src/videolib/videolib_mainloop.c

   1 /* coded by Ketmar // Vampire Avalon (psyc://ketmar.no-ip.org/~Ketmar)
   2  * Understanding is not required. Only obedience.
   3  *
   4  * This program is free software. It comes without any warranty, to
   5  * the extent permitted by applicable law. You can redistribute it
   6  * and/or modify it under the terms of the Do What The Fuck You Want
   7  * To Public License, Version 2, as published by Sam Hocevar. See
   8  * http://sam.zoy.org/wtfpl/COPYING for more details.
   9  */
  10 #include "videolib.h"
  11 #ifdef VIDEOLIB_ENABLE_MAIN_LOOP
  12
  13
  14 ////////////////////////////////////////////////////////////////////////////////
  15 // main loop
  16 int vl_fps = 60;
  17
  18
  19 ////////////////////////////////////////////////////////////////////////////////
  20 void (*vl_update) (int elapsed_ms) = NULL;
  21 void (*vl_rebuild) (void) = NULL;
  22 int (*vl_preprocess_event) (SDL_Event *ev) = NULL;
  23 void (*vl_postprocess_event) (SDL_Event *ev) = NULL;
  24 void (*vl_process_keydown) (SDL_KeyboardEvent *ev) = NULL;
  25 void (*vl_process_keyup) (SDL_KeyboardEvent *ev) = NULL;
  26 void (*vl_process_mousedown) (SDL_MouseButtonEvent *ev) = NULL;
  27 void (*vl_process_mouseup) (SDL_MouseButtonEvent *ev) = NULL;
  28 void (*vl_process_mousemotion) (SDL_MouseMotionEvent *ev) = NULL;
  29 void (*vl_process_mousewheel) (SDL_MouseWheelEvent *ev) = NULL;
  30
  31
  32 ////////////////////////////////////////////////////////////////////////////////
  33 static SDL_TimerID sdl_tidframe = 0;
  34 static Uint64 last_update_call = 0;
  35
  36
  37 ////////////////////////////////////////////////////////////////////////////////
  38 static Uint32 timer_cb (Uint32 interval, void *param) {
  39   SDL_Event event;
  40   event.type = SDL_USEREVENT;
  41   event.user.code = VL_EVT_SHOW_FRAME;
  42   event.user.data1 = NULL;
  43   event.user.data2 = NULL;
  44   SDL_PushEvent(&event);
  45   return interval;
  46 }
  47
  48
  49 ////////////////////////////////////////////////////////////////////////////////
  50 /* return !0 to stop event loop; <0: from event preprocessor; >0: from SDL_QUIT */
  51 int vl_process_event (SDL_Event *ev) {
  52   Uint64 tm;
  53   if (ev == NULL) return 0;
  54   if (vl_preprocess_event != NULL) {
  55     int res = vl_preprocess_event(ev);
  56     if (res < 0) return -1;
  57     if (res > 0) return 0;
  58   }
  59   if (ev->type == SDL_QUIT) return 1;
  60   switch (ev->type) {
  61     case SDL_KEYDOWN: if (vl_process_keydown != NULL) vl_process_keydown(&ev->key); break;
  62     case SDL_KEYUP: if (vl_process_keyup != NULL) vl_process_keyup(&ev->key); break;
  63     case SDL_MOUSEBUTTONDOWN: if (vl_process_mousedown != NULL) vl_process_mousedown(&ev->button); break;
  64     case SDL_MOUSEBUTTONUP: if (vl_process_mouseup != NULL) vl_process_mouseup(&ev->button); break;
  65     case SDL_MOUSEMOTION: if (vl_process_mousemotion != NULL) vl_process_mousemotion(&ev->motion); break;
  66     case SDL_MOUSEWHEEL: if (vl_process_mousewheel != NULL) vl_process_mousewheel(&ev->wheel); break;
  67     case SDL_USEREVENT:
  68       switch (ev->user.code) {
  69         case VL_EVT_SHOW_FRAME:
  70           tm = vl_clock_milli();
  71           if (vl_update != NULL) vl_update(tm-last_update_call);
  72           last_update_call = tm;
  73           if (sdl_frame_changed) {
  74             if (vl_rebuild != NULL) vl_rebuild();
  75             paint_screen();
  76           }
  77           break;
  78       }
  79       break;
  80     case SDL_WINDOWEVENT:
  81       switch (ev->window.event) {
  82         case SDL_WINDOWEVENT_EXPOSED:
  83           paint_screen();
  84           break;
  85       }
  86   }
  87   return 0;
  88 }
  89
  90
  91 void vl_start_fps_timer (void) {
  92   int fps = vl_fps;
  93   if (sdl_tidframe != 0) SDL_RemoveTimer(sdl_tidframe);
  94   if (fps < 1) fps = 1; else if (fps > 1000) fps = 1000;
  95   vl_fps = fps;
  96   sdl_tidframe = SDL_AddTimer(1000/fps, timer_cb, NULL);
  97 }
  98
  99
 100 void vl_stop_fps_timer (void) {
 101   if (sdl_tidframe != 0) SDL_RemoveTimer(sdl_tidframe);
 102   sdl_tidframe = 0;
 103 }
 104
 105
 106 void vl_main_loop (void) {
 107   SDL_Event ev;
 108   if (vl_update != NULL) vl_update(0);
 109   if (vl_rebuild != NULL) vl_rebuild();
 110   paint_screen();
 111   last_update_call = vl_clock_milli();
 112   vl_start_fps_timer();
 113   while (SDL_WaitEvent(&ev)) {
 114     int res = vl_process_event(&ev);
 115     if (res) break;
 116   }
 117   vl_stop_fps_timer();
 118 }
 119 #endif