adding top collision

src/world.h

@@ -18,6 +18,7 @@ extern const float MAX_PLAYER_SPEED;
 
 extern const float PLAYER_SPEED_FACTOR;
 
+
 void ApplyForce(Entity *e, Vector2 force);
 bool IsGrounded(Entity *e);
 
@@ -26,7 +27,8 @@ Entity *SpawnEntity(
     float y,
     float size,
     float mass,
-    Color color);
+    Color color,
+    float drag);
 
 void ClearWorld(void);
 void InitWorld(void);