game.c

   1
   2 /**
   3  *
   4  * Tennix! SDL Port
   5  * Copyright (C) 2003, 2007, 2008 Thomas Perl <thp@perli.net>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  20  * MA  02110-1301, USA.
  21  *
  22  **/
  23
  24 #include <stdio.h>
  25 #include <math.h>
  26
  27 #include "tennix.h"
  28 #include "game.h"
  29 #include "graphics.h"
  30 #include "input.h"
  31 #include "sound.h"
  32
  33 void game( bool singleplayer) {
  34     GameState s = {
  35         { 0, 0, 0.0, 0.0, 0.0 },
  36         { 0, 0, 0, 0, 0 },
  37         { GAME_X_MIN-RACKET_X_MID*2, GAME_Y_MID, 0, 0, 1, DESIRE_NORMAL, PLAYER_TYPE_HUMAN, GAME_Y_MID, false, 0, {0}, 0, 0, PLAYER_ACCEL_DEFAULT, true },
  38         { GAME_X_MAX+RACKET_X_MID*2, GAME_Y_MID, 0, 0, 0, DESIRE_NORMAL, PLAYER_TYPE_HUMAN, GAME_Y_MID, false, 0, {0}, 0, 0, PLAYER_ACCEL_DEFAULT, true },
  39         0,
  40         0,
  41         0,
  42         true,
  43         "welcome to tennix " VERSION,
  44         { 0 },
  45         { 0 },
  46         REFEREE_NORMAL,
  47         0,
  48         WINNER_NONE,
  49         false,
  50         GR_CTT_GRASS,
  51         -1,
  52         { 0 },
  53         0,
  54         false,
  55         { { { 0 } } },
  56         0.0,
  57         SOUND_MAX,
  58         0.0,
  59         0.0,
  60         0
  61     };
  62
  63     strcpy( s.game_score_str, format_game( &s));
  64     strcpy( s.sets_score_str, format_sets( &s));
  65
  66     Uint32 ot = SDL_GetTicks();
  67     Uint32 nt;
  68     Uint32 dt = GAME_TICKS;
  69     Uint32 diff;
  70     Uint32 accumulator = 0;
  71     bool quit = false;
  72     int x, y, z;
  73
  74 #ifdef ENABLE_FPS_LIMIT
  75     Uint32 ft, frames; /* frame timer and frames */
  76 #endif
  77
  78     if( singleplayer) {
  79 #ifdef DEBUG
  80         s.player1.type = PLAYER_TYPE_AI;
  81 #endif
  82         s.player2.type = PLAYER_TYPE_AI;
  83     }
  84
  85     game_setup_serve( &s);
  86
  87     /* smoothen n-gram */
  88     for( x = 0; x<NGRAM_STEPS; x++) {
  89         for( y = 0; y<NGRAM_STEPS; y++) {
  90             for( z = 0; z<NGRAM_STEPS; z++) {
  91                 s.ngram[x][y][z] = 1;
  92             }
  93         }
  94     }
  95
  96 #ifdef ENABLE_FPS_LIMIT
  97     frames = 0;
  98     ft = SDL_GetTicks();
  99 #endif
 100     while( !quit) {
 101         nt = SDL_GetTicks();
 102         diff = nt-ot;
 103         if( diff > 2000) {
 104             diff = 0;
 105         }
 106
 107         accumulator += diff;
 108         ot = nt;
 109
 110         while( accumulator >= dt) {
 111             quit = step( &s);
 112             s.time += dt;
 113             accumulator -= dt;
 114
 115             if( s.was_stopped) {
 116                 ot = SDL_GetTicks();
 117                 s.was_stopped = false;
 118             }
 119         }
 120
 121 #ifdef ENABLE_FPS_LIMIT
 122         while (frames*1000.0/((float)(SDL_GetTicks()-ft+1))>(float)(DEFAULT_FPS)) {
 123             SDL_Delay(10);
 124         }
 125         frames++;
 126 #endif
 127
 128         render( &s);
 129     }
 130
 131 }
 132
 133 bool step( GameState* s) {
 134     Uint8 *keys;
 135     SDL_Event e;
 136
 137     if( get_phase( s) < 1.0) {
 138         if( !s->ground.jump) {
 139             s->play_sound = SOUND_GROUND;
 140
 141             if( IS_OUT_Y( s->ball.y)) {
 142                 /* out - responsibilities stay the same */
 143                 s->status = "out!";
 144                 s->play_sound = SOUND_OUT;
 145                 s->referee = REFEREE_OUT;
 146             } else {
 147                 /* not out - responsibilities change */
 148                 s->player1.responsible = !(s->player2.responsible = !s->player2.responsible);
 149                 s->status = format_status( s);
 150                 s->referee = REFEREE_NORMAL;
 151             }
 152         }
 153         s->ground.jump = 3;
 154         s->ground.x = s->ball.x;
 155         s->ground.y = s->ball.y;
 156     } else {
 157         if( s->ground.jump && !(s->time%5)) s->ground.jump--;
 158     }
 159
 160     if( IS_OUT_X(s->ball.x) || IS_OFFSCREEN_Y(s->ball.y)) {
 161         if( IS_OFFSCREEN( s->ball.x, s->ball.y)) {
 162             s->player1_serves = s->player1.responsible;
 163
 164             score_game( s, s->player2.responsible);
 165             strcpy( s->game_score_str, format_game( s));
 166             strcpy( s->sets_score_str, format_sets( s));
 167
 168             if( s->player1.responsible) {
 169                 if( s->player1.type == PLAYER_TYPE_HUMAN && s->player2.type == PLAYER_TYPE_AI) {
 170                     s->status = "computer scores";
 171                 } else {
 172                     s->status = "player 2 scores";
 173                 }
 174                 s->referee = REFEREE_PLAYER2;
 175             } else {
 176                 if( s->player1.type == PLAYER_TYPE_HUMAN && s->player2.type == PLAYER_TYPE_AI) {
 177                     s->status = "player scores";
 178                 } else {
 179                     s->status = "player 1 scores";
 180                 }
 181                 s->referee = REFEREE_PLAYER1;
 182             }
 183
 184             game_setup_serve( s);
 185             s->play_sound = SOUND_APPLAUSE;
 186             SDL_Delay( 500);
 187             start_fade();
 188             s->was_stopped = true;
 189             s->history_size = 0;
 190             s->history_is_locked = 0;
 191             s->ngram_prediction = 0.0;
 192 #ifdef DEBUG
 193             printf( "-- game reset --\n");
 194 #endif
 195         }
 196
 197         if( IS_OUT_X(s->ball.x)) {
 198             if( !s->history_is_locked && s->referee != REFEREE_OUT) {
 199                 s->history[s->history_size] = (int)(NGRAM_STEPS*s->ball.y/HEIGHT);
 200                 s->history_size++;
 201                 if( s->history_size == 3) {
 202                     s->ngram[s->history[0]][s->history[1]][s->history[2]] += 10;
 203 #ifdef DEBUG
 204                     printf( "history: %d, %d, %d\n", s->history[0], s->history[1], s->history[2]);
 205 #endif
 206                     s->ngram_prediction = ngram_predictor( s);
 207                     s->history[0] = s->history[1];
 208                     s->history[1] = s->history[2];
 209                     s->history_size--;
 210                 }
 211                 s->history_is_locked = true;
 212             }
 213             if( s->ball.move_x <= 0 && IS_NEAR_X( s->player1.x, s->ball.x) && IS_NEAR_Y( s->player1.y, s->ball.y) && s->player1.state && s->referee != REFEREE_OUT) {
 214                 s->ball.x = GAME_X_MIN;
 215                 if( s->player1.state == PLAYER_STATE_MAX) {
 216                     s->ball.move_x = PLAYER_POWERSHOT;
 217                 } else {
 218                     s->ball.move_x = 2.5 + 2.0*s->player1.state/PLAYER_STATE_MAX;
 219                 }
 220                 s->ball.move_y = get_move_y( s, 1);
 221                 s->player2.responsible = !(s->player1.responsible = 1);
 222                 s->ball.jump += 1.0-2.0*(s->player1.state<5);
 223                 s->play_sound = SOUND_RACKET;
 224                 pan_sample(SOUND_RACKET, 0.4);
 225             } else if( s->ball.move_x >= 0 && IS_NEAR_X( s->player2.x, s->ball.x) && IS_NEAR_Y( s->player2.y, s->ball.y) && s->player2.state && s->referee != REFEREE_OUT) {
 226                 s->ball.x = GAME_X_MAX;
 227                 if( s->player2.state == PLAYER_STATE_MAX) {
 228                     s->ball.move_x = -PLAYER_POWERSHOT;
 229                 } else {
 230                     s->ball.move_x = -(2.5 + 2.0*s->player2.state/PLAYER_STATE_MAX);
 231                 }
 232                 s->ball.move_y = get_move_y( s, 2);
 233                 s->player1.responsible = !(s->player2.responsible = 1);
 234                 s->ball.jump += 1.0-2.0*(s->player2.state<5);
 235                 s->play_sound = SOUND_RACKET;
 236                 pan_sample(SOUND_RACKET, 0.6);
 237             }
 238         }
 239     } else {
 240         s->history_is_locked = false;
 241     }
 242
 243     SDL_PollEvent( &e);
 244     keys = SDL_GetKeyState( NULL);
 245     switch(e.type) {
 246         case SDL_JOYAXISMOTION:
 247             if (e.jaxis.axis == JOYSTICK_Y_AXIS) {
 248                 s->joystick_y = JOYSTICK_PERCENTIZE(e.jaxis.value);
 249             } else if (e.jaxis.axis == JOYSTICK_X_AXIS) {
 250                 s->joystick_x = JOYSTICK_PERCENTIZE(e.jaxis.value);
 251             }
 252             break;
 253         case SDL_JOYBUTTONUP: case SDL_JOYBUTTONDOWN:
 254             if (e.jbutton.button == JOYSTICK_BUTTON_A) {
 255                 s->joystick_a = (e.jbutton.state == SDL_PRESSED);
 256             }
 257             break;
 258     }
 259
 260     if( keys['c'] && s->time%50==0) {
 261         s->court_type++;
 262         if( s->court_type > GR_CTT_LAST) {
 263             s->court_type = GR_CTT_FIRST;
 264         }
 265     }
 266
 267     if( !is_fading() && !s->is_over) {
 268         if( s->player1.type == PLAYER_TYPE_HUMAN) {
 269            input_human( &s->player1,
 270                    keys['w'] || keys[SDLK_UP] || s->joystick_y < -JOYSTICK_TRESHOLD,
 271                    keys['s'] || keys[SDLK_DOWN] || s->joystick_y > JOYSTICK_TRESHOLD,
 272                    keys['d'] || keys[SDLK_SPACE] || keys[SDLK_LCTRL] || s->joystick_a,
 273 #ifdef ENABLE_MOUSE
 274                    true,
 275 #else
 276                    false,
 277 #endif
 278                    s);
 279         } else {
 280             input_ai( &s->player1, &s->ball, &s->player2, s);
 281         }
 282
 283         if( s->player2.type == PLAYER_TYPE_HUMAN) {
 284             input_human( &s->player2, keys['o'], keys['l'], keys['k'], false, s);
 285         } else {
 286             input_ai( &s->player2, &s->ball, &s->player1, s);
 287         }
 288     }
 289
 290     if( keys['f']) SDL_WM_ToggleFullScreen( screen);
 291     if( keys['y']) SDL_SaveBMP( screen, "screenshot.bmp");
 292
 293     if( keys['p']) {
 294         while( keys['p']) {
 295             SDL_PollEvent( &e);
 296             keys = SDL_GetKeyState( NULL);
 297             SDL_Delay( 10);
 298         }
 299         while( keys['p'] == 0) {
 300             SDL_PollEvent( &e);
 301             keys = SDL_GetKeyState( NULL);
 302             SDL_Delay( 10);
 303         }
 304         while( keys['p']) {
 305             SDL_PollEvent( &e);
 306             keys = SDL_GetKeyState( NULL);
 307             SDL_Delay( 10);
 308         }
 309         s->was_stopped = true;
 310     }
 311
 312     if( keys[SDLK_ESCAPE] || keys['q']) return true;
 313
 314     limit_value( &s->player1.y, PLAYER_Y_MIN, PLAYER_Y_MAX);
 315     limit_value( &s->player2.y, PLAYER_Y_MIN, PLAYER_Y_MAX);
 316     limit_value( &s->ball.jump, BALL_JUMP_MIN, BALL_JUMP_MAX);
 317
 318     /* Update ball_dest for debugging purposes */
 319     get_move_y(s, 1);
 320     get_move_y(s, 2);
 321
 322     s->ball.x += s->ball.move_x;
 323     s->ball.y += s->ball.move_y;
 324
 325     if(s->player1.state) s->player1.state--;
 326     if(s->player2.state) s->player2.state--;
 327
 328     return false;
 329 }
 330
 331 void render( GameState* s) {
 332     if (s->play_sound != SOUND_MAX) {
 333         play_sample(s->play_sound);
 334         s->play_sound = SOUND_MAX;
 335     }
 336     if( s->winner != WINNER_NONE) {
 337         if( !s->is_over) {
 338             start_fade();
 339             s->is_over = true;
 340         }
 341         clear_screen();
 342         store_screen();
 343         show_sprite( GR_RACKET, 2*(s->winner-1), 4, WIDTH/2 - get_image_width( GR_RACKET)/8, HEIGHT/2 - get_image_height( GR_RACKET), 255);
 344         sprintf( s->game_score_str, "player %d wins the match with %s", s->winner, format_sets( s));
 345         font_draw_string( GR_DKC2_FONT, s->game_score_str, (WIDTH-font_get_string_width( GR_DKC2_FONT, s->game_score_str))/2, HEIGHT/2 + 30, s->time/20, ANIMATION_WAVE | ANIMATION_BUNGEE);
 346         updatescr();
 347         return;
 348     }
 349     if (s->old_court_type != s->court_type) {
 350         clear_screen();
 351         fill_image(s->court_type, 120, 120, 400, 250);
 352         show_image(GR_COURT, 0, 0, 255);
 353         s->old_court_type = s->court_type;
 354         store_screen();
 355     }
 356     show_sprite( GR_REFEREE, s->referee, 4, 250, 10, 255);
 357     show_image( GR_SHADOW, s->ball.x-BALL_X_MID, s->ball.y + get_phase( s) - BALL_Y_MID, 255);
 358
 359     show_sprite( GR_RACKET, (!s->player1.state), 4, s->player1.x-RACKET_X_MID, s->player1.y-RACKET_Y_MID, 255);
 360     show_sprite( GR_RACKET, (!s->player2.state)+2, 4, s->player2.x-RACKET_X_MID, s->player2.y-RACKET_Y_MID, 255);
 361
 362     if( s->ground.jump) {
 363         show_sprite( GR_GROUND, s->ground.jump-1, 3, s->ground.x - BALL_X_MID, s->ground.y - BALL_Y_MID, 128);
 364     }
 365
 366     if( s->ball.move_x > 0) {
 367         show_sprite( GR_BALL, (s->time/500)%4, 4, s->ball.x-BALL_X_MID, s->ball.y-BALL_Y_MID, 255);
 368     } else if( s->ball.move_x < 0) {
 369         show_sprite( GR_BALL, 3-(s->time/500)%4, 4, s->ball.x-BALL_X_MID, s->ball.y-BALL_Y_MID, 255);
 370     } else {
 371         show_sprite( GR_BALL, 0, 4, s->ball.x-BALL_X_MID, s->ball.y-BALL_Y_MID, 255);
 372     }
 373
 374     /* Player 1's mouse rectangle */
 375     if (!(s->player1.mouse_locked)) {
 376         rectangle(s->player1.x-2+5, s->player1.mouse_y-2, 4, 4, 255, 255, 255);
 377         rectangle(s->player1.x-1+5, s->player1.mouse_y-1, 2, 2, 0, 0, 0);
 378     }
 379
 380     font_draw_string( GR_DKC2_FONT, s->game_score_str, 14, 14, 0, ANIMATION_NONE);
 381     font_draw_string( GR_DKC2_FONT, s->sets_score_str, (WIDTH-font_get_string_width( GR_DKC2_FONT, s->sets_score_str))-14, 14, 0, ANIMATION_NONE);
 382
 383     font_draw_string( GR_DKC2_FONT, s->status, (WIDTH-font_get_string_width( GR_DKC2_FONT, s->status))/2, HEIGHT-50, s->time/30, ANIMATION_WAVE);
 384
 385 #ifdef DEBUG
 386     line_horiz( s->player1.y, 255, 0, 0);
 387     line_horiz( s->player2.y, 0, 0, 255);
 388     line_horiz( s->ball.y, 0, 255, 0);
 389
 390     line_vert( s->player1.x, 255, 0, 0);
 391     line_vert( s->player2.x, 0, 0, 255);
 392     line_vert( s->ball.x, 0, 255, 0);
 393
 394     line_horiz( s->player1.ball_dest, 255, 0, 255);
 395     line_horiz( s->player2.ball_dest, 0, 255, 255);
 396
 397     line_horiz( GAME_Y_MIN, 100, 100, 100);
 398     line_horiz( GAME_Y_MAX, 100, 100, 100);
 399 #endif
 400
 401     updatescr();
 402 }
 403
 404 void limit_value( float* value, float min, float max) {
 405     if( *value < min) {
 406         *value = min;
 407     } else if( *value > max) {
 408         *value = max;
 409     }
 410 }
 411
 412 float get_phase( GameState* s) {
 413     float pos, fract;
 414     float x, min, max, direction;
 415
 416     x = s->ball.x;
 417     min = GAME_X_MIN;
 418     max = GAME_X_MAX;
 419     direction = s->ball.move_x;
 420
 421     pos = (direction>0)?(1-GROUND_PHASE):(GROUND_PHASE);
 422
 423     fract = (x-min)/(max-min);
 424
 425     if( fract < pos) {
 426         fract = fract/pos;
 427         return fabsf( cosf(PI*fract/2))*PHASE_AMP*s->ball.jump;
 428     } else {
 429         fract = (pos-fract)/(1-pos);
 430         return fabsf( sinf(PI*fract/2))*PHASE_AMP*s->ball.jump;
 431     }
 432 }
 433
 434 float get_move_y( GameState* s, unsigned char player) {
 435     float pct, dest, x_len, y_len;
 436     float py, by, pa, move_x;
 437
 438     py = (player==1)?(s->player1.y):(s->player2.y);
 439     by = s->ball.y;
 440     pa = RACKET_Y_MID*2;
 441     move_x = s->ball.move_x;
 442
 443     /* -1.0 .. 1.0 for racket hit position */
 444     pct = (by-py)/(pa/2);
 445     limit_value( &pct, -1.0, 1.0);
 446
 447     /* Y destination for ball */
 448     dest = GAME_Y_MID + pct*(GAME_Y_MAX-GAME_Y_MIN);
 449     if( player == 1) {
 450         s->player1.ball_dest = dest;
 451     } else {
 452         s->player2.ball_dest = dest;
 453     }
 454
 455     /* lengths for the ball's journey */
 456     if( player == 1) {
 457         x_len = fabsf(GAME_X_MAX - s->ball.x);
 458         y_len = dest - by + MOVE_Y_SEED-rand()%MOVE_Y_SEED*2;
 459     } else {
 460         x_len = s->ball.x - GAME_X_MIN;
 461         y_len = by - dest + MOVE_Y_SEED-rand()%MOVE_Y_SEED*2;
 462     }
 463
 464     /* return the should-be value for move_y */
 465     return (y_len*move_x)/(x_len);
 466 }
 467
 468 void input_human( Player* player, bool up, bool down, bool hit, bool use_mouse, GameState* s) {
 469     int diff = PLAYER_MOVE_Y;
 470     int mb;
 471
 472     /**
 473      * Only use mouse control if the user isn't pressing any buttons
 474      * this way, keyboard control still works when mouse control is
 475      * enabled.
 476      **/
 477     if (use_mouse && (down || up || hit)) {
 478         /**
 479          * this is here so if the user decides to play
 480          * with keyboard controls, we will lock the
 481          * mouse and disable displaying the mouse cursor
 482          **/
 483         player->mouse_locked = true;
 484     }
 485     if (use_mouse && !down && !up && !hit) {
 486         mb = SDL_GetMouseState(&(player->mouse_x), &(player->mouse_y));
 487         if (mb&SDL_BUTTON(SDL_BUTTON_LEFT)) {
 488             if (player->mouse_y < player->y) {
 489                 down = false;
 490                 up = true;
 491                 diff = (player->y-player->mouse_y<diff)?(player->y-player->mouse_y):(diff);
 492             } else if (player->mouse_y > player->y) {
 493                 up = false;
 494                 down = true;
 495                 diff = (player->mouse_y-player->y<diff)?(player->mouse_y-player->y):(diff);
 496             }
 497             player->mouse_locked = false;
 498         } else if (!player->mouse_locked) {
 499             hit = true;
 500         }
 501     }
 502
 503     if (fabsf(s->joystick_y) > JOYSTICK_TRESHOLD) {
 504         diff = PLAYER_MOVE_Y*fabsf(s->joystick_y)/40.0;
 505         if (diff > PLAYER_MOVE_Y) {
 506             diff = PLAYER_MOVE_Y;
 507         }
 508     }
 509
 510     if (up) {
 511         player->y -= fminf(diff, diff*player->accelerate);
 512         player->accelerate *= PLAYER_ACCEL_INCREASE;
 513     } else if (down) {
 514         player->y += fminf(diff, diff*player->accelerate);
 515         player->accelerate *= PLAYER_ACCEL_INCREASE;
 516     } else {
 517         player->accelerate = PLAYER_ACCEL_DEFAULT;
 518     }
 519
 520     if( hit) {
 521         if( !player->state && !player->state_locked) {
 522             player->state = PLAYER_STATE_MAX;
 523             player->state_locked = true;
 524         }
 525     } else {
 526         player->state_locked = false;
 527     }
 528 }
 529
 530 void input_ai( Player* player, Ball* ball, Player* opponent, GameState* s) {
 531     float fact = 1.7;
 532     float target;
 533
 534     if( fabsf( player->y - ball->y) > RACKET_Y_MID*5) {
 535         fact = 3.5;
 536     }
 537
 538     target = GAME_Y_MID + (opponent->ball_dest - GAME_Y_MID)/5;
 539
 540     if( player->responsible) {
 541         if( player->desire == DESIRE_NORMAL && !IS_NEAR_Y_AI( player->y, ball->y)) {
 542             if( player->y < ball->y) {
 543                 player->y += fmin( 2*fact, ball->y - player->y);
 544             } else if( player->y > ball->y) {
 545                 player->y -= fmin( 2*fact, player->y - ball->y);
 546             }
 547         }
 548
 549         if( (ball->move_x != 0 || IS_NEAR_Y_AI( player->y, ball->y)) && IS_NEAR_X_AI( player->x, ball->x) && !player->state && rand()%4) {
 550             player->state = PLAYER_STATE_MAX;
 551         }
 552     } else if( ball->move_x == 0) {
 553         if( player->desire == DESIRE_NORMAL && !IS_NEAR_Y_AI( player->y, target)) {
 554             if( player->y < target) {
 555                 player->y += fmin( fact, (target-player->y)/40.0);
 556             } else if( player->y > target) {
 557                 player->y -= fmin( fact, (player->y-target)/40.0);
 558             }
 559         }
 560     } else if( s->ngram_prediction > 0.0) {
 561         target = s->ngram_prediction*((float)HEIGHT)/((float)(NGRAM_STEPS));
 562         target = GAME_Y_MID + (target-GAME_Y_MID)*1.5;
 563
 564         if( player->desire == DESIRE_NORMAL && !IS_NEAR_Y_AI( player->y, target)) {
 565             if( player->y < target) {
 566                 player->y += fmin( fact, (target-player->y)/40.0);
 567             } else if( player->y > target) {
 568                 player->y -= fmin( fact, (player->y-target)/40.0);
 569             }
 570         }
 571     } else {/*
 572         if( player->desire == DESIRE_NORMAL) {
 573             if( !IS_NEAR_Y_AI( player->y, target)) {
 574                 player->y += (target - player->y)/40.0;
 575             }
 576         }*/
 577     }
 578 }
 579
 580 void game_setup_serve( GameState* s) {
 581     s->ball.jump = 7.5;
 582     s->ball.y = GAME_Y_MID;
 583     s->ball.move_x = 0.0;
 584     s->ball.move_y = 0.0;
 585
 586     if( s->player1_serves) {
 587         s->player1.responsible = true;
 588         s->player1.ball_dest = 0.0;
 589         s->ball.x = GAME_X_MIN-RACKET_X_MID*1.5;
 590     } else {
 591         s->player1.responsible = false;
 592         s->player2.ball_dest = 0.0;
 593         s->ball.x = GAME_X_MAX+RACKET_X_MID*1.5;
 594     }
 595
 596     s->player2.responsible = !(s->player1.responsible);
 597 }
 598
 599 float ngram_predictor( GameState* s) {
 600     unsigned int count = 0;
 601     unsigned long sum = 0;
 602     int x, y, z;
 603     float result;
 604
 605     if( s->history_size < 3) {
 606         return 0.0;
 607     }
 608
 609     x = s->history[1];
 610     y = s->history[2];
 611
 612     for( z = 0; z<NGRAM_STEPS; z++) {
 613         count += s->ngram[x][y][z];
 614         sum += z * s->ngram[x][y][z];
 615     }
 616
 617     result = ((float)(sum))/((float)(count));
 618 #ifdef DEBUG
 619     printf( "predicting next = %.2f\n", result);
 620 #endif
 621
 622     return result;
 623 }
 624
 625 void score_game( GameState* s, bool player1_scored) {
 626     Player* winner = (player1_scored)?(&(s->player1)):(&(s->player2));
 627     Player* loser = (player1_scored)?(&(s->player2)):(&(s->player1));
 628
 629     if( s->current_set >= SETS_TO_WIN*2-1) {
 630         return;
 631     }
 632
 633     winner->game++;
 634     if( loser->game < winner->game-1) {
 635         if( winner->game >= 4) {
 636             winner->game = loser->game = 0;
 637             winner->sets[s->current_set]++;
 638             /* scoring the set.. */
 639             if( (winner->sets[s->current_set] == 6 && loser->sets[s->current_set] < 5) ||
 640                 winner->sets[s->current_set] == 7) {
 641                 s->current_set++;
 642                 s->winner = game_get_winner( s);
 643             }
 644         }
 645     }
 646 }
 647
 648 char* format_sets( GameState* s) {
 649     static char sets[100];
 650     static char tmp[100];
 651     int i, max = s->current_set;
 652
 653     sets[0] = '\0';
 654
 655     if( s->winner != WINNER_NONE) {
 656         max--;
 657     }
 658     for( i=0; i<=max; i++) {
 659         sprintf( tmp, "%d:%d, ", s->player1.sets[i], s->player2.sets[i]);
 660         strcat( sets, tmp);
 661     }
 662
 663     sets[strlen(sets)-2] = '\0';
 664
 665     return sets;
 666 }
 667
 668 char* format_game( GameState* s) {
 669     static char game[100];
 670     static const int game_scoring[] = { 0, 15, 30, 40 };
 671
 672     if( s->player1.game < 4 && s->player2.game < 4) {
 673         sprintf( game, "%d - %d", game_scoring[s->player1.game], game_scoring[s->player2.game]);
 674     } else if( s->player1.game > s->player2.game) {
 675         strcpy( game, "advantage player 1");
 676     } else if( s->player1.game < s->player2.game) {
 677         strcpy( game, "advantage player 2");
 678     } else {
 679         strcpy( game, "deuce");
 680     }
 681
 682     return game;
 683 }
 684
 685 char* format_status( GameState* s) {
 686     static char status[100];
 687     static const char* set_names[] = { "first", "second", "third", "fourth", "fifth" };
 688
 689     sprintf( status, "%d:%d in %s set", s->player1.sets[s->current_set], s->player2.sets[s->current_set], set_names[s->current_set]);
 690
 691     return status;
 692 }
 693
 694 int game_get_winner( GameState* s) {
 695     int i;
 696     int sets[2] = {0};
 697
 698     for( i=0; i<s->current_set; i++) {
 699         if( s->player1.sets[i] > s->player2.sets[i]) {
 700             sets[0]++;
 701         } else {
 702             sets[1]++;
 703         }
 704     }
 705
 706     if( sets[0] == SETS_TO_WIN) return WINNER_PLAYER1;
 707     if( sets[1] == SETS_TO_WIN) return WINNER_PLAYER2;
 708
 709     return WINNER_NONE;
 710 }
 711