Playing around with it some more to see how a move would work.

scratchpad/collider.cpp

@@ -1,6 +1,9 @@
 #include <iostream>
 #include <vector>
 #include <unordered_map>
+#include <fmt/core.h>
+
+using namespace fmt;
 
 struct Point {
   int x, y;
@@ -22,13 +25,17 @@ struct PointHash {
 };
 
 class SpatialHashTable {
-public:
+  public:
     SpatialHashTable() {}
 
     void insert(Object* obj) {
       table[obj->position].push_back(obj);
     }
 
+    void remove(Object* obj) {
+      table.erase(obj->position);
+    }
+
     std::vector<Object*> getNearbyObjects(Point position) {
       std::vector<Object*> result;
       Point cell = position;
@@ -47,7 +54,7 @@ public:
       return result;
     }
 
-private:
+  private:
     std::unordered_map<Point, std::vector<Object*>, PointHash> table;
 };
 
@@ -62,8 +69,37 @@ int main() {
   hashTable.insert(&bomb);
 
   std::vector<Object*> nearby = hashTable.getNearbyObjects({24, 24});
+
+  for (Object* obj : nearby) {
+    println("{},{}", obj->position.x, obj->position.y);
+  }
+
+  println("AFTER MOVE");
+
+  // now attempt a move
+  hashTable.remove(&bomb);
+  bomb.position.x += 1;
+  bomb.position.y += 1;
+  hashTable.insert(&bomb);
+
+  nearby = hashTable.getNearbyObjects({24, 24});
+
+  for (Object* obj : nearby) {
+    println("{},{}", obj->position.x, obj->position.y);
+  }
+
+  println("AFTER MOVE BACK");
+
+  // now attempt a move
+  hashTable.remove(&bomb);
+  bomb.position.x -= 3;
+  bomb.position.y -= 2;
+  hashTable.insert(&bomb);
+
+  nearby = hashTable.getNearbyObjects({24, 24});
+
   for (Object* obj : nearby) {
-        std::cout << obj->position.x << ", " << obj->position.y << std::endl;
+    println("{},{}", obj->position.x, obj->position.y);
   }
 
   return 0;