Add IModel.AggregateBounds and ModelAnimation.ScreenBounds.

The bounds define the smallest Rectangle that covers all
rotations of all frames within a model sequence.

OpenRA.Game/Graphics/Model.cs

@@ -10,6 +10,7 @@
 #endregion
 
 using System;
+using System.Drawing;
 using OpenRA.FileSystem;
 
 namespace OpenRA.Graphics
@@ -23,6 +24,9 @@ namespace OpenRA.Graphics
 		float[] Size { get; }
 		float[] Bounds(uint frame);
 		ModelRenderData RenderData(uint section);
+
+		/// <summary>Returns the smallest rectangle that covers all rotations of all frames in a model</summary>
+		Rectangle AggregateBounds { get; }
 	}
 
 	public struct ModelRenderData

OpenRA.Game/Graphics/ModelAnimation.cs

@@ -11,6 +11,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 
 namespace OpenRA.Graphics
 {
@@ -33,6 +34,19 @@ namespace OpenRA.Graphics
 			ShowShadow = showshadow;
 		}
 
+		public Rectangle ScreenBounds(WPos pos, WorldRenderer wr, float scale)
+		{
+			var r = Model.AggregateBounds;
+			var offset = OffsetFunc != null ? OffsetFunc() : WVec.Zero;
+			var xy = wr.ScreenPxPosition(pos) + wr.ScreenPxOffset(offset);
+
+			return Rectangle.FromLTRB(
+				xy.X + (int)(r.Left * scale),
+				xy.Y + (int)(r.Top * scale),
+				xy.X + (int)(r.Right * scale),
+				xy.Y + (int)(r.Bottom * scale));
+		}
+
 		public bool IsVisible
 		{
 			get

OpenRA.Mods.Cnc/Graphics/Voxel.cs

@@ -10,6 +10,7 @@
 #endregion
 
 using System;
+using System.Drawing;
 using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Cnc.FileFormats;
@@ -125,5 +126,33 @@ namespace OpenRA.Mods.Cnc.Graphics
 
 			return ret;
 		}
+
+		public Rectangle AggregateBounds
+		{
+			get
+			{
+				// Corner offsets
+				var ix = new uint[] { 0, 0, 0, 0, 3, 3, 3, 3 };
+				var iy = new uint[] { 1, 1, 4, 4, 1, 1, 4, 4 };
+				var iz = new uint[] { 2, 5, 2, 5, 2, 5, 2, 5 };
+
+				// Calculate the smallest sphere that covers the model limbs
+				var rSquared = 0f;
+				for (var f = 0U; f < frames; f++)
+				{
+					var bounds = Bounds(f);
+					for (var i = 0; i < 8; i++)
+					{
+						var x = bounds[ix[i]];
+						var y = bounds[iy[i]];
+						var z = bounds[iz[i]];
+						rSquared = Math.Max(rSquared, x * x + y * y + z * z);
+					}
+				}
+
+				var r = (int)Math.Sqrt(rSquared) + 1;
+				return Rectangle.FromLTRB(-r, -r, r, r);
+			}
+		}
 	}
 }