handle movement events more smoothly

src/game.d

@@ -1,4 +1,5 @@
 static enum uint TICK_MS = 50;
+static enum int MOVE_PER_TICK = 1;
 
 enum
 {
@@ -26,16 +27,50 @@ class Game
 public:
     void change_player()
     {
-        m_pindex = (m_pindex + 1) % 2;
+        m_pindex ^= 1;
     }
     void handle_move_event(int type, bool stop)
     {
-        m_players[m_pindex].x += [-10, 10, 0, 0][type];
+        final switch (type)
-        m_players[m_pindex].y += [0, 0, 10, -10][type];
+        {
+        case MOVE_LEFT:
+            m_left = !stop;
+            break;
+        case MOVE_RIGHT:
+            m_right = !stop;
+            break;
+        case MOVE_UP:
+            m_up = !stop;
+            break;
+        case MOVE_DOWN:
+            m_down = !stop;
+            break;
+        }
+    }
+    void update(uint ms)
+    {
+        while (ms > (m_last_tick_ms + TICK_MS))
+        {
+            if (m_left)
+                m_players[m_pindex].x -= MOVE_PER_TICK;
+            if (m_right)
+                m_players[m_pindex].x += MOVE_PER_TICK;
+            if (m_up)
+                m_players[m_pindex].y += MOVE_PER_TICK;
+            if (m_down)
+                m_players[m_pindex].y -= MOVE_PER_TICK;
+            m_last_tick_ms += TICK_MS;
+            m_tick++;
+        }
     }
     Player[] get_players() { return m_players; }
 protected:
+    bool m_left;
+    bool m_right;
+    bool m_up;
+    bool m_down;
     uint m_tick;
+    uint m_last_tick_ms;
     Player[2] m_players;
     int m_pindex;
 };

src/main.d

@@ -137,6 +137,7 @@ int main(char[][] args)
         }
         if (exit)
             break;
+        game.update(SDL_GetTicks());
         display(game);
     }