Add raw joystick fallback for non-standard controllers

Open the joystick via SDL_JoystickOpen() when no GameController mapping
exists, fixing d-pad and face button input on devices like the Anbernic
retro handheld (GUID not in SDL's database). Handles JOYHATMOTION for
d-pad navigation and JOYBUTTONDOWN button 0 for activation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/sdlamp2-fsd.md

@@ -43,6 +43,12 @@ This document specifies the functional requirements for an SDL2 based media play
 
 ## 6. Changelog
 
+### 2026-02-13 — Raw joystick fallback for non-standard controllers
+
+- **Joystick fallback**: When no SDL GameController mapping exists for a connected device, the joystick is now opened directly via `SDL_JoystickOpen()` as a fallback. This fixes d-pad and face button input on devices like the Anbernic retro handheld whose GUID is not in SDL's GameController database.
+- **Hat/button handling**: `SDL_JOYHATMOTION` events drive d-pad navigation (left/right to move focus, up/down for volume), and `SDL_JOYBUTTONDOWN` button 0 (BTN_SOUTH / A) activates the focused button.
+- **Hot-unplug**: Raw joystick is properly closed on `SDL_JOYDEVICEREMOVED`.
+
 ### 2026-02-13 — Embed controls spritesheet into binary
 
 - **Embedded asset**: `controls.png` is now compiled into the binary as a C byte array (`src/controls_png.h`), eliminating the requirement to run from the `build/` directory.

src/sdlamp2.c

@@ -67,6 +67,7 @@ static int current_file_index = 0;
 static float volume = 0.5f;
 static int focus_index = FOCUS_PLAY;
 static SDL_GameController* controller = NULL;
+static SDL_Joystick* joystick = NULL;
 static int debug_mode = 0;
 
 /* --- Utility --- */
@@ -627,6 +628,16 @@ int main(int argc, char** argv) {
     }
   }
 
+  if (!controller) {
+    for (int i = 0; i < num_joy; i++) {
+      joystick = SDL_JoystickOpen(i);
+      if (joystick) {
+        printf("Joystick: %s\n", SDL_JoystickName(joystick));
+        break;
+      }
+    }
+  }
+
   SDL_Surface* controls_surface = IMG_Load("controls.png");
   if (!controls_surface) {
     SDL_RWops* rw = SDL_RWFromConstMem(controls_png_data, controls_png_size);
@@ -763,6 +774,26 @@ int main(int argc, char** argv) {
           }
           break;
 
+        case SDL_JOYHATMOTION: {
+          Uint8 hat = e.jhat.value;
+          if (hat & SDL_HAT_LEFT) {
+            focus_index = (focus_index - 1 + FOCUS_COUNT) % FOCUS_COUNT;
+          } else if (hat & SDL_HAT_RIGHT) {
+            focus_index = (focus_index + 1) % FOCUS_COUNT;
+          } else if (hat & SDL_HAT_UP) {
+            if (focus_index == FOCUS_VOLUME) adjust_volume(0.05f);
+          } else if (hat & SDL_HAT_DOWN) {
+            if (focus_index == FOCUS_VOLUME) adjust_volume(-0.05f);
+          }
+          break;
+        }
+
+        case SDL_JOYBUTTONDOWN:
+          if (e.jbutton.button == 0) {
+            activate_focused_button();
+          }
+          break;
+
         case SDL_CONTROLLERDEVICEADDED:
           if (!controller && SDL_IsGameController(e.cdevice.which)) {
             controller = SDL_GameControllerOpen(e.cdevice.which);
@@ -786,6 +817,13 @@ int main(int argc, char** argv) {
             printf("Controller removed\n");
           }
           break;
+
+        case SDL_JOYDEVICEREMOVED:
+          if (joystick && e.jdevice.which == SDL_JoystickInstanceID(joystick)) {
+            SDL_JoystickClose(joystick);
+            joystick = NULL;
+          }
+          break;
       }
     }
 
@@ -898,6 +936,7 @@ int main(int argc, char** argv) {
   decoder_close();
   SDL_FreeAudioStream(stream);
   SDL_DestroyTexture(controls_texture);
+  if (joystick) SDL_JoystickClose(joystick);
   if (controller) SDL_GameControllerClose(controller);
   SDL_CloseAudioDevice(audio_device);
   SDL_DestroyRenderer(renderer);