smooth unit-movement. Doesn't look right yet, but it's getting there.

OpenRa.Game/Actor.cs

@@ -17,7 +17,7 @@ namespace OpenRa.Game
 		public readonly UnitInfo unitInfo;
 
 		public int2 Location;
-		public Player Owner;
+		public Player Owner;
 		public int Health;
 
 		public Actor( string name, int2 location, Player owner )
@@ -25,21 +25,21 @@ namespace OpenRa.Game
 			unitInfo = Rules.UnitInfo[ name ];
 			Location = location;
 			CenterLocation = new float2( 12, 12 ) + Game.CellSize * (float2)Location;
-			Owner = owner;
-			Health = unitInfo.Strength;	/* todo: handle cases where this is not true! */
-
-			if( unitInfo.Traits != null )
-			{
-				foreach( var traitName in unitInfo.Traits )
-				{
-					var type = typeof( Traits.Mobile ).Assembly.GetType( typeof( Traits.Mobile ).Namespace + "." + traitName, true, false );
-					var ctor = type.GetConstructor( new[] { typeof( Actor ) } );
-					traits.Add( type, ctor.Invoke( new object[] { this } ) );
-				}
-			}
-			else
-				throw new InvalidOperationException( "No Actor traits for " + unitInfo.Name 
-					+ "; add Traits= to units.ini for appropriate unit" );
+			Owner = owner;
+			Health = unitInfo.Strength;	/* todo: handle cases where this is not true! */
+
+			if( unitInfo.Traits != null )
+			{
+				foreach( var traitName in unitInfo.Traits )
+				{
+					var type = typeof( Traits.Mobile ).Assembly.GetType( typeof( Traits.Mobile ).Namespace + "." + traitName, true, false );
+					var ctor = type.GetConstructor( new[] { typeof( Actor ) } );
+					traits.Add( type, ctor.Invoke( new object[] { this } ) );
+				}
+			}
+			else
+				throw new InvalidOperationException( "No Actor traits for " + unitInfo.Name 
+					+ "; add Traits= to units.ini for appropriate unit" );
 		}
 
 		public Actor( TreeReference tree, TreeCache treeRenderer, int2 mapOffset )
@@ -49,8 +49,8 @@ namespace OpenRa.Game
 		}
 
 		public void Tick()
-		{
-			foreach (var tick in traits.WithInterface<Traits.ITick>())
+		{
+			foreach (var tick in traits.WithInterface<Traits.ITick>())
 				tick.Tick(this);
 		}
 
@@ -63,8 +63,8 @@ namespace OpenRa.Game
 		}
 
 		public Order Order( int2 xy )
-		{
-			if (Owner != Game.LocalPlayer)
+		{
+			if (Owner != Game.LocalPlayer)
 				return null;
 
 			return traits.WithInterface<Traits.IOrder>()
@@ -80,32 +80,32 @@ namespace OpenRa.Game
 				var loc = CenterLocation - 0.5f * size;
 				return new RectangleF(loc.X, loc.Y, size.X, size.Y);
 			}
-		}
-
-		public bool IsDead { get { return Health <= 0; } }
-
-		public void InflictDamage(Actor attacker, Bullet inflictor, int damage)
-		{
-			/* todo: auto-retaliate, etc */
-			/* todo: death sequence for infantry based on inflictor */
-			/* todo: start smoking if < conditionYellow and took damage, and not already smoking */
-
-			if (Health <= 0) return;		/* overkill! don't count extra hits as more kills! */
-
-			Health -= damage;
-			if (Health <= 0)
-			{
-				Health = 0;
-				if (attacker.Owner != null)
-					attacker.Owner.Kills++;
-
-				Game.world.AddFrameEndTask(w => w.Remove(this));
-
-				if (Owner == Game.LocalPlayer)
-					Game.PlaySound("unitlst1.aud", false);
-
-				/* todo: explosion */
-			}
+		}
+
+		public bool IsDead { get { return Health <= 0; } }
+
+		public void InflictDamage(Actor attacker, Bullet inflictor, int damage)
+		{
+			/* todo: auto-retaliate, etc */
+			/* todo: death sequence for infantry based on inflictor */
+			/* todo: start smoking if < conditionYellow and took damage, and not already smoking */
+
+			if (Health <= 0) return;		/* overkill! don't count extra hits as more kills! */
+
+			Health -= damage;
+			if (Health <= 0)
+			{
+				Health = 0;
+				if (attacker.Owner != null)
+					attacker.Owner.Kills++;
+
+				Game.world.AddFrameEndTask(w => w.Remove(this));
+
+				if (Owner == Game.LocalPlayer)
+					Game.PlaySound("unitlst1.aud", false);
+
+				/* todo: explosion */
+			}
 		}
 	}
 }

OpenRa.Game/Traits/Mobile.cs

@@ -87,7 +87,8 @@ namespace OpenRa.Game.Traits
 			List<int2> path;
 
 			int moveFraction, moveFractionTotal;
-			float2 from, to;
+			float2 from, to;
+			int fromFacing, toFacing;
 
 			Action<Actor, Mobile> OnComplete;
 
@@ -129,28 +130,41 @@ namespace OpenRa.Game.Traits
 					path.RemoveAt( path.Count - 1 );
 					moveFractionTotal = ( dir.X != 0 && dir.Y != 0 ) ? 35 : 25;
 					from = CenterOfCell( mobile.fromCell );
-					to = BetweenCells( mobile.fromCell, mobile.toCell );
+					to = BetweenCells( mobile.fromCell, mobile.toCell );
+					CalculateMoveFraction();
+					fromFacing = mobile.facing;
+					toFacing = mobile.facing;
 					OnComplete = OnCompleteFirstHalf;
 				}
 				mobile.currentAction.Tick( self, mobile );
-			}
+			}
 
 			void TickMove( Actor self, Mobile mobile )
 			{
 				moveFraction += ( self.unitInfo as UnitInfo.MobileInfo ).Speed;
-				UpdateCenterLocation( self, (float)moveFraction / moveFractionTotal, from, to );
+				UpdateCenterLocation( self, mobile, (float)moveFraction / moveFractionTotal );
 				if( moveFraction >= moveFractionTotal )
 				{
 					moveFraction -= moveFractionTotal;
 					OnComplete( self, mobile );
-					mobile.fromCell = mobile.toCell;
+					//mobile.fromCell = mobile.toCell;
 				}
 				return;
-			}
-
-			static void UpdateCenterLocation( Actor self, float frac, float2 from, float2 to )
-			{
-				self.CenterLocation = float2.Lerp( from, to, frac );
+			}
+
+			void UpdateCenterLocation( Actor self, Mobile mobile, float frac )
+			{
+				self.CenterLocation = float2.Lerp( from, to, frac );
+				if( moveFraction >= moveFractionTotal )
+					mobile.facing = toFacing;
+				else
+					mobile.facing = ( fromFacing + ( toFacing - fromFacing ) * moveFraction / moveFractionTotal ) & 0xFF;
+			}
+
+			void CalculateMoveFraction()
+			{
+				var d = to - from;
+				moveFractionTotal = (int)Math.Sqrt( d.X * d.X + d.Y * d.Y ) * (25 / 6);
 			}
 
 			static float2 CenterOfCell( int2 loc )
@@ -164,17 +178,38 @@ namespace OpenRa.Game.Traits
 			}
 
 			void OnCompleteFirstHalf( Actor self, Mobile mobile )
-			{
-				from = BetweenCells( mobile.fromCell, mobile.toCell );
-				to = CenterOfCell( mobile.toCell );
-				OnComplete = OnCompleteSecondHalf;
+			{
+				if( path.Count > 0 )
+				{
+					var nextCell = path[ path.Count - 1 ];
+					if( ( nextCell - mobile.toCell ) != ( mobile.toCell - mobile.fromCell ) )
+					{
+						path.RemoveAt( path.Count - 1 );
+						from = BetweenCells( mobile.fromCell, mobile.toCell );
+						to = BetweenCells( mobile.toCell, nextCell );
+						CalculateMoveFraction();
+						mobile.fromCell = mobile.toCell;
+						mobile.toCell = nextCell;
+						fromFacing = mobile.facing;
+						toFacing = Util.GetNearestFacing( fromFacing, Util.GetFacing( mobile.toCell-mobile.fromCell, fromFacing ) );
+						OnComplete = OnCompleteFirstHalf;
+						return;
+					}
+				}
+				from = BetweenCells( mobile.fromCell, mobile.toCell );
+				to = CenterOfCell( mobile.toCell );
+				CalculateMoveFraction();
+				fromFacing = toFacing = mobile.facing;
+				OnComplete = OnCompleteSecondHalf;
+				mobile.fromCell = mobile.toCell;
 			}
 
 			void OnCompleteSecondHalf( Actor self, Mobile mobile )
-			{
+			{
 				moveFractionTotal = 0;
 				self.CenterLocation = CenterOfCell( mobile.toCell );
-				OnComplete = null;
+				OnComplete = null;
+				mobile.fromCell = mobile.toCell;
 			}
 		}
 	}

OpenRa.Game/Traits/Util.cs

@@ -43,5 +43,15 @@ namespace OpenRa.Game.Traits
 			return highest * 8;
 		}
 
+		public static int GetNearestFacing( int facing, int desiredFacing )
+		{
+			var turn = desiredFacing - facing;
+			if( turn > 128 )
+				turn -= 256;
+			if( turn < -128 )
+				turn += 256;
+
+			return facing + turn;
+		}
 	}
 }