;
+using System.Linq;
 
 namespace OpenRA.Graphics
 {
@@ -47,6 +48,8 @@ namespace OpenRA.Graphics
 
 	public struct SpriteRenderable : IRenderable
 	{
+		public static readonly IEnumerable<IRenderable> None = new IRenderable[0].AsEnumerable();
+
 		readonly Sprite sprite;
 		readonly WPos pos;
 		readonly int zOffset;

OpenRA.Game/Traits/Render/RenderSimple.cs

@@ -25,7 +25,7 @@ namespace OpenRA.Traits
 			var anim = new Animation(RenderSimple.GetImage(ai), () => 0);
 			anim.PlayRepeating("idle");
 
-			yield return new SpriteRenderable(anim.Image, WPos.Zero, 0, pr, 1f);
+			return anim.Render(WPos.Zero, pr);
 		}
 	}
 

OpenRA.Game/Traits/Render/RenderSprites.cs

@@ -90,8 +90,13 @@ namespace OpenRA.Traits
 			}
 
 			foreach (var a in anims.Values)
-				if (a.DisableFunc == null || !a.DisableFunc())
-					yield return a.Image(self, wr, palette, Info.Scale);
+			{
+				if (a.DisableFunc != null && a.DisableFunc())
+					continue;
+
+				foreach (var r in a.Render(self, wr, palette, Info.Scale))
+					yield return r;
+			}
 		}
 
 		public virtual void Tick(Actor self)