Add conversions and helpers for world coordinates.

OpenRA.Game/Actor.cs

@@ -28,6 +28,8 @@ namespace OpenRA
 		Lazy<IOccupySpace> occupySpace;
 		IHasLocation HasLocation;
 		Lazy<IMove> Move;
+		Lazy<IFacing> Facing;
+
 		public Cached<Rectangle> Bounds;
 		public Cached<Rectangle> ExtendedBounds;
 
@@ -45,6 +47,25 @@ namespace OpenRA
 			}
 		}
 
+		public WPos CenterPosition
+		{
+			get
+			{
+				var altitude = Move.Value != null ? Move.Value.Altitude : 0;
+				return CenterLocation.ToWPos(altitude);
+			}
+		}
+
+		public WRot Orientation
+		{
+			get
+			{
+				// TODO: Support non-zero pitch/roll in IFacing (IOrientation?)
+				var facing = Facing.Value != null ? Facing.Value.Facing : 0;
+				return new WRot(WAngle.Zero, WAngle.Zero, WAngle.FromFacing(facing));
+			}
+		}
+
 		public Shroud.ActorVisibility Sight;
 
 		[Sync] public Player Owner;
@@ -74,6 +95,7 @@ namespace OpenRA
 			}
 
 			Move = Lazy.New(() => TraitOrDefault<IMove>());
+			Facing = Lazy.New(() => TraitOrDefault<IFacing>());
 
 			Size = Lazy.New(() =>
 			{

OpenRA.Game/Graphics/WorldRenderer.cs

@@ -211,5 +211,25 @@ namespace OpenRA.Graphics
 		{
 			palette.Update( world.WorldActor.TraitsImplementing<IPaletteModifier>() );
 		}
+
+		// Conversion between world and screen coordinates
+		public float2 ScreenPosition(WPos pos)
+		{
+			var c = Game.CellSize/1024f;
+			return new float2(c*pos.X, c*(pos.Y - pos.Z));
+		}
+
+		public int2 ScreenPxPosition(WPos pos)
+		{
+			var c = Game.CellSize/1024f;
+			return new int2((int)(c*pos.X), (int)(c*(pos.Y - pos.Z)));
+		}
+		public float ScreenZOffset(WPos pos) { return pos.Z*Game.CellSize/1024f; }
+
+		public float[] ScreenOffset(WVec vec)
+		{
+			var c = Game.CellSize/1024f;
+			return new float[] {c*vec.X, c*vec.Y, c*vec.Z};
+		}
 	}
 }

OpenRA.Game/PPos.cs

@@ -23,6 +23,18 @@ namespace OpenRA
 		public PPos(int x, int y) { X = x; Y = y; }
 
 		public static readonly PPos Zero = new PPos(0, 0);
+		public static PPos FromWPos(WPos pos)
+		{
+			return new PPos(Game.CellSize*pos.X/1024, Game.CellSize*pos.Y/1024);
+		}
+
+		// Temporary hack for things that throw away altitude and
+		// cache screen positions directly. This can go once all
+		// the callers understand world coordinates
+		public static PPos FromWPosHackZ(WPos pos)
+		{
+			return new PPos(Game.CellSize*pos.X/1024, Game.CellSize*(pos.Y - pos.Z)/1024);
+		}
 
 		public static explicit operator PPos(int2 a) { return new PPos(a.X, a.Y); }
 
@@ -74,6 +86,13 @@ namespace OpenRA
 							Math.Min(r.Bottom, Math.Max(Y, r.Top)));
 		}
 
+		public WPos ToWPos(int z)
+		{
+			return new WPos(1024*X/Game.CellSize,
+			                1024*Y/Game.CellSize,
+			                1024*z/Game.CellSize);
+		}
+
 		public override int GetHashCode() { return X.GetHashCode() ^ Y.GetHashCode(); }
 
 		public override bool Equals(object obj)

OpenRA.Game/Traits/Render/RenderSimple.cs

@@ -27,6 +27,10 @@ namespace OpenRA.Traits
 		[Desc("Change the sprite image size.")]
 		public readonly float Scale = 1f;
 
+		[Desc("Number of facings for gameplay calculations. -1 indiciates auto-detection from sequence")]
+		public readonly int QuantizedFacings = -1;
+
+		public readonly WAngle CameraPitch = WAngle.FromDegrees(40);
 		public virtual object Create(ActorInitializer init) { return new RenderSimple(init.self); }
 
 		public virtual IEnumerable<Renderable> RenderPreview(ActorInfo building, PaletteReference pr)
@@ -38,7 +42,7 @@ namespace OpenRA.Traits
 		}
 	}
 
-	public class RenderSimple : IRender, IAutoSelectionSize, ITick, INotifyOwnerChanged
+	public class RenderSimple : IRender, ILocalCoordinatesModel, IAutoSelectionSize, ITick, INotifyOwnerChanged
 	{
 		public Dictionary<string, AnimationWithOffset> anims = new Dictionary<string, AnimationWithOffset>();
 
@@ -140,5 +144,22 @@ namespace OpenRA.Traits
 				anim.PlayThen(NormalizeSequence(self, name),
 					() => anim.PlayRepeating(NormalizeSequence(self, "idle")));
 		}
+
+		public WVec LocalToWorld(WVec vec)
+		{
+			// RA's 2d perspective doesn't correspond to an orthonormal 3D
+			// coordinate system, so fudge the y axis to make things look good
+			return new WVec(vec.Y, -Info.CameraPitch.Sin()*vec.X/1024, vec.Z);
+		}
+
+		public WRot QuantizeOrientation(Actor self, WRot orientation)
+		{
+			// Map yaw to the closest facing
+			var numDirs = Info.QuantizedFacings == -1 ? anim.CurrentSequence.Facings : Info.QuantizedFacings;
+			var facing = Util.QuantizeFacing(orientation.Yaw.Angle / 4, numDirs) * (256 / numDirs);
+
+			// Roll and pitch are always zero
+			return new WRot(WAngle.Zero, WAngle.Zero, WAngle.FromFacing(facing));
+		}
 	}
 }

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -211,6 +211,11 @@ namespace OpenRA.Traits
 	public interface IPostRenderSelection { void RenderAfterWorld(WorldRenderer wr); }
 	public interface IPreRenderSelection { void RenderBeforeWorld(WorldRenderer wr, Actor self); }
 	public interface IRenderAsTerrain { IEnumerable<Renderable> RenderAsTerrain(WorldRenderer wr, Actor self); }
+	public interface ILocalCoordinatesModel
+	{
+		WVec LocalToWorld(WVec vec);
+		WRot QuantizeOrientation(Actor self, WRot orientation);
+	}
 
 	public interface ITargetable
 	{