Shots keep track of their launch time

src/common/Shot.cc

@@ -44,8 +44,9 @@ Shot::Shot(const Vector2f & origin, double direction, double target_dist)
         / (2 * t * GRAVITY);
 }
 
-Vector3f Shot::get_pos_at_time(double time)
+Vector3f Shot::get_position()
 {
+    float time = m_clock.getElapsedTime().asSeconds();
     float horiz_dist = m_speed * time;
     float z = INITIAL_SHOT_HEIGHT + m_speed * time - GRAVITY * time * time / 2.0;
     Vector2f xy = m_direction * horiz_dist;

src/common/Shot.h

@@ -8,11 +8,12 @@ class Shot
 {
     public:
         Shot(const sf::Vector2f & origin, double direction, double target_dist);
-        sf::Vector3f get_pos_at_time(double time);
+        sf::Vector3f get_position();
     protected:
         sf::Vector2f m_origin;
         sf::Vector2f m_direction;
         double m_speed;
+        sf::Clock m_clock;
 };
 
 #endif