src/core/main.c

   1 /*!@file
   2   \brief   engine entry
   3   \details initializes necessary subsystems before invoking the preloader,
   4            which loads initial game data, before finally invoking the
   5            main loop gameloop(void)
   6   \author  K
   7   \date    2016
   8 ------------------------------------------------------------------------------*/
   9 #ifdef __EMSCRIPTEN__
  10 /* Web Environment */
  11 #define main em_main
  12 #include <SDL_ttf.h>
  13 #include <emscripten/emscripten.h>
  14 #else
  15 /* Traditional Environment */
  16 #ifdef __Win32
  17 #include <windows.h>
  18 #endif //__Win32
  19 #include <SDL2/SDL_ttf.h>
  20 #endif
  21 /* ENVIRONMENT-AGNOSTIC DEFINES */
  22 #include <SDL2/SDL.h>
  23 #include <SDL2/SDL_image.h>
  24 #include <stdint.h>
  25 #include <setjmp.h>
  26 #include <stdio.h>
  27 #define TRIGGERS quit_trigger
  28 #include <core/trigger.h>
  29 #include <core/engine.h>
  30 #include <wolfssl/wolfcrypt/sha256.h>
  31
  32 /* exposed functions */
  33 void main_loop(void);
  34
  35 /* private functions */
  36 static int main_init(void);
  37
  38 /* unexposed externs *
  39 extern int         state_init(void);
  40 extern void        state_tick(uint32_t delta_ticks);
  41 extern const char* state_get_error(void);
  42 extern void        state_quit(void);
  43 extern void        state_handle_event(SDL_Event event);
  44 extern int         io_init(void);
  45 extern const char* io_get_error(void);
  46 extern void        io_quit(void);*/
  47
  48 /* main jump buffer */
  49 jmp_buf jmp_main;
  50
  51 /*@
  52   initializes subsystems and calls main_loop(void)
  53
  54   main sets a jump buffer for its primary switch, which may be jumped to
  55   at any time.  Jumping with a 0 return value is equivalent to calling
  56   setjmp directly, which initializes the system and begins the main loop.
  57   Jumping with any other value will process one of the directives associated
  58   with the exit codes in core.h
  59 */
  60 #ifdef __EMSCRIPTEN__
  61 #define main_loop()\
  62   emscripten_set_main_loop(main_loop,0,0);\
  63   TRIGGER_SET(quit_trigger, emscripten_cancel_main_loop);\
  64   return 0;
  65 #endif
  66
  67 int
  68 main (int argc, char** argv)
  69 { Sha256 shstr = {0};
  70   wc_InitSha256(&shstr);
  71
  72   printf("%d %d\n", sizeof(long), sizeof(long long));
  73
  74   switch(setjmp(jmp_main))
  75     { case 0:
  76         if (main_init())
  77           return -1;
  78         main_loop();
  79       case EXIT_GRACEFUL:
  80         break;
  81       default:
  82       case EXIT_PANIC:
  83         //dump some debug info
  84         break;
  85     }
  86   TRIGGER(quit_trigger);
  87   return 0;
  88 }
  89
  90 #ifdef __EMSCRIPTEN__
  91 #undef main_loop
  92 #endif
  93
  94 /** subsystem initializer
  95     Calling main_init() bootstraps the system, and may be called multiple
  96     times to cause a system-wide reboot.
  97   @return 0 if successful, -1 SDL, -2 IMG, -3 TTF, -4 STATE.
  98   SDL and logging is available after this is called
  99  ******************************************************************************/
 100 #define INIT(_subsys_id,_cond,_errorstring,_quit)\
 101   if (_cond)\
 102     { fprintf(stderr, #_cond " failed: %s\n", _errorstring());\
 103       return -_subsys_id;\
 104     }\
 105   TRIGGER_SET(quit_trigger, _quit)
 106
 107 #define SDL_FLAGS SDL_INIT_EVERYTHING & ~(SDL_INIT_TIMER | SDL_INIT_HAPTIC)
 108
 109 static
 110 int
 111 main_init()
 112 { static char bInitialized = 0;
 113   if (bInitialized++)
 114     { TRIGGER(quit_trigger);
 115       SDL_LogInfo(SDL_LOG_CATEGORY_APPLICATION, "Resetting [%d]\n",
 116                   bInitialized);
 117     }
 118
 119   INIT(1, SDL_Init(SDL_FLAGS) < 0, SDL_GetError, SDL_Quit);
 120   INIT(2, IMG_Init(IMG_INIT_PNG) != IMG_INIT_PNG, IMG_GetError, IMG_Quit);
 121   INIT(3, TTF_Init() == -1, TTF_GetError, TTF_Quit);
 122
 123 /*TODO:
 124   INIT(4, io_init(), io_get_error, io_quit);
 125   INIT(5, state_init(), state_get_error, state_quit);
 126 */
 127
 128   SDL_Log("Initialization Complete.");
 129   return 0;
 130 }
 131
 132 /** main loop.
 133  *******************************************************************************/
 134 void
 135 main_loop()
 136 { static uint32_t main_loop_last_ticks = 0;
 137   SDL_Event event;
 138   uint32_t delta_ticks;
 139
 140 #ifdef LOOP_YIELD_OPTIONAL
 141 loop:
 142 #endif
 143   /* Poll events (user/system inputs) */
 144   while (SDL_PollEvent(&event))
 145     //state_handle_event(&event);
 146     ;
 147
 148   /* change in time since last loop */
 149   delta_ticks = SDL_GetTicks() - main_loop_last_ticks;
 150
 151   /* handle breakpoints (long pause likely a breakpoint) */
 152   if (delta_ticks > 1000)
 153     { SDL_LogWarn(SDL_LOG_CATEGORY_SYSTEM, "Recovering from long pause.");
 154       delta_ticks = TARGET_DT;
 155     }
 156
 157   /* tick the state manager forward by the change in time */
 158   //state_tick(delta_ticks);
 159   main_loop_last_ticks = SDL_GetTicks();
 160
 161   /* render the scene to backbuffer */
 162 ////TODO: state_tick(delta_ticks);
 163   /* swap in the backbuffer for display */
 164 ////TODO: state_render();
 165
 166 #ifdef LOOP_YIELD_OPTIONAL
 167 #define DIV_UP(x,y) ((x + (y / 2)) / y)
 168
 169   /* cap the framerate if we're handling the loop mechanism directly, but only
 170      yield if we have a substantial portion of time to yield (1/10th of the
 171      target delta) */
 172   delta_ticks = SDL_GetTicks() - main_loop_last_ticks;
 173   if ((delta_ticks + DIV_UP(TARGET_DT, 10)) < TARGET_DT)
 174     SDL_Delay(TARGET_DT - delta_ticks);
 175
 176   goto loop;
 177 #endif
 178 }
 179