Implement walk_to()

DMCompiler/DMStandard/_Standard.dm

@@ -112,7 +112,6 @@ proc/viewers(Depth, Center = usr) as /list
 proc/walk(Ref, Dir, Lag = 0, Speed = 0)
 proc/walk_rand(Ref,Lag = 0,Speed = 0)
 proc/walk_to(Ref, Trg, Min = 0, Lag = 0, Speed = 0)
-	set opendream_unimplemented = 1
 proc/walk_towards(Ref,Trg,Lag=0,Speed=0)
 proc/winclone(player, window_name, clone_name)
 proc/winexists(player, control_id) as text

OpenDreamRuntime/Procs/Native/DreamProcNative.cs

@@ -113,6 +113,7 @@ public static void SetupNativeProcs(DreamObjectTree objectTree) {
         objectTree.SetGlobalNativeProc(DreamProcNativeRoot.NativeProc_walk);
         objectTree.SetGlobalNativeProc(DreamProcNativeRoot.NativeProc_walk_rand);
         objectTree.SetGlobalNativeProc(DreamProcNativeRoot.NativeProc_walk_towards);
+        objectTree.SetGlobalNativeProc(DreamProcNativeRoot.NativeProc_walk_to);
         objectTree.SetGlobalNativeProc(DreamProcNativeRoot.NativeProc_winclone);
         objectTree.SetGlobalNativeProc(DreamProcNativeRoot.NativeProc_winexists);
         objectTree.SetGlobalNativeProc(DreamProcNativeRoot.NativeProc_winget);

OpenDreamRuntime/Procs/Native/DreamProcNativeRoot.cs

@@ -3213,6 +3213,29 @@ public static DreamValue NativeProc_walk_towards(NativeProc.Bundle bundle, Dream
         return DreamValue.Null;
     }
 
+    [DreamProc("walk_to")]
+    [DreamProcParameter("Ref", Type = DreamValueTypeFlag.DreamObject)]
+    [DreamProcParameter("Trg", Type = DreamValueTypeFlag.DreamObject)]
+    [DreamProcParameter("Min", Type = DreamValueTypeFlag.Float, DefaultValue = 0)]
+    [DreamProcParameter("Lag", Type = DreamValueTypeFlag.Float, DefaultValue = 0)]
+    [DreamProcParameter("Speed", Type = DreamValueTypeFlag.Float, DefaultValue = 0)]
+    public static DreamValue NativeProc_walk_to(NativeProc.Bundle bundle, DreamObject? src, DreamObject? usr) {
+        if (!bundle.GetArgument(0, "Ref").TryGetValueAsDreamObject<DreamObjectMovable>(out var refAtom))
+            return DreamValue.Null;
+
+        if (!bundle.GetArgument(1, "Trg").TryGetValueAsDreamObject<DreamObjectAtom>(out var trgAtom)) {
+            bundle.WalkManager.StopWalks(refAtom);
+            return DreamValue.Null;
+        }
+
+        bundle.GetArgument(2, "Min").TryGetValueAsInteger(out var min);
+        bundle.GetArgument(3, "Lag").TryGetValueAsInteger(out var lag);
+        bundle.GetArgument(4, "Speed").TryGetValueAsInteger(out var speed);
+
+        bundle.WalkManager.StartWalkTo(refAtom, trgAtom, min, lag, speed);
+        return DreamValue.Null;
+    }
+
     [DreamProc("winclone")]
     [DreamProcParameter("player", Type = DreamValueTypeFlag.DreamObject)]
     [DreamProcParameter("window_name", Type = DreamValueTypeFlag.String)]

OpenDreamRuntime/WalkManager.cs

@@ -1,3 +1,4 @@
+using System.Linq;
 using System.Threading;
 using OpenDreamRuntime.Map;
 using OpenDreamRuntime.Objects.Types;
@@ -111,4 +112,39 @@
             return DreamValue.Null;
         });
     }
+
+    /// <summary>
+    /// Walk towards the target with pathfinding taken into account
+    /// </summary>
+    public void StartWalkTo(DreamObjectMovable movable, DreamObjectAtom target, int min, int lag, int speed) { // TODO: Implement speed. Speed=0 uses Ref.step_size
+        StopWalks(movable);
+
+        lag = Math.Max(lag, 1); // Minimum of 1 tick lag
+
+        CancellationTokenSource cancelSource = new();
+        _walkTasks[movable] = cancelSource;
+
+        DreamThread.Run($"walk_to {movable}", async state => {
+            var moveProc = movable.GetProc("Move");
+
+            while (true) {
+                await _scheduler.CreateDelayTicks(lag);
+                if (cancelSource.IsCancellationRequested)
+                    break;
+
+                var currentLoc = _atomManager.GetAtomPosition(movable);
+                var targetLoc = _atomManager.GetAtomPosition(target);
+                var steps = _dreamMapManager.CalculateSteps(currentLoc, targetLoc, min);
+                using var enumerator = steps.GetEnumerator();
+                if (!enumerator.MoveNext()) // No more steps to take
+                    break;
+
+                var dir = enumerator.Current;
+                var newLoc = DreamProcNativeHelpers.GetStep(_atomManager, _dreamMapManager, movable, dir);
+                await state.Call(moveProc, movable, null, new(newLoc), new((int)dir));
+            }
+
+            return DreamValue.Null;
+        });
+    }
 }