SpatialMap now uses unordered_multimap to allow for multiple items in a square, but they're also tagged to mark some with collision.

spatialmap.cpp

@@ -6,46 +6,49 @@ using namespace fmt;
 using DinkyECS::Entity;
 
 void SpatialMap::insert(Point pos, Entity ent, bool has_collision) {
-  if(has_collision) {
-    dbc::check(!yes_collision.contains(pos), "YES_collision already has entity");
-    yes_collision.insert_or_assign(pos, ent);
-  } else {
-    dbc::check(!no_collision.contains(pos), "no_collision already has entity");
-    no_collision.insert_or_assign(pos, ent);
-  }
+  dbc::check(!occupied(pos), "attempt to insert an entity with collision in space with collision");
+
+  $collision.emplace(pos, CollisionData{ent, has_collision});
 }
 
-bool SpatialMap::remove(Point pos) {
-  if(yes_collision.contains(pos)) {
-    yes_collision.erase(pos);
-    return true;
-  } else {
-    dbc::check(no_collision.contains(pos), "remove of entity that's not in no_collision");
-    no_collision.erase(pos);
-    return false;
+CollisionData SpatialMap::remove(Point pos, Entity ent) {
+  auto [begin, end] = $collision.equal_range(pos);
+  for(auto it = begin; it != end; ++it) {
+    if(it->second.entity == ent) {
+      // does the it->second go invalid after erase?
+      auto copy = it->second;
+      $collision.erase(it);
+      return copy;
+    }
   }
+
+  dbc::sentinel("failed to find entity to remove");
 }
 
 void SpatialMap::move(Point from, Point to, Entity ent) {
-  dbc::check(!occupied(to), "attempt to move to point with an existing entity");
-  bool has_collision = remove(from);
-  insert(to, ent, has_collision);
+  auto data = remove(from, ent);
+  insert(to, ent, data.collision);
 }
 
 bool SpatialMap::occupied(Point at) const {
-  return yes_collision.contains(at);
+  auto [begin, end] = $collision.equal_range(at);
+  for(auto it = begin; it != end; ++it) {
+    if(it->second.collision) {
+      return true;
+    }
+  }
+
+  return false;
 }
 
 bool SpatialMap::something_there(Point at) const {
-  return yes_collision.contains(at) || no_collision.contains(at);
+  return $collision.count(at) > 0;
 }
 
 Entity SpatialMap::get(Point at) const {
-  if(yes_collision.contains(at)) {
-    return yes_collision.at(at);
-  } else {
-    return no_collision.at(at);
-  }
+  dbc::check($collision.contains(at), "attempt to get entity when none there");
+  auto [begin, end] = $collision.equal_range(at);
+  return begin->second.entity;
 }
 
 /*
@@ -63,7 +66,7 @@ inline void find_neighbor(const PointEntityMap &table, EntityList &result, Point
 
   auto it = table.find(cell);
   if (it != table.end()) {
-    result.insert(result.end(), it->second);
+    result.insert(result.end(), it->second.entity);
   }
 }
 
@@ -72,16 +75,16 @@ FoundEntities SpatialMap::neighbors(Point cell, bool diag) const {
 
   // just unroll the loop since we only check four directions
   // this also solves the problem that it was detecting that the cell was automatically included as a "neighbor" but it's not
-  find_neighbor(yes_collision, result, cell, 0, 1); // north
-  find_neighbor(yes_collision, result, cell, 0, -1); // south
-  find_neighbor(yes_collision, result, cell, 1, 0); // east
-  find_neighbor(yes_collision, result, cell, -1, 0); // west
+  find_neighbor($collision, result, cell, 0, 1); // north
+  find_neighbor($collision, result, cell, 0, -1); // south
+  find_neighbor($collision, result, cell, 1, 0); // east
+  find_neighbor($collision, result, cell, -1, 0); // west
 
   if(diag) {
-    find_neighbor(yes_collision, result, cell, 1, -1); // south east
-    find_neighbor(yes_collision, result, cell, -1, -1); // south west
-    find_neighbor(yes_collision, result, cell, 1, 1); // north east
-    find_neighbor(yes_collision, result, cell, -1, 1); // north west
+    find_neighbor($collision, result, cell, 1, -1); // south east
+    find_neighbor($collision, result, cell, -1, -1); // south west
+    find_neighbor($collision, result, cell, 1, 1); // north east
+    find_neighbor($collision, result, cell, -1, 1); // north west
   }
 
   return {!result.empty(), result};
@@ -94,7 +97,7 @@ inline void update_sorted(SortedEntities& sprite_distance, PointEntityMap& table
         (from.y - sprite.y) * (from.y - sprite.y);
 
     if(inside < max_dist) {
-      sprite_distance.push_back({inside, rec.second});
+      sprite_distance.push_back({inside, rec.second.entity});
     }
   }
 }
@@ -102,8 +105,7 @@ inline void update_sorted(SortedEntities& sprite_distance, PointEntityMap& table
 SortedEntities SpatialMap::distance_sorted(Point from, int max_dist) {
   SortedEntities sprite_distance;
 
-  update_sorted(sprite_distance, yes_collision, from, max_dist);
-  update_sorted(sprite_distance, no_collision, from, max_dist);
+  update_sorted(sprite_distance, $collision, from, max_dist);
 
   std::sort(sprite_distance.begin(), sprite_distance.end(), std::greater<>());