rework dimensions and orientation into Placement, optimise requirements to work on previous candidates, use vec3 for positions

Assets/Engine/Runtime/Requirements/Requirement.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 using EscapeRoomEngine.Engine.Runtime.Modules;
 using UnityEngine;
 
@@ -6,22 +7,15 @@ namespace EscapeRoomEngine.Engine.Runtime.Requirements
 {
     public abstract class Requirement<T> : ScriptableObject
     {
-        protected abstract IEnumerable<T> GenerateCandidates(Module module, Space space);
+        protected abstract List<T> FilterCandidates(List<T> candidates, Module module, Space space);
 
-        public void Restrict(HashSet<T> candidates, Module module, Space space) =>
-            candidates.IntersectWith(GenerateCandidates(module, space));
-
-        public static HashSet<T> Candidates(
-            HashSet<T> initialCandidates,
+        protected static List<T> Candidates(
+            List<T> candidates,
             IEnumerable<Requirement<T>> requirements,
             Module module, Space space)
         {
-            foreach (var requirement in requirements)
-            {
-                requirement.Restrict(initialCandidates, module, space);
-            }
-
-            return initialCandidates;
+            return requirements.Aggregate(candidates,
+                (current, requirement) => requirement.FilterCandidates(current, module, space));
         }
     }
 }