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             start_fade();
 202             s->was_stopped = true;
 203             s->history_size = 0;
 204             s->history_is_locked = 0;
 205             s->ngram_prediction = 0.0;
 206 #ifdef DEBUG
 207             printf( "-- game reset --\n");
 208 #endif
 209         }
 210
 211         if( IS_OUT_X(s->ball.x)) {
 212             if( !s->history_is_locked && s->referee != REFEREE_OUT) {
 213                 s->history[s->history_size] = (int)(NGRAM_STEPS*s->ball.y/HEIGHT);
 214                 s->history_size++;
 215                 if( s->history_size == 3) {
 216                     s->ngram[s->history[0]][s->history[1]][s->history[2]] += 10;
 217 #ifdef DEBUG
 218                     printf( "history: %d, %d, %d\n", s->history[0], s->history[1], s->history[2]);
 219 #endif
 220                     s->ngram_prediction = ngram_predictor( s);
 221                     s->history[0] = s->history[1];
 222                     s->history[1] = s->history[2];
 223                     s->history_size--;
 224                 }
 225                 s->history_is_locked = true;
 226             }
 227             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) {
 228                 s->ball.x = GAME_X_MIN;
 229                 if( s->player1.state == PLAYER_STATE_MAX) {
 230                     s->ball.move_x = PLAYER_POWERSHOT;
 231                 } else {
 232                     s->ball.move_x = 2.5 + 2.0*s->player1.state/PLAYER_STATE_MAX;
 233                 }
 234                 s->ball.move_y = get_move_y( s, 1);
 235                 s->player2.responsible = !(s->player1.responsible = 1);
 236                 s->ball.jump += 1.0-2.0*(s->player1.state<5);
 237                 s->play_sound = SOUND_RACKET;
 238                 pan_sample(SOUND_RACKET, 0.4);
 239             } 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) {
 240                 s->ball.x = GAME_X_MAX;
 241                 if( s->player2.state == PLAYER_STATE_MAX) {
 242                     s->ball.move_x = -PLAYER_POWERSHOT;
 243                 } else {
 244                     s->ball.move_x = -(2.5 + 2.0*s->player2.state/PLAYER_STATE_MAX);
 245                 }
 246                 s->ball.move_y = get_move_y( s, 2);
 247                 s->player1.responsible = !(s->player2.responsible = 1);
 248                 s->ball.jump += 1.0-2.0*(s->player2.state<5);
 249                 s->play_sound = SOUND_RACKET;
 250                 pan_sample(SOUND_RACKET, 0.6);
 251             }
 252         }
 253     } else {
 254         s->history_is_locked = false;
 255     }
 256
 257     SDL_PollEvent( &e);
 258     keys = SDL_GetKeyState( NULL);
 259     switch(e.type) {
 260         case SDL_JOYAXISMOTION:
 261             if (e.jaxis.axis == JOYSTICK_Y_AXIS) {
 262                 s->joystick_y = JOYSTICK_PERCENTIZE(e.jaxis.value);
 263             } else if (e.jaxis.axis == JOYSTICK_X_AXIS) {
 264                 s->joystick_x = JOYSTICK_PERCENTIZE(e.jaxis.value);
 265             }
 266             break;
 267         case SDL_JOYBUTTONUP: case SDL_JOYBUTTONDOWN:
 268             if (e.jbutton.button == JOYSTICK_BUTTON_A) {
 269                 s->joystick_a = (e.jbutton.state == SDL_PRESSED);
 270             }
 271             break;
 272     }
 273
 274     if( s->time%50==0) {
 275         /**
 276          * Maemo keys:
 277          * F7 = "Decrease" key
 278          * F8 = "Increase" key
 279          **/
 280         if (keys['c'] || keys[SDLK_F8]) {
 281             s->court_type++;
 282         } else if (keys[SDLK_F7]) {
 283             s->court_type--;
 284         }
 285         if( s->court_type > GR_CTT_LAST) {
 286             s->court_type = GR_CTT_FIRST;
 287         } else if (s->court_type < GR_CTT_FIRST) {
 288             s->court_type = GR_CTT_LAST;
 289         }
 290     }
 291
 292     if( !is_fading() && !s->is_over) {
 293         if( s->player1.type == PLAYER_TYPE_HUMAN) {
 294            input_human( &s->player1,
 295                    keys['w'] || keys[SDLK_UP] || s->joystick_y < -JOYSTICK_TRESHOLD,
 296                    keys['s'] || keys[SDLK_DOWN] || s->joystick_y > JOYSTICK_TRESHOLD,
 297                    keys['d'] || keys[SDLK_SPACE] || keys[SDLK_LCTRL] || keys[SDLK_RETURN] || s->joystick_a,
 298 #ifdef ENABLE_MOUSE
 299                    true,
 300 #else
 301                    false,
 302 #endif
 303                    s);
 304         } else {
 305             input_ai( &s->player1, &s->ball, &s->player2, s);
 306         }
 307
 308         if( s->player2.type == PLAYER_TYPE_HUMAN) {
 309             input_human( &s->player2, keys['o'], keys['l'], keys['k'], false, s);
 310         } else {
 311             input_ai( &s->player2, &s->ball, &s->player1, s);
 312         }
 313     }
 314
 315     /* Maemo: The "F6" button is the "Fullscreen" button */
 316     if( keys['f'] || keys[SDLK_F6]) SDL_WM_ToggleFullScreen( screen);
 317     if( keys['y']) SDL_SaveBMP( screen, "screenshot.bmp");
 318
 319     /* Maemo: The "F4" button is the "Open menu" button */
 320     if( keys['p'] || keys[SDLK_F4]) {
 321         while( keys['p'] || keys[SDLK_F4]) {
 322             SDL_PollEvent( &e);
 323             keys = SDL_GetKeyState( NULL);
 324             SDL_Delay( 10);
 325         }
 326         while( (keys['p'] || keys[SDLK_F4]) == 0) {
 327             SDL_PollEvent( &e);
 328             keys = SDL_GetKeyState( NULL);
 329             SDL_Delay( 10);
 330         }
 331         while( keys['p'] || keys[SDLK_F4]) {
 332             SDL_PollEvent( &e);
 333             keys = SDL_GetKeyState( NULL);
 334             SDL_Delay( 10);
 335         }
 336         s->was_stopped = true;
 337     }
 338
 339     if( keys[SDLK_ESCAPE] || keys['q']) return true;
 340
 341     limit_value( &s->player1.y, PLAYER_Y_MIN, PLAYER_Y_MAX);
 342     limit_value( &s->player2.y, PLAYER_Y_MIN, PLAYER_Y_MAX);
 343     limit_value( &s->ball.jump, BALL_JUMP_MIN, BALL_JUMP_MAX);
 344
 345     /* Update ball_dest for debugging purposes */
 346     get_move_y(s, 1);
 347     get_move_y(s, 2);
 348
 349     s->ball.x += s->ball.move_x;
 350     s->ball.y += s->ball.move_y;
 351
 352     if(s->player1.state) s->player1.state--;
 353     if(s->player2.state) s->player2.state--;
 354
 355     return false;
 356 }
 357
 358 void render( GameState* s) {
 359     if (s->play_sound != SOUND_MAX) {
 360         play_sample(s->play_sound);
 361         s->play_sound = SOUND_MAX;
 362     }
 363     if( s->winner != WINNER_NONE) {
 364         if( !s->is_over) {
 365             start_fade();
 366             s->is_over = true;
 367         }
 368         clear_screen();
 369         store_screen();
 370         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);
 371         sprintf( s->game_score_str, "player %d wins the match with %s", s->winner, format_sets( s));
 372         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);
 373         updatescr();
 374         return;
 375     }
 376     if (s->old_court_type != s->court_type) {
 377         clear_screen();
 378         fill_image(s->court_type, 120, 120, 400, 250);
 379         show_image(GR_COURT, 0, 0, 255);
 380         s->old_court_type = s->court_type;
 381         store_screen();
 382     }
 383     show_sprite( GR_REFEREE, s->referee, 4, 250, 10, 255);
 384     show_image( GR_SHADOW, s->ball.x-BALL_X_MID, s->ball.y + get_phase( s) - BALL_Y_MID, 255);
 385
 386     show_sprite( GR_RACKET, (!s->player1.state), 4, s->player1.x-RACKET_X_MID, s->player1.y-RACKET_Y_MID, 255);
 387     show_sprite( GR_RACKET, (!s->player2.state)+2, 4, s->player2.x-RACKET_X_MID, s->player2.y-RACKET_Y_MID, 255);
 388
 389     if( s->ball.move_x > 0) {
 390         show_sprite( GR_BALL, (s->time/500)%4, 4, s->ball.x-BALL_X_MID, s->ball.y-BALL_Y_MID, 255);
 391     } else if( s->ball.move_x < 0) {
 392         show_sprite( GR_BALL, 3-(s->time/500)%4, 4, s->ball.x-BALL_X_MID, s->ball.y-BALL_Y_MID, 255);
 393     } else {
 394         show_sprite( GR_BALL, 0, 4, s->ball.x-BALL_X_MID, s->ball.y-BALL_Y_MID, 255);
 395     }
 396
 397     /* Player 1's mouse rectangle */
 398     if (!(s->player1.mouse_locked)) {
 399         rectangle(s->player1.x-2+5, s->player1.mouse_y-2, 4, 4, 255, 255, 255);
 400         rectangle(s->player1.x-1+5, s->player1.mouse_y-1, 2, 2, 0, 0, 0);
 401     }
 402
 403     font_draw_string( GR_DKC2_FONT, s->game_score_str, 14, 14, 0, ANIMATION_NONE);
 404     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);
 405
 406     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);
 407
 408 #ifdef DEBUG
 409     line_horiz( s->player1.y, 255, 0, 0);
 410     line_horiz( s->player2.y, 0, 0, 255);
 411     line_horiz( s->ball.y, 0, 255, 0);
 412
 413     line_vert( s->player1.x, 255, 0, 0);
 414     line_vert( s->player2.x, 0, 0, 255);
 415     line_vert( s->ball.x, 0, 255, 0);
 416
 417     line_horiz( s->player1.ball_dest, 255, 0, 255);
 418     line_horiz( s->player2.ball_dest, 0, 255, 255);
 419
 420     line_horiz( GAME_Y_MIN, 100, 100, 100);
 421     line_horiz( GAME_Y_MAX, 100, 100, 100);
 422 #endif
 423
 424     updatescr();
 425 }
 426
 427 void limit_value( float* value, float min, float max) {
 428     if( *value < min) {
 429         *value = min;
 430     } else if( *value > max) {
 431         *value = max;
 432     }
 433 }
 434
 435 float get_phase( GameState* s) {
 436     float pos, fract;
 437     float x, min, max, direction;
 438
 439     x = s->ball.x;
 440     min = GAME_X_MIN;
 441     max = GAME_X_MAX;
 442     direction = s->ball.move_x;
 443
 444     pos = (direction>0)?(1-GROUND_PHASE):(GROUND_PHASE);
 445
 446     fract = (x-min)/(max-min);
 447
 448     if( fract < pos) {
 449         fract = fract/pos;
 450         return fabsf( cosf(PI*fract/2))*PHASE_AMP*s->ball.jump;
 451     } else {
 452         fract = (pos-fract)/(1-pos);
 453         return fabsf( sinf(PI*fract/2))*PHASE_AMP*s->ball.jump;
 454     }
 455 }
 456
 457 float get_move_y( GameState* s, unsigned char player) {
 458     float pct, dest, x_len, y_len;
 459     float py, by, pa, move_x;
 460
 461     py = (player==1)?(s->player1.y):(s->player2.y);
 462     by = s->ball.y;
 463     pa = RACKET_Y_MID*2;
 464     move_x = s->ball.move_x;
 465
 466     /* -1.0 .. 1.0 for racket hit position */
 467     pct = (by-py)/(pa/2);
 468     limit_value( &pct, -1.0, 1.0);
 469
 470     /* Y destination for ball */
 471     dest = GAME_Y_MID + pct*(GAME_Y_MAX-GAME_Y_MIN);
 472     if( player == 1) {
 473         s->player1.ball_dest = dest;
 474     } else {
 475         s->player2.ball_dest = dest;
 476     }
 477
 478     /* lengths for the ball's journey */
 479     if( player == 1) {
 480         x_len = fabsf(GAME_X_MAX - s->ball.x);
 481         y_len = dest - by + MOVE_Y_SEED-rand()%MOVE_Y_SEED*2;
 482     } else {
 483         x_len = s->ball.x - GAME_X_MIN;
 484         y_len = by - dest + MOVE_Y_SEED-rand()%MOVE_Y_SEED*2;
 485     }
 486
 487     /* return the should-be value for move_y */
 488     return (y_len*move_x)/(x_len);
 489 }
 490
 491 void input_human( Player* player, bool up, bool down, bool hit, bool use_mouse, GameState* s) {
 492     int diff = PLAYER_MOVE_Y;
 493     int mb;
 494
 495     /**
 496      * Only use mouse control if the user isn't pressing any buttons
 497      * this way, keyboard control still works when mouse control is
 498      * enabled.
 499      **/
 500     if (use_mouse && (down || up || hit)) {
 501         /**
 502          * this is here so if the user decides to play
 503          * with keyboard controls, we will lock the
 504          * mouse and disable displaying the mouse cursor
 505          **/
 506         player->mouse_locked = true;
 507     }
 508     if (use_mouse && !down && !up && !hit) {
 509         mb = SDL_GetMouseState(&(player->mouse_x), &(player->mouse_y));
 510         if (mb&SDL_BUTTON(SDL_BUTTON_LEFT)) {
 511             if (player->mouse_y < player->y) {
 512                 down = false;
 513                 up = true;
 514                 diff = (player->y-player->mouse_y<diff)?(player->y-player->mouse_y):(diff);
 515             } else if (player->mouse_y > player->y) {
 516                 up = false;
 517                 down = true;
 518                 diff = (player->mouse_y-player->y<diff)?(player->mouse_y-player->y):(diff);
 519             }
 520             player->mouse_locked = false;
 521         } else if (!player->mouse_locked) {
 522             hit = true;
 523         }
 524     }
 525
 526     if (fabsf(s->joystick_y) > JOYSTICK_TRESHOLD) {
 527         diff = PLAYER_MOVE_Y*fabsf(s->joystick_y)/40.0;
 528         if (diff > PLAYER_MOVE_Y) {
 529             diff = PLAYER_MOVE_Y;
 530         }
 531     }
 532
 533     if (up) {
 534         player->y -= fminf(diff, diff*player->accelerate);
 535         player->accelerate *= PLAYER_ACCEL_INCREASE;
 536     } else if (down) {
 537         player->y += fminf(diff, diff*player->accelerate);
 538         player->accelerate *= PLAYER_ACCEL_INCREASE;
 539     } else {
 540         player->accelerate = PLAYER_ACCEL_DEFAULT;
 541     }
 542
 543     if( hit) {
 544         if( !player->state && !player->state_locked) {
 545             player->state = PLAYER_STATE_MAX;
 546             player->state_locked = true;
 547         }
 548     } else {
 549         player->state_locked = false;
 550     }
 551 }
 552
 553 void input_ai( Player* player, Ball* ball, Player* opponent, GameState* s) {
 554     float fact = 1.7;
 555     float target;
 556
 557     if( fabsf( player->y - ball->y) > RACKET_Y_MID*5) {
 558         fact = 3.5;
 559     }
 560
 561     target = GAME_Y_MID + (opponent->ball_dest - GAME_Y_MID)/5;
 562
 563     if( player->responsible) {
 564         if( player->desire == DESIRE_NORMAL && !IS_NEAR_Y_AI( player->y, ball->y)) {
 565             if( player->y < ball->y) {
 566                 player->y += fmin( 2*fact, ball->y - player->y);
 567             } else if( player->y > ball->y) {
 568                 player->y -= fmin( 2*fact, player->y - ball->y);
 569             }
 570         }
 571
 572         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) {
 573             player->state = PLAYER_STATE_MAX;
 574         }
 575     } else if( ball->move_x == 0) {
 576         if( player->desire == DESIRE_NORMAL && !IS_NEAR_Y_AI( player->y, target)) {
 577             if( player->y < target) {
 578                 player->y += fmin( fact, (target-player->y)/40.0);
 579             } else if( player->y > target) {
 580                 player->y -= fmin( fact, (player->y-target)/40.0);
 581             }
 582         }
 583     } else if( s->ngram_prediction > 0.0) {
 584         target = s->ngram_prediction*((float)HEIGHT)/((float)(NGRAM_STEPS));
 585         target = GAME_Y_MID + (target-GAME_Y_MID)*1.5;
 586
 587         if( player->desire == DESIRE_NORMAL && !IS_NEAR_Y_AI( player->y, target)) {
 588             if( player->y < target) {
 589                 player->y += fmin( fact, (target-player->y)/40.0);
 590             } else if( player->y > target) {
 591                 player->y -= fmin( fact, (player->y-target)/40.0);
 592             }
 593         }
 594     } else {/*
 595         if( player->desire == DESIRE_NORMAL) {
 596             if( !IS_NEAR_Y_AI( player->y, target)) {
 597                 player->y += (target - player->y)/40.0;
 598             }
 599         }*/
 600     }
 601 }
 602
 603 void game_setup_serve( GameState* s) {
 604     s->ball.jump = 7.5;
 605     s->ball.y = GAME_Y_MID;
 606     s->ball.move_x = 0.0;
 607     s->ball.move_y = 0.0;
 608
 609     if( s->player1_serves) {
 610         s->player1.responsible = true;
 611         s->player1.ball_dest = 0.0;
 612         s->ball.x = GAME_X_MIN-RACKET_X_MID*1.5;
 613     } else {
 614         s->player1.responsible = false;
 615         s->player2.ball_dest = 0.0;
 616         s->ball.x = GAME_X_MAX+RACKET_X_MID*1.5;
 617     }
 618
 619     s->player2.responsible = !(s->player1.responsible);
 620 }
 621
 622 float ngram_predictor( GameState* s) {
 623     unsigned int count = 0;
 624     unsigned long sum = 0;
 625     int x, y, z;
 626     float result;
 627
 628     if( s->history_size < 3) {
 629         return 0.0;
 630     }
 631
 632     x = s->history[1];
 633     y = s->history[2];
 634
 635     for( z = 0; z<NGRAM_STEPS; z++) {
 636         count += s->ngram[x][y][z];
 637         sum += z * s->ngram[x][y][z];
 638     }
 639
 640     result = ((float)(sum))/((float)(count));
 641 #ifdef DEBUG
 642     printf( "predicting next = %.2f\n", result);
 643 #endif
 644
 645     return result;
 646 }
 647
 648 void score_game( GameState* s, bool player1_scored) {
 649     Player* winner = (player1_scored)?(&(s->player1)):(&(s->player2));
 650     Player* loser = (player1_scored)?(&(s->player2)):(&(s->player1));
 651
 652     if( s->current_set >= SETS_TO_WIN*2-1) {
 653         return;
 654     }
 655
 656     winner->game++;
 657     if( loser->game < winner->game-1) {
 658         if( winner->game >= 4) {
 659             winner->game = loser->game = 0;
 660             winner->sets[s->current_set]++;
 661             /* scoring the set.. */
 662             if( (winner->sets[s->current_set] == 6 && loser->sets[s->current_set] < 5) ||
 663                 winner->sets[s->current_set] == 7) {
 664                 s->current_set++;
 665                 s->winner = game_get_winner( s);
 666             }
 667         }
 668     }
 669 }
 670
 671 char* format_sets( GameState* s) {
 672     static char sets[100];
 673     static char tmp[100];
 674     int i, max = s->current_set;
 675
 676     sets[0] = '\0';
 677
 678     if( s->winner != WINNER_NONE) {
 679         max--;
 680     }
 681     for( i=0; i<=max; i++) {
 682         sprintf( tmp, "%d:%d, ", s->player1.sets[i], s->player2.sets[i]);
 683         strcat( sets, tmp);
 684     }
 685
 686     sets[strlen(sets)-2] = '\0';
 687
 688     return sets;
 689 }
 690
 691 char* format_game( GameState* s) {
 692     static char game[100];
 693     static const int game_scoring[] = { 0, 15, 30, 40 };
 694
 695     if( s->player1.game < 4 && s->player2.game < 4) {
 696         sprintf( game, "%d - %d", game_scoring[s->player1.game], game_scoring[s->player2.game]);
 697     } else if( s->player1.game > s->player2.game) {
 698         strcpy( game, "advantage player 1");
 699     } else if( s->player1.game < s->player2.game) {
 700         strcpy( game, "advantage player 2");
 701     } else {
 702         strcpy( game, "deuce");
 703     }
 704
 705     return game;
 706 }
 707
 708 char* format_status( GameState* s) {
 709     static char status[100];
 710     static const char* set_names[] = { "first", "second", "third", "fourth", "fifth" };
 711
 712     sprintf( status, "%d:%d in %s set", s->player1.sets[s->current_set], s->player2.sets[s->current_set], set_names[s->current_set]);
 713
 714     return status;
 715 }
 716
 717 int game_get_winner( GameState* s) {
 718     int i;
 719     int sets[2] = {0};
 720
 721     for( i=0; i<s->current_set; i++) {
 722         if( s->player1.sets[i] > s->player2.sets[i]) {
 723             sets[0]++;
 724         } else {
 725             sets[1]++;
 726         }
 727     }
 728
 729     if( sets[0] == SETS_TO_WIN) return WINNER_PLAYER1;
 730     if( sets[1] == SETS_TO_WIN) return WINNER_PLAYER2;
 731
 732     return WINNER_NONE;
 733 }
 734