src/guitimer_func.h

   1 /*
   2  * This file is part of OpenTTD.
   3  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   4  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   5  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   6  */
   7
   8 /** @file guitimer_func.h GUI Timers. */
   9
  10 #ifndef GUITIMER_FUNC_H
  11 #define GUITIMER_FUNC_H
  12
  13 class GUITimer
  14 {
  15 protected:
  16         uint timer;
  17         uint interval;
  18
  19 public:
  20         GUITimer() : timer(0), interval(0) { }
  21         explicit GUITimer(uint interval) : timer(0), interval(interval) { }
  22
  23         inline bool HasElapsed() const
  24         {
  25                 return this->interval == 0;
  26         }
  27
  28         inline void SetInterval(uint interval)
  29         {
  30                 this->timer = 0;
  31                 this->interval = interval;
  32         }
  33
  34         /**
  35          * Count how many times the interval has elapsed.
  36          * Use to ensure a specific amount of events happen within a timeframe, e.g. for animation.
  37          * @param delta Time since last test.
  38          * @return Number of times the interval has elapsed.
  39          */
  40         inline uint CountElapsed(uint delta)
  41         {
  42                 if (this->interval == 0) return 0;
  43                 uint count = delta / this->interval;
  44                 if (this->timer + (delta % this->interval) >= this->interval) count++;
  45                 this->timer = (this->timer + delta) % this->interval;
  46                 return count;
  47         }
  48
  49         /**
  50          * Test if a timer has elapsed.
  51          * Use to ensure an event happens only once within a timeframe, e.g. for window updates.
  52          * @param delta Time since last test.
  53          * @return True iff the timer has elapsed.
  54          */
  55         inline bool Elapsed(uint delta)
  56         {
  57                 if (this->CountElapsed(delta) == 0) return false;
  58                 this->SetInterval(0);
  59                 return true;
  60         }
  61 };
  62
  63 #endif /* GUITIMER_FUNC_H */