Attempt to add rumble support to SDL. Who knows it might work.

Cocoa/Preferences.xib

@@ -603,13 +603,13 @@
                 <popUpButton verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="Ogs-xG-b4b">
                     <rect key="frame" x="30" y="58" width="245" height="22"/>
                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
-                    <popUpButtonCell key="cell" type="push" title="Never" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" borderStyle="borderAndBezel" imageScaling="proportionallyDown" inset="2" selectedItem="jki-7x-bnM" id="o9b-MH-8kd">
+                    <popUpButtonCell key="cell" type="push" title="Never" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="proportionallyDown" inset="2" selectedItem="jki-7x-bnM" id="o9b-MH-8kd">
                         <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                         <font key="font" metaFont="menu"/>
                         <menu key="menu" id="8p7-je-0Fh">
                             <items>
-                                <menuItem title="Never" id="jki-7x-bnM"/>
-                                <menuItem title="For rumble-enabled cartridges" state="on" tag="1" id="58e-Tp-TWd"/>
+                                <menuItem title="Never" state="on" id="jki-7x-bnM"/>
+                                <menuItem title="For rumble-enabled Game Paks" tag="1" id="58e-Tp-TWd"/>
                                 <menuItem title="Always" tag="2" id="qVe-2b-W1P"/>
                             </items>
                         </menu>

SDL/gui.c

@@ -108,6 +108,7 @@ configuration_t configuration =
     .rewind_length = 60 * 2,
     .model = MODEL_CGB,
     .volume = 100,
+    .rumble_mode = GB_RUMBLE_ALL_GAMES,
 };
 
 
@@ -763,6 +764,7 @@ static void enter_controls_menu(unsigned index)
 static unsigned joypad_index = 0;
 static SDL_Joystick *joystick = NULL;
 static SDL_GameController *controller = NULL;
+SDL_Haptic *haptic = NULL;
 
 const char *current_joypad_name(unsigned index)
 {
@@ -792,6 +794,12 @@ static void cycle_joypads(unsigned index)
     if (joypad_index >= SDL_NumJoysticks()) {
         joypad_index = 0;
     }
+    
+    if (haptic) {
+        SDL_HapticClose(haptic);
+        haptic = NULL;
+    }
+    
     if (controller) {
         SDL_GameControllerClose(controller);
         controller = NULL;
@@ -806,14 +814,22 @@ static void cycle_joypads(unsigned index)
     else {
         joystick = SDL_JoystickOpen(joypad_index);
     }
-}
+    if (joystick) {
+        haptic = SDL_HapticOpenFromJoystick(joystick);
+    }}
 
 static void cycle_joypads_backwards(unsigned index)
 {
-    joypad_index++;
+    joypad_index--;
     if (joypad_index >= SDL_NumJoysticks()) {
         joypad_index = SDL_NumJoysticks() - 1;
     }
+    
+    if (haptic) {
+        SDL_HapticClose(haptic);
+        haptic = NULL;
+    }
+    
     if (controller) {
         SDL_GameControllerClose(controller);
         controller = NULL;
@@ -828,7 +844,9 @@ static void cycle_joypads_backwards(unsigned index)
     else {
         joystick = SDL_JoystickOpen(joypad_index);
     }
-}
+    if (joystick) {
+        haptic = SDL_HapticOpenFromJoystick(joystick);
+    }}
 
 static void detect_joypad_layout(unsigned index)
 {
@@ -837,9 +855,36 @@ static void detect_joypad_layout(unsigned index)
     joypad_axis_temp = -1;
 }
 
+static void cycle_rumble_mode(unsigned index)
+{
+    if (configuration.rumble_mode == GB_RUMBLE_ALL_GAMES) {
+        configuration.rumble_mode = GB_RUMBLE_DISABLED;
+    }
+    else {
+        configuration.rumble_mode++;
+    }
+}
+
+static void cycle_rumble_mode_backwards(unsigned index)
+{
+    if (configuration.rumble_mode == GB_RUMBLE_DISABLED) {
+        configuration.rumble_mode = GB_RUMBLE_ALL_GAMES;
+    }
+    else {
+        configuration.rumble_mode--;
+    }
+}
+
+const char *current_rumble_mode(unsigned index)
+{
+    return (const char *[]){"Disabled", "Rumble Game Paks Only", "All Games"}
+    [configuration.rumble_mode];
+}
+
 static const struct menu_item joypad_menu[] = {
     {"Joypad:", cycle_joypads, current_joypad_name, cycle_joypads_backwards},
     {"Configure layout", detect_joypad_layout},
+    {"Rumble Mode:", cycle_rumble_mode, current_rumble_mode, cycle_rumble_mode_backwards},
     {"Back", return_to_root_menu},
     {NULL,}
 };
@@ -893,6 +938,9 @@ void connect_joypad(void)
             joystick = SDL_JoystickOpen(0);
         }
     }
+    if (joystick) {
+        haptic = SDL_HapticOpenFromJoystick(joystick);
+    }
 }
 
 void run_gui(bool is_running)

SDL/gui.h

@@ -21,6 +21,7 @@ extern SDL_Window *window;
 extern SDL_Renderer *renderer;
 extern SDL_Texture *texture;
 extern SDL_PixelFormat *pixel_format;
+extern SDL_Haptic *haptic;
 extern shader_t shader;
 
 enum scaling_mode {
@@ -105,6 +106,7 @@ typedef struct {
     uint8_t dmg_palette;
     GB_border_mode_t border_mode;
     uint8_t volume;
+    GB_rumble_mode_t rumble_mode;
 } configuration_t;
 
 extern configuration_t configuration;

SDL/main.c

@@ -367,6 +367,11 @@ static uint32_t rgb_encode(GB_gameboy_t *gb, uint8_t r, uint8_t g, uint8_t b)
     return SDL_MapRGB(pixel_format, r, g, b);
 }
 
+static void rumble(GB_gameboy_t *gb, double amp)
+{
+    SDL_HapticRumblePlay(haptic, amp, 250);
+}
+
 static void debugger_interrupt(int ignore)
 {
     if (!GB_is_inited(&gb)) return;
@@ -488,6 +493,8 @@ restart:
         GB_set_vblank_callback(&gb, (GB_vblank_callback_t) vblank);
         GB_set_pixels_output(&gb, active_pixel_buffer);
         GB_set_rgb_encode_callback(&gb, rgb_encode);
+        GB_set_rumble_callback(&gb, rumble);
+        GB_set_rumble_mode(&gb, configuration.rumble_mode);
         GB_set_sample_rate(&gb, GB_audio_get_frequency());
         GB_set_color_correction_mode(&gb, configuration.color_correction_mode);
         update_palette();