src/gamesequence/gamesequence.cpp

   1 /*
   2  * Copyright (C) Volition, Inc. 1999.  All rights reserved.
   3  *
   4  * All source code herein is the property of Volition, Inc. You may not sell
   5  * or otherwise commercially exploit the source or things you created based on
   6  * the source.
   7  */
   8
   9 /*
  10  * $Logfile: /Freespace2/code/GameSequence/GameSequence.cpp $
  11  * $Revision$
  12  * $Date$
  13  * $Author$
  14  *
  15  * File to control Game Sequencing
  16  *
  17  * $Log$
  18  * Revision 1.2  2002/06/09 04:41:17  relnev
  19  * added copyright header
  20  *
  21  * Revision 1.1.1.1  2002/05/03 03:28:09  root
  22  * Initial import.
  23  *
  24  *
  25  * 3     2/23/99 2:29p Dave
  26  * First run of oldschool dogfight mode.
  27  *
  28  * 2     10/07/98 10:52a Dave
  29  * Initial checkin.
  30  *
  31  * 1     10/07/98 10:48a Dave
  32  *
  33  * 65    5/15/98 12:09a Dave
  34  * New tracker api code. New game tracker code. Finished up first run of
  35  * the PXO screen. Fixed a few game server list exceptions.
  36  *
  37  * 64    5/12/98 2:46a Dave
  38  * Rudimentary communication between Parallax Online and freespace. Can
  39  * get and store channel lists.
  40  *
  41  * 63    5/06/98 1:12a Allender
  42  * fix sequencing names, added nprintf to help respawn debugging
  43  *
  44  * 62    4/25/98 7:39p Allender
  45  * fixd some small hotkey stuff.  Worked on turret orientation being
  46  * correct for multiplayer.  new sexpression called end-campaign will will
  47  * end the main campaign
  48  *
  49  * 61    4/23/98 7:08p John
  50  * Removed some obsoleted states.
  51  *
  52  * 60    4/16/98 4:31p Hoffoss
  53  * Changed demo screen referenced to view cutscenes screen, which is now
  54  * what it's called.
  55  *
  56  * 59    4/02/98 5:40p Hoffoss
  57  * Added the Load Mission screen to FreeSpace.
  58  *
  59  * 58    3/11/98 5:32p Lawrance
  60  * Fix up text arrays for events/states
  61  *
  62  * 57    3/09/98 12:13a Lawrance
  63  * Add support for Red Alert missions
  64  *
  65  * 56    3/05/98 4:12p John
  66  * Made Debug+F4 switch Glide and windowed.
  67  *
  68  * 55    3/03/98 1:00p Hoffoss
  69  * Added new command briefing event and state.
  70  *
  71  * 54    3/02/98 4:23p Hoffoss
  72  * Forgot to add state label.
  73  *
  74  * 53    3/02/98 3:44p Hoffoss
  75  * Added new Campaign Room state and event.
  76  *
  77  * 52    2/21/98 11:58a John
  78  * Put in some stuff to externalize strings
  79  *
  80  * 51    2/19/98 6:26p Dave
  81  * Fixed a few file xfer bugs. Tweaked mp team select screen. Put in
  82  * initial support for player data uploading.
  83  *
  84  * 50    2/18/98 10:21p Dave
  85  * Ripped out old file xfer system. Put in brand new xfer system.
  86  *
  87  * 49    2/08/98 5:07p Dave
  88  * Put in support for multiplayer furball mode.
  89  *
  90  * 48    1/28/98 6:21p Dave
  91  * Made the standalone use ~8 megs less memory. Fixed multiplayer submenu
  92  * endgame problem.
  93  *
  94  * 47    1/23/98 5:43p Dave
  95  * Finished bringing standalone up to speed. Coded in new host options
  96  * screen.
  97  *
  98  * 46    1/22/98 5:25p Dave
  99  * Modified some pregame sequencing packets. Starting to repair broken
 100  * standalone stuff.
 101  *
 102  * 45    1/22/98 4:15p Hoffoss
 103  * Added code to allow popup to tell player he needs to bind a key for the
 104  * training mission.
 105  *
 106  * 44    1/20/98 5:42p Dave
 107  * Moved ingame join to its own module. Improved it a bit.
 108  *
 109  * 43    1/19/98 12:57p Allender
 110  * removed confusing comment
 111  *
 112  * 42    1/19/98 12:56p Allender
 113  * fix problem of freespace_start_misison possibly failing due to mission
 114  * not properly loading (for single player only right now).
 115  *
 116  * 41    1/15/98 6:12p Dave
 117  * Fixed weapons loadout bugs with multiplayer respawning. Added
 118  * multiplayer start screen. Fixed a few chatbox bugs.
 119  *
 120  * 40    1/15/98 6:00p Hoffoss
 121  * Added option to quit menu (in game) to restart the mission.  Doesn't
 122  * seem to quite work, though.  Checking code in so someone else can look
 123  * into it.
 124  *
 125  * 39    1/05/98 10:05a Dave
 126  * Big re-sequencing of server transfer. Centralized _all_ server transfer
 127  * code to one module.
 128  *
 129  * 38    12/30/97 4:28p Lawrance
 130  * Give text descriptions for events, change debug output to give text
 131  * desciption of event/state
 132  *
 133  * 37    12/24/97 8:56p Lawrance
 134  * took out obsolete state used for non-existant sound config screen
 135  *
 136  * 36    11/19/97 8:28p Dave
 137  * Hooked in Main Hall screen. Put in Anim support for ping ponging
 138  * animations as well as general reversal of anim direction.
 139  *
 140  * 35    11/15/97 2:36p Dave
 141  * Added more multiplayer campaign support.
 142  *
 143  * 34    11/13/97 7:01p Hoffoss
 144  * Fixed GS_state_text[], which didn't match the current states we have
 145  * available.
 146  *
 147  * 33    11/10/97 6:02p Hoffoss
 148  * Added new debug paused state.
 149  *
 150  * 32    11/03/97 10:12p Hoffoss
 151  * Finished up work on the hud message/mission log scrollback screen.
 152  *
 153  * 31    10/22/97 11:00p Lawrance
 154  * modify pop_and_discard() to allow discarding of all states on the stack
 155  *
 156  * 30    10/22/97 5:08p John
 157  * fixed a whole slew of bugs and clean up a bunch of stuff dealing with
 158  * end of mission stuff.
 159  *
 160  * 29    10/02/97 9:49p Hoffoss
 161  * Added event evaluation analysis debug screen so we can determine the
 162  * state of events and their sexp trees to track down logic problems and
 163  * such.
 164  *
 165  * 28    9/23/97 11:53p Lawrance
 166  * add state do perform multiplayer on-line help
 167  *
 168  * 27    9/22/97 4:55p Hoffoss
 169  * Added a training message window display thingy.
 170  *
 171  * 26    9/19/97 4:24p Allender
 172  * added team selection state -- initialze player* variable in
 173  * player_level_init
 174  *
 175  * 25    9/18/97 10:17p Lawrance
 176  * add help state for briefing
 177  *
 178  * 24    9/18/97 10:15p Lawrance
 179  * add help state for briefing
 180  *
 181  * 23    7/14/97 12:03a Lawrance
 182  * added navmap state
 183  *
 184  * 22    6/13/97 2:30p Lawrance
 185  * Added debriefings
 186  *
 187  * 21    5/20/97 10:02a Lawrance
 188  * added view medals screen
 189  *
 190  * 20    4/28/97 2:17p Lawrance
 191  * added help state for hotkey assignment screen
 192  *
 193  * 19    4/25/97 3:41p Lawrance
 194  * added support for hotkey assignment screen
 195  *
 196  * 18    4/23/97 9:54a Lawrance
 197  * made show goals screen a separate state
 198  *
 199  * 17    4/22/97 11:06a Lawrance
 200  * added credits state
 201  *
 202  * 16    4/17/97 9:01p Allender
 203  * start of campaign stuff.  Campaigns now stored in external file (no
 204  * filenames in code).  Continuing campaign won't work at this point
 205  *
 206  * 15    4/03/97 8:40p Lawrance
 207  * add new player death states to GS_state_text[]
 208  *
 209  * 14    3/05/97 5:04p Lawrance
 210  * added new states for different context help
 211  *
 212  * 13    1/09/97 12:41a Lawrance
 213  * added function to pop a state without restoring that state
 214  *
 215  * 12    12/22/96 3:41p Lawrance
 216  * integrating energy transfer system
 217  *
 218  * 11    12/09/96 2:35p Allender
 219  * modifed game sequencing so that game_leave_state and game_enter_state
 220  * are *always* called.
 221  *
 222  * 10    12/08/96 1:54a Lawrance
 223  * put check in to see if a state change request is invalid (ie already in
 224  * that state)
 225  *
 226  * 9     11/18/96 5:07p John
 227  * Changed sequencing code to call entry,leave functions for each state
 228  * change.   Added Shift+Pause debug pause thing.
 229  *
 230  * 8     11/13/96 4:02p Lawrance
 231  * complete over-haul of the menu system and the states associated with
 232  * them
 233  *
 234  * 7     10/23/96 9:08a Allender
 235  * Removed primary and secondary goal complete states -- to be implemented
 236  * later.
 237  *
 238 */
 239
 240 /*
 241  *  All states for game sequencing are defined in GameSequence.h.
 242  *  States should always be referred to using the macros.
 243 */
 244
 245 #include "freespace.h"
 246 #include "gamesequence.h"
 247
 248 // local defines
 249 #define MAX_GAMESEQ_EVENTS              20              // maximum number of events on the game sequencing queue
 250 #define GS_STACK_SIZE                   10              // maximum number of stacked states
 251
 252 // local variables
 253 typedef struct state_stack {
 254         int     current_state;
 255         int     event_queue[MAX_GAMESEQ_EVENTS];
 256         int     queue_tail, queue_head;
 257 } state_stack;
 258
 259 // DO NOT MAKE THIS NON-STATIC!!!!
 260 LOCAL state_stack gs[GS_STACK_SIZE];
 261 LOCAL int gs_current_stack = -1;                                                // index of top state on stack.
 262
 263 static int state_reentry = 0;  // set if we are already in state processing
 264 static int state_processing_event_post = 0;  // set if we are already processing an event to switch states
 265 static int state_in_event_processer = 0;
 266
 267 // Text of state, corresponding to #define values for GS_STATE_*
 268 //XSTR:OFF
 269 const char *GS_event_text[] =
 270 {
 271         "GS_EVENT_MAIN_MENU",
 272         "GS_EVENT_START_GAME",
 273         "GS_EVENT_ENTER_GAME",
 274         "GS_EVENT_START_GAME_QUICK",
 275         "GS_EVENT_END_GAME",
 276         "GS_EVENT_QUIT_GAME",                                                           // 5
 277         "GS_EVENT_PAUSE_GAME",
 278         "GS_EVENT_PREVIOUS_STATE",
 279         "GS_EVENT_OPTIONS_MENU",
 280         "GS_EVENT_BARRACKS_MENU",
 281         "GS_EVENT_TRAINING_MENU",                                                       // 10
 282         "GS_EVENT_TECH_MENU",
 283         "GS_EVENT_LOAD_MISSION_MENU",
 284         "GS_EVENT_SHIP_SELECTION",
 285         "GS_EVENT_TOGGLE_FULLSCREEN",
 286         "GS_EVENT_WEAPON_SELECT_HELP",                                  // 15
 287         "GS_EVENT_START_BRIEFING",
 288         "GS_EVENT_DEBUG_PAUSE_GAME",
 289         "GS_EVENT_HUD_CONFIG",
 290         "GS_EVENT_MULTI_SETUP",
 291         "GS_EVENT_MULTI_JOIN_GAME",                                             // 20
 292         "GS_EVENT_CONTROL_CONFIG",
 293         "GS_EVENT_EVENT_DEBUG",
 294         "GS_EVENT_MULTI_PROTO_CHOICE",
 295         "GS_EVENT_SAVE_RESTORE",
 296         "GS_EVENT_CHOOSE_SAVE_OR_RESTORE",                              // 25
 297         "GS_EVENT_WEAPON_SELECTION",
 298         "GS_EVENT_MISSION_LOG_SCROLLBACK",
 299         "GS_EVENT_MAIN_MENU_HELP",
 300         "GS_EVENT_GAMEPLAY_HELP",
 301         "GS_EVENT_SHIP_SELECT_HELP",                                            // 30
 302         "GS_EVENT_DEATH_DIED",
 303         "GS_EVENT_DEATH_BLEW_UP",
 304         "GS_EVENT_NEW_CAMPAIGN",
 305         "GS_EVENT_CREDITS",
 306         "GS_EVENT_SHOW_GOALS",                                                          // 35
 307         "GS_EVENT_HOTKEY_SCREEN",
 308         "GS_EVENT_HOTKEY_SCREEN_HELP",
 309         "GS_EVENT_VIEW_MEDALS",
 310         "GS_EVENT_MULTI_HOST_SETUP",
 311         "GS_EVENT_MULTI_CLIENT_SETUP",                                  // 40
 312         "GS_EVENT_DEBRIEF",
 313         "GS_EVENT_NAVMAP",
 314         "GS_EVENT_MULTI_JOIN_TRACKER",
 315         "GS_EVENT_GOTO_VIEW_CUTSCENES_SCREEN",
 316         "GS_EVENT_MULTI_STD_WAIT",                                                      // 45
 317         "GS_EVENT_STANDALONE_MAIN",
 318         "GS_EVENT_MULTI_PAUSE",
 319         "GS_EVENT_BRIEFING_HELP",
 320         "GS_EVENT_TEAM_SELECT",
 321         "GS_EVENT_TRAINING_PAUSE",                                                      // 50
 322         "GS_EVENT_MULTI_HELP",
 323         "GS_EVENT_INGAME_PRE_JOIN",
 324         "GS_EVENT_PLAYER_WARPOUT_START",
 325         "GS_EVENT_PLAYER_WARPOUT_START_FORCED",
 326         "GS_EVENT_PLAYER_WARPOUT_STOP",                                 // 55
 327         "GS_EVENT_PLAYER_WARPOUT_DONE_STAGE1",
 328         "GS_EVENT_PLAYER_WARPOUT_DONE_STAGE2",
 329         "GS_EVENT_PLAYER_WARPOUT_DONE",
 330         "GS_EVENT_STANDALONE_POSTGAME",
 331         "GS_EVENT_INITIAL_PLAYER_SELECT",                               // 60
 332         "GS_EVENT_GAME_INIT",
 333         "GS_EVENT_MULTI_MISSION_SYNC",
 334         "GS_EVENT_MULTI_CAMPAIGN_SELECT",
 335         "GS_EVENT_MULTI_SERVER_TRANSFER",
 336         "GS_EVENT_MULTI_START_GAME",                                            // 65
 337         "GS_EVENT_MULTI_HOST_OPTIONS",
 338         "GS_EVENT_MULTI_DOGFIGHT_DEBRIEF",
 339         "GS_EVENT_CAMPAIGN_ROOM",
 340         "GS_EVENT_CMD_BRIEF",
 341         "GS_EVENT_TOGGLE_GLIDE",                                                        // 70
 342         "GS_EVENT_RED_ALERT",
 343         "GS_EVENT_SIMULATOR_ROOM",
 344         "GS_EVENT_EMD_CAMPAIGN",
 345 };
 346 //XSTR:ON
 347
 348 // Text of state, corresponding to #define values for GS_STATE_*
 349 //XSTR:OFF
 350 const char *GS_state_text[] =
 351 {
 352         "NOT A VALID STATE",
 353         "GS_STATE_MAIN_MENU",                                                           // 1
 354         "GS_STATE_GAME_PLAY",
 355         "GS_STATE_GAME_PAUSED",
 356         "GS_STATE_QUIT_GAME",
 357         "GS_STATE_OPTIONS_MENU",                                                        // 5
 358         "GS_EVENT_WEAPON_SELECT_HELP",
 359         "GS_STATE_BARRACKS_MENU",
 360         "GS_STATE_TECH_MENU",
 361         "GS_STATE_TRAINING_MENU",
 362         "GS_STATE_LOAD_MISSION_MENU",                                           // 10
 363         "GS_STATE_BRIEFING",
 364         "GS_STATE_SHIP_SELECT",
 365         "GS_STATE_DEBUG_PAUSED",
 366         "GS_STATE_HUD_CONFIG",
 367         "GS_STATE_MULTI_SETUP",                                                         // 15
 368         "GS_STATE_MULTI_JOIN_GAME",
 369         "GS_STATE_CONTROL_CONFIG",
 370         "GS_STATE_MULTI_PROTO_CHOICE",
 371         "GS_STATE_SAVE_RESTORE",
 372         "GS_STATE_WEAPON_SELECT",                                                       // 20
 373         "GS_STATE_MISSION_LOG_SCROLLBACK",
 374         "GS_STATE_MAIN_MENU_HELP",
 375         "GS_STATE_GAMEPLAY_HELP",
 376         "GS_STATE_SHIP_SELECT_HELP",
 377         "GS_STATE_DEATH_DIED",                                                          // 25
 378         "GS_STATE_DEATH_BLEW_UP",
 379         "GS_STATE_SIMULATOR_ROOM",
 380         "GS_STATE_CREDITS",
 381         "GS_STATE_SHOW_GOALS",
 382         "GS_STATE_HOTKEY_SCREEN",                                                       // 30
 383         "GS_STATE_HOTKEY_SCREEN_HELP",
 384         "GS_STATE_VIEW_MEDALS",
 385         "GS_STATE_MULTI_HOST_SETUP",
 386         "GS_STATE_MULTI_CLIENT_SETUP",
 387         "GS_STATE_DEBRIEF",                                                                     // 35
 388         "GS_STATE_NAVMAP",
 389         "GS_STATE_MULTI_JOIN_TRACKER",
 390         "GS_STATE_VIEW_CUTSCENES",
 391         "GS_STATE_MULTI_STD_WAIT",
 392         "GS_STATE_STANDALONE_MAIN",                                             // 40
 393         "GS_STATE_MULTI_PAUSED",
 394         "GS_STATE_BRIEFING_HELP",
 395         "GS_STATE_TEAM_SELECT",
 396         "GS_STATE_TRAINING_PAUSED",
 397         "GS_STATE_MULTI_HELP",                                                          // 45
 398         "GS_STATE_INGAME_PRE_JOIN",
 399         "GS_STATE_EVENT_DEBUG",
 400         "GS_STATE_STANDALONE_POSTGAME",
 401         "GS_STATE_INITIAL_PLAYER_SELECT",
 402         "GS_STATE_MULTI_MISSION_SYNC",                                  // 50
 403         "GS_STATE_MULTI_SERVER_TRANSFER",
 404         "GS_STATE_MULTI_START_GAME",
 405         "GS_STATE_MULTI_HOST_OPTIONS",
 406         "GS_STATE_MULTI_DOGFIGHT_DEBRIEF",
 407         "GS_STATE_CAMPAIGN_ROOM",                                                       // 55
 408         "GS_STATE_CMD_BRIEF",
 409         "GS_STATE_RED_ALERT",
 410         "GS_STATE_END_OF_CAMPAIGN",
 411 };
 412 //XSTR:ON
 413
 414 void gameseq_init()
 415 {
 416         int i;
 417
 418         for (i=0; i<GS_STACK_SIZE; i++ )        {
 419                 // gs[i].current_state = GS_STATE_MAIN_MENU;
 420                 gs[i].current_state = 0;
 421                 gs[i].queue_tail=0;
 422                 gs[i].queue_head=0;
 423         }
 424
 425         gs_current_stack = 0;
 426         state_reentry = 0;
 427         state_processing_event_post = 0;
 428         state_in_event_processer = 0;
 429 }
 430
 431 // gameseq_post_event posts a new game sequencing event onto the gameseq
 432 // event queue
 433
 434 void gameseq_post_event( int event )
 435 {
 436         if (state_processing_event_post) {
 437                 nprintf(("Warning", "Received post for event %s during state transtition. Find Allender if you are unsure if this is bad.\n", GS_event_text[event] ));
 438         }
 439
 440         SDL_assert(gs[gs_current_stack].queue_tail < MAX_GAMESEQ_EVENTS);
 441         gs[gs_current_stack].event_queue[gs[gs_current_stack].queue_tail++] = event;
 442         if ( gs[gs_current_stack].queue_tail == MAX_GAMESEQ_EVENTS )
 443                 gs[gs_current_stack].queue_tail = 0;
 444 }
 445
 446 // returns one of the GS_EVENT_ id's on the game sequencing queue
 447
 448 int gameseq_get_event()
 449 {
 450         int event;
 451
 452         if ( gs[gs_current_stack].queue_head == gs[gs_current_stack].queue_tail )
 453                 return -1;
 454         event = gs[gs_current_stack].event_queue[gs[gs_current_stack].queue_head++];
 455         if ( gs[gs_current_stack].queue_head == MAX_GAMESEQ_EVENTS )
 456                 gs[gs_current_stack].queue_head = 0;
 457
 458         return event;
 459 }
 460
 461 // returns one of the GS_STATE_ macros
 462 int gameseq_get_state(int depth)
 463 {
 464         SDL_assert(depth <= gs_current_stack);
 465
 466         return gs[gs_current_stack - depth].current_state;
 467 }
 468
 469 int gameseq_get_depth()
 470 {
 471         return gs_current_stack;
 472 }
 473
 474 void gameseq_set_state(int new_state, int override)
 475 {
 476         int event, old_state;
 477
 478         if ( (new_state == gs[gs_current_stack].current_state) && !override )
 479                 return;
 480
 481         old_state = gs[gs_current_stack].current_state;
 482
 483         // Flush all events!!
 484         while ( (event = gameseq_get_event()) != -1 ) {
 485                 mprintf(( "Throwing out event %d because of state set from %d to %d\n", event, old_state, new_state ));
 486         }
 487
 488         SDL_assert( state_reentry == 1 );               // Get John! (Invalid state sequencing!)
 489         SDL_assert( state_in_event_processer == 1 );            // can only call from game_process_event
 490
 491         state_processing_event_post++;
 492         state_reentry++;
 493         game_leave_state(gs[gs_current_stack].current_state,new_state);
 494
 495         gs[gs_current_stack].current_state = new_state;
 496
 497         game_enter_state(old_state,gs[gs_current_stack].current_state);
 498         state_reentry--;
 499         state_processing_event_post--;
 500 }
 501
 502 void gameseq_push_state( int new_state )
 503 {
 504         if ( new_state == gs[gs_current_stack].current_state )
 505                 return;
 506
 507         int old_state = gs[gs_current_stack].current_state;
 508
 509         // Flush all events!!
 510 // I commented out because I'm not sure if we should throw out events when pushing or not.
 511 //      int event;
 512 //      while( (event = gameseq_get_event()) != -1 )    {
 513 //              mprintf(( "Throwing out event %d because of state push from %d to %d\n", event, old_state, new_state ));
 514 //      }
 515
 516         SDL_assert( state_reentry == 1 );               // Get John! (Invalid state sequencing!)
 517         SDL_assert( state_in_event_processer == 1 );            // can only call from game_process_event
 518
 519         gs_current_stack++;
 520         SDL_assert(gs_current_stack < GS_STACK_SIZE);
 521
 522         state_processing_event_post++;
 523         state_reentry++;
 524         game_leave_state(old_state,new_state);
 525
 526         gs[gs_current_stack].current_state = new_state;
 527         gs[gs_current_stack].queue_tail = 0;
 528         gs[gs_current_stack].queue_head = 0;
 529
 530         game_enter_state(old_state,gs[gs_current_stack].current_state);
 531         state_reentry--;
 532         state_processing_event_post--;
 533 }
 534
 535 void gameseq_pop_state()
 536 {
 537         int popped_state = 0;
 538
 539         SDL_assert(state_reentry == 1);         // Get John! (Invalid state sequencing!)
 540
 541         if (gs_current_stack >= 1) {
 542                 int old_state;
 543
 544                 // set the old state to be the state which is about to be popped off the queue
 545                 old_state = gs[gs_current_stack].current_state;
 546
 547                 // set the popped_state to be the state which is going to be moved into
 548                 popped_state = gs[gs_current_stack-1].current_state;
 549
 550                 // leave the current state
 551                 state_reentry++;
 552                 game_leave_state(gs[gs_current_stack].current_state,popped_state);
 553
 554                 // set the popped_state to be the one we moved into
 555                 gs_current_stack--;
 556
 557                 // swap all remaining events from the state which just got popped to this new state
 558                 while(gs[gs_current_stack+1].queue_head != gs[gs_current_stack+1].queue_tail){
 559                         gameseq_post_event(gs[gs_current_stack+1].event_queue[gs[gs_current_stack+1].queue_head++]);
 560                 }
 561
 562                 game_enter_state(old_state, gs[gs_current_stack].current_state);
 563                 state_reentry--;
 564
 565         }
 566
 567 }
 568
 569 // gameseq_pop_and_discard_state() is used to remove a state that was pushed onto the stack, but
 570 // will never need to be popped.  An example of this is entering a state that may require returning
 571 // to the previous state (then you would call gameseq_pop_state).  Or you may simply continue to
 572 // another part of the game, to avoid filling up the stack with states that may never be popped, you
 573 // call this function to discard the top of the gs.
 574 //
 575
 576 void gameseq_pop_and_discard_state()
 577 {
 578         if (gs_current_stack > 0 ) {
 579                 gs_current_stack--;
 580         }
 581 }
 582
 583 // Returns the last state pushed on stack
 584 int gameseq_get_pushed_state()
 585 {
 586         if (gs_current_stack >= 1) {
 587                 return gs[gs_current_stack-1].current_state;
 588         } else
 589                 return -1;
 590 }
 591
 592 // gameseq_process_events gets called every time through high level loops
 593 // (i.e. game loops, main menu loop).  Function is responsible for pulling
 594 // game sequence events off the queue and changing the state when necessary.
 595 // Returns the current state.
 596                 // pull events game sequence events off of the queue.  Process one at a time
 597                 // based on the current state and the new event.
 598
 599 int gameseq_process_events()
 600 {
 601         int event, old_state;
 602         old_state = gs[gs_current_stack].current_state;
 603
 604         SDL_assert(state_reentry == 0);         // Get John! (Invalid state sequencing!)
 605
 606         while ( (event = gameseq_get_event()) != -1 ) {
 607                 state_reentry++;
 608                 state_in_event_processer++;
 609                 game_process_event(gs[gs_current_stack].current_state, event);
 610                 state_in_event_processer--;
 611                 state_reentry--;
 612                 // break when state changes so that code will get called at
 613                 // least one frame for each state.
 614                 if (old_state != gs[gs_current_stack].current_state)
 615                         break;
 616         }
 617
 618         state_reentry++;
 619         game_do_state(gs[gs_current_stack].current_state);
 620         state_reentry--;
 621
 622         return gs[gs_current_stack].current_state;
 623 }
 624