Add Map.DistanceAboveTerrain(WPos) and Actor.IsAtGroundLevel() extension method

OpenRA.Game/Map/Map.cs

@@ -775,6 +775,13 @@ namespace OpenRA
 			return CenterOfCell(cell);
 		}
 
+		public WDist DistanceAboveTerrain(WPos pos)
+		{
+			var cell = CellContaining(pos);
+			var delta = pos - CenterOfCell(cell);
+			return new WDist(delta.Z);
+		}
+
 		public CPos CellContaining(WPos pos)
 		{
 			if (TileShape == TileShape.Rectangle)

OpenRA.Mods.Common/ActorExts.cs

@@ -18,6 +18,25 @@ namespace OpenRA.Mods.Common
 {
 	public static class ActorExts
 	{
+		public static bool IsAtGroundLevel(this Actor self)
+		{
+			if (self.IsDead)
+				return false;
+
+			if (!self.HasTrait<IPositionable>())
+				return false;
+
+			if (!self.IsInWorld)
+				return false;
+
+			var map = self.World.Map;
+
+			if (!map.Contains(self.Location))
+				return false;
+
+			return map.DistanceAboveTerrain(self.CenterPosition).Length == 0;
+		}
+
 		public static bool AppearsFriendlyTo(this Actor self, Actor toActor)
 		{
 			var stance = toActor.Owner.Stances[self.Owner];

OpenRA.Mods.Common/Graphics/VoxelRenderable.cs

@@ -104,8 +104,7 @@ namespace OpenRA.Mods.Common.Graphics
 
 			public void Render(WorldRenderer wr)
 			{
-				// TODO: This is a temporary workaround until we have a proper ramp-aware height calculation
-				var groundPos = wr.World.Map.CenterOfCell(wr.World.Map.CellContaining(voxel.pos));
+				var groundPos = voxel.pos - new WVec(0, 0, wr.World.Map.DistanceAboveTerrain(voxel.pos).Length);
 
 				var ts = Game.ModData.Manifest.TileSize;
 				var groundZ = ts.Height * (groundPos.Z - voxel.pos.Z) / 1024f;

OpenRA.Mods.Common/Traits/Cargo.cs

@@ -171,7 +171,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		public bool CanLoad(Actor self, Actor a)
 		{
-			return (reserves.Contains(a) || HasSpace(GetWeight(a))) && self.CenterPosition.Z == 0;
+			return (reserves.Contains(a) || HasSpace(GetWeight(a))) && self.IsAtGroundLevel();
 		}
 
 		internal bool ReserveSpace(Actor a)

OpenRA.Mods.Common/Traits/Crates/Crate.cs

@@ -189,11 +189,8 @@ namespace OpenRA.Mods.Common.Traits
 
 		public bool CrushableBy(string[] crushClasses, Player owner)
 		{
-			// Crate can only be crushed if it is not in the air or underground
-			if (CenterPosition.Z != 0)
-				return false;
-
-			return crushClasses.Contains(info.CrushClass);
+			// Crate can only be crushed if it is not in the air.
+			return self.IsAtGroundLevel() && crushClasses.Contains(info.CrushClass);
 		}
 
 		public void AddedToWorld(Actor self)

OpenRA.Mods.Common/Traits/Crushable.cs

@@ -65,8 +65,8 @@ namespace OpenRA.Mods.Common.Traits
 
 		public bool CrushableBy(string[] crushClasses, Player crushOwner)
 		{
-			// Only make actor crushable if it is on the ground
-			if (self.CenterPosition.Z != 0)
+			// Only make actor crushable if it is on the ground.
+			if (!self.IsAtGroundLevel())
 				return false;
 
 			if (!info.CrushedByFriendlies && crushOwner.IsAlliedWith(self.Owner))

OpenRA.Mods.Common/Traits/EjectOnDeath.cs

@@ -65,7 +65,8 @@ namespace OpenRA.Mods.Common.Traits
 				return;
 
 			var cp = self.CenterPosition;
-			if ((cp.Z > 0 && !info.EjectInAir) || (cp.Z == 0 && !info.EjectOnGround))
+			var inAir = !self.IsAtGroundLevel();
+			if ((inAir && !info.EjectInAir) || (!inAir && !info.EjectOnGround))
 				return;
 
 			var pilot = self.World.CreateActor(false, info.PilotActor.ToLowerInvariant(),
@@ -73,7 +74,7 @@ namespace OpenRA.Mods.Common.Traits
 
 			if (info.AllowUnsuitableCell || IsSuitableCell(self, pilot))
 			{
-				if (cp.Z > 0)
+				if (inAir)
 				{
 					self.World.AddFrameEndTask(w =>
 					{

OpenRA.Mods.Common/Traits/Mobile.cs

@@ -565,7 +565,7 @@ namespace OpenRA.Mods.Common.Traits
 		public void FinishedMoving(Actor self)
 		{
 			// Only make actor crush if it is on the ground
-			if (self.CenterPosition.Z != 0)
+			if (!self.IsAtGroundLevel())
 				return;
 
 			var crushables = self.World.ActorMap.GetUnitsAt(ToCell).Where(a => a != self)