Add very crude disk swapping.

Needs to be written more cleanly. Here as a POC.

libretro.cpp

@@ -161,9 +161,71 @@ static void check_system_specs(void)
    environ_cb(RETRO_ENVIRONMENT_SET_PERFORMANCE_LEVEL, &level);
 }
 
+#if defined(WANT_PSX_EMU)
+#include "mednafen/psx/psx.h"
+namespace MDFN_IEN_PSX
+{
+   extern int CD_SelectedDisc;
+   extern std::vector<CDIF*> *cdifs;
+}
+
+using MDFN_IEN_PSX::CD_SelectedDisc;
+using MDFN_IEN_PSX::cdifs;
+
+static unsigned disk_get_num_images(void)
+{
+   return cdifs ? cdifs->size() : 0;
+}
+
+static bool eject_state;
+static bool disk_set_eject_state(bool ejected)
+{
+   fprintf(stderr, "[Mednafen]: Ejected: %u.\n", ejected);
+   if (ejected == eject_state)
+      return false;
+
+   game->DoSimpleCommand(ejected ? MDFN_MSC_EJECT_DISK : MDFN_MSC_INSERT_DISK);
+   eject_state = ejected;
+   return true;
+}
+
+static bool disk_get_eject_state(void)
+{
+   return eject_state;
+}
+
+static unsigned disk_get_image_index(void)
+{
+   // PSX global. Hacky.
+   return MDFN_IEN_PSX::CD_SelectedDisc;
+}
+
+static bool disk_set_image_index(unsigned index)
+{
+   CD_SelectedDisc = index;
+   if (CD_SelectedDisc > disk_get_num_images())
+      CD_SelectedDisc = disk_get_num_images();
+
+   // Very hacky. CDSelect command will increment first.
+   CD_SelectedDisc--;
+
+   game->DoSimpleCommand(MDFN_MSC_SELECT_DISK);
+   return true;
+}
+
+static struct retro_disk_control_callback disk_interface = {
+   disk_set_eject_state,
+   disk_get_eject_state,
+   disk_get_image_index,
+   disk_set_image_index,
+   disk_get_num_images,
+};
+#endif
+
 void retro_init()
 {
    MDFNI_InitializeModule();
+   eject_state = false;
 
    const char *dir = NULL;
 
@@ -192,6 +254,10 @@ void retro_init()
       fprintf(stderr, "Frontend supports RGB565 - will use that instead of XRGB1555.\n");
 #endif
 
+#if defined(WANT_PSX_EMU)
+   environ_cb(RETRO_ENVIRONMENT_SET_DISK_CONTROL_INTERFACE, &disk_interface);
+#endif
+
    check_system_specs();
 }
 

libretro.h

@@ -19,7 +19,7 @@ extern "C" {
 #endif
 
 // Used for checking API/ABI mismatches that can break libretro implementations.
-// It is not incremented for compatible changes.
+// It is not incremented for compatible changes to the API.
 #define RETRO_API_VERSION         1
 
 // Libretro's fundamental device abstractions.
@@ -50,6 +50,28 @@ extern "C" {
 // Only use ANALOG type when polling for analog values of the axes.
 #define RETRO_DEVICE_ANALOG       5
 
+// Abstracts the concept of a pointing mechanism, e.g. touch.
+// This allows libretro to query in absolute coordinates where on the screen a mouse (or something similar) is being placed.
+// For a touch centric device, coordinates reported are the coordinates of the press.
+//
+// Coordinates in X and Y are reported as:
+// [-0x7fff, 0x7fff]: -0x7fff corresponds to the far left/top of the screen,
+// and 0x7fff corresponds to the far right/bottom of the screen.
+// The "screen" is here defined as area that is passed to the frontend and later displayed on the monitor.
+// The frontend is free to scale/resize this screen as it sees fit, however,
+// (X, Y) = (-0x7fff, -0x7fff) will correspond to the top-left pixel of the game image, etc.
+//
+// To check if the pointer coordinates are valid (e.g. a touch display actually being touched),
+// PRESSED returns 1 or 0.
+// If using a mouse, PRESSED will usually correspond to the left mouse button.
+// PRESSED will only return 1 if the pointer is inside the game screen.
+//
+// For multi-touch, the index variable can be used to successively query more presses.
+// If index = 0 returns true for _PRESSED, coordinates can be extracted
+// with _X, _Y for index = 0. One can then query _PRESSED, _X, _Y with index = 1, and so on.
+// Eventually _PRESSED will return false for an index. No further presses are registered at this point.
+#define RETRO_DEVICE_POINTER      6
+
 // These device types are specializations of the base types above.
 // They should only be used in retro_set_controller_type() to inform libretro implementations
 // about use of a very specific device type.
@@ -101,6 +123,11 @@ extern "C" {
 #define RETRO_DEVICE_ID_LIGHTGUN_PAUSE    5
 #define RETRO_DEVICE_ID_LIGHTGUN_START    6
 
+// Id values for POINTER.
+#define RETRO_DEVICE_ID_POINTER_X         0
+#define RETRO_DEVICE_ID_POINTER_Y         1
+#define RETRO_DEVICE_ID_POINTER_PRESSED   2
+
 // Returned from retro_get_region().
 #define RETRO_REGION_NTSC  0
 #define RETRO_REGION_PAL   1
@@ -285,9 +312,28 @@ enum retro_key
    RETROK_EURO           = 321,
    RETROK_UNDO           = 322,
 
-   RETROK_LAST
+   RETROK_LAST,
+
+   RETROK_DUMMY          = INT_MAX // Ensure sizeof(enum) == sizeof(int)
 };
 
+enum retro_mod
+{
+   RETROKMOD_NONE       = 0x0000,
+
+   RETROKMOD_SHIFT      = 0x01,
+   RETROKMOD_CTRL       = 0x02,
+   RETROKMOD_ALT        = 0x04,
+   RETROKMOD_META       = 0x08,
+
+   RETROKMOD_NUMLOCK    = 0x10,
+   RETROKMOD_CAPSLOCK   = 0x20,
+   RETROKMOD_SCROLLOCK  = 0x40,
+
+   RETROKMOD_DUMMY = INT_MAX // Ensure sizeof(enum) == sizeof(int)
+};
+
+
 // Environment commands.
 #define RETRO_ENVIRONMENT_SET_ROTATION  1  // const unsigned * --
                                            // Sets screen rotation of graphics.
@@ -331,7 +377,7 @@ enum retro_key
                                            //
                                            // It can be used by the frontend to potentially warn
                                            // about too demanding implementations.
-                                           // 
+                                           //
                                            // The levels are "floating", but roughly defined as:
                                            // 0: Low-powered embedded devices such as Raspberry Pi
                                            // 1: 6th generation consoles, such as Wii/Xbox 1, and phones, tablets, etc.
@@ -366,8 +412,60 @@ enum retro_key
                                            // It is up to the frontend to present this in a usable way.
                                            // The array is terminated by retro_input_descriptor::description being set to NULL.
                                            // This function can be called at any time, but it is recommended to call it as early as possible.
+#define RETRO_ENVIRONMENT_SET_KEYBOARD_CALLBACK 12
+                                           // const struct retro_keyboard_callback * --
+                                           // Sets a callback function used to notify core about keyboard events.
+                                           //
+#define RETRO_ENVIRONMENT_SET_DISK_CONTROL_INTERFACE 13
+                                           // const struct retro_disk_control_callback * --
+                                           // Sets an interface which frontend can use to eject and insert disk images.
+                                           // This is used for games which consist of multiple images and must be manually
+                                           // swapped out by the user (e.g. PSX).
 
 
+// Callback type passed in RETRO_ENVIRONMENT_SET_KEYBOARD_CALLBACK. Called by the frontend in response to keyboard events.
+// down is set if the key is being pressed, or false if it is being released.
+// keycode is the RETROK value of the char.
+// character is the text character of the pressed key. (UTF-32).
+// key_modifiers is a set of RETROKMOD values or'ed together.
+typedef void (*retro_keyboard_event_t)(bool down, unsigned keycode, uint32_t character, uint16_t key_modifiers);
+
+struct retro_keyboard_callback
+{
+    retro_keyboard_event_t callback;
+};
+
+// Callback for RETRO_ENVIRONMENT_SET_DISK_CONTROL_INTERFACE.
+// Should be set for implementations which can swap out multiple disk images in runtime.
+// If the implementation can do this automatically, it should strive to do so.
+// However, there are cases where the user must manually do so.
+//
+// Overview: To swap a disk image, eject the disk image with set_eject_state(true).
+// Set the disk index with set_image_index(index). Insert the disk again with set_eject_state(false).
+
+// If ejected is true, "ejects" the virtual disk tray. When ejected, the disk image index can be set.
+typedef bool (*retro_set_eject_state_t)(bool ejected);
+// Gets current eject state. The initial state is not ejected.
+typedef bool (*retro_get_eject_state_t)(void);
+// Gets current disk index. First disk is index 0.
+// If return value is >= get_num_images(), no disk is currently inserted.
+typedef unsigned (*retro_get_image_index_t)(void);
+// Sets image index. Can only be called when disk is ejected.
+// The implementation supports setting "no disk" by using an index >= get_num_images().
+typedef bool (*retro_set_image_index_t)(unsigned index);
+// Gets total number of images which are available to use.
+typedef unsigned (*retro_get_num_images_t)(void);
+
+struct retro_disk_control_callback
+{
+   retro_set_eject_state_t set_eject_state;
+   retro_get_eject_state_t get_eject_state;
+
+   retro_get_image_index_t get_image_index;
+   retro_set_image_index_t set_image_index;
+   retro_get_num_images_t  get_num_images;
+};
+
 enum retro_pixel_format
 {
    // 0RGB1555, native endian. 0 bit must be set to 0.

mednafen/mednafen.cpp

@@ -156,7 +156,7 @@ MDFNGI *MDFNI_LoadCD(const char *force_module, const char *devicename)
 {
  uint8 LayoutMD5[16];
 #ifdef NEED_CD
- std::vector<CDIF *> CDInterfaces;	// FIXME: Cleanup on error out.
+ static std::vector<CDIF *> CDInterfaces;	// FIXME: Cleanup on error out.
 #endif
 
  MDFN_printf(_("Loading %s...\n\n"), devicename ? devicename : _("PHYSICAL CD"));

mednafen/psx/psx.cpp

@@ -55,10 +55,12 @@ static uint32 ReadCounter = 0;
 static uint32 WriteCounter = 0;
 #endif
 
-static std::vector<CDIF*> *cdifs = NULL;
 static std::vector<const char *> cdifs_scex_ids;
 static bool CD_TrayOpen;
-static int CD_SelectedDisc;     // -1 for no disc
+
+// Libretro. Needs to be global.
+int CD_SelectedDisc;     // -1 for no disc
+std::vector<CDIF*> *cdifs;
 
 static uint64 Memcard_PrevDC[8];
 static int64 Memcard_SaveDelay[8];