Add basic controller input using the SDL2 GameController API

include/emulator.hpp

@@ -23,6 +23,8 @@ class Emulator {
 
     SDL_Window* window;
     SDL_GLContext glContext;
+    SDL_GameController* gameController;
+    int gameControllerID;
 
     static constexpr u32 width = 400;
     static constexpr u32 height = 240 * 2; // * 2 because 2 screens
@@ -40,6 +42,13 @@ public:
             Helpers::panic("Failed to initialize SDL2");
         }
 
+        // Make SDL use consistent positional button mapping
+        SDL_SetHint(SDL_HINT_GAMECONTROLLER_USE_BUTTON_LABELS, "0");
+
+        if (SDL_Init(SDL_INIT_GAMECONTROLLER) < 0) {
+            Helpers::warn("Failed to initialize SDL2 GameController: %s", SDL_GetError());
+        }
+
         // Request OpenGL 4.1 Core (Max available on MacOS)
         // MacOS gets mad if we don't explicitly demand a core profile
         SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
@@ -61,6 +70,15 @@ public:
             Helpers::panic("OpenGL init failed: %s", SDL_GetError());
         }
 
+        if (SDL_WasInit(SDL_INIT_GAMECONTROLLER)) {
+            gameController = SDL_GameControllerOpen(0);
+
+            if (gameController != nullptr) {
+                SDL_Joystick* stick = SDL_GameControllerGetJoystick(gameController);
+                gameControllerID = SDL_JoystickInstanceID(stick);
+            }
+        }
+
         reset();
     }
 

include/services/hid.hpp

@@ -87,6 +87,14 @@ public:
 	void pressKey(u32 mask) { newButtons |= mask; }
 	void releaseKey(u32 mask) { newButtons &= ~mask; }
 
+    s16 getCirclepadX() {
+        return circlePadX;
+    }
+
+    s16 getCirclepadY() {
+        return circlePadY;
+    }
+
 	void setCirclepadX(s16 x) {
 		circlePadX = x;
 

include/services/service_manager.hpp

@@ -90,8 +90,10 @@ class ServiceManager {
 	// Input function wrappers
 	void pressKey(u32 key) { hid.pressKey(key); }
 	void releaseKey(u32 key) { hid.releaseKey(key); }
-	void setCirclepadX(u16 x) { hid.setCirclepadX(x); }
+	s16 getCirclepadX() { return hid.getCirclepadX(); }
-	void setCirclepadY(u16 y) { hid.setCirclepadY(y); }
+	s16 getCirclepadY() { return hid.getCirclepadY(); }
+	void setCirclepadX(s16 x) { hid.setCirclepadX(x); }
+	void setCirclepadY(s16 y) { hid.setCirclepadY(y); }
 	void updateInputs(u64 currentTimestamp) { hid.updateInputs(currentTimestamp); }
 	void setTouchScreenPress(u16 x, u16 y) { hid.setTouchScreenPress(x, y); }
 	void releaseTouchScreen() { hid.releaseTouchScreen(); }

src/emulator.cpp

@@ -117,6 +117,74 @@ void Emulator::run() {
                         srv.releaseTouchScreen();
                     }
                     break;
+
+                case SDL_CONTROLLERDEVICEADDED:
+                    if (gameController != nullptr) {
+                        break;
+                    }
+
+                    gameController = SDL_GameControllerOpen(event.cdevice.which);
+                    break;
+
+                case SDL_CONTROLLERDEVICEREMOVED:
+                    if (event.cdevice.which == gameControllerID) {
+                        SDL_GameControllerClose(gameController);
+                        gameController = nullptr;
+                        gameControllerID = 0;
+                    }
+
+                case SDL_CONTROLLERBUTTONUP:
+                case SDL_CONTROLLERBUTTONDOWN: {
+                    u32 key = 0;
+
+                    switch (event.cbutton.button) {
+                        case SDL_CONTROLLER_BUTTON_A: key = Keys::B; break;
+                        case SDL_CONTROLLER_BUTTON_B: key = Keys::A; break;
+                        case SDL_CONTROLLER_BUTTON_X: key = Keys::Y; break;
+                        case SDL_CONTROLLER_BUTTON_Y: key = Keys::X; break;
+                        case SDL_CONTROLLER_BUTTON_LEFTSHOULDER: key = Keys::L; break;
+                        case SDL_CONTROLLER_BUTTON_RIGHTSHOULDER: key = Keys::R; break;
+                        case SDL_CONTROLLER_BUTTON_DPAD_LEFT: key = Keys::Left; break;
+                        case SDL_CONTROLLER_BUTTON_DPAD_RIGHT: key = Keys::Right; break;
+                        case SDL_CONTROLLER_BUTTON_DPAD_UP: key = Keys::Up; break;
+                        case SDL_CONTROLLER_BUTTON_DPAD_DOWN: key = Keys::Down; break;
+                        case SDL_CONTROLLER_BUTTON_BACK: key = Keys::Select; break;
+                        case SDL_CONTROLLER_BUTTON_START: key = Keys::Start; break;
+                    }
+
+                    if (key != 0) {
+                        if (event.cbutton.state == SDL_PRESSED) {
+                            srv.pressKey(key);
+                        } else {
+                            srv.releaseKey(key);
+                        }
+                    }
+                }
+            }
+        }
+
+        if (gameController != nullptr) {
+            const s16 stickX = SDL_GameControllerGetAxis(gameController, SDL_CONTROLLER_AXIS_LEFTX);
+            const s16 stickY = SDL_GameControllerGetAxis(gameController, SDL_CONTROLLER_AXIS_LEFTY);
+            const s16 deadzone = 3276;
+            const s16 maxValue = 0x9C;
+            const s16 div = 0x8000 / maxValue;
+
+            if (abs(stickX) < deadzone) {
+                // Avoid overriding the keyboard's circlepad input
+                if (abs(srv.getCirclepadX()) != maxValue) {
+                    srv.setCirclepadX(0);
+                }
+            } else {
+                srv.setCirclepadX(stickX / div);
+            }
+
+            if (abs(stickY) < deadzone) {
+                if (abs(srv.getCirclepadY()) != maxValue) {
+                    srv.setCirclepadY(0);
+                }
+            } else {
+                srv.setCirclepadY(-(stickY / div));
             }
         }