Add input filter callback

.gitignore

@@ -3,3 +3,6 @@
 /.vscode
 /projects/unix/*.dll
 /src/asm_defines/*.h
+
+.cache/
+compile_commands.json

src/api/frontend.c

@@ -29,6 +29,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <md5.h>
+#include "backends/plugins_compat/plugins_compat.h"
 
 #define M64P_CORE_PROTOTYPES 1
 #include "callbacks.h"
@@ -318,6 +319,7 @@ EXPORT m64p_error CALL CoreDoCommand(m64p_command Command, int ParamInt, void *P
         case M64CMD_SET_FRAME_CALLBACK:
             *(void**)&g_FrameCallback = ParamPtr;
             return M64ERR_SUCCESS;
+            return M64ERR_SUCCESS;
         case M64CMD_TAKE_NEXT_SCREENSHOT:
             if (!g_EmulatorRunning)
                 return M64ERR_INVALID_STATE;
@@ -347,6 +349,11 @@ EXPORT m64p_error CALL CoreDoCommand(m64p_command Command, int ParamInt, void *P
                 return M64ERR_INPUT_INVALID;
             g_media_loader = *(m64p_media_loader*)ParamPtr;
             return M64ERR_SUCCESS;
+        case M64CMD_SET_INPUT_FILTER:
+            if (ParamInt != sizeof(m64p_input_filter) || ParamPtr == NULL)
+                return M64ERR_INPUT_INVALID;
+            g_input_filter = *(m64p_input_filter*)ParamPtr;
+            return M64ERR_SUCCESS;
         case M64CMD_NETPLAY_INIT:
             if (ParamInt < 1 || ParamPtr == NULL)
                 return M64ERR_INPUT_INVALID;

src/api/m64p_plugin.h

@@ -147,32 +147,6 @@ typedef struct {
     int Type;
 } CONTROL;
 
-typedef union {
-    unsigned int Value;
-    struct {
-        unsigned R_DPAD       : 1;
-        unsigned L_DPAD       : 1;
-        unsigned D_DPAD       : 1;
-        unsigned U_DPAD       : 1;
-        unsigned START_BUTTON : 1;
-        unsigned Z_TRIG       : 1;
-        unsigned B_BUTTON     : 1;
-        unsigned A_BUTTON     : 1;
-
-        unsigned R_CBUTTON    : 1;
-        unsigned L_CBUTTON    : 1;
-        unsigned D_CBUTTON    : 1;
-        unsigned U_CBUTTON    : 1;
-        unsigned R_TRIG       : 1;
-        unsigned L_TRIG       : 1;
-        unsigned Reserved1    : 1;
-        unsigned Reserved2    : 1;
-
-        signed   X_AXIS       : 8;
-        signed   Y_AXIS       : 8;
-    };
-} BUTTONS;
-
 typedef struct {
     CONTROL *Controls;      /* A pointer to an array of 4 controllers .. eg:
                                CONTROL Controls[4]; */

src/api/m64p_types.h

@@ -1,6 +1,7 @@
 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
  *   Mupen64plus-core - m64p_types.h                                       *
  *   Mupen64Plus homepage: https://mupen64plus.org/                        *
+ *   Copyright (C) 2024 Jacky Guo                                          *
  *   Copyright (C) 2012 CasualJames                                        *
  *   Copyright (C) 2009 Richard Goedeken                                   *
  *                                                                         *
@@ -29,6 +30,7 @@
 
 /* necessary headers */
 #include <stdint.h>
+#include <stdbool.h>
 #if defined(WIN32)
   #include <windows.h>
 #endif
@@ -62,6 +64,32 @@ typedef void (*m64p_input_callback)(void);
 typedef void (*m64p_audio_callback)(void);
 typedef void (*m64p_vi_callback)(void);
 
+typedef union {
+    unsigned int Value;
+    struct {
+        unsigned R_DPAD       : 1;
+        unsigned L_DPAD       : 1;
+        unsigned D_DPAD       : 1;
+        unsigned U_DPAD       : 1;
+        unsigned START_BUTTON : 1;
+        unsigned Z_TRIG       : 1;
+        unsigned B_BUTTON     : 1;
+        unsigned A_BUTTON     : 1;
+
+        unsigned R_CBUTTON    : 1;
+        unsigned L_CBUTTON    : 1;
+        unsigned D_CBUTTON    : 1;
+        unsigned U_CBUTTON    : 1;
+        unsigned R_TRIG       : 1;
+        unsigned L_TRIG       : 1;
+        unsigned Reserved1    : 1;
+        unsigned Reserved2    : 1;
+
+        signed   X_AXIS       : 8;
+        signed   Y_AXIS       : 8;
+    };
+} BUTTONS;
+
 typedef enum {
   M64TYPE_INT = 1,
   M64TYPE_FLOAT,
@@ -171,7 +199,8 @@ typedef enum {
   M64CMD_PIF_OPEN,
   M64CMD_ROM_SET_SETTINGS,
   M64CMD_DISK_OPEN,
-  M64CMD_DISK_CLOSE
+  M64CMD_DISK_CLOSE,
+  M64CMD_SET_INPUT_FILTER,
 } m64p_command;
 
 typedef struct {
@@ -220,6 +249,12 @@ typedef struct {
   char* (*get_dd_disk)(void* cb_data);
 } m64p_media_loader;
 
+typedef struct {
+  void* cb_data;
+
+  bool (*filter_input)(void* cb_data, int controller_num, BUTTONS* keys);
+} m64p_input_filter;
+
 /* ----------------------------------------- */
 /* Structures to hold ROM image information  */
 /* ----------------------------------------- */

src/backends/plugins_compat/input_plugin_compat.c

@@ -29,6 +29,7 @@
 #include "main/main.h"
 #include "main/netplay.h"
 
+#include <stdbool.h>
 #include <stdint.h>
 #include <string.h>
 #include <api/m64p_plugin.h>
@@ -85,8 +86,10 @@ static m64p_error input_plugin_get_input(void* opaque, uint32_t* input_)
         cin_compat->last_pak_type = Controls[cin_compat->control_id].Plugin; //disable pak switching for netplay
     }
 
-    /* return an error if controller is not plugged */
-    if (!Controls[cin_compat->control_id].Present) {
+    bool is_override = g_input_filter.filter_input(g_input_filter.cb_data, cin_compat->control_id, &keys);
+
+    /* return an error if controller is not plugged OR input was not provided by the filter callback */
+    if (!Controls[cin_compat->control_id].Present || is_override) {
         return M64ERR_SYSTEM_FAIL;
     }
 
@@ -228,3 +231,5 @@ const struct joybus_device_interface
     input_plugin_read_controller,
     input_plugin_controller_command,
 };
+
+m64p_input_filter g_input_filter;

src/backends/plugins_compat/plugins_compat.h

@@ -22,6 +22,7 @@
 #ifndef M64P_BACKENDS_PLUGINS_COMPAT_PLUGINS_COMPAT_H
 #define M64P_BACKENDS_PLUGINS_COMPAT_PLUGINS_COMPAT_H
 
+#include "api/m64p_types.h"
 #include "backends/api/audio_out_backend.h"
 #include "backends/api/controller_input_backend.h"
 #include "backends/api/rumble_backend.h"
@@ -55,6 +56,8 @@ struct controller_input_compat
     struct netplay_event* event_first;
 };
 
+extern m64p_input_filter g_input_filter;
+
 extern const struct controller_input_backend_interface
     g_icontroller_input_backend_plugin_compat;