all repos — mgba @ cf71d39bf031322cdec54ffffe947bda070f4125

mGBA Game Boy Advance Emulator

src/platform/libretro/libretro.h (view raw)

   1/* Copyright (C) 2010-2015 The RetroArch team
   2 *
   3 * ---------------------------------------------------------------------------------------
   4 * The following license statement only applies to this libretro API header (libretro.h).
   5 * ---------------------------------------------------------------------------------------
   6 *
   7 * Permission is hereby granted, free of charge,
   8 * to any person obtaining a copy of this software and associated documentation files (the "Software"),
   9 * to deal in the Software without restriction, including without limitation the rights to
  10 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
  11 * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
  12 *
  13 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
  14 *
  15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
  16 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  18 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  19 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  21 */
  22
  23#ifndef LIBRETRO_H__
  24#define LIBRETRO_H__
  25
  26#include <stdint.h>
  27#include <stddef.h>
  28#include <limits.h>
  29
  30#ifdef __cplusplus
  31extern "C" {
  32#endif
  33
  34#ifndef __cplusplus
  35#if defined(_MSC_VER) && !defined(SN_TARGET_PS3)
  36/* Hack applied for MSVC when compiling in C89 mode
  37 * as it isn't C99-compliant. */
  38#define bool unsigned char
  39#define true 1
  40#define false 0
  41#else
  42#include <stdbool.h>
  43#endif
  44#endif
  45
  46/* Used for checking API/ABI mismatches that can break libretro 
  47 * implementations.
  48 * It is not incremented for compatible changes to the API.
  49 */
  50#define RETRO_API_VERSION         1
  51
  52/*
  53 * Libretro's fundamental device abstractions.
  54 *
  55 * Libretro's input system consists of some standardized device types,
  56 * such as a joypad (with/without analog), mouse, keyboard, lightgun 
  57 * and a pointer.
  58 *
  59 * The functionality of these devices are fixed, and individual cores 
  60 * map their own concept of a controller to libretro's abstractions.
  61 * This makes it possible for frontends to map the abstract types to a 
  62 * real input device, and not having to worry about binding input 
  63 * correctly to arbitrary controller layouts.
  64 */
  65
  66#define RETRO_DEVICE_TYPE_SHIFT         8
  67#define RETRO_DEVICE_MASK               ((1 << RETRO_DEVICE_TYPE_SHIFT) - 1)
  68#define RETRO_DEVICE_SUBCLASS(base, id) (((id + 1) << RETRO_DEVICE_TYPE_SHIFT) | base)
  69
  70/* Input disabled. */
  71#define RETRO_DEVICE_NONE         0
  72
  73/* The JOYPAD is called RetroPad. It is essentially a Super Nintendo 
  74 * controller, but with additional L2/R2/L3/R3 buttons, similar to a 
  75 * PS1 DualShock. */
  76#define RETRO_DEVICE_JOYPAD       1
  77
  78/* The mouse is a simple mouse, similar to Super Nintendo's mouse.
  79 * X and Y coordinates are reported relatively to last poll (poll callback).
  80 * It is up to the libretro implementation to keep track of where the mouse 
  81 * pointer is supposed to be on the screen.
  82 * The frontend must make sure not to interfere with its own hardware 
  83 * mouse pointer.
  84 */
  85#define RETRO_DEVICE_MOUSE        2
  86
  87/* KEYBOARD device lets one poll for raw key pressed.
  88 * It is poll based, so input callback will return with the current 
  89 * pressed state.
  90 * For event/text based keyboard input, see
  91 * RETRO_ENVIRONMENT_SET_KEYBOARD_CALLBACK.
  92 */
  93#define RETRO_DEVICE_KEYBOARD     3
  94
  95/* Lightgun X/Y coordinates are reported relatively to last poll,
  96 * similar to mouse. */
  97#define RETRO_DEVICE_LIGHTGUN     4
  98
  99/* The ANALOG device is an extension to JOYPAD (RetroPad).
 100 * Similar to DualShock it adds two analog sticks.
 101 * This is treated as a separate device type as it returns values in the 
 102 * full analog range of [-0x8000, 0x7fff]. Positive X axis is right.
 103 * Positive Y axis is down.
 104 * Only use ANALOG type when polling for analog values of the axes.
 105 */
 106#define RETRO_DEVICE_ANALOG       5
 107
 108/* Abstracts the concept of a pointing mechanism, e.g. touch.
 109 * This allows libretro to query in absolute coordinates where on the 
 110 * screen a mouse (or something similar) is being placed.
 111 * For a touch centric device, coordinates reported are the coordinates
 112 * of the press.
 113 *
 114 * Coordinates in X and Y are reported as:
 115 * [-0x7fff, 0x7fff]: -0x7fff corresponds to the far left/top of the screen,
 116 * and 0x7fff corresponds to the far right/bottom of the screen.
 117 * The "screen" is here defined as area that is passed to the frontend and 
 118 * later displayed on the monitor.
 119 *
 120 * The frontend is free to scale/resize this screen as it sees fit, however,
 121 * (X, Y) = (-0x7fff, -0x7fff) will correspond to the top-left pixel of the 
 122 * game image, etc.
 123 *
 124 * To check if the pointer coordinates are valid (e.g. a touch display 
 125 * actually being touched), PRESSED returns 1 or 0.
 126 *
 127 * If using a mouse on a desktop, PRESSED will usually correspond to the 
 128 * left mouse button, but this is a frontend decision.
 129 * PRESSED will only return 1 if the pointer is inside the game screen.
 130 *
 131 * For multi-touch, the index variable can be used to successively query 
 132 * more presses.
 133 * If index = 0 returns true for _PRESSED, coordinates can be extracted
 134 * with _X, _Y for index = 0. One can then query _PRESSED, _X, _Y with 
 135 * index = 1, and so on.
 136 * Eventually _PRESSED will return false for an index. No further presses 
 137 * are registered at this point. */
 138#define RETRO_DEVICE_POINTER      6
 139
 140/* Buttons for the RetroPad (JOYPAD).
 141 * The placement of these is equivalent to placements on the 
 142 * Super Nintendo controller.
 143 * L2/R2/L3/R3 buttons correspond to the PS1 DualShock. */
 144#define RETRO_DEVICE_ID_JOYPAD_B        0
 145#define RETRO_DEVICE_ID_JOYPAD_Y        1
 146#define RETRO_DEVICE_ID_JOYPAD_SELECT   2
 147#define RETRO_DEVICE_ID_JOYPAD_START    3
 148#define RETRO_DEVICE_ID_JOYPAD_UP       4
 149#define RETRO_DEVICE_ID_JOYPAD_DOWN     5
 150#define RETRO_DEVICE_ID_JOYPAD_LEFT     6
 151#define RETRO_DEVICE_ID_JOYPAD_RIGHT    7
 152#define RETRO_DEVICE_ID_JOYPAD_A        8
 153#define RETRO_DEVICE_ID_JOYPAD_X        9
 154#define RETRO_DEVICE_ID_JOYPAD_L       10
 155#define RETRO_DEVICE_ID_JOYPAD_R       11
 156#define RETRO_DEVICE_ID_JOYPAD_L2      12
 157#define RETRO_DEVICE_ID_JOYPAD_R2      13
 158#define RETRO_DEVICE_ID_JOYPAD_L3      14
 159#define RETRO_DEVICE_ID_JOYPAD_R3      15
 160
 161/* Index / Id values for ANALOG device. */
 162#define RETRO_DEVICE_INDEX_ANALOG_LEFT   0
 163#define RETRO_DEVICE_INDEX_ANALOG_RIGHT  1
 164#define RETRO_DEVICE_ID_ANALOG_X         0
 165#define RETRO_DEVICE_ID_ANALOG_Y         1
 166
 167/* Id values for MOUSE. */
 168#define RETRO_DEVICE_ID_MOUSE_X          0
 169#define RETRO_DEVICE_ID_MOUSE_Y          1
 170#define RETRO_DEVICE_ID_MOUSE_LEFT       2
 171#define RETRO_DEVICE_ID_MOUSE_RIGHT      3
 172#define RETRO_DEVICE_ID_MOUSE_WHEELUP    4
 173#define RETRO_DEVICE_ID_MOUSE_WHEELDOWN  5
 174#define RETRO_DEVICE_ID_MOUSE_MIDDLE     6
 175
 176/* Id values for LIGHTGUN types. */
 177#define RETRO_DEVICE_ID_LIGHTGUN_X        0
 178#define RETRO_DEVICE_ID_LIGHTGUN_Y        1
 179#define RETRO_DEVICE_ID_LIGHTGUN_TRIGGER  2
 180#define RETRO_DEVICE_ID_LIGHTGUN_CURSOR   3
 181#define RETRO_DEVICE_ID_LIGHTGUN_TURBO    4
 182#define RETRO_DEVICE_ID_LIGHTGUN_PAUSE    5
 183#define RETRO_DEVICE_ID_LIGHTGUN_START    6
 184
 185/* Id values for POINTER. */
 186#define RETRO_DEVICE_ID_POINTER_X         0
 187#define RETRO_DEVICE_ID_POINTER_Y         1
 188#define RETRO_DEVICE_ID_POINTER_PRESSED   2
 189
 190/* Returned from retro_get_region(). */
 191#define RETRO_REGION_NTSC  0
 192#define RETRO_REGION_PAL   1
 193
 194/* Id values for LANGUAGE */
 195enum retro_language
 196{
 197   RETRO_LANGUAGE_ENGLISH             =  0,
 198   RETRO_LANGUAGE_JAPANESE            =  1,
 199   RETRO_LANGUAGE_FRENCH              =  2,
 200   RETRO_LANGUAGE_SPANISH             =  3,
 201   RETRO_LANGUAGE_GERMAN              =  4,
 202   RETRO_LANGUAGE_ITALIAN             =  5,
 203   RETRO_LANGUAGE_DUTCH               =  6,
 204   RETRO_LANGUAGE_PORTUGUESE          =  7,
 205   RETRO_LANGUAGE_RUSSIAN             =  8,
 206   RETRO_LANGUAGE_KOREAN              =  9,
 207   RETRO_LANGUAGE_CHINESE_TRADITIONAL = 10,
 208   RETRO_LANGUAGE_CHINESE_SIMPLIFIED  = 11,
 209   RETRO_LANGUAGE_LAST,
 210
 211   /* Ensure sizeof(enum) == sizeof(int) */
 212   RETRO_LANGUAGE_DUMMY          = INT_MAX 
 213};
 214
 215/* Passed to retro_get_memory_data/size().
 216 * If the memory type doesn't apply to the 
 217 * implementation NULL/0 can be returned.
 218 */
 219#define RETRO_MEMORY_MASK        0xff
 220
 221/* Regular save RAM. This RAM is usually found on a game cartridge,
 222 * backed up by a battery.
 223 * If save game data is too complex for a single memory buffer,
 224 * the SAVE_DIRECTORY (preferably) or SYSTEM_DIRECTORY environment
 225 * callback can be used. */
 226#define RETRO_MEMORY_SAVE_RAM    0
 227
 228/* Some games have a built-in clock to keep track of time.
 229 * This memory is usually just a couple of bytes to keep track of time.
 230 */
 231#define RETRO_MEMORY_RTC         1
 232
 233/* System ram lets a frontend peek into a game systems main RAM. */
 234#define RETRO_MEMORY_SYSTEM_RAM  2
 235
 236/* Video ram lets a frontend peek into a game systems video RAM (VRAM). */
 237#define RETRO_MEMORY_VIDEO_RAM   3
 238
 239/* Keysyms used for ID in input state callback when polling RETRO_KEYBOARD. */
 240enum retro_key
 241{
 242   RETROK_UNKNOWN        = 0,
 243   RETROK_FIRST          = 0,
 244   RETROK_BACKSPACE      = 8,
 245   RETROK_TAB            = 9,
 246   RETROK_CLEAR          = 12,
 247   RETROK_RETURN         = 13,
 248   RETROK_PAUSE          = 19,
 249   RETROK_ESCAPE         = 27,
 250   RETROK_SPACE          = 32,
 251   RETROK_EXCLAIM        = 33,
 252   RETROK_QUOTEDBL       = 34,
 253   RETROK_HASH           = 35,
 254   RETROK_DOLLAR         = 36,
 255   RETROK_AMPERSAND      = 38,
 256   RETROK_QUOTE          = 39,
 257   RETROK_LEFTPAREN      = 40,
 258   RETROK_RIGHTPAREN     = 41,
 259   RETROK_ASTERISK       = 42,
 260   RETROK_PLUS           = 43,
 261   RETROK_COMMA          = 44,
 262   RETROK_MINUS          = 45,
 263   RETROK_PERIOD         = 46,
 264   RETROK_SLASH          = 47,
 265   RETROK_0              = 48,
 266   RETROK_1              = 49,
 267   RETROK_2              = 50,
 268   RETROK_3              = 51,
 269   RETROK_4              = 52,
 270   RETROK_5              = 53,
 271   RETROK_6              = 54,
 272   RETROK_7              = 55,
 273   RETROK_8              = 56,
 274   RETROK_9              = 57,
 275   RETROK_COLON          = 58,
 276   RETROK_SEMICOLON      = 59,
 277   RETROK_LESS           = 60,
 278   RETROK_EQUALS         = 61,
 279   RETROK_GREATER        = 62,
 280   RETROK_QUESTION       = 63,
 281   RETROK_AT             = 64,
 282   RETROK_LEFTBRACKET    = 91,
 283   RETROK_BACKSLASH      = 92,
 284   RETROK_RIGHTBRACKET   = 93,
 285   RETROK_CARET          = 94,
 286   RETROK_UNDERSCORE     = 95,
 287   RETROK_BACKQUOTE      = 96,
 288   RETROK_a              = 97,
 289   RETROK_b              = 98,
 290   RETROK_c              = 99,
 291   RETROK_d              = 100,
 292   RETROK_e              = 101,
 293   RETROK_f              = 102,
 294   RETROK_g              = 103,
 295   RETROK_h              = 104,
 296   RETROK_i              = 105,
 297   RETROK_j              = 106,
 298   RETROK_k              = 107,
 299   RETROK_l              = 108,
 300   RETROK_m              = 109,
 301   RETROK_n              = 110,
 302   RETROK_o              = 111,
 303   RETROK_p              = 112,
 304   RETROK_q              = 113,
 305   RETROK_r              = 114,
 306   RETROK_s              = 115,
 307   RETROK_t              = 116,
 308   RETROK_u              = 117,
 309   RETROK_v              = 118,
 310   RETROK_w              = 119,
 311   RETROK_x              = 120,
 312   RETROK_y              = 121,
 313   RETROK_z              = 122,
 314   RETROK_DELETE         = 127,
 315
 316   RETROK_KP0            = 256,
 317   RETROK_KP1            = 257,
 318   RETROK_KP2            = 258,
 319   RETROK_KP3            = 259,
 320   RETROK_KP4            = 260,
 321   RETROK_KP5            = 261,
 322   RETROK_KP6            = 262,
 323   RETROK_KP7            = 263,
 324   RETROK_KP8            = 264,
 325   RETROK_KP9            = 265,
 326   RETROK_KP_PERIOD      = 266,
 327   RETROK_KP_DIVIDE      = 267,
 328   RETROK_KP_MULTIPLY    = 268,
 329   RETROK_KP_MINUS       = 269,
 330   RETROK_KP_PLUS        = 270,
 331   RETROK_KP_ENTER       = 271,
 332   RETROK_KP_EQUALS      = 272,
 333
 334   RETROK_UP             = 273,
 335   RETROK_DOWN           = 274,
 336   RETROK_RIGHT          = 275,
 337   RETROK_LEFT           = 276,
 338   RETROK_INSERT         = 277,
 339   RETROK_HOME           = 278,
 340   RETROK_END            = 279,
 341   RETROK_PAGEUP         = 280,
 342   RETROK_PAGEDOWN       = 281,
 343
 344   RETROK_F1             = 282,
 345   RETROK_F2             = 283,
 346   RETROK_F3             = 284,
 347   RETROK_F4             = 285,
 348   RETROK_F5             = 286,
 349   RETROK_F6             = 287,
 350   RETROK_F7             = 288,
 351   RETROK_F8             = 289,
 352   RETROK_F9             = 290,
 353   RETROK_F10            = 291,
 354   RETROK_F11            = 292,
 355   RETROK_F12            = 293,
 356   RETROK_F13            = 294,
 357   RETROK_F14            = 295,
 358   RETROK_F15            = 296,
 359
 360   RETROK_NUMLOCK        = 300,
 361   RETROK_CAPSLOCK       = 301,
 362   RETROK_SCROLLOCK      = 302,
 363   RETROK_RSHIFT         = 303,
 364   RETROK_LSHIFT         = 304,
 365   RETROK_RCTRL          = 305,
 366   RETROK_LCTRL          = 306,
 367   RETROK_RALT           = 307,
 368   RETROK_LALT           = 308,
 369   RETROK_RMETA          = 309,
 370   RETROK_LMETA          = 310,
 371   RETROK_LSUPER         = 311,
 372   RETROK_RSUPER         = 312,
 373   RETROK_MODE           = 313,
 374   RETROK_COMPOSE        = 314,
 375
 376   RETROK_HELP           = 315,
 377   RETROK_PRINT          = 316,
 378   RETROK_SYSREQ         = 317,
 379   RETROK_BREAK          = 318,
 380   RETROK_MENU           = 319,
 381   RETROK_POWER          = 320,
 382   RETROK_EURO           = 321,
 383   RETROK_UNDO           = 322,
 384
 385   RETROK_LAST,
 386
 387   RETROK_DUMMY          = INT_MAX /* Ensure sizeof(enum) == sizeof(int) */
 388};
 389
 390enum retro_mod
 391{
 392   RETROKMOD_NONE       = 0x0000,
 393
 394   RETROKMOD_SHIFT      = 0x01,
 395   RETROKMOD_CTRL       = 0x02,
 396   RETROKMOD_ALT        = 0x04,
 397   RETROKMOD_META       = 0x08,
 398
 399   RETROKMOD_NUMLOCK    = 0x10,
 400   RETROKMOD_CAPSLOCK   = 0x20,
 401   RETROKMOD_SCROLLOCK  = 0x40,
 402
 403   RETROKMOD_DUMMY = INT_MAX /* Ensure sizeof(enum) == sizeof(int) */
 404};
 405
 406/* If set, this call is not part of the public libretro API yet. It can 
 407 * change or be removed at any time. */
 408#define RETRO_ENVIRONMENT_EXPERIMENTAL 0x10000
 409/* Environment callback to be used internally in frontend. */
 410#define RETRO_ENVIRONMENT_PRIVATE 0x20000
 411
 412/* Environment commands. */
 413#define RETRO_ENVIRONMENT_SET_ROTATION  1  /* const unsigned * --
 414                                            * Sets screen rotation of graphics.
 415                                            * Is only implemented if rotation can be accelerated by hardware.
 416                                            * Valid values are 0, 1, 2, 3, which rotates screen by 0, 90, 180, 
 417                                            * 270 degrees counter-clockwise respectively.
 418                                            */
 419#define RETRO_ENVIRONMENT_GET_OVERSCAN  2  /* bool * --
 420                                            * Boolean value whether or not the implementation should use overscan, 
 421                                            * or crop away overscan.
 422                                            */
 423#define RETRO_ENVIRONMENT_GET_CAN_DUPE  3  /* bool * --
 424                                            * Boolean value whether or not frontend supports frame duping,
 425                                            * passing NULL to video frame callback.
 426                                            */
 427
 428                                           /* Environ 4, 5 are no longer supported (GET_VARIABLE / SET_VARIABLES), 
 429                                            * and reserved to avoid possible ABI clash.
 430                                            */
 431
 432#define RETRO_ENVIRONMENT_SET_MESSAGE   6  /* const struct retro_message * --
 433                                            * Sets a message to be displayed in implementation-specific manner 
 434                                            * for a certain amount of 'frames'.
 435                                            * Should not be used for trivial messages, which should simply be 
 436                                            * logged via RETRO_ENVIRONMENT_GET_LOG_INTERFACE (or as a 
 437                                            * fallback, stderr).
 438                                            */
 439#define RETRO_ENVIRONMENT_SHUTDOWN      7  /* N/A (NULL) --
 440                                            * Requests the frontend to shutdown.
 441                                            * Should only be used if game has a specific
 442                                            * way to shutdown the game from a menu item or similar.
 443                                            */
 444#define RETRO_ENVIRONMENT_SET_PERFORMANCE_LEVEL 8
 445                                           /* const unsigned * --
 446                                            * Gives a hint to the frontend how demanding this implementation
 447                                            * is on a system. E.g. reporting a level of 2 means
 448                                            * this implementation should run decently on all frontends
 449                                            * of level 2 and up.
 450                                            *
 451                                            * It can be used by the frontend to potentially warn
 452                                            * about too demanding implementations.
 453                                            *
 454                                            * The levels are "floating".
 455                                            *
 456                                            * This function can be called on a per-game basis,
 457                                            * as certain games an implementation can play might be
 458                                            * particularly demanding.
 459                                            * If called, it should be called in retro_load_game().
 460                                            */
 461#define RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY 9
 462                                           /* const char ** --
 463                                            * Returns the "system" directory of the frontend.
 464                                            * This directory can be used to store system specific 
 465                                            * content such as BIOSes, configuration data, etc.
 466                                            * The returned value can be NULL.
 467                                            * If so, no such directory is defined,
 468                                            * and it's up to the implementation to find a suitable directory.
 469                                            *
 470                                            * NOTE: Some cores used this folder also for "save" data such as 
 471                                            * memory cards, etc, for lack of a better place to put it.
 472                                            * This is now discouraged, and if possible, cores should try to 
 473                                            * use the new GET_SAVE_DIRECTORY.
 474                                            */
 475#define RETRO_ENVIRONMENT_SET_PIXEL_FORMAT 10
 476                                           /* const enum retro_pixel_format * --
 477                                            * Sets the internal pixel format used by the implementation.
 478                                            * The default pixel format is RETRO_PIXEL_FORMAT_0RGB1555.
 479                                            * This pixel format however, is deprecated (see enum retro_pixel_format).
 480                                            * If the call returns false, the frontend does not support this pixel 
 481                                            * format.
 482                                            *
 483                                            * This function should be called inside retro_load_game() or 
 484                                            * retro_get_system_av_info().
 485                                            */
 486#define RETRO_ENVIRONMENT_SET_INPUT_DESCRIPTORS 11
 487                                           /* const struct retro_input_descriptor * --
 488                                            * Sets an array of retro_input_descriptors.
 489                                            * It is up to the frontend to present this in a usable way.
 490                                            * The array is terminated by retro_input_descriptor::description 
 491                                            * being set to NULL.
 492                                            * This function can be called at any time, but it is recommended 
 493                                            * to call it as early as possible.
 494                                            */
 495#define RETRO_ENVIRONMENT_SET_KEYBOARD_CALLBACK 12
 496                                           /* const struct retro_keyboard_callback * --
 497                                            * Sets a callback function used to notify core about keyboard events.
 498                                            */
 499#define RETRO_ENVIRONMENT_SET_DISK_CONTROL_INTERFACE 13
 500                                           /* const struct retro_disk_control_callback * --
 501                                            * Sets an interface which frontend can use to eject and insert 
 502                                            * disk images.
 503                                            * This is used for games which consist of multiple images and 
 504                                            * must be manually swapped out by the user (e.g. PSX).
 505                                            */
 506#define RETRO_ENVIRONMENT_SET_HW_RENDER 14
 507                                           /* struct retro_hw_render_callback * --
 508                                            * Sets an interface to let a libretro core render with 
 509                                            * hardware acceleration.
 510                                            * Should be called in retro_load_game().
 511                                            * If successful, libretro cores will be able to render to a 
 512                                            * frontend-provided framebuffer.
 513                                            * The size of this framebuffer will be at least as large as 
 514                                            * max_width/max_height provided in get_av_info().
 515                                            * If HW rendering is used, pass only RETRO_HW_FRAME_BUFFER_VALID or 
 516                                            * NULL to retro_video_refresh_t.
 517                                            */
 518#define RETRO_ENVIRONMENT_GET_VARIABLE 15
 519                                           /* struct retro_variable * --
 520                                            * Interface to acquire user-defined information from environment
 521                                            * that cannot feasibly be supported in a multi-system way.
 522                                            * 'key' should be set to a key which has already been set by 
 523                                            * SET_VARIABLES.
 524                                            * 'data' will be set to a value or NULL.
 525                                            */
 526#define RETRO_ENVIRONMENT_SET_VARIABLES 16
 527                                           /* const struct retro_variable * --
 528                                            * Allows an implementation to signal the environment
 529                                            * which variables it might want to check for later using 
 530                                            * GET_VARIABLE.
 531                                            * This allows the frontend to present these variables to 
 532                                            * a user dynamically.
 533                                            * This should be called as early as possible (ideally in 
 534                                            * retro_set_environment).
 535                                            *
 536                                            * 'data' points to an array of retro_variable structs 
 537                                            * terminated by a { NULL, NULL } element.
 538                                            * retro_variable::key should be namespaced to not collide 
 539                                            * with other implementations' keys. E.g. A core called 
 540                                            * 'foo' should use keys named as 'foo_option'.
 541                                            * retro_variable::value should contain a human readable 
 542                                            * description of the key as well as a '|' delimited list 
 543                                            * of expected values.
 544                                            *
 545                                            * The number of possible options should be very limited, 
 546                                            * i.e. it should be feasible to cycle through options 
 547                                            * without a keyboard.
 548                                            *
 549                                            * First entry should be treated as a default.
 550                                            *
 551                                            * Example entry:
 552                                            * { "foo_option", "Speed hack coprocessor X; false|true" }
 553                                            *
 554                                            * Text before first ';' is description. This ';' must be 
 555                                            * followed by a space, and followed by a list of possible 
 556                                            * values split up with '|'.
 557                                            *
 558                                            * Only strings are operated on. The possible values will 
 559                                            * generally be displayed and stored as-is by the frontend.
 560                                            */
 561#define RETRO_ENVIRONMENT_GET_VARIABLE_UPDATE 17
 562                                           /* bool * --
 563                                            * Result is set to true if some variables are updated by
 564                                            * frontend since last call to RETRO_ENVIRONMENT_GET_VARIABLE.
 565                                            * Variables should be queried with GET_VARIABLE.
 566                                            */
 567#define RETRO_ENVIRONMENT_SET_SUPPORT_NO_GAME 18
 568                                           /* const bool * --
 569                                            * If true, the libretro implementation supports calls to 
 570                                            * retro_load_game() with NULL as argument.
 571                                            * Used by cores which can run without particular game data.
 572                                            * This should be called within retro_set_environment() only.
 573                                            */
 574#define RETRO_ENVIRONMENT_GET_LIBRETRO_PATH 19
 575                                           /* const char ** --
 576                                            * Retrieves the absolute path from where this libretro 
 577                                            * implementation was loaded.
 578                                            * NULL is returned if the libretro was loaded statically 
 579                                            * (i.e. linked statically to frontend), or if the path cannot be 
 580                                            * determined.
 581                                            * Mostly useful in cooperation with SET_SUPPORT_NO_GAME as assets can 
 582                                            * be loaded without ugly hacks.
 583                                            */
 584                                           
 585                                           /* Environment 20 was an obsolete version of SET_AUDIO_CALLBACK. 
 586                                            * It was not used by any known core at the time,
 587                                            * and was removed from the API. */
 588#define RETRO_ENVIRONMENT_SET_AUDIO_CALLBACK 22
 589                                           /* const struct retro_audio_callback * --
 590                                            * Sets an interface which is used to notify a libretro core about audio 
 591                                            * being available for writing.
 592                                            * The callback can be called from any thread, so a core using this must 
 593                                            * have a thread safe audio implementation.
 594                                            * It is intended for games where audio and video are completely 
 595                                            * asynchronous and audio can be generated on the fly.
 596                                            * This interface is not recommended for use with emulators which have 
 597                                            * highly synchronous audio.
 598                                            *
 599                                            * The callback only notifies about writability; the libretro core still 
 600                                            * has to call the normal audio callbacks
 601                                            * to write audio. The audio callbacks must be called from within the 
 602                                            * notification callback.
 603                                            * The amount of audio data to write is up to the implementation.
 604                                            * Generally, the audio callback will be called continously in a loop.
 605                                            *
 606                                            * Due to thread safety guarantees and lack of sync between audio and 
 607                                            * video, a frontend  can selectively disallow this interface based on 
 608                                            * internal configuration. A core using this interface must also 
 609                                            * implement the "normal" audio interface.
 610                                            *
 611                                            * A libretro core using SET_AUDIO_CALLBACK should also make use of 
 612                                            * SET_FRAME_TIME_CALLBACK.
 613                                            */
 614#define RETRO_ENVIRONMENT_SET_FRAME_TIME_CALLBACK 21
 615                                           /* const struct retro_frame_time_callback * --
 616                                            * Lets the core know how much time has passed since last 
 617                                            * invocation of retro_run().
 618                                            * The frontend can tamper with the timing to fake fast-forward, 
 619                                            * slow-motion, frame stepping, etc.
 620                                            * In this case the delta time will use the reference value 
 621                                            * in frame_time_callback..
 622                                            */
 623#define RETRO_ENVIRONMENT_GET_RUMBLE_INTERFACE 23
 624                                           /* struct retro_rumble_interface * --
 625                                            * Gets an interface which is used by a libretro core to set 
 626                                            * state of rumble motors in controllers.
 627                                            * A strong and weak motor is supported, and they can be 
 628                                            * controlled indepedently.
 629                                            */
 630#define RETRO_ENVIRONMENT_GET_INPUT_DEVICE_CAPABILITIES 24
 631                                           /* uint64_t * --
 632                                            * Gets a bitmask telling which device type are expected to be 
 633                                            * handled properly in a call to retro_input_state_t.
 634                                            * Devices which are not handled or recognized always return 
 635                                            * 0 in retro_input_state_t.
 636                                            * Example bitmask: caps = (1 << RETRO_DEVICE_JOYPAD) | (1 << RETRO_DEVICE_ANALOG).
 637                                            * Should only be called in retro_run().
 638                                            */
 639#define RETRO_ENVIRONMENT_GET_SENSOR_INTERFACE (25 | RETRO_ENVIRONMENT_EXPERIMENTAL)
 640                                           /* struct retro_sensor_interface * --
 641                                            * Gets access to the sensor interface.
 642                                            * The purpose of this interface is to allow
 643                                            * setting state related to sensors such as polling rate, 
 644                                            * enabling/disable it entirely, etc.
 645                                            * Reading sensor state is done via the normal 
 646                                            * input_state_callback API.
 647                                            */
 648#define RETRO_ENVIRONMENT_GET_CAMERA_INTERFACE (26 | RETRO_ENVIRONMENT_EXPERIMENTAL)
 649                                           /* struct retro_camera_callback * --
 650                                            * Gets an interface to a video camera driver.
 651                                            * A libretro core can use this interface to get access to a 
 652                                            * video camera.
 653                                            * New video frames are delivered in a callback in same 
 654                                            * thread as retro_run().
 655                                            *
 656                                            * GET_CAMERA_INTERFACE should be called in retro_load_game().
 657                                            *
 658                                            * Depending on the camera implementation used, camera frames 
 659                                            * will be delivered as a raw framebuffer,
 660                                            * or as an OpenGL texture directly.
 661                                            *
 662                                            * The core has to tell the frontend here which types of 
 663                                            * buffers can be handled properly.
 664                                            * An OpenGL texture can only be handled when using a 
 665                                            * libretro GL core (SET_HW_RENDER).
 666                                            * It is recommended to use a libretro GL core when 
 667                                            * using camera interface.
 668                                            *
 669                                            * The camera is not started automatically. The retrieved start/stop 
 670                                            * functions must be used to explicitly
 671                                            * start and stop the camera driver.
 672                                            */
 673#define RETRO_ENVIRONMENT_GET_LOG_INTERFACE 27
 674                                           /* struct retro_log_callback * --
 675                                            * Gets an interface for logging. This is useful for 
 676                                            * logging in a cross-platform way
 677                                            * as certain platforms cannot use use stderr for logging. 
 678                                            * It also allows the frontend to
 679                                            * show logging information in a more suitable way.
 680                                            * If this interface is not used, libretro cores should 
 681                                            * log to stderr as desired.
 682                                            */
 683#define RETRO_ENVIRONMENT_GET_PERF_INTERFACE 28
 684                                           /* struct retro_perf_callback * --
 685                                            * Gets an interface for performance counters. This is useful 
 686                                            * for performance logging in a cross-platform way and for detecting 
 687                                            * architecture-specific features, such as SIMD support.
 688                                            */
 689#define RETRO_ENVIRONMENT_GET_LOCATION_INTERFACE 29
 690                                           /* struct retro_location_callback * --
 691                                            * Gets access to the location interface.
 692                                            * The purpose of this interface is to be able to retrieve 
 693                                            * location-based information from the host device,
 694                                            * such as current latitude / longitude.
 695                                            */
 696#define RETRO_ENVIRONMENT_GET_CONTENT_DIRECTORY 30
 697                                           /* const char ** --
 698                                            * Returns the "content" directory of the frontend.
 699                                            * This directory can be used to store specific assets that the 
 700                                            * core relies upon, such as art assets,
 701                                            * input data, etc etc.
 702                                            * The returned value can be NULL.
 703                                            * If so, no such directory is defined,
 704                                            * and it's up to the implementation to find a suitable directory.
 705                                            */
 706#define RETRO_ENVIRONMENT_GET_SAVE_DIRECTORY 31
 707                                           /* const char ** --
 708                                            * Returns the "save" directory of the frontend.
 709                                            * This directory can be used to store SRAM, memory cards, 
 710                                            * high scores, etc, if the libretro core
 711                                            * cannot use the regular memory interface (retro_get_memory_data()).
 712                                            *
 713                                            * NOTE: libretro cores used to check GET_SYSTEM_DIRECTORY for 
 714                                            * similar things before.
 715                                            * They should still check GET_SYSTEM_DIRECTORY if they want to 
 716                                            * be backwards compatible.
 717                                            * The path here can be NULL. It should only be non-NULL if the 
 718                                            * frontend user has set a specific save path.
 719                                            */
 720#define RETRO_ENVIRONMENT_SET_SYSTEM_AV_INFO 32
 721                                           /* const struct retro_system_av_info * --
 722                                            * Sets a new av_info structure. This can only be called from 
 723                                            * within retro_run().
 724                                            * This should *only* be used if the core is completely altering the 
 725                                            * internal resolutions, aspect ratios, timings, sampling rate, etc.
 726                                            * Calling this can require a full reinitialization of video/audio 
 727                                            * drivers in the frontend,
 728                                            *
 729                                            * so it is important to call it very sparingly, and usually only with 
 730                                            * the users explicit consent.
 731                                            * An eventual driver reinitialize will happen so that video and 
 732                                            * audio callbacks
 733                                            * happening after this call within the same retro_run() call will 
 734                                            * target the newly initialized driver.
 735                                            *
 736                                            * This callback makes it possible to support configurable resolutions 
 737                                            * in games, which can be useful to
 738                                            * avoid setting the "worst case" in max_width/max_height.
 739                                            *
 740                                            * ***HIGHLY RECOMMENDED*** Do not call this callback every time 
 741                                            * resolution changes in an emulator core if it's
 742                                            * expected to be a temporary change, for the reasons of possible 
 743                                            * driver reinitialization.
 744                                            * This call is not a free pass for not trying to provide 
 745                                            * correct values in retro_get_system_av_info(). If you need to change 
 746                                            * things like aspect ratio or nominal width/height, 
 747                                            * use RETRO_ENVIRONMENT_SET_GEOMETRY, which is a softer variant 
 748                                            * of SET_SYSTEM_AV_INFO.
 749                                            *
 750                                            * If this returns false, the frontend does not acknowledge a 
 751                                            * changed av_info struct.
 752                                            */
 753#define RETRO_ENVIRONMENT_SET_PROC_ADDRESS_CALLBACK 33
 754                                           /* const struct retro_get_proc_address_interface * --
 755                                            * Allows a libretro core to announce support for the 
 756                                            * get_proc_address() interface.
 757                                            * This interface allows for a standard way to extend libretro where 
 758                                            * use of environment calls are too indirect,
 759                                            * e.g. for cases where the frontend wants to call directly into the core.
 760                                            *
 761                                            * If a core wants to expose this interface, SET_PROC_ADDRESS_CALLBACK 
 762                                            * **MUST** be called from within retro_set_environment().
 763                                            */
 764#define RETRO_ENVIRONMENT_SET_SUBSYSTEM_INFO 34
 765                                           /* const struct retro_subsystem_info * --
 766                                            * This environment call introduces the concept of libretro "subsystems".
 767                                            * A subsystem is a variant of a libretro core which supports 
 768                                            * different kinds of games.
 769                                            * The purpose of this is to support e.g. emulators which might 
 770                                            * have special needs, e.g. Super Nintendo's Super GameBoy, Sufami Turbo.
 771                                            * It can also be used to pick among subsystems in an explicit way 
 772                                            * if the libretro implementation is a multi-system emulator itself.
 773                                            *
 774                                            * Loading a game via a subsystem is done with retro_load_game_special(),
 775                                            * and this environment call allows a libretro core to expose which 
 776                                            * subsystems are supported for use with retro_load_game_special().
 777                                            * A core passes an array of retro_game_special_info which is terminated 
 778                                            * with a zeroed out retro_game_special_info struct.
 779                                            *
 780                                            * If a core wants to use this functionality, SET_SUBSYSTEM_INFO
 781                                            * **MUST** be called from within retro_set_environment().
 782                                            */
 783#define RETRO_ENVIRONMENT_SET_CONTROLLER_INFO 35
 784                                           /* const struct retro_controller_info * --
 785                                            * This environment call lets a libretro core tell the frontend 
 786                                            * which controller types are recognized in calls to 
 787                                            * retro_set_controller_port_device().
 788                                            *
 789                                            * Some emulators such as Super Nintendo
 790                                            * support multiple lightgun types which must be specifically 
 791                                            * selected from.
 792                                            * It is therefore sometimes necessary for a frontend to be able 
 793                                            * to tell the core about a special kind of input device which is 
 794                                            * not covered by the libretro input API.
 795                                            *
 796                                            * In order for a frontend to understand the workings of an input device,
 797                                            * it must be a specialized type
 798                                            * of the generic device types already defined in the libretro API.
 799                                            *
 800                                            * Which devices are supported can vary per input port.
 801                                            * The core must pass an array of const struct retro_controller_info which 
 802                                            * is terminated with a blanked out struct. Each element of the struct 
 803                                            * corresponds to an ascending port index to 
 804                                            * retro_set_controller_port_device().
 805                                            * Even if special device types are set in the libretro core, 
 806                                            * libretro should only poll input based on the base input device types.
 807                                            */
 808#define RETRO_ENVIRONMENT_SET_MEMORY_MAPS (36 | RETRO_ENVIRONMENT_EXPERIMENTAL)
 809                                           /* const struct retro_memory_map * --
 810                                            * This environment call lets a libretro core tell the frontend 
 811                                            * about the memory maps this core emulates.
 812                                            * This can be used to implement, for example, cheats in a core-agnostic way.
 813                                            *
 814                                            * Should only be used by emulators; it doesn't make much sense for 
 815                                            * anything else.
 816                                            * It is recommended to expose all relevant pointers through 
 817                                            * retro_get_memory_* as well.
 818                                            *
 819                                            * Can be called from retro_init and retro_load_game.
 820                                            */
 821#define RETRO_ENVIRONMENT_SET_GEOMETRY 37
 822                                           /* const struct retro_game_geometry * --
 823                                            * This environment call is similar to SET_SYSTEM_AV_INFO for changing 
 824                                            * video parameters, but provides a guarantee that drivers will not be 
 825                                            * reinitialized.
 826                                            * This can only be called from within retro_run().
 827                                            *
 828                                            * The purpose of this call is to allow a core to alter nominal 
 829                                            * width/heights as well as aspect ratios on-the-fly, which can be 
 830                                            * useful for some emulators to change in run-time.
 831                                            *
 832                                            * max_width/max_height arguments are ignored and cannot be changed
 833                                            * with this call as this could potentially require a reinitialization or a 
 834                                            * non-constant time operation.
 835                                            * If max_width/max_height are to be changed, SET_SYSTEM_AV_INFO is required.
 836                                            *
 837                                            * A frontend must guarantee that this environment call completes in 
 838                                            * constant time.
 839                                            */
 840#define RETRO_ENVIRONMENT_GET_USERNAME 38 
 841                                           /* const char **
 842                                            * Returns the specified username of the frontend, if specified by the user.
 843                                            * This username can be used as a nickname for a core that has online facilities 
 844                                            * or any other mode where personalization of the user is desirable.
 845                                            * The returned value can be NULL.
 846                                            * If this environ callback is used by a core that requires a valid username, 
 847                                            * a default username should be specified by the core.
 848                                            */
 849#define RETRO_ENVIRONMENT_GET_LANGUAGE 39
 850                                           /* unsigned * --
 851                                            * Returns the specified language of the frontend, if specified by the user.
 852                                            * It can be used by the core for localization purposes.
 853                                            */
 854
 855#define RETRO_MEMDESC_CONST     (1 << 0)   /* The frontend will never change this memory area once retro_load_game has returned. */
 856#define RETRO_MEMDESC_BIGENDIAN (1 << 1)   /* The memory area contains big endian data. Default is little endian. */
 857#define RETRO_MEMDESC_ALIGN_2   (1 << 16)  /* All memory access in this area is aligned to their own size, or 2, whichever is smaller. */
 858#define RETRO_MEMDESC_ALIGN_4   (2 << 16)
 859#define RETRO_MEMDESC_ALIGN_8   (3 << 16)
 860#define RETRO_MEMDESC_MINSIZE_2 (1 << 24)  /* All memory in this region is accessed at least 2 bytes at the time. */
 861#define RETRO_MEMDESC_MINSIZE_4 (2 << 24)
 862#define RETRO_MEMDESC_MINSIZE_8 (3 << 24)
 863struct retro_memory_descriptor
 864{
 865   uint64_t flags;
 866
 867   /* Pointer to the start of the relevant ROM or RAM chip.
 868    * It's strongly recommended to use 'offset' if possible, rather than 
 869    * doing math on the pointer.
 870    *
 871    * If the same byte is mapped my multiple descriptors, their descriptors 
 872    * must have the same pointer.
 873    * If 'start' does not point to the first byte in the pointer, put the 
 874    * difference in 'offset' instead.
 875    *
 876    * May be NULL if there's nothing usable here (e.g. hardware registers and 
 877    * open bus). No flags should be set if the pointer is NULL.
 878    * It's recommended to minimize the number of descriptors if possible,
 879    * but not mandatory. */
 880   void *ptr;
 881   size_t offset;
 882
 883   /* This is the location in the emulated address space 
 884    * where the mapping starts. */
 885   size_t start;
 886
 887   /* Which bits must be same as in 'start' for this mapping to apply.
 888    * The first memory descriptor to claim a certain byte is the one 
 889    * that applies.
 890    * A bit which is set in 'start' must also be set in this.
 891    * Can be zero, in which case each byte is assumed mapped exactly once. 
 892    * In this case, 'len' must be a power of two. */
 893   size_t select;
 894
 895   /* If this is nonzero, the set bits are assumed not connected to the 
 896    * memory chip's address pins. */
 897   size_t disconnect;
 898
 899   /* This one tells the size of the current memory area.
 900    * If, after start+disconnect are applied, the address is higher than 
 901    * this, the highest bit of the address is cleared.
 902    *
 903    * If the address is still too high, the next highest bit is cleared.
 904    * Can be zero, in which case it's assumed to be infinite (as limited 
 905    * by 'select' and 'disconnect'). */
 906   size_t len;
 907
 908   /* To go from emulated address to physical address, the following 
 909    * order applies:
 910    * Subtract 'start', pick off 'disconnect', apply 'len', add 'offset'.
 911    *
 912    * The address space name must consist of only a-zA-Z0-9_-, 
 913    * should be as short as feasible (maximum length is 8 plus the NUL),
 914    * and may not be any other address space plus one or more 0-9A-F 
 915    * at the end.
 916    * However, multiple memory descriptors for the same address space is 
 917    * allowed, and the address space name can be empty. NULL is treated 
 918    * as empty.
 919    *
 920    * Address space names are case sensitive, but avoid lowercase if possible.
 921    * The same pointer may exist in multiple address spaces.
 922    *
 923    * Examples:
 924    * blank+blank - valid (multiple things may be mapped in the same namespace)
 925    * 'Sp'+'Sp' - valid (multiple things may be mapped in the same namespace)
 926    * 'A'+'B' - valid (neither is a prefix of each other)
 927    * 'S'+blank - valid ('S' is not in 0-9A-F)
 928    * 'a'+blank - valid ('a' is not in 0-9A-F)
 929    * 'a'+'A' - valid (neither is a prefix of each other)
 930    * 'AR'+blank - valid ('R' is not in 0-9A-F)
 931    * 'ARB'+blank - valid (the B can't be part of the address either, because 
 932    * there is no namespace 'AR')
 933    * blank+'B' - not valid, because it's ambigous which address space B1234 
 934    * would refer to.
 935    * The length can't be used for that purpose; the frontend may want 
 936    * to append arbitrary data to an address, without a separator. */
 937   const char *addrspace;
 938};
 939
 940/* The frontend may use the largest value of 'start'+'select' in a 
 941 * certain namespace to infer the size of the address space.
 942 *
 943 * If the address space is larger than that, a mapping with .ptr=NULL 
 944 * should be at the end of the array, with .select set to all ones for 
 945 * as long as the address space is big.
 946 *
 947 * Sample descriptors (minus .ptr, and RETRO_MEMFLAG_ on the flags):
 948 * SNES WRAM:
 949 * .start=0x7E0000, .len=0x20000
 950 * (Note that this must be mapped before the ROM in most cases; some of the 
 951 * ROM mappers 
 952 * try to claim $7E0000, or at least $7E8000.)
 953 * SNES SPC700 RAM:
 954 * .addrspace="S", .len=0x10000
 955 * SNES WRAM mirrors:
 956 * .flags=MIRROR, .start=0x000000, .select=0xC0E000, .len=0x2000
 957 * .flags=MIRROR, .start=0x800000, .select=0xC0E000, .len=0x2000
 958 * SNES WRAM mirrors, alternate equivalent descriptor:
 959 * .flags=MIRROR, .select=0x40E000, .disconnect=~0x1FFF
 960 * (Various similar constructions can be created by combining parts of 
 961 * the above two.)
 962 * SNES LoROM (512KB, mirrored a couple of times):
 963 * .flags=CONST, .start=0x008000, .select=0x408000, .disconnect=0x8000, .len=512*1024
 964 * .flags=CONST, .start=0x400000, .select=0x400000, .disconnect=0x8000, .len=512*1024
 965 * SNES HiROM (4MB):
 966 * .flags=CONST,                 .start=0x400000, .select=0x400000, .len=4*1024*1024
 967 * .flags=CONST, .offset=0x8000, .start=0x008000, .select=0x408000, .len=4*1024*1024
 968 * SNES ExHiROM (8MB):
 969 * .flags=CONST, .offset=0,                  .start=0xC00000, .select=0xC00000, .len=4*1024*1024
 970 * .flags=CONST, .offset=4*1024*1024,        .start=0x400000, .select=0xC00000, .len=4*1024*1024
 971 * .flags=CONST, .offset=0x8000,             .start=0x808000, .select=0xC08000, .len=4*1024*1024
 972 * .flags=CONST, .offset=4*1024*1024+0x8000, .start=0x008000, .select=0xC08000, .len=4*1024*1024
 973 * Clarify the size of the address space:
 974 * .ptr=NULL, .select=0xFFFFFF
 975 * .len can be implied by .select in many of them, but was included for clarity.
 976 */
 977
 978struct retro_memory_map
 979{
 980   const struct retro_memory_descriptor *descriptors;
 981   unsigned num_descriptors;
 982};
 983
 984struct retro_controller_description
 985{
 986   /* Human-readable description of the controller. Even if using a generic 
 987    * input device type, this can be set to the particular device type the 
 988    * core uses. */
 989   const char *desc;
 990
 991   /* Device type passed to retro_set_controller_port_device(). If the device 
 992    * type is a sub-class of a generic input device type, use the 
 993    * RETRO_DEVICE_SUBCLASS macro to create an ID.
 994    *
 995    * E.g. RETRO_DEVICE_SUBCLASS(RETRO_DEVICE_JOYPAD, 1). */
 996   unsigned id;
 997};
 998
 999struct retro_controller_info
1000{
1001   const struct retro_controller_description *types;
1002   unsigned num_types;
1003};
1004
1005struct retro_subsystem_memory_info
1006{
1007   /* The extension associated with a memory type, e.g. "psram". */
1008   const char *extension;
1009
1010   /* The memory type for retro_get_memory(). This should be at 
1011    * least 0x100 to avoid conflict with standardized 
1012    * libretro memory types. */
1013   unsigned type;
1014};
1015
1016struct retro_subsystem_rom_info
1017{
1018   /* Describes what the content is (SGB BIOS, GB ROM, etc). */
1019   const char *desc;
1020
1021   /* Same definition as retro_get_system_info(). */
1022   const char *valid_extensions;
1023
1024   /* Same definition as retro_get_system_info(). */
1025   bool need_fullpath;
1026
1027   /* Same definition as retro_get_system_info(). */
1028   bool block_extract;
1029
1030   /* This is set if the content is required to load a game. 
1031    * If this is set to false, a zeroed-out retro_game_info can be passed. */
1032   bool required;
1033
1034   /* Content can have multiple associated persistent 
1035    * memory types (retro_get_memory()). */
1036   const struct retro_subsystem_memory_info *memory;
1037   unsigned num_memory;
1038};
1039
1040struct retro_subsystem_info
1041{
1042   /* Human-readable string of the subsystem type, e.g. "Super GameBoy" */
1043   const char *desc;
1044
1045   /* A computer friendly short string identifier for the subsystem type.
1046    * This name must be [a-z].
1047    * E.g. if desc is "Super GameBoy", this can be "sgb".
1048    * This identifier can be used for command-line interfaces, etc.
1049    */
1050   const char *ident;
1051
1052   /* Infos for each content file. The first entry is assumed to be the 
1053    * "most significant" content for frontend purposes.
1054    * E.g. with Super GameBoy, the first content should be the GameBoy ROM, 
1055    * as it is the most "significant" content to a user.
1056    * If a frontend creates new file paths based on the content used 
1057    * (e.g. savestates), it should use the path for the first ROM to do so. */
1058   const struct retro_subsystem_rom_info *roms;
1059
1060   /* Number of content files associated with a subsystem. */
1061   unsigned num_roms;
1062   
1063   /* The type passed to retro_load_game_special(). */
1064   unsigned id;
1065};
1066
1067typedef void (*retro_proc_address_t)(void);
1068
1069/* libretro API extension functions:
1070 * (None here so far).
1071 *
1072 * Get a symbol from a libretro core.
1073 * Cores should only return symbols which are actual 
1074 * extensions to the libretro API.
1075 *
1076 * Frontends should not use this to obtain symbols to standard 
1077 * libretro entry points (static linking or dlsym).
1078 *
1079 * The symbol name must be equal to the function name, 
1080 * e.g. if void retro_foo(void); exists, the symbol must be called "retro_foo".
1081 * The returned function pointer must be cast to the corresponding type.
1082 */
1083typedef retro_proc_address_t (*retro_get_proc_address_t)(const char *sym);
1084
1085struct retro_get_proc_address_interface
1086{
1087   retro_get_proc_address_t get_proc_address;
1088};
1089
1090enum retro_log_level
1091{
1092   RETRO_LOG_DEBUG = 0,
1093   RETRO_LOG_INFO,
1094   RETRO_LOG_WARN,
1095   RETRO_LOG_ERROR,
1096
1097   RETRO_LOG_DUMMY = INT_MAX
1098};
1099
1100/* Logging function. Takes log level argument as well. */
1101typedef void (*retro_log_printf_t)(enum retro_log_level level,
1102      const char *fmt, ...);
1103
1104struct retro_log_callback
1105{
1106   retro_log_printf_t log;
1107};
1108
1109/* Performance related functions */
1110
1111/* ID values for SIMD CPU features */
1112#define RETRO_SIMD_SSE      (1 << 0)
1113#define RETRO_SIMD_SSE2     (1 << 1)
1114#define RETRO_SIMD_VMX      (1 << 2)
1115#define RETRO_SIMD_VMX128   (1 << 3)
1116#define RETRO_SIMD_AVX      (1 << 4)
1117#define RETRO_SIMD_NEON     (1 << 5)
1118#define RETRO_SIMD_SSE3     (1 << 6)
1119#define RETRO_SIMD_SSSE3    (1 << 7)
1120#define RETRO_SIMD_MMX      (1 << 8)
1121#define RETRO_SIMD_MMXEXT   (1 << 9)
1122#define RETRO_SIMD_SSE4     (1 << 10)
1123#define RETRO_SIMD_SSE42    (1 << 11)
1124#define RETRO_SIMD_AVX2     (1 << 12)
1125#define RETRO_SIMD_VFPU     (1 << 13)
1126#define RETRO_SIMD_PS       (1 << 14)
1127#define RETRO_SIMD_AES      (1 << 15)
1128
1129typedef uint64_t retro_perf_tick_t;
1130typedef int64_t retro_time_t;
1131
1132struct retro_perf_counter
1133{
1134   const char *ident;
1135   retro_perf_tick_t start;
1136   retro_perf_tick_t total;
1137   retro_perf_tick_t call_cnt;
1138
1139   bool registered;
1140};
1141
1142/* Returns current time in microseconds.
1143 * Tries to use the most accurate timer available.
1144 */
1145typedef retro_time_t (*retro_perf_get_time_usec_t)(void);
1146
1147/* A simple counter. Usually nanoseconds, but can also be CPU cycles.
1148 * Can be used directly if desired (when creating a more sophisticated 
1149 * performance counter system).
1150 * */
1151typedef retro_perf_tick_t (*retro_perf_get_counter_t)(void);
1152
1153/* Returns a bit-mask of detected CPU features (RETRO_SIMD_*). */
1154typedef uint64_t (*retro_get_cpu_features_t)(void);
1155
1156/* Asks frontend to log and/or display the state of performance counters.
1157 * Performance counters can always be poked into manually as well.
1158 */
1159typedef void (*retro_perf_log_t)(void);
1160
1161/* Register a performance counter.
1162 * ident field must be set with a discrete value and other values in 
1163 * retro_perf_counter must be 0.
1164 * Registering can be called multiple times. To avoid calling to 
1165 * frontend redundantly, you can check registered field first. */
1166typedef void (*retro_perf_register_t)(struct retro_perf_counter *counter);
1167
1168/* Starts a registered counter. */
1169typedef void (*retro_perf_start_t)(struct retro_perf_counter *counter);
1170
1171/* Stops a registered counter. */
1172typedef void (*retro_perf_stop_t)(struct retro_perf_counter *counter);
1173
1174/* For convenience it can be useful to wrap register, start and stop in macros.
1175 * E.g.:
1176 * #ifdef LOG_PERFORMANCE
1177 * #define RETRO_PERFORMANCE_INIT(perf_cb, name) static struct retro_perf_counter name = {#name}; if (!name.registered) perf_cb.perf_register(&(name))
1178 * #define RETRO_PERFORMANCE_START(perf_cb, name) perf_cb.perf_start(&(name))
1179 * #define RETRO_PERFORMANCE_STOP(perf_cb, name) perf_cb.perf_stop(&(name))
1180 * #else
1181 * ... Blank macros ...
1182 * #endif
1183 *
1184 * These can then be used mid-functions around code snippets.
1185 *
1186 * extern struct retro_perf_callback perf_cb;  * Somewhere in the core.
1187 *
1188 * void do_some_heavy_work(void)
1189 * {
1190 *    RETRO_PERFORMANCE_INIT(cb, work_1;
1191 *    RETRO_PERFORMANCE_START(cb, work_1);
1192 *    heavy_work_1();
1193 *    RETRO_PERFORMANCE_STOP(cb, work_1);
1194 *
1195 *    RETRO_PERFORMANCE_INIT(cb, work_2);
1196 *    RETRO_PERFORMANCE_START(cb, work_2);
1197 *    heavy_work_2();
1198 *    RETRO_PERFORMANCE_STOP(cb, work_2);
1199 * }
1200 *
1201 * void retro_deinit(void)
1202 * {
1203 *    perf_cb.perf_log();  * Log all perf counters here for example.
1204 * }
1205 */
1206
1207struct retro_perf_callback
1208{
1209   retro_perf_get_time_usec_t    get_time_usec;
1210   retro_get_cpu_features_t      get_cpu_features;
1211
1212   retro_perf_get_counter_t      get_perf_counter;
1213   retro_perf_register_t         perf_register;
1214   retro_perf_start_t            perf_start;
1215   retro_perf_stop_t             perf_stop;
1216   retro_perf_log_t              perf_log;
1217};
1218
1219/* FIXME: Document the sensor API and work out behavior.
1220 * It will be marked as experimental until then.
1221 */
1222enum retro_sensor_action
1223{
1224   RETRO_SENSOR_ACCELEROMETER_ENABLE = 0,
1225   RETRO_SENSOR_ACCELEROMETER_DISABLE,
1226
1227   RETRO_SENSOR_DUMMY = INT_MAX
1228};
1229
1230/* Id values for SENSOR types. */
1231#define RETRO_SENSOR_ACCELEROMETER_X 0
1232#define RETRO_SENSOR_ACCELEROMETER_Y 1
1233#define RETRO_SENSOR_ACCELEROMETER_Z 2
1234
1235typedef bool (*retro_set_sensor_state_t)(unsigned port, 
1236      enum retro_sensor_action action, unsigned rate);
1237
1238typedef float (*retro_sensor_get_input_t)(unsigned port, unsigned id);
1239
1240struct retro_sensor_interface
1241{
1242   retro_set_sensor_state_t set_sensor_state;
1243   retro_sensor_get_input_t get_sensor_input;
1244};
1245
1246enum retro_camera_buffer
1247{
1248   RETRO_CAMERA_BUFFER_OPENGL_TEXTURE = 0,
1249   RETRO_CAMERA_BUFFER_RAW_FRAMEBUFFER,
1250
1251   RETRO_CAMERA_BUFFER_DUMMY = INT_MAX
1252};
1253
1254/* Starts the camera driver. Can only be called in retro_run(). */
1255typedef bool (*retro_camera_start_t)(void);
1256
1257/* Stops the camera driver. Can only be called in retro_run(). */
1258typedef void (*retro_camera_stop_t)(void);
1259
1260/* Callback which signals when the camera driver is initialized 
1261 * and/or deinitialized.
1262 * retro_camera_start_t can be called in initialized callback.
1263 */
1264typedef void (*retro_camera_lifetime_status_t)(void);
1265
1266/* A callback for raw framebuffer data. buffer points to an XRGB8888 buffer.
1267 * Width, height and pitch are similar to retro_video_refresh_t.
1268 * First pixel is top-left origin.
1269 */
1270typedef void (*retro_camera_frame_raw_framebuffer_t)(const uint32_t *buffer, 
1271      unsigned width, unsigned height, size_t pitch);
1272
1273/* A callback for when OpenGL textures are used.
1274 *
1275 * texture_id is a texture owned by camera driver.
1276 * Its state or content should be considered immutable, except for things like 
1277 * texture filtering and clamping.
1278 *
1279 * texture_target is the texture target for the GL texture.
1280 * These can include e.g. GL_TEXTURE_2D, GL_TEXTURE_RECTANGLE, and possibly 
1281 * more depending on extensions.
1282 *
1283 * affine points to a packed 3x3 column-major matrix used to apply an affine 
1284 * transform to texture coordinates. (affine_matrix * vec3(coord_x, coord_y, 1.0))
1285 * After transform, normalized texture coord (0, 0) should be bottom-left 
1286 * and (1, 1) should be top-right (or (width, height) for RECTANGLE).
1287 *
1288 * GL-specific typedefs are avoided here to avoid relying on gl.h in 
1289 * the API definition.
1290 */
1291typedef void (*retro_camera_frame_opengl_texture_t)(unsigned texture_id, 
1292      unsigned texture_target, const float *affine);
1293
1294struct retro_camera_callback
1295{
1296   /* Set by libretro core. 
1297    * Example bitmask: caps = (1 << RETRO_CAMERA_BUFFER_OPENGL_TEXTURE) | (1 << RETRO_CAMERA_BUFFER_RAW_FRAMEBUFFER).
1298    */
1299   uint64_t caps; 
1300
1301   unsigned width; /* Desired resolution for camera. Is only used as a hint. */
1302   unsigned height;
1303   retro_camera_start_t start; /* Set by frontend. */
1304   retro_camera_stop_t stop; /* Set by frontend. */
1305
1306   /* Set by libretro core if raw framebuffer callbacks will be used. */
1307   retro_camera_frame_raw_framebuffer_t frame_raw_framebuffer;
1308   /* Set by libretro core if OpenGL texture callbacks will be used. */
1309   retro_camera_frame_opengl_texture_t frame_opengl_texture; 
1310
1311   /* Set by libretro core. Called after camera driver is initialized and 
1312    * ready to be started.
1313    * Can be NULL, in which this callback is not called.
1314    */
1315   retro_camera_lifetime_status_t initialized;
1316
1317   /* Set by libretro core. Called right before camera driver is 
1318    * deinitialized.
1319    * Can be NULL, in which this callback is not called.
1320    */
1321   retro_camera_lifetime_status_t deinitialized;
1322};
1323
1324/* Sets the interval of time and/or distance at which to update/poll 
1325 * location-based data.
1326 *
1327 * To ensure compatibility with all location-based implementations,
1328 * values for both interval_ms and interval_distance should be provided.
1329 *
1330 * interval_ms is the interval expressed in milliseconds.
1331 * interval_distance is the distance interval expressed in meters.
1332 */
1333typedef void (*retro_location_set_interval_t)(unsigned interval_ms,
1334      unsigned interval_distance);
1335
1336/* Start location services. The device will start listening for changes to the
1337 * current location at regular intervals (which are defined with 
1338 * retro_location_set_interval_t). */
1339typedef bool (*retro_location_start_t)(void);
1340
1341/* Stop location services. The device will stop listening for changes 
1342 * to the current location. */
1343typedef void (*retro_location_stop_t)(void);
1344
1345/* Get the position of the current location. Will set parameters to 
1346 * 0 if no new  location update has happened since the last time. */
1347typedef bool (*retro_location_get_position_t)(double *lat, double *lon,
1348      double *horiz_accuracy, double *vert_accuracy);
1349
1350/* Callback which signals when the location driver is initialized 
1351 * and/or deinitialized.
1352 * retro_location_start_t can be called in initialized callback.
1353 */
1354typedef void (*retro_location_lifetime_status_t)(void);
1355
1356struct retro_location_callback
1357{
1358   retro_location_start_t         start;
1359   retro_location_stop_t          stop;
1360   retro_location_get_position_t  get_position;
1361   retro_location_set_interval_t  set_interval;
1362
1363   retro_location_lifetime_status_t initialized;
1364   retro_location_lifetime_status_t deinitialized;
1365};
1366
1367enum retro_rumble_effect
1368{
1369   RETRO_RUMBLE_STRONG = 0,
1370   RETRO_RUMBLE_WEAK = 1,
1371
1372   RETRO_RUMBLE_DUMMY = INT_MAX
1373};
1374
1375/* Sets rumble state for joypad plugged in port 'port'. 
1376 * Rumble effects are controlled independently,
1377 * and setting e.g. strong rumble does not override weak rumble.
1378 * Strength has a range of [0, 0xffff].
1379 *
1380 * Returns true if rumble state request was honored. 
1381 * Calling this before first retro_run() is likely to return false. */
1382typedef bool (*retro_set_rumble_state_t)(unsigned port, 
1383      enum retro_rumble_effect effect, uint16_t strength);
1384
1385struct retro_rumble_interface
1386{
1387   retro_set_rumble_state_t set_rumble_state;
1388};
1389
1390/* Notifies libretro that audio data should be written. */
1391typedef void (*retro_audio_callback_t)(void);
1392
1393/* True: Audio driver in frontend is active, and callback is 
1394 * expected to be called regularily.
1395 * False: Audio driver in frontend is paused or inactive. 
1396 * Audio callback will not be called until set_state has been 
1397 * called with true.
1398 * Initial state is false (inactive).
1399 */
1400typedef void (*retro_audio_set_state_callback_t)(bool enabled);
1401
1402struct retro_audio_callback
1403{
1404   retro_audio_callback_t callback;
1405   retro_audio_set_state_callback_t set_state;
1406};
1407
1408/* Notifies a libretro core of time spent since last invocation 
1409 * of retro_run() in microseconds.
1410 *
1411 * It will be called right before retro_run() every frame.
1412 * The frontend can tamper with timing to support cases like 
1413 * fast-forward, slow-motion and framestepping.
1414 *
1415 * In those scenarios the reference frame time value will be used. */
1416typedef int64_t retro_usec_t;
1417typedef void (*retro_frame_time_callback_t)(retro_usec_t usec);
1418struct retro_frame_time_callback
1419{
1420   retro_frame_time_callback_t callback;
1421   /* Represents the time of one frame. It is computed as 
1422    * 1000000 / fps, but the implementation will resolve the 
1423    * rounding to ensure that framestepping, etc is exact. */
1424   retro_usec_t reference;
1425};
1426
1427/* Pass this to retro_video_refresh_t if rendering to hardware.
1428 * Passing NULL to retro_video_refresh_t is still a frame dupe as normal.
1429 * */
1430#define RETRO_HW_FRAME_BUFFER_VALID ((void*)-1)
1431
1432/* Invalidates the current HW context.
1433 * Any GL state is lost, and must not be deinitialized explicitly.
1434 * If explicit deinitialization is desired by the libretro core,
1435 * it should implement context_destroy callback.
1436 * If called, all GPU resources must be reinitialized.
1437 * Usually called when frontend reinits video driver.
1438 * Also called first time video driver is initialized, 
1439 * allowing libretro core to initialize resources.
1440 */
1441typedef void (*retro_hw_context_reset_t)(void);
1442
1443/* Gets current framebuffer which is to be rendered to.
1444 * Could change every frame potentially.
1445 */
1446typedef uintptr_t (*retro_hw_get_current_framebuffer_t)(void);
1447
1448/* Get a symbol from HW context. */
1449typedef retro_proc_address_t (*retro_hw_get_proc_address_t)(const char *sym);
1450
1451enum retro_hw_context_type
1452{
1453   RETRO_HW_CONTEXT_NONE             = 0,
1454   /* OpenGL 2.x. Driver can choose to use latest compatibility context. */
1455   RETRO_HW_CONTEXT_OPENGL           = 1, 
1456   /* OpenGL ES 2.0. */
1457   RETRO_HW_CONTEXT_OPENGLES2        = 2,
1458   /* Modern desktop core GL context. Use version_major/
1459    * version_minor fields to set GL version. */
1460   RETRO_HW_CONTEXT_OPENGL_CORE      = 3,
1461   /* OpenGL ES 3.0 */
1462   RETRO_HW_CONTEXT_OPENGLES3        = 4,
1463   /* OpenGL ES 3.1+. Set version_major/version_minor. For GLES2 and GLES3,
1464    * use the corresponding enums directly. */
1465   RETRO_HW_CONTEXT_OPENGLES_VERSION = 5,
1466
1467   RETRO_HW_CONTEXT_DUMMY = INT_MAX
1468};
1469
1470struct retro_hw_render_callback
1471{
1472   /* Which API to use. Set by libretro core. */
1473   enum retro_hw_context_type context_type;
1474
1475   /* Called when a context has been created or when it has been reset.
1476    * An OpenGL context is only valid after context_reset() has been called.
1477    *
1478    * When context_reset is called, OpenGL resources in the libretro 
1479    * implementation are guaranteed to be invalid.
1480    *
1481    * It is possible that context_reset is called multiple times during an 
1482    * application lifecycle.
1483    * If context_reset is called without any notification (context_destroy),
1484    * the OpenGL context was lost and resources should just be recreated
1485    * without any attempt to "free" old resources.
1486    */
1487   retro_hw_context_reset_t context_reset;
1488
1489   /* Set by frontend. */
1490   retro_hw_get_current_framebuffer_t get_current_framebuffer;
1491
1492   /* Set by frontend. */
1493   retro_hw_get_proc_address_t get_proc_address;
1494
1495   /* Set if render buffers should have depth component attached. */
1496   bool depth;
1497
1498   /* Set if stencil buffers should be attached. */
1499   bool stencil;
1500
1501   /* If depth and stencil are true, a packed 24/8 buffer will be added. 
1502    * Only attaching stencil is invalid and will be ignored. */
1503
1504   /* Use conventional bottom-left origin convention. If false, 
1505    * standard libretro top-left origin semantics are used. */
1506   bool bottom_left_origin;
1507   
1508   /* Major version number for core GL context or GLES 3.1+. */
1509   unsigned version_major;
1510
1511   /* Minor version number for core GL context or GLES 3.1+. */
1512   unsigned version_minor;
1513
1514   /* If this is true, the frontend will go very far to avoid 
1515    * resetting context in scenarios like toggling fullscreen, etc.
1516    */
1517   bool cache_context;
1518
1519   /* The reset callback might still be called in extreme situations 
1520    * such as if the context is lost beyond recovery.
1521    *
1522    * For optimal stability, set this to false, and allow context to be 
1523    * reset at any time.
1524    */
1525   
1526   /* A callback to be called before the context is destroyed in a 
1527    * controlled way by the frontend. */
1528   retro_hw_context_reset_t context_destroy;
1529
1530   /* OpenGL resources can be deinitialized cleanly at this step.
1531    * context_destroy can be set to NULL, in which resources will 
1532    * just be destroyed without any notification.
1533    *
1534    * Even when context_destroy is non-NULL, it is possible that 
1535    * context_reset is called without any destroy notification.
1536    * This happens if context is lost by external factors (such as 
1537    * notified by GL_ARB_robustness).
1538    *
1539    * In this case, the context is assumed to be already dead,
1540    * and the libretro implementation must not try to free any OpenGL 
1541    * resources in the subsequent context_reset.
1542    */
1543
1544   /* Creates a debug context. */
1545   bool debug_context;
1546};
1547
1548/* Callback type passed in RETRO_ENVIRONMENT_SET_KEYBOARD_CALLBACK. 
1549 * Called by the frontend in response to keyboard events.
1550 * down is set if the key is being pressed, or false if it is being released.
1551 * keycode is the RETROK value of the char.
1552 * character is the text character of the pressed key. (UTF-32).
1553 * key_modifiers is a set of RETROKMOD values or'ed together.
1554 *
1555 * The pressed/keycode state can be indepedent of the character.
1556 * It is also possible that multiple characters are generated from a 
1557 * single keypress.
1558 * Keycode events should be treated separately from character events.
1559 * However, when possible, the frontend should try to synchronize these.
1560 * If only a character is posted, keycode should be RETROK_UNKNOWN.
1561 *
1562 * Similarily if only a keycode event is generated with no corresponding 
1563 * character, character should be 0.
1564 */
1565typedef void (*retro_keyboard_event_t)(bool down, unsigned keycode, 
1566      uint32_t character, uint16_t key_modifiers);
1567
1568struct retro_keyboard_callback
1569{
1570   retro_keyboard_event_t callback;
1571};
1572
1573/* Callbacks for RETRO_ENVIRONMENT_SET_DISK_CONTROL_INTERFACE.
1574 * Should be set for implementations which can swap out multiple disk 
1575 * images in runtime.
1576 *
1577 * If the implementation can do this automatically, it should strive to do so.
1578 * However, there are cases where the user must manually do so.
1579 *
1580 * Overview: To swap a disk image, eject the disk image with 
1581 * set_eject_state(true).
1582 * Set the disk index with set_image_index(index). Insert the disk again 
1583 * with set_eject_state(false).
1584 */
1585
1586/* If ejected is true, "ejects" the virtual disk tray.
1587 * When ejected, the disk image index can be set.
1588 */
1589typedef bool (*retro_set_eject_state_t)(bool ejected);
1590
1591/* Gets current eject state. The initial state is 'not ejected'. */
1592typedef bool (*retro_get_eject_state_t)(void);
1593
1594/* Gets current disk index. First disk is index 0.
1595 * If return value is >= get_num_images(), no disk is currently inserted.
1596 */
1597typedef unsigned (*retro_get_image_index_t)(void);
1598
1599/* Sets image index. Can only be called when disk is ejected.
1600 * The implementation supports setting "no disk" by using an 
1601 * index >= get_num_images().
1602 */
1603typedef bool (*retro_set_image_index_t)(unsigned index);
1604
1605/* Gets total number of images which are available to use. */
1606typedef unsigned (*retro_get_num_images_t)(void);
1607
1608struct retro_game_info;
1609
1610/* Replaces the disk image associated with index.
1611 * Arguments to pass in info have same requirements as retro_load_game().
1612 * Virtual disk tray must be ejected when calling this.
1613 *
1614 * Replacing a disk image with info = NULL will remove the disk image 
1615 * from the internal list.
1616 * As a result, calls to get_image_index() can change.
1617 *
1618 * E.g. replace_image_index(1, NULL), and previous get_image_index() 
1619 * returned 4 before.
1620 * Index 1 will be removed, and the new index is 3.
1621 */
1622typedef bool (*retro_replace_image_index_t)(unsigned index,
1623      const struct retro_game_info *info);
1624
1625/* Adds a new valid index (get_num_images()) to the internal disk list.
1626 * This will increment subsequent return values from get_num_images() by 1.
1627 * This image index cannot be used until a disk image has been set 
1628 * with replace_image_index. */
1629typedef bool (*retro_add_image_index_t)(void);
1630
1631struct retro_disk_control_callback
1632{
1633   retro_set_eject_state_t set_eject_state;
1634   retro_get_eject_state_t get_eject_state;
1635
1636   retro_get_image_index_t get_image_index;
1637   retro_set_image_index_t set_image_index;
1638   retro_get_num_images_t  get_num_images;
1639
1640   retro_replace_image_index_t replace_image_index;
1641   retro_add_image_index_t add_image_index;
1642};
1643
1644enum retro_pixel_format
1645{
1646   /* 0RGB1555, native endian.
1647    * 0 bit must be set to 0.
1648    * This pixel format is default for compatibility concerns only.
1649    * If a 15/16-bit pixel format is desired, consider using RGB565. */
1650   RETRO_PIXEL_FORMAT_0RGB1555 = 0,
1651
1652   /* XRGB8888, native endian.
1653    * X bits are ignored. */
1654   RETRO_PIXEL_FORMAT_XRGB8888 = 1,
1655
1656   /* RGB565, native endian.
1657    * This pixel format is the recommended format to use if a 15/16-bit
1658    * format is desired as it is the pixel format that is typically 
1659    * available on a wide range of low-power devices.
1660    *
1661    * It is also natively supported in APIs like OpenGL ES. */
1662   RETRO_PIXEL_FORMAT_RGB565   = 2,
1663
1664   /* Ensure sizeof() == sizeof(int). */
1665   RETRO_PIXEL_FORMAT_UNKNOWN  = INT_MAX
1666};
1667
1668struct retro_message
1669{
1670   const char *msg;        /* Message to be displayed. */
1671   unsigned    frames;     /* Duration in frames of message. */
1672};
1673
1674/* Describes how the libretro implementation maps a libretro input bind
1675 * to its internal input system through a human readable string.
1676 * This string can be used to better let a user configure input. */
1677struct retro_input_descriptor
1678{
1679   /* Associates given parameters with a description. */
1680   unsigned port;
1681   unsigned device;
1682   unsigned index;
1683   unsigned id;
1684
1685   /* Human readable description for parameters.
1686    * The pointer must remain valid until
1687    * retro_unload_game() is called. */
1688   const char *description; 
1689};
1690
1691struct retro_system_info
1692{
1693   /* All pointers are owned by libretro implementation, and pointers must 
1694    * remain valid until retro_deinit() is called. */
1695
1696   const char *library_name;      /* Descriptive name of library. Should not 
1697                                   * contain any version numbers, etc. */
1698   const char *library_version;   /* Descriptive version of core. */
1699
1700   const char *valid_extensions;  /* A string listing probably content 
1701                                   * extensions the core will be able to 
1702                                   * load, separated with pipe.
1703                                   * I.e. "bin|rom|iso".
1704                                   * Typically used for a GUI to filter 
1705                                   * out extensions. */
1706
1707   /* If true, retro_load_game() is guaranteed to provide a valid pathname 
1708    * in retro_game_info::path.
1709    * ::data and ::size are both invalid.
1710    *
1711    * If false, ::data and ::size are guaranteed to be valid, but ::path 
1712    * might not be valid.
1713    *
1714    * This is typically set to true for libretro implementations that must 
1715    * load from file.
1716    * Implementations should strive for setting this to false, as it allows 
1717    * the frontend to perform patching, etc. */
1718   bool        need_fullpath;                                       
1719
1720   /* If true, the frontend is not allowed to extract any archives before 
1721    * loading the real content.
1722    * Necessary for certain libretro implementations that load games 
1723    * from zipped archives. */
1724   bool        block_extract;     
1725};
1726
1727struct retro_game_geometry
1728{
1729   unsigned base_width;    /* Nominal video width of game. */
1730   unsigned base_height;   /* Nominal video height of game. */
1731   unsigned max_width;     /* Maximum possible width of game. */
1732   unsigned max_height;    /* Maximum possible height of game. */
1733
1734   float    aspect_ratio;  /* Nominal aspect ratio of game. If
1735                            * aspect_ratio is <= 0.0, an aspect ratio
1736                            * of base_width / base_height is assumed.
1737                            * A frontend could override this setting,
1738                            * if desired. */
1739};
1740
1741struct retro_system_timing
1742{
1743   double fps;             /* FPS of video content. */
1744   double sample_rate;     /* Sampling rate of audio. */
1745};
1746
1747struct retro_system_av_info
1748{
1749   struct retro_game_geometry geometry;
1750   struct retro_system_timing timing;
1751};
1752
1753struct retro_variable
1754{
1755   /* Variable to query in RETRO_ENVIRONMENT_GET_VARIABLE.
1756    * If NULL, obtains the complete environment string if more 
1757    * complex parsing is necessary.
1758    * The environment string is formatted as key-value pairs 
1759    * delimited by semicolons as so:
1760    * "key1=value1;key2=value2;..."
1761    */
1762   const char *key;
1763   
1764   /* Value to be obtained. If key does not exist, it is set to NULL. */
1765   const char *value;
1766};
1767
1768struct retro_game_info
1769{
1770   const char *path;       /* Path to game, UTF-8 encoded.
1771                            * Usually used as a reference.
1772                            * May be NULL if rom was loaded from stdin
1773                            * or similar. 
1774                            * retro_system_info::need_fullpath guaranteed 
1775                            * that this path is valid. */
1776   const void *data;       /* Memory buffer of loaded game. Will be NULL 
1777                            * if need_fullpath was set. */
1778   size_t      size;       /* Size of memory buffer. */
1779   const char *meta;       /* String of implementation specific meta-data. */
1780};
1781
1782/* Callbacks */
1783
1784/* Environment callback. Gives implementations a way of performing 
1785 * uncommon tasks. Extensible. */
1786typedef bool (*retro_environment_t)(unsigned cmd, void *data);
1787
1788/* Render a frame. Pixel format is 15-bit 0RGB1555 native endian 
1789 * unless changed (see RETRO_ENVIRONMENT_SET_PIXEL_FORMAT).
1790 *
1791 * Width and height specify dimensions of buffer.
1792 * Pitch specifices length in bytes between two lines in buffer.
1793 *
1794 * For performance reasons, it is highly recommended to have a frame 
1795 * that is packed in memory, i.e. pitch == width * byte_per_pixel.
1796 * Certain graphic APIs, such as OpenGL ES, do not like textures 
1797 * that are not packed in memory.
1798 */
1799typedef void (*retro_video_refresh_t)(const void *data, unsigned width,
1800      unsigned height, size_t pitch);
1801
1802/* Renders a single audio frame. Should only be used if implementation 
1803 * generates a single sample at a time.
1804 * Format is signed 16-bit native endian.
1805 */
1806typedef void (*retro_audio_sample_t)(int16_t left, int16_t right);
1807
1808/* Renders multiple audio frames in one go.
1809 *
1810 * One frame is defined as a sample of left and right channels, interleaved.
1811 * I.e. int16_t buf[4] = { l, r, l, r }; would be 2 frames.
1812 * Only one of the audio callbacks must ever be used.
1813 */
1814typedef size_t (*retro_audio_sample_batch_t)(const int16_t *data,
1815      size_t frames);
1816
1817/* Polls input. */
1818typedef void (*retro_input_poll_t)(void);
1819
1820/* Queries for input for player 'port'. device will be masked with 
1821 * RETRO_DEVICE_MASK.
1822 *
1823 * Specialization of devices such as RETRO_DEVICE_JOYPAD_MULTITAP that 
1824 * have been set with retro_set_controller_port_device()
1825 * will still use the higher level RETRO_DEVICE_JOYPAD to request input.
1826 */
1827typedef int16_t (*retro_input_state_t)(unsigned port, unsigned device, 
1828      unsigned index, unsigned id);
1829
1830/* Sets callbacks. retro_set_environment() is guaranteed to be called 
1831 * before retro_init().
1832 *
1833 * The rest of the set_* functions are guaranteed to have been called 
1834 * before the first call to retro_run() is made. */
1835void retro_set_environment(retro_environment_t);
1836void retro_set_video_refresh(retro_video_refresh_t);
1837void retro_set_audio_sample(retro_audio_sample_t);
1838void retro_set_audio_sample_batch(retro_audio_sample_batch_t);
1839void retro_set_input_poll(retro_input_poll_t);
1840void retro_set_input_state(retro_input_state_t);
1841
1842/* Library global initialization/deinitialization. */
1843void retro_init(void);
1844void retro_deinit(void);
1845
1846/* Must return RETRO_API_VERSION. Used to validate ABI compatibility
1847 * when the API is revised. */
1848unsigned retro_api_version(void);
1849
1850/* Gets statically known system info. Pointers provided in *info 
1851 * must be statically allocated.
1852 * Can be called at any time, even before retro_init(). */
1853void retro_get_system_info(struct retro_system_info *info);
1854
1855/* Gets information about system audio/video timings and geometry.
1856 * Can be called only after retro_load_game() has successfully completed.
1857 * NOTE: The implementation of this function might not initialize every 
1858 * variable if needed.
1859 * E.g. geom.aspect_ratio might not be initialized if core doesn't 
1860 * desire a particular aspect ratio. */
1861void retro_get_system_av_info(struct retro_system_av_info *info);
1862
1863/* Sets device to be used for player 'port'.
1864 * By default, RETRO_DEVICE_JOYPAD is assumed to be plugged into all 
1865 * available ports.
1866 * Setting a particular device type is not a guarantee that libretro cores 
1867 * will only poll input based on that particular device type. It is only a 
1868 * hint to the libretro core when a core cannot automatically detect the 
1869 * appropriate input device type on its own. It is also relevant when a 
1870 * core can change its behavior depending on device type. */
1871void retro_set_controller_port_device(unsigned port, unsigned device);
1872
1873/* Resets the current game. */
1874void retro_reset(void);
1875
1876/* Runs the game for one video frame.
1877 * During retro_run(), input_poll callback must be called at least once.
1878 * 
1879 * If a frame is not rendered for reasons where a game "dropped" a frame,
1880 * this still counts as a frame, and retro_run() should explicitly dupe 
1881 * a frame if GET_CAN_DUPE returns true.
1882 * In this case, the video callback can take a NULL argument for data.
1883 */
1884void retro_run(void);
1885
1886/* Returns the amount of data the implementation requires to serialize 
1887 * internal state (save states).
1888 * Between calls to retro_load_game() and retro_unload_game(), the 
1889 * returned size is never allowed to be larger than a previous returned 
1890 * value, to ensure that the frontend can allocate a save state buffer once.
1891 */
1892size_t retro_serialize_size(void);
1893
1894/* Serializes internal state. If failed, or size is lower than
1895 * retro_serialize_size(), it should return false, true otherwise. */
1896bool retro_serialize(void *data, size_t size);
1897bool retro_unserialize(const void *data, size_t size);
1898
1899void retro_cheat_reset(void);
1900void retro_cheat_set(unsigned index, bool enabled, const char *code);
1901
1902/* Loads a game. */
1903bool retro_load_game(const struct retro_game_info *game);
1904
1905/* Loads a "special" kind of game. Should not be used,
1906 * except in extreme cases. */
1907bool retro_load_game_special(
1908  unsigned game_type,
1909  const struct retro_game_info *info, size_t num_info
1910);
1911
1912/* Unloads a currently loaded game. */
1913void retro_unload_game(void);
1914
1915/* Gets region of game. */
1916unsigned retro_get_region(void);
1917
1918/* Gets region of memory. */
1919void *retro_get_memory_data(unsigned id);
1920size_t retro_get_memory_size(unsigned id);
1921
1922#ifdef __cplusplus
1923}
1924#endif
1925
1926#endif