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
  34 GameState *gamestate_new() {
  35     int x, y, z;
  36     GameState *s;
  37
  38     GameState template = {
  39         { 0, 0, 0.0, 0.0, 0.0 },
  40         { 0, 0, 0, 0, 0 },
  41         { 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 },
  42         { GAME_X_MAX+RACKET_X_MID*2, GAME_Y_MID, 0, 0, 0, DESIRE_NORMAL, PLAYER_TYPE_AI, GAME_Y_MID, false, 0, {0}, 0, 0, PLAYER_ACCEL_DEFAULT, true },
  43         0,
  44         0,
  45         0,
  46         true,
  47         "welcome to tennix " VERSION,
  48         { 0 },
  49         { 0 },
  50         REFEREE_NORMAL,
  51         0,
  52         WINNER_NONE,
  53         false,
  54         GR_CTT_GRASS,
  55         -1,
  56         { 0 },
  57         0,
  58         false,
  59         { { { 0 } } },
  60         0.0,
  61         SOUND_MAX,
  62         0.0,
  63         0.0,
  64         0
  65     };
  66
  67     s = (GameState*)malloc(sizeof(GameState));
  68     if (s == NULL) abort();
  69
  70     memcpy(s, &template, sizeof(GameState));
  71
  72     game_setup_serve(s);
  73
  74     /* smoothen n-gram */
  75     for( x = 0; x<NGRAM_STEPS; x++) {
  76         for( y = 0; y<NGRAM_STEPS; y++) {
  77             for( z = 0; z<NGRAM_STEPS; z++) {
  78                 s->ngram[x][y][z] = 1;
  79             }
  80         }
  81     }
  82
  83     return s;
  84 }
  85
  86
  87 void gameloop(GameState *s) {
  88     strcpy(s->game_score_str, format_game(s));
  89     strcpy(s->sets_score_str, format_sets(s));
  90
  91     Uint32 ot = SDL_GetTicks();
  92     Uint32 nt;
  93     Uint32 dt = GAME_TICKS;
  94     Uint32 diff;
  95     Uint32 accumulator = 0;
  96     bool quit = false;
  97
  98 #ifdef ENABLE_FPS_LIMIT
  99     Uint32 ft, frames; /* frame timer and frames */
 100 #endif
 101
 102     play_sample_loop(SOUND_AUDIENCE);
 103     /* Reset the court type, so it is redrawn on first display */
 104     s->old_court_type = -1;
 105
 106 #ifdef ENABLE_FPS_LIMIT
 107     frames = 0;
 108     ft = SDL_GetTicks();
 109 #endif
 110     while( !quit) {
 111         nt = SDL_GetTicks();
 112         diff = nt-ot;
 113         if( diff > 2000) {
 114             diff = 0;
 115         }
 116
 117         accumulator += diff;
 118         ot = nt;
 119
 120         while( accumulator >= dt) {
 121             quit = step(s);
 122             s->time += dt;
 123             accumulator -= dt;
 124
 125             if( s->was_stopped) {
 126                 ot = SDL_GetTicks();
 127                 s->was_stopped = false;
 128             }
 129         }
 130
 131 #ifdef ENABLE_FPS_LIMIT
 132         while (frames*1000.0/((float)(SDL_GetTicks()-ft+1))>(float)(DEFAULT_FPS)) {
 133             SDL_Delay(10);
 134         }
 135         frames++;
 136 #endif
 137
 138         render(s);
 139     }
 140
 141     clear_screen();
 142     store_screen();
 143
 144     stop_sample(SOUND_AUDIENCE);
 145 }
 146
 147 bool step( GameState* s) {
 148     Uint8 *keys;
 149     SDL_Event e;
 150
 151     if( get_phase( s) < 1.0) {
 152         if( !s->ground.jump) {
 153             s->play_sound = SOUND_GROUND;
 154
 155             if( IS_OUT_Y( s->ball.y)) {
 156                 /* out - responsibilities stay the same */
 157                 s->status = "out!";
 158                 s->play_sound = SOUND_OUT;
 159                 s->referee = REFEREE_OUT;
 160             } else {
 161                 /* not out - responsibilities change */
 162                 s->player1.responsible = !(s->player2.responsible = !s->player2.responsible);
 163                 s->status = format_status( s);
 164                 s->referee = REFEREE_NORMAL;
 165             }
 166         }
 167         s->ground.jump = 3;
 168         s->ground.x = s->ball.x;
 169         s->ground.y = s->ball.y;
 170     } else {
 171         if( s->ground.jump && !(s->time%5)) s->ground.jump--;
 172     }
 173
 174     if( IS_OUT_X(s->ball.x) || IS_OFFSCREEN_Y(s->ball.y)) {
 175         if( IS_OFFSCREEN( s->ball.x, s->ball.y)) {
 176             s->player1_serves = s->player1.responsible;
 177
 178             score_game( s, s->player2.responsible);
 179             strcpy( s->game_score_str, format_game( s));
 180             strcpy( s->sets_score_str, format_sets( s));
 181
 182             if( s->player1.responsible) {
 183                 if( s->player1.type == PLAYER_TYPE_HUMAN && s->player2.type == PLAYER_TYPE_AI) {
 184                     s->status = "computer scores";
 185                 } else {
 186                     s->status = "player 2 scores";
 187                 }
 188                 s->referee = REFEREE_PLAYER2;
 189             } else {
 190                 if( s->player1.type == PLAYER_TYPE_HUMAN && s->player2.type == PLAYER_TYPE_AI) {
 191                     s->status = "player scores";
 192                 } else {
 193                     s->status = "player 1 scores";
 194                 }
 195                 s->referee = REFEREE_PLAYER1;
 196             }
 197
 198             game_setup_serve( s);
 199             s->play_sound = SOUND_APPLAUSE;
 200             SDL_Delay( 500);
 201             s->was_stopped = true;
 202             s->history_size = 0;
 203             s->history_is_locked = 0;
 204             s->ngram_prediction = 0.0;
 205 #ifdef DEBUG
 206             printf( "-- game reset --\n");
 207 #endif
 208         }
 209
 210         if( IS_OUT_X(s->ball.x)) {
 211             if( !s->history_is_locked && s->referee != REFEREE_OUT) {
 212                 s->history[s->history_size] = (int)(NGRAM_STEPS*s->ball.y/HEIGHT);
 213                 s->history_size++;
 214                 if( s->history_size == 3) {
 215                     s->ngram[s->history[0]][s->history[1]][s->history[2]] += 10;
 216 #ifdef DEBUG
 217                     printf( "history: %d, %d, %d\n", s->history[0], s->history[1], s->history[2]);
 218 #endif
 219                     s->ngram_prediction = ngram_predictor( s);
 220                     s->history[0] = s->history[1];
 221                     s->history[1] = s->history[2];
 222                     s->history_size--;
 223                 }
 224                 s->history_is_locked = true;
 225             }
 226             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) {
 227                 s->ball.x = GAME_X_MIN;
 228                 if( s->player1.state == PLAYER_STATE_MAX) {
 229                     s->ball.move_x = PLAYER_POWERSHOT;
 230                 } else {
 231                     s->ball.move_x = 2.5 + 2.0*s->player1.state/PLAYER_STATE_MAX;
 232                 }
 233                 s->ball.move_y = get_move_y( s, 1);
 234                 s->player2.responsible = !(s->player1.responsible = 1);
 235                 s->ball.jump += 1.0-2.0*(s->player1.state<5);
 236                 s->play_sound = SOUND_RACKET;
 237                 pan_sample(SOUND_RACKET, 0.4);
 238             } 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) {
 239                 s->ball.x = GAME_X_MAX;
 240                 if( s->player2.state == PLAYER_STATE_MAX) {
 241                     s->ball.move_x = -PLAYER_POWERSHOT;
 242                 } else {
 243                     s->ball.move_x = -(2.5 + 2.0*s->player2.state/PLAYER_STATE_MAX);
 244                 }
 245                 s->ball.move_y = get_move_y( s, 2);
 246                 s->player1.responsible = !(s->player2.responsible = 1);
 247                 s->ball.jump += 1.0-2.0*(s->player2.state<5);
 248                 s->play_sound = SOUND_RACKET;
 249                 pan_sample(SOUND_RACKET, 0.6);
 250             }
 251         }
 252     } else {
 253         s->history_is_locked = false;
 254     }
 255
 256     SDL_PollEvent( &e);
 257     keys = SDL_GetKeyState( NULL);
 258     switch(e.type) {
 259         case SDL_JOYAXISMOTION:
 260             if (e.jaxis.axis == JOYSTICK_Y_AXIS) {
 261                 s->joystick_y = JOYSTICK_PERCENTIZE(e.jaxis.value);
 262             } else if (e.jaxis.axis == JOYSTICK_X_AXIS) {
 263                 s->joystick_x = JOYSTICK_PERCENTIZE(e.jaxis.value);
 264             }
 265             break;
 266         case SDL_JOYBUTTONUP: case SDL_JOYBUTTONDOWN:
 267             if (e.jbutton.button == JOYSTICK_BUTTON_A) {
 268                 s->joystick_a = (e.jbutton.state == SDL_PRESSED);
 269             }
 270             break;
 271     }
 272
 273     if( s->time%50==0) {
 274         /**
 275          * Maemo keys:
 276          * F7 = "Decrease" key
 277          * F8 = "Increase" key
 278          **/
 279         if (keys['c'] || keys[SDLK_F8]) {
 280             s->court_type++;
 281         } else if (keys[SDLK_F7]) {
 282             s->court_type--;
 283         }
 284         if( s->court_type > GR_CTT_LAST) {
 285             s->court_type = GR_CTT_FIRST;
 286         } else if (s->court_type < GR_CTT_FIRST) {
 287             s->court_type = GR_CTT_LAST;
 288         }
 289     }
 290
 291     if( !is_fading() && !s->is_over) {
 292         if( s->player1.type == PLAYER_TYPE_HUMAN) {
 293            input_human( &s->player1,
 294                    keys['w'] || keys[SDLK_UP] || s->joystick_y < -JOYSTICK_TRESHOLD,
 295                    keys['s'] || keys[SDLK_DOWN] || s->joystick_y > JOYSTICK_TRESHOLD,
 296                    keys['d'] || keys[SDLK_SPACE] || keys[SDLK_LCTRL] || keys[SDLK_RETURN] || s->joystick_a,
 297 #ifdef ENABLE_MOUSE
 298                    true,
 299 #else
 300                    false,
 301 #endif
 302                    s);
 303         } else {
 304             input_ai( &s->player1, &s->ball, &s->player2, s);
 305         }
 306
 307         if( s->player2.type == PLAYER_TYPE_HUMAN) {
 308             input_human( &s->player2, keys['o'], keys['l'], keys['k'], false, s);
 309         } else {
 310             input_ai( &s->player2, &s->ball, &s->player1, s);
 311         }
 312     }
 313
 314     /* Maemo: The "F6" button is the "Fullscreen" button */
 315     if( keys['f'] || keys[SDLK_F6]) SDL_WM_ToggleFullScreen( screen);
 316     if( keys['y']) SDL_SaveBMP( screen, "screenshot.bmp");
 317
 318     /* Maemo: The "F4" button is the "Open menu" button */
 319     if( keys['p'] || keys[SDLK_F4]) {
 320         while( keys['p'] || keys[SDLK_F4]) {
 321             SDL_PollEvent( &e);
 322             keys = SDL_GetKeyState( NULL);
 323             SDL_Delay( 10);
 324         }
 325         while( (keys['p'] || keys[SDLK_F4]) == 0) {
 326             SDL_PollEvent( &e);
 327             keys = SDL_GetKeyState( NULL);
 328             SDL_Delay( 10);
 329         }
 330         while( keys['p'] || keys[SDLK_F4]) {
 331             SDL_PollEvent( &e);
 332             keys = SDL_GetKeyState( NULL);
 333             SDL_Delay( 10);
 334         }
 335         s->was_stopped = true;
 336     }
 337
 338     if( keys[SDLK_ESCAPE] || keys['q']) return true;
 339
 340     limit_value( &s->player1.y, PLAYER_Y_MIN, PLAYER_Y_MAX);
 341     limit_value( &s->player2.y, PLAYER_Y_MIN, PLAYER_Y_MAX);
 342     limit_value( &s->ball.jump, BALL_JUMP_MIN, BALL_JUMP_MAX);
 343
 344     /* Update ball_dest for debugging purposes */
 345     get_move_y(s, 1);
 346     get_move_y(s, 2);
 347
 348     s->ball.x += s->ball.move_x;
 349     s->ball.y += s->ball.move_y;
 350
 351     if(s->player1.state) s->player1.state--;
 352     if(s->player2.state) s->player2.state--;
 353
 354     return false;
 355 }
 356
 357 void render( GameState* s) {
 358     if (s->play_sound != SOUND_MAX) {
 359         play_sample(s->play_sound);
 360         s->play_sound = SOUND_MAX;
 361     }
 362     if( s->winner != WINNER_NONE) {
 363         if( !s->is_over) {
 364             start_fade();
 365             s->is_over = true;
 366         }
 367         clear_screen();
 368         store_screen();
 369         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);
 370         sprintf( s->game_score_str, "player %d wins the match with %s", s->winner, format_sets( s));
 371         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);
 372         updatescr();
 373         return;
 374     }
 375     if (s->old_court_type != s->court_type) {
 376         clear_screen();
 377         fill_image(s->court_type, 120, 120, 400, 250);
 378         show_image(GR_COURT, 0, 0, 255);
 379         s->old_court_type = s->court_type;
 380         store_screen();
 381     }
 382     show_sprite( GR_REFEREE, s->referee, 4, 250, 10, 255);
 383     show_image( GR_SHADOW, s->ball.x-BALL_X_MID, s->ball.y + get_phase( s) - BALL_Y_MID, 255);
 384
 385     show_sprite( GR_RACKET, (!s->player1.state), 4, s->player1.x-RACKET_X_MID, s->player1.y-RACKET_Y_MID, 255);
 386     show_sprite( GR_RACKET, (!s->player2.state)+2, 4, s->player2.x-RACKET_X_MID, s->player2.y-RACKET_Y_MID, 255);
 387
 388     if( s->ball.move_x > 0) {
 389         show_sprite( GR_BALL, (s->time/500)%4, 4, s->ball.x-BALL_X_MID, s->ball.y-BALL_Y_MID, 255);
 390     } else if( s->ball.move_x < 0) {
 391         show_sprite( GR_BALL, 3-(s->time/500)%4, 4, s->ball.x-BALL_X_MID, s->ball.y-BALL_Y_MID, 255);
 392     } else {
 393         show_sprite( GR_BALL, 0, 4, s->ball.x-BALL_X_MID, s->ball.y-BALL_Y_MID, 255);
 394     }
 395
 396     /* Player 1's mouse rectangle */
 397     if (!(s->player1.mouse_locked)) {
 398         rectangle(s->player1.x-2+5, s->player1.mouse_y-2, 4, 4, 255, 255, 255);
 399         rectangle(s->player1.x-1+5, s->player1.mouse_y-1, 2, 2, 0, 0, 0);
 400     }
 401
 402     font_draw_string( GR_DKC2_FONT, s->game_score_str, 14, 14, 0, ANIMATION_NONE);
 403     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);
 404
 405     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);
 406
 407 #ifdef DEBUG
 408     line_horiz( s->player1.y, 255, 0, 0);
 409     line_horiz( s->player2.y, 0, 0, 255);
 410     line_horiz( s->ball.y, 0, 255, 0);
 411
 412     line_vert( s->player1.x, 255, 0, 0);
 413     line_vert( s->player2.x, 0, 0, 255);
 414     line_vert( s->ball.x, 0, 255, 0);
 415
 416     line_horiz( s->player1.ball_dest, 255, 0, 255);
 417     line_horiz( s->player2.ball_dest, 0, 255, 255);
 418
 419     line_horiz( GAME_Y_MIN, 100, 100, 100);
 420     line_horiz( GAME_Y_MAX, 100, 100, 100);
 421 #endif
 422
 423     updatescr();
 424 }
 425
 426 void limit_value( float* value, float min, float max) {
 427     if( *value < min) {
 428         *value = min;
 429     } else if( *value > max) {
 430         *value = max;
 431     }
 432 }
 433
 434 float get_phase( GameState* s) {
 435     float pos, fract;
 436     float x, min, max, direction;
 437
 438     x = s->ball.x;
 439     min = GAME_X_MIN;
 440     max = GAME_X_MAX;
 441     direction = s->ball.move_x;
 442
 443     pos = (direction>0)?(1-GROUND_PHASE):(GROUND_PHASE);
 444
 445     fract = (x-min)/(max-min);
 446
 447     if( fract < pos) {
 448         fract = fract/pos;
 449         return fabsf( cosf(PI*fract/2))*PHASE_AMP*s->ball.jump;
 450     } else {
 451         fract = (pos-fract)/(1-pos);
 452         return fabsf( sinf(PI*fract/2))*PHASE_AMP*s->ball.jump;
 453     }
 454 }
 455
 456 float get_move_y( GameState* s, unsigned char player) {
 457     float pct, dest, x_len, y_len;
 458     float py, by, pa, move_x;
 459
 460     py = (player==1)?(s->player1.y):(s->player2.y);
 461     by = s->ball.y;
 462     pa = RACKET_Y_MID*2;
 463     move_x = s->ball.move_x;
 464
 465     /* -1.0 .. 1.0 for racket hit position */
 466     pct = (by-py)/(pa/2);
 467     limit_value( &pct, -1.0, 1.0);
 468
 469     /* Y destination for ball */
 470     dest = GAME_Y_MID + pct*(GAME_Y_MAX-GAME_Y_MIN);
 471     if( player == 1) {
 472         s->player1.ball_dest = dest;
 473     } else {
 474         s->player2.ball_dest = dest;
 475     }
 476
 477     /* lengths for the ball's journey */
 478     if( player == 1) {
 479         x_len = fabsf(GAME_X_MAX - s->ball.x);
 480         y_len = dest - by + MOVE_Y_SEED-rand()%MOVE_Y_SEED*2;
 481     } else {
 482         x_len = s->ball.x - GAME_X_MIN;
 483         y_len = by - dest + MOVE_Y_SEED-rand()%MOVE_Y_SEED*2;
 484     }
 485
 486     /* return the should-be value for move_y */
 487     return (y_len*move_x)/(x_len);
 488 }
 489
 490 void input_human( Player* player, bool up, bool down, bool hit, bool use_mouse, GameState* s) {
 491     int diff = PLAYER_MOVE_Y;
 492     int mb;
 493
 494     /**
 495      * Only use mouse control if the user isn't pressing any buttons
 496      * this way, keyboard control still works when mouse control is
 497      * enabled.
 498      **/
 499     if (use_mouse && (down || up || hit)) {
 500         /**
 501          * this is here so if the user decides to play
 502          * with keyboard controls, we will lock the
 503          * mouse and disable displaying the mouse cursor
 504          **/
 505         player->mouse_locked = true;
 506     }
 507     if (use_mouse && !down && !up && !hit) {
 508         mb = SDL_GetMouseState(&(player->mouse_x), &(player->mouse_y));
 509         if (mb&SDL_BUTTON(SDL_BUTTON_LEFT)) {
 510             if (player->mouse_y < player->y) {
 511                 down = false;
 512                 up = true;
 513                 diff = (player->y-player->mouse_y<diff)?(player->y-player->mouse_y):(diff);
 514             } else if (player->mouse_y > player->y) {
 515                 up = false;
 516                 down = true;
 517                 diff = (player->mouse_y-player->y<diff)?(player->mouse_y-player->y):(diff);
 518             }
 519             player->mouse_locked = false;
 520         } else if (!player->mouse_locked) {
 521             hit = true;
 522         }
 523     }
 524
 525     if (fabsf(s->joystick_y) > JOYSTICK_TRESHOLD) {
 526         diff = PLAYER_MOVE_Y*fabsf(s->joystick_y)/40.0;
 527         if (diff > PLAYER_MOVE_Y) {
 528             diff = PLAYER_MOVE_Y;
 529         }
 530     }
 531
 532     if (up) {
 533         player->y -= fminf(diff, diff*player->accelerate);
 534         player->accelerate *= PLAYER_ACCEL_INCREASE;
 535     } else if (down) {
 536         player->y += fminf(diff, diff*player->accelerate);
 537         player->accelerate *= PLAYER_ACCEL_INCREASE;
 538     } else {
 539         player->accelerate = PLAYER_ACCEL_DEFAULT;
 540     }
 541
 542     if( hit) {
 543         if( !player->state && !player->state_locked) {
 544             player->state = PLAYER_STATE_MAX;
 545             player->state_locked = true;
 546         }
 547     } else {
 548         player->state_locked = false;
 549     }
 550 }
 551
 552 void input_ai( Player* player, Ball* ball, Player* opponent, GameState* s) {
 553     float fact = 1.7;
 554     float target;
 555
 556     if( fabsf( player->y - ball->y) > RACKET_Y_MID*5) {
 557         fact = 3.5;
 558     }
 559
 560     target = GAME_Y_MID + (opponent->ball_dest - GAME_Y_MID)/5;
 561
 562     if( player->responsible) {
 563         if( player->desire == DESIRE_NORMAL && !IS_NEAR_Y_AI( player->y, ball->y)) {
 564             if( player->y < ball->y) {
 565                 player->y += fmin( 2*fact, ball->y - player->y);
 566             } else if( player->y > ball->y) {
 567                 player->y -= fmin( 2*fact, player->y - ball->y);
 568             }
 569         }
 570
 571         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) {
 572             player->state = PLAYER_STATE_MAX;
 573         }
 574     } else if( ball->move_x == 0) {
 575         if( player->desire == DESIRE_NORMAL && !IS_NEAR_Y_AI( player->y, target)) {
 576             if( player->y < target) {
 577                 player->y += fmin( fact, (target-player->y)/40.0);
 578             } else if( player->y > target) {
 579                 player->y -= fmin( fact, (player->y-target)/40.0);
 580             }
 581         }
 582     } else if( s->ngram_prediction > 0.0) {
 583         target = s->ngram_prediction*((float)HEIGHT)/((float)(NGRAM_STEPS));
 584         target = GAME_Y_MID + (target-GAME_Y_MID)*1.5;
 585
 586         if( player->desire == DESIRE_NORMAL && !IS_NEAR_Y_AI( player->y, target)) {
 587             if( player->y < target) {
 588                 player->y += fmin( fact, (target-player->y)/40.0);
 589             } else if( player->y > target) {
 590                 player->y -= fmin( fact, (player->y-target)/40.0);
 591             }
 592         }
 593     } else {/*
 594         if( player->desire == DESIRE_NORMAL) {
 595             if( !IS_NEAR_Y_AI( player->y, target)) {
 596                 player->y += (target - player->y)/40.0;
 597             }
 598         }*/
 599     }
 600 }
 601
 602 void game_setup_serve( GameState* s) {
 603     s->ball.jump = 7.5;
 604     s->ball.y = GAME_Y_MID;
 605     s->ball.move_x = 0.0;
 606     s->ball.move_y = 0.0;
 607
 608     if( s->player1_serves) {
 609         s->player1.responsible = true;
 610         s->player1.ball_dest = 0.0;
 611         s->ball.x = GAME_X_MIN-RACKET_X_MID*1.5;
 612     } else {
 613         s->player1.responsible = false;
 614         s->player2.ball_dest = 0.0;
 615         s->ball.x = GAME_X_MAX+RACKET_X_MID*1.5;
 616     }
 617
 618     s->player2.responsible = !(s->player1.responsible);
 619 }
 620
 621 float ngram_predictor( GameState* s) {
 622     unsigned int count = 0;
 623     unsigned long sum = 0;
 624     int x, y, z;
 625     float result;
 626
 627     if( s->history_size < 3) {
 628         return 0.0;
 629     }
 630
 631     x = s->history[1];
 632     y = s->history[2];
 633
 634     for( z = 0; z<NGRAM_STEPS; z++) {
 635         count += s->ngram[x][y][z];
 636         sum += z * s->ngram[x][y][z];
 637     }
 638
 639     result = ((float)(sum))/((float)(count));
 640 #ifdef DEBUG
 641     printf( "predicting next = %.2f\n", result);
 642 #endif
 643
 644     return result;
 645 }
 646
 647 void score_game( GameState* s, bool player1_scored) {
 648     Player* winner = (player1_scored)?(&(s->player1)):(&(s->player2));
 649     Player* loser = (player1_scored)?(&(s->player2)):(&(s->player1));
 650
 651     if( s->current_set >= SETS_TO_WIN*2-1) {
 652         return;
 653     }
 654
 655     winner->game++;
 656     if( loser->game < winner->game-1) {
 657         if( winner->game >= 4) {
 658             winner->game = loser->game = 0;
 659             winner->sets[s->current_set]++;
 660             /* scoring the set.. */
 661             if( (winner->sets[s->current_set] == 6 && loser->sets[s->current_set] < 5) ||
 662                 winner->sets[s->current_set] == 7) {
 663                 s->current_set++;
 664                 s->winner = game_get_winner( s);
 665             }
 666         }
 667     }
 668 }
 669
 670 char* format_sets( GameState* s) {
 671     static char sets[100];
 672     static char tmp[100];
 673     int i, max = s->current_set;
 674
 675     sets[0] = '\0';
 676
 677     if( s->winner != WINNER_NONE) {
 678         max--;
 679     }
 680     for( i=0; i<=max; i++) {
 681         sprintf( tmp, "%d:%d, ", s->player1.sets[i], s->player2.sets[i]);
 682         strcat( sets, tmp);
 683     }
 684
 685     sets[strlen(sets)-2] = '\0';
 686
 687     return sets;
 688 }
 689
 690 char* format_game( GameState* s) {
 691     static char game[100];
 692     static const int game_scoring[] = { 0, 15, 30, 40 };
 693
 694     if( s->player1.game < 4 && s->player2.game < 4) {
 695         sprintf( game, "%d - %d", game_scoring[s->player1.game], game_scoring[s->player2.game]);
 696     } else if( s->player1.game > s->player2.game) {
 697         strcpy( game, "advantage player 1");
 698     } else if( s->player1.game < s->player2.game) {
 699         strcpy( game, "advantage player 2");
 700     } else {
 701         strcpy( game, "deuce");
 702     }
 703
 704     return game;
 705 }
 706
 707 char* format_status( GameState* s) {
 708     static char status[100];
 709     static const char* set_names[] = { "first", "second", "third", "fourth", "fifth" };
 710
 711     sprintf( status, "%d:%d in %s set", s->player1.sets[s->current_set], s->player2.sets[s->current_set], set_names[s->current_set]);
 712
 713     return status;
 714 }
 715
 716 int game_get_winner( GameState* s) {
 717     int i;
 718     int sets[2] = {0};
 719
 720     for( i=0; i<s->current_set; i++) {
 721         if( s->player1.sets[i] > s->player2.sets[i]) {
 722             sets[0]++;
 723         } else {
 724             sets[1]++;
 725         }
 726     }
 727
 728     if( sets[0] == SETS_TO_WIN) return WINNER_PLAYER1;
 729     if( sets[1] == SETS_TO_WIN) return WINNER_PLAYER2;
 730
 731     return WINNER_NONE;
 732 }
 733