src/mercenary/main.c

   1 /* main routine
   2  *
   3  * (C) 2018 by Andreas Eversberg <jolly@eversberg.eu>
   4  * All Rights Reserved
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdint.h>
  22 #include <stdlib.h>
  23 #include <sys/stat.h>
  24 #include <sys/types.h>
  25 #include "../libsdl/sdl.h"
  26 #include "../libsdl/opengl.h"
  27 #include "../libsdl/print.h"
  28 #include "../libcpu/m68k.h"
  29 #include "../libcpu/execute.h"
  30 #include "../libvideo/video.h"
  31 #include "../libsound/sound.h"
  32 #include "../libjoystick/joystick.h"
  33 #include "../libkeyboard/keyboard.h"
  34 #include "../libdisk/disk.h"
  35 #include "mercenary.h"
  36 #include "render.h"
  37
  38 static int config_amiga_speed = 1;
  39 static const char *config_gamesave_dir = ".mercenary";
  40 static int config_video_filter = 1;
  41 static int config_audio_filter = 1;
  42 static int config_render = 0;
  43 static int config_debug_opengl = 0;
  44
  45 #define CPU_SPEED       7093790.0;
  46
  47 #define SOUND_SAMPLERATE 48000
  48 /* - game IRQ rate
  49  * - must be used for sound rendering chunk
  50  */
  51 #define IRQ_RATE        50
  52 /* numbe of buffer chunks to dejitter:
  53  * - SDL render interval
  54  * - sound rendering interval
  55  * - sound card interval
  56  * 4 should be minimum, if video rate is >=50 Hz
  57  */
  58 #define SOUND_CHUNKS    4
  59
  60 /* test sound to check if buffer does not overflow / underrun */
  61 //#define DEBUG_SOUND_BUFFERING
  62
  63 #define IOSIZE          0x1000 /* bytes in io space */
  64 #define MEMORY_SIZE     0x80000
  65 static uint8_t *memory = NULL;
  66 static uint8_t *image = NULL;
  67 #define SCREEN_WIDTH    320
  68 #define SCREEN_HEIGHT   200
  69 #define IMAGE_WIDTH     320
  70 #define IMAGE_HEIGHT    200
  71 #define BENSON_AT_LINE  136
  72 #define IMAGE_DIWSTART  0x2c
  73 static uint16_t *chipreg = NULL;
  74 static stereo_t *sound_buffer = NULL; /* sound buffer memory */
  75 static int sound_buffer_size; /* buffer sample size */
  76 static int sound_buffer_writep; /* write pointer at buffer */
  77 static int sound_buffer_readp; /* read pointer at buffer */
  78 static int double_size = 1; /* render in double size, so each pixle is 2*2 pixles wide */
  79 static int render_legacy = 0; /* render original amiga screen, if set */
  80 static int render_improved = 0; /* render improved image, if set */
  81 static int render_debug = 0; /* render both, amiga screen and  improved image, if set */
  82
  83 static const char *home_dir;
  84
  85 static int quit = 0;
  86
  87 int parse_args(int argc, char *argv[])
  88 {
  89         int i = 1;
  90
  91         while (argc > i) {
  92                 if (!strcmp(argv[i], "-h") || !strcmp(argv[i], "--help")) {
  93                         print_info("Usage: %s\n", argv[0]);
  94                         print_info(" -s --amiga-speed original | full\n");
  95                         print_info("        Set speed of rendering to original Amiga or full speed.\n");
  96                         print_info(" -v --video-filter on | off\n");
  97                         print_info("        Set video filter.\n");
  98                         print_info(" -a --audio-filter on | off\n");
  99                         print_info("        Set audio filter.\n");
 100                         print_info(" -r --render original | opegl\n");
 101                         print_info("        Set speed of rendering to original Amiga or full speed.\n");
 102                         print_info(" -o --debug-opengl\n");
 103                         print_info("        Use split screen to debug opengl rendering vs. amiga rendering.\n");
 104                         return -1;
 105                 } else
 106                 if (!strcmp(argv[i], "-s") || !strcmp(argv[i], "--amiga-speed")) {
 107                         i++;
 108                         if (argc == i) {
 109 missing_parameter:
 110                                 print_info("Missing parameter, use '--help'!\n");
 111                                 return -1;
 112                         }
 113                         if (!strcmp(argv[i], "original"))
 114                                 config_amiga_speed = 1;
 115                         else
 116                         if (!strcmp(argv[i], "full"))
 117                                 config_amiga_speed = 0;
 118                         else {
 119 illegal_parameter:
 120                                 print_info("Illegal parameter, use '--help'!\n");
 121                                 return -1;
 122                         }
 123                 } else
 124                 if (!strcmp(argv[i], "-v") || !strcmp(argv[i], "--video-filter")) {
 125                         i++;
 126                         if (argc == i)
 127                                 goto missing_parameter;
 128                         if (!strcmp(argv[i], "on"))
 129                                 config_video_filter = 1;
 130                         else
 131                         if (!strcmp(argv[i], "off"))
 132                                 config_video_filter = 0;
 133                         else
 134                                 goto illegal_parameter;
 135                 } else
 136                 if (!strcmp(argv[i], "-a") || !strcmp(argv[i], "--audio-filter")) {
 137                         i++;
 138                         if (argc == i)
 139                                 goto missing_parameter;
 140                         if (!strcmp(argv[i], "on"))
 141                                 config_audio_filter = 1;
 142                         else
 143                         if (!strcmp(argv[i], "off"))
 144                                 config_audio_filter = 0;
 145                         else
 146                                 goto illegal_parameter;
 147                 } else
 148                 if (!strcmp(argv[i], "-r") || !strcmp(argv[i], "--render")) {
 149                         i++;
 150                         if (argc == i)
 151                                 goto missing_parameter;
 152                         if (!strcmp(argv[i], "original"))
 153                                 config_render = 0;
 154                         else
 155                         if (!strcmp(argv[i], "opengl"))
 156                                 config_render = 1;
 157                         else
 158                                 goto illegal_parameter;
 159                 } else
 160                 if (!strcmp(argv[i], "-o") || !strcmp(argv[i], "--debug-opengl")) {
 161                         config_debug_opengl = 1;
 162                 } else {
 163                         print_info("Illegal option '%s', use '--help'!\n", argv[i]);
 164                         return -1;
 165                 }
 166                 i++;
 167         }
 168
 169         return 0;
 170 }
 171
 172 static void special_event(int event)
 173 {
 174         if (render_improved)
 175                 render_improved_event(event);
 176 }
 177
 178 static void main_loop(void)
 179 {
 180         int had_first_irq = 0;
 181         static uint32_t current_time, last_time = 0, diff;
 182         int i, rc;
 183         int space, length;
 184         int cycle_count, event;
 185         double render_delay = 0.0;
 186         uint32_t palette_address;
 187         uint16_t palette[16];
 188
 189         last_time = SDL_GetTicks();
 190
 191         /* render result on window */
 192         while (!quit) {
 193                 /* handle SDL events */
 194                 rc = event_sdl();
 195                 if (rc)
 196                         break;
 197
 198                 /* clear screen */
 199                 opengl_clear();
 200
 201                 /* initialize rendering */
 202                 render_debug = config_debug_opengl;
 203                 render_legacy = (!config_render) || render_debug;
 204                 render_improved = config_render || render_debug;
 205                 /* start rendering for improved graphics */
 206                 if (render_improved)
 207                         opengl_viewport_improved(render_debug, (double_size) ? BENSON_AT_LINE * 2 : BENSON_AT_LINE);
 208
 209                 /* STEP 1: let the CPU render/process the game */
 210                 /* don't render if we still delay */
 211                 if (!render_delay) {
 212                         /* execute until the rendered image is ready (wait for VBL) */
 213                         cycle_count = 0;
 214                         do {
 215                                 cycle_count += execute_cpu(0, mercenary_stop_at, &event);
 216                                 /* handle special events */
 217                                 if (event != STOP_AT_WAIT_VBL)
 218                                         special_event(event);
 219                         } while (event != STOP_AT_WAIT_VBL);
 220                         /* copy palette */
 221                         palette_address = mercenary_palette();
 222                         for (i = 0; i < 16; i++)
 223                                 palette[i] = m68k_read_memory_16(palette_address + i*2);
 224                         /* for amiga speed: set delay by the number of cycles */
 225                         if (config_amiga_speed)
 226                                 render_delay = (double)cycle_count / CPU_SPEED;
 227                 }
 228
 229                 /* STEP 2: transfer legacy image in memory to OpenGL texture */
 230                 if (had_first_irq) {
 231                         /* render game view without benson
 232                          * because benson is not updated before VBL IRQ, we don't want old image from double buffer
 233                          */
 234                         if (render_legacy)
 235                                 emul_video(image, memory, palette, IMAGE_WIDTH, IMAGE_HEIGHT, IMAGE_DIWSTART, chipreg, 0, BENSON_AT_LINE, double_size);
 236                 }
 237                 /* render benson on improved rendering, if enabled */
 238                 if (render_improved)
 239                         opengl_render_benson(image, config_video_filter, (double_size) ? BENSON_AT_LINE * 2 : BENSON_AT_LINE);
 240                 /* setup viewport for legacy image and render image, if enabled */
 241                 if (render_legacy) {
 242                         opengl_viewport_legacy(render_debug);
 243                         opengl_render_legacy(image, config_video_filter);
 244                 }
 245                 swap_sdl();
 246
 247                 /* STEP 3: execute interrupt at rate of 50Hz, render sound */
 248                 current_time = SDL_GetTicks();
 249                 diff = current_time - last_time;
 250                 /* in case of timer glitch, execute IRQ only by maximum number of SOUND_CHUNKS */
 251                 if (diff > 1000 * SOUND_CHUNKS / IRQ_RATE) {
 252                         diff = 1000 * SOUND_CHUNKS / IRQ_RATE;
 253                         last_time = current_time - 1000 * SOUND_CHUNKS / IRQ_RATE;
 254                 }
 255                 while (diff > 1000 / IRQ_RATE) {
 256                         execute_cpu(3, NULL, NULL);
 257                         execute_cpu(4, NULL, NULL);
 258                         had_first_irq = 1;
 259                         /* render benson without game view
 260                          * because we only got benson refreshed during VBL IRQ
 261                          */
 262                         emul_video(image, memory, palette, IMAGE_WIDTH, IMAGE_HEIGHT, IMAGE_DIWSTART, chipreg, BENSON_AT_LINE, IMAGE_HEIGHT, double_size);
 263                         /* render sound to sound buffer
 264                          * buffer pointer read and write is atomic, so no locking required!
 265                          */
 266                         space = (sound_buffer_readp - sound_buffer_writep - 1 + sound_buffer_size) % sound_buffer_size;
 267                         if (space < SOUND_SAMPLERATE / IRQ_RATE) {
 268 #ifdef DEBUG_SOUND_BUFFERING
 269                                 fprintf(stderr, "sound buffer overflow\n");
 270 #endif
 271                                 length = space;
 272                         } else
 273                                 length = SOUND_SAMPLERATE / IRQ_RATE;
 274 #ifdef DEBUG_SOUND_BUFFERING
 275                         printf("can write %d, write %d\n", space, length);
 276                         static int cnt = 0;
 277                         int s;
 278                         for (s = 0; s < length; s++) {
 279                                 sound_buffer[(sound_buffer_writep + s) % sound_buffer_size].left =
 280                                 sound_buffer[(sound_buffer_writep + s) % sound_buffer_size].right
 281                                         = sin(2 * M_PI * 999 * cnt / SOUND_SAMPLERATE)
 282                                         * sin(2 * M_PI * 21 * cnt / SOUND_SAMPLERATE)
 283                                         * sin(2 * M_PI * 0.5 * cnt / SOUND_SAMPLERATE);
 284                                  cnt++;
 285                         }
 286 #else
 287                         render_sound(memory, sound_buffer, sound_buffer_size, sound_buffer_writep, length, config_audio_filter);
 288 #endif
 289                         sound_buffer_writep = (sound_buffer_writep + length) % sound_buffer_size;
 290                         diff -= 1000 / IRQ_RATE;
 291                         last_time += 1000 / IRQ_RATE;
 292
 293                         /* count down render delay */
 294                         if (render_delay) {
 295                                 render_delay -= 1.0 / (double)IRQ_RATE;
 296                                 if (render_delay < 0.0)
 297                                         render_delay = 0.0;
 298                         }
 299                 }
 300         }
 301 }
 302
 303 static uint16_t io_read(uint32_t address)
 304 {
 305         uint16_t value = 0xffff;
 306
 307         /* joystick and fire button */
 308         if (address == 0xbfe000 || address == 0xdff00c)
 309                 value &= emulate_joystick_read(address);
 310         /* keyboard */
 311         if (address == 0xbfec00 || address == 0xbfed00 || address == 0xbfee00)
 312                 value &= emulate_keyboard_read(address);
 313         /* diskette */
 314         if (address == 0xbfd100 || address == 0xbfe000 || address == 0xdff01a || address == 0xdff01e)
 315                 value &= emulate_disk_read(address);
 316
 317         return value;
 318 }
 319
 320 static void io_write(uint32_t address, uint16_t value)
 321 {
 322         /* dmacon and sound registers */
 323         if (address == 0xdff096 || (address >= 0xdff0a0 && address <= 0xdff0df))
 324                 emulate_sound_write(address, value, SOUND_SAMPLERATE);
 325         if (address == 0xbfd100 || (address >= 0xdff020 && address <= 0xdff024))
 326                 emulate_disk_write(address, value);
 327 }
 328
 329 /* two tracks with 0x1820 words of length */
 330 static uint8_t game_save[2][0x1820 << 1];
 331 static int last_track = 0;
 332
 333 /* game reads track with saved game */
 334 static void disk_read(int track, int __attribute__((unused)) side, uint32_t data, uint16_t length)
 335 {
 336         if (length > sizeof(game_save[0])) {
 337                 print_error("loading game state failed, because length exceeds game save data size, please fix!\n");
 338                 return;
 339         }
 340
 341         /* if even track is selected, load game */
 342         if (!(track & 1)) {
 343                 char filename[256];
 344                 int gamesave_num = (track - 2) >> 1;
 345                 int got;
 346                 FILE *fp;
 347
 348                 memset(game_save, 0, sizeof(game_save)); /* clear so make the game fail, if we fail */
 349 #if defined(_WIN32)
 350                 filename[0] = '\0';
 351 #else
 352                 sprintf(filename, "%s/%s/", home_dir, config_gamesave_dir);
 353                 mkdir(filename, 0777);
 354 #endif
 355                 sprintf(filename + strlen(filename), "%d%s", gamesave_num, mercenary_gamesavesuffix);
 356                 fp = fopen(filename, "r");
 357                 if (!fp) {
 358 fail:
 359                         print_error("failed to load game from '%s'\n", filename);
 360                         goto copy;
 361                 }
 362                 got = fread(game_save, sizeof(game_save[0]), 2, fp);
 363                 fclose(fp);
 364                 if (got != 2)
 365                         goto fail;
 366         }
 367
 368 copy:
 369         /* copy track */
 370         memcpy(memory + data, game_save[track & 1], length /* sizeof(game_save[0])*/);
 371 }
 372
 373 /* game writes track with saved game */
 374 static void disk_write(int track, int __attribute__((unused)) side, uint32_t data, uint16_t length)
 375 {
 376         /* skip sync info that is provided by game and only relevant for a real disk track */
 377         data += 0x200;
 378         length -= 0x200;
 379
 380         if (length != sizeof(game_save[0])) {
 381                 print_error("saving game state failed, because length of data does not match, please fix!\n");
 382                 return;
 383         }
 384
 385         /* don't save if last track is the same, because disk is written on both sides with the same data */
 386         if (track == last_track) {
 387                 if (memcmp(memory + data, game_save[track & 1], length)) {
 388                         print_error("saving game data on other side of the disk is different, please fix!\n");
 389                 }
 390                 return;
 391         }
 392         last_track = track;
 393
 394         /* save game data */
 395         memcpy(game_save[track & 1], memory + data, length);
 396
 397         /* if done with saving */
 398         if ((track & 1)) {
 399                 char filename[256];
 400                 int gamesave_num = (track - 2) >> 1;
 401                 int wrote;
 402                 FILE *fp;
 403
 404 #if defined(_WIN32)
 405                 filename[0] = '\0';
 406 #else
 407                 sprintf(filename, "%s/%s/", home_dir, config_gamesave_dir);
 408                 mkdir(filename, 0777);
 409 #endif
 410                 sprintf(filename + strlen(filename), "%d%s", gamesave_num, mercenary_gamesavesuffix);
 411                 fp = fopen(filename, "w");
 412                 if (!fp) {
 413 fail:
 414                         print_error("failed to save game to '%s'\n", filename);
 415                         return;
 416                 }
 417                 print_info("Game state saved to '%s'\n", filename);
 418                 wrote = fwrite(game_save, sizeof(game_save[0]), 2, fp);
 419                 fclose(fp);
 420                 if (wrote != 2)
 421                         goto fail;
 422         }
 423 }
 424
 425 static int shift = 0, ctrl = 0;
 426
 427 static void keyboard_sdl(int down, SDL_Keycode sym)
 428 {
 429         switch (sym) {
 430         case SDLK_LCTRL:
 431         case SDLK_RCTRL:
 432                 ctrl = down;
 433                 break;
 434         case SDLK_v:
 435                 if (down && ctrl) {
 436                         config_video_filter ^= 1;
 437                         print_info("video filter: %s\n", (config_video_filter) ? "on" : "off");
 438                 }
 439                 break;
 440         case SDLK_a:
 441                 if (down && ctrl) {
 442                         config_audio_filter ^= 1;
 443                         print_info("audio filter: %s\n", (config_audio_filter) ? "on" : "off");
 444                 }
 445                 break;
 446         case SDLK_s:
 447                 if (down && ctrl) {
 448                         config_amiga_speed ^= 1;
 449                         print_info("amiga speed: %s\n", (config_amiga_speed) ? "original" : "full");
 450                 }
 451                 break;
 452         case SDLK_r:
 453                 if (down && ctrl) {
 454                         config_render ^= 1;
 455                         printf("render: %s\n", (config_render) ? "opengl" : "original");
 456                 }
 457                 break;
 458         case SDLK_c:
 459                 if (down)
 460                         quit = 1;
 461                 break;
 462         }
 463
 464         switch (sym) {
 465         case SDLK_LSHIFT:
 466                 set_key("LSH", down);
 467                 shift = down;
 468                 break;
 469         case SDLK_RSHIFT:
 470                 set_key("RSH", down);
 471                 shift = down;
 472                 break;
 473         case SDLK_LEFT:
 474                 if (shift && down) {
 475                         set_key("LF", down);
 476                         set_joystick(-1, -1, -1, -1, -1);
 477                         break;
 478                 }
 479                 set_key("LF", 0);
 480                 set_joystick(down, -1, -1, -1, -1);
 481                 break;
 482         case SDLK_RIGHT:
 483                 if (shift && down) {
 484                         set_key("RT", down);
 485                         set_joystick(-1, -1, -1, -1, -1);
 486                         break;
 487                 }
 488                 set_key("RT", 0);
 489                 set_joystick(-1, down, -1, -1, -1);
 490                 break;
 491         case SDLK_UP:
 492                 if (shift && down) {
 493                         set_key("UP", down);
 494                         set_joystick(-1, -1, -1, -1, -1);
 495                         break;
 496                 }
 497                 set_key("UP", 0);
 498                 set_joystick(-1, -1, down, -1, -1);
 499                 break;
 500         case SDLK_DOWN:
 501                 if (shift && down) {
 502                         set_key("DN", down);
 503                         set_joystick(-1, -1, -1, -1, -1);
 504                         break;
 505                 }
 506                 set_key("DN", 0);
 507                 set_joystick(-1, -1, -1, down, -1);
 508                 break;
 509         case SDLK_END:
 510                 set_joystick(-1, -1, -1, -1, down);
 511                 break;
 512
 513         case SDLK_a: set_key("A", down); break;
 514         case SDLK_b: set_key("B", down); break;
 515         case SDLK_c: set_key("C", down); break;
 516         case SDLK_d: set_key("D", down); break;
 517         case SDLK_e: set_key("E", down); break;
 518         case SDLK_f: set_key("F", down); break;
 519         case SDLK_g: set_key("G", down); break;
 520         case SDLK_h: set_key("H", down); break;
 521         case SDLK_i: set_key("I", down); break;
 522         case SDLK_j: set_key("J", down); break;
 523         case SDLK_k: set_key("K", down); break;
 524         case SDLK_l: set_key("L", down); break;
 525         case SDLK_m: set_key("M", down); break;
 526         case SDLK_n: set_key("N", down); break;
 527         case SDLK_o: set_key("O", down); break;
 528         case SDLK_p: set_key("P", down); break;
 529         case SDLK_q: set_key("Q", down); break;
 530         case SDLK_r: set_key("R", down); break;
 531         case SDLK_s: set_key("S", down); break;
 532         case SDLK_t: set_key("T", down); break;
 533         case SDLK_u: set_key("U", down); break;
 534         case SDLK_v: set_key("V", down); break;
 535         case SDLK_w: set_key("W", down); break;
 536         case SDLK_x: set_key("X", down); break;
 537         case SDLK_y: set_key("Y", down); break;
 538         case SDLK_z: set_key("Z", down); break;
 539
 540         case SDLK_0: set_key("0", down); break;
 541         case SDLK_1: set_key("1", down); break;
 542         case SDLK_2: set_key("2", down); break;
 543         case SDLK_3: set_key("3", down); break;
 544         case SDLK_4: set_key("4", down); break;
 545         case SDLK_5: set_key("5", down); break;
 546         case SDLK_6: set_key("6", down); break;
 547         case SDLK_7: set_key("7", down); break;
 548         case SDLK_8: set_key("8", down); break;
 549         case SDLK_9: set_key("9", down); break;
 550
 551         case SDLK_KP_0: set_key("NP0", down); break;
 552         case SDLK_KP_1: set_key("NP1", down); break;
 553         case SDLK_KP_2: set_key("NP2", down); break;
 554         case SDLK_KP_3: set_key("NP3", down); break;
 555         case SDLK_KP_4: set_key("NP4", down); break;
 556         case SDLK_KP_5: set_key("NP5", down); break;
 557         case SDLK_KP_6: set_key("NP6", down); break;
 558         case SDLK_KP_7: set_key("NP7", down); break;
 559         case SDLK_KP_8: set_key("NP8", down); break;
 560         case SDLK_KP_9: set_key("NP9", down); break;
 561         case SDLK_KP_DIVIDE: set_key("NPDIV", down); break;
 562         case SDLK_KP_MULTIPLY: set_key("NPMUL", down); break;
 563         case SDLK_KP_MINUS: set_key("NPSUB", down); break;
 564         case SDLK_KP_PLUS: set_key("NPADD", down); break;
 565         case SDLK_KP_PERIOD: set_key("NPDEL", down); break;
 566         // NPLPAREN and NPRPAREN are not emulated
 567
 568         case SDLK_F1: set_key("F1", down); break;
 569         case SDLK_F2: set_key("F2", down); break;
 570         case SDLK_F3: set_key("F3", down); break;
 571         case SDLK_F4: set_key("F4", down); break;
 572         case SDLK_F5: set_key("F5", down); break;
 573         case SDLK_F6: set_key("F6", down); break;
 574         case SDLK_F7: set_key("F7", down); break;
 575         case SDLK_F8: set_key("F8", down); break;
 576         case SDLK_F9: set_key("F9", down); break;
 577         case SDLK_F10: set_key("F10", down); break;
 578
 579         case SDLK_SPACE: set_key("SPC", down); break;
 580         case SDLK_BACKSPACE: set_key("BS", down); break;
 581         case SDLK_TAB: set_key("TAB", down); break;
 582         case SDLK_KP_ENTER: set_key("ENT", down); break;
 583         case SDLK_RETURN: set_key("RET", down); break;
 584         case SDLK_ESCAPE: set_key("ESC", down); break;
 585         case SDLK_DELETE: set_key("DEL", down); break;
 586         case SDLK_INSERT: set_key("HELP", down); break;
 587
 588         }
 589 }
 590
 591 void audio_sdl(float *data, int length)
 592 {
 593         int fill, s;
 594
 595         /* read sound from sound buffer
 596          * buffer pointer read and write is atomic, so no locking required!
 597          */
 598         fill = (sound_buffer_writep - sound_buffer_readp + sound_buffer_size) % sound_buffer_size;
 599         if (fill < length) {
 600 #ifdef DEBUG_SOUND_BUFFERING
 601                 fprintf(stderr, "sound buffer underrun\n");
 602 #endif
 603                 /* correct read pointer as if the buffer would have 'length' of samples stored inside */
 604                 sound_buffer_readp = (sound_buffer_readp + fill - length + sound_buffer_size) % sound_buffer_size;
 605         }
 606         for (s = 0; s < length; s++) {
 607                 *data++ = sound_buffer[(sound_buffer_readp + s) % sound_buffer_size].left;
 608                 *data++ = sound_buffer[(sound_buffer_readp + s) % sound_buffer_size].right;
 609         }
 610 #ifdef DEBUG_SOUND_BUFFERING
 611         printf("fill %d = %.4f\n", length, sound_buffer[sound_buffer_readp][0]);
 612 #endif
 613         sound_buffer_readp =(sound_buffer_readp + length) % sound_buffer_size;
 614 }
 615
 616 int main(int argc, char *argv[])
 617 {
 618         int rc;
 619         int sdl_sound_chunk;
 620
 621         home_dir = getenv("HOME");
 622         if (!home_dir)
 623                 home_dir = "";
 624
 625         rc = parse_args(argc, argv);
 626         if (rc)
 627                 return 0;
 628
 629         /* allocate image */
 630         image = calloc(IMAGE_WIDTH * IMAGE_HEIGHT * ((double_size) ? 4 : 1), 3);
 631         if (!image) {
 632                 print_error("Failed to allocate image buffer\n");
 633                 goto done;
 634         }
 635
 636         if ((SOUND_SAMPLERATE % IRQ_RATE)) {
 637                 print_error("Sample rate must be a multiple of IRQ rate, please fix!\n");
 638                 goto done;
 639         }
 640         if ((1000 % IRQ_RATE)) {
 641                 print_error("1000 (Ticks per second) rate must be a multiple of IRQ rate, please fix!\n");
 642                 goto done;
 643         }
 644
 645         /* calculate SDL chunk size for audio
 646          * it must be a power of two, but not more than the chunk size for each IRQ!
 647          */
 648         for (sdl_sound_chunk = 2; sdl_sound_chunk <= (SOUND_SAMPLERATE / IRQ_RATE); sdl_sound_chunk <<= 1)
 649                 ;
 650         sdl_sound_chunk >>= 1;
 651 //      printf("samples per IRQ = %d, samples per SDL audio = %d\n", SOUND_SAMPLERATE / IRQ_RATE, sdl_sound_chunk); exit(0);
 652
 653         /* allocate sound buffers */
 654         sound_buffer_size = SOUND_SAMPLERATE / IRQ_RATE * SOUND_CHUNKS;
 655         sound_buffer = calloc(sound_buffer_size, sizeof(*sound_buffer));
 656         if (!sound_buffer) {
 657                 print_error("Failed to allocate image buffer\n");
 658                 goto done;
 659         }
 660
 661         /* allocate memory */
 662         memory = calloc(MEMORY_SIZE, 1);
 663         if (!memory) {
 664                 print_error("Failed to allocate cpu's memory\n");
 665                 goto done;
 666         }
 667         chipreg = calloc(IOSIZE, 1);
 668         if (!chipreg) {
 669                 print_error("Failed to allocate chip register\n");
 670                 goto done;
 671         }
 672
 673         /* init cpu code */
 674         execute_init(MEMORY_SIZE, memory, chipreg, io_read, io_write);
 675
 676         /* init disk emulation */
 677         disk_init(disk_read, disk_write);
 678
 679         /* load binary */
 680         mercenary_load();
 681
 682         /* patch some stuff */
 683         mercenary_patch();
 684
 685         /* init SDL and OpenGL */
 686         rc = init_sdl(argv[0], (config_debug_opengl) ? SCREEN_WIDTH * 2 : SCREEN_WIDTH * 3, (config_debug_opengl) ? SCREEN_HEIGHT * 4 : SCREEN_HEIGHT * 3, SOUND_SAMPLERATE, sdl_sound_chunk, keyboard_sdl, audio_sdl);
 687         if (rc < 0)
 688                 goto done;
 689         rc = init_opengl((double_size) ? IMAGE_WIDTH * 2 : IMAGE_WIDTH, (double_size) ? IMAGE_HEIGHT * 2 : IMAGE_HEIGHT);
 690         if (rc < 0)
 691                 goto done;
 692         resize_opengl((config_debug_opengl) ? SCREEN_WIDTH * 2 : SCREEN_WIDTH * 3, (config_debug_opengl) ? SCREEN_HEIGHT * 4 : SCREEN_HEIGHT * 3);
 693
 694         /* init audio filter */
 695         sound_init_filter(SOUND_SAMPLERATE);
 696
 697         /* start cpu */
 698         reset_cpu();
 699
 700         print_info("**********************************\n");
 701         print_info("* Welcome to Mercenary Reloaded! *\n");
 702         print_info("**********************************\n\n");
 703         print_info("Press CTRL + cursor keys to select inventory or pickup/drop item.\n");
 704         print_info("Press CTRL + f to toggle full screen.\n");
 705         print_info("Press CTRL + s to toggle rendering speed.\n");
 706         print_info("Press CTRL + v to toggle video filter.\n");
 707         print_info("Press CTRL + a to toggle audio filter.\n");
 708         print_info("Press CTRL + r to toggle rendering with opengl or orignal code.\n");
 709         print_info("Press CTRL + c to exit game.\n\n");
 710         print_info("Use '--help' as command line option for configuration settings.\n\n");
 711
 712         /* run game */
 713         main_loop();
 714
 715 done:
 716         exit_opengl();
 717         exit_sdl();
 718
 719         if (chipreg)
 720                 free(chipreg);
 721         if (memory)
 722                 free(memory);
 723         if (sound_buffer)
 724                 free(sound_buffer);
 725         if (image)
 726                 free(image);
 727
 728         return 0;
 729 }
 730