fix FaceSpaceCenter requirement

Assets/Engine/Runtime/Placement.cs

@@ -32,22 +32,46 @@ namespace EscapeRoomEngine.Engine.Runtime
         }
 
         /// <summary>
-        /// Get the positions of the two back corners. The first one is just the position of the placement.
+        /// Get the geometric center of this placement taking into account its orientation.
+        /// </summary>
+        public Vector3 GeometricCenter
+        {
+            get
+            {
+                var sizeMinusOne = size - Vector2Int.one;
+                var half = new Vector2(sizeMinusOne.x/2f, sizeMinusOne.y/2f);
+                var horizontal = new Vector3(half.x, 0, half.y);
+                var vertical = new Vector3(half.y, 0, -half.x);
+                var geometricPosition = position + new Vector3(0.5f, 0, 0.5f);
+#pragma warning disable CS8524
+                return orientation switch
+#pragma warning restore CS8524
+                {
+                    Orientation.North => geometricPosition + horizontal,
+                    Orientation.East => geometricPosition + vertical,
+                    Orientation.South => geometricPosition - horizontal,
+                    Orientation.West => geometricPosition - vertical
+                };
+            }
+        }
+        
+        /// <summary>
+        /// Get the integer positions of the two back corners. The first one is just the position of the placement.
         /// </summary>
-        /// <exception cref="ArgumentOutOfRangeException"></exception>
         public (Vector3Int, Vector3Int) BackCorners {
             get
             {
                 var width = size.x - 1;
                 var horizontal = new Vector3Int(width, 0, 0);
                 var vertical = new Vector3Int(0, 0, width);
+#pragma warning disable CS8524
                 var otherCorner = orientation switch
+#pragma warning restore CS8524
                 {
                     Orientation.North => position + horizontal,
                     Orientation.East => position - vertical,
                     Orientation.South => position - horizontal,
-                    Orientation.West => position + vertical,
+                    Orientation.West => position + vertical
-                    _ => throw new ArgumentOutOfRangeException()
                 };
                 return (position, otherCorner);
             }

Assets/Engine/Runtime/Requirements/FaceSpaceCenter.cs

@@ -14,20 +14,40 @@ namespace EscapeRoomEngine.Engine.Runtime.Requirements
 
             candidates.RemoveAll(candidate =>
             {
-                var bottomLeft = candidate.BottomLeft;
+                var orientation = candidate.orientation;
-                var center = new Vector2(bottomLeft.x, bottomLeft.z) +
+                var center = candidate.GeometricCenter;
-                             new Vector2(candidate.size.x / 2f, candidate.size.y / 2f);
                 var xRel = center.x / width;
-                var zRel = center.y / length;
+                var zRel = center.z / length;
+                bool keep;
 
-                return candidate.orientation !=
+                // check the space diagonals
-                       (zRel > xRel
+                if (Mathf.Approximately(xRel, zRel))
-                           ? zRel > 1 - xRel
+                {
-                               ? Orientation.South
+                    keep = Mathf.Approximately(xRel, 0.5f) ||
-                               : Orientation.East
+                           (xRel < 0.5f
-                           : zRel > 1 - xRel
+                               ? orientation is Orientation.East or Orientation.North // on bottom left diagonal of space
-                               ? Orientation.West
+                               : orientation is Orientation.West or Orientation.South); // on top right diagonal of space
-                               : Orientation.North);
+                }
+                else if (Mathf.Approximately(xRel, 1 - zRel))
+                {
+                    keep = xRel < 0.5f
+                        ? orientation is Orientation.East or Orientation.South // on top left diagonal of space
+                        : orientation is Orientation.West or Orientation.North; // on bottom right diagonal of space
+                }
+                else
+                {
+                    // check the areas between the diagonals
+                    keep = orientation ==
+                           (zRel > xRel
+                               ? zRel > 1 - xRel
+                                   ? Orientation.South
+                                   : Orientation.East
+                               : zRel > 1 - xRel
+                                   ? Orientation.West
+                                   : Orientation.North);
+                }
+                
+                return !keep;
             });
 
             return candidates;