Give the player first move advantage, but maybe this should be a setting on motion so that some enemies can beat the player.

systems.cpp

@@ -33,12 +33,7 @@ void System::init_positions(DinkyECS::World &world) {
   });
 }
 
-void System::motion(DinkyECS::World &world, Map &game_map) {
+inline void move_entity(spatial_map &collider, Map &game_map, Position &position, Motion &motion, DinkyECS::Entity ent) {
-  auto &collider = world.get<spatial_map>();
-
-  world.system<Position, Motion>([&](const auto &ent, auto &position, auto &motion) {
-    // don't process entities that don't move
-    if(motion.dx != 0 || motion.dy != 0) {
   Point move_to = {
     position.location.x + motion.dx,
     position.location.y + motion.dy
@@ -53,6 +48,19 @@ void System::motion(DinkyECS::World &world, Map &game_map) {
     position.location = move_to;
   }
 }
+
+void System::motion(DinkyECS::World &world, Map &game_map) {
+  auto &collider = world.get<spatial_map>();
+  auto &player = world.get<Player>();
+  auto &player_position = world.component<Position>(player.entity);
+  auto &player_motion = world.component<Motion>(player.entity);
+  move_entity(collider, game_map, player_position, player_motion, player.entity);
+
+  world.system<Position, Motion>([&](const auto &ent, auto &position, auto &motion) {
+    // don't process entities that don't move
+    if(motion.dx != 0 || motion.dy != 0) {
+      move_entity(collider, game_map, position, motion, ent);
+    }
   });
 }