Add multitap support to SNES

Change SNES emulator to Snes9X
Add client control to toggle multitap

pkg/config/config.go

@@ -61,6 +61,7 @@ type EmulatorMeta struct {
 	Rotation        image.Rotate
 	IsGlAllowed     bool
 	UsesLibCo       bool
+	HasMultitap     bool
 }
 
 var EmulatorConfig = map[string]EmulatorMeta{
@@ -80,9 +81,10 @@ var EmulatorConfig = map[string]EmulatorMeta{
 		Height: 240,
 	},
 	"snes": {
-		Path:   "assets/emulator/libretro/cores/mednafen_snes_libretro",
+		Path:   "assets/emulator/libretro/cores/snes9x_libretro",
 		Width:  256,
 		Height: 224,
+		HasMultitap: true,
 	},
 	"mame": {
 		Path:   "assets/emulator/libretro/cores/fbneo_libretro",

pkg/coordinator/browser.go

@@ -171,4 +171,19 @@ func (o *Server) RouteBrowser(client *BrowserClient) {
 
 		return resp
 	})
+
+	client.Receive("multitap", func(resp cws.WSPacket) (req cws.WSPacket) {
+		client.Println("Received multitap request from a browser -> relay to worker")
+
+		// TODO: Async
+		resp.SessionID = client.SessionID
+		resp.RoomID = client.RoomID
+		wc, ok := o.workerClients[client.WorkerID]
+		if !ok {
+			return cws.EmptyPacket
+		}
+		resp = wc.SyncSend(resp)
+
+		return resp
+	})
 }

pkg/emulator/libretro/nanoarch/cfuncs.go

@@ -83,6 +83,10 @@ bool bridge_retro_unserialize(void *f, void *data, size_t size) {
   return ((bool (*)(void*, size_t))f)(data, size);
 }
 
+void bridge_retro_set_controller_port_device(void *f, unsigned port, unsigned device) {
+  return ((void (*)(unsigned, unsigned))f)(port, device);
+}
+
 bool coreEnvironment_cgo(unsigned cmd, void *data) {
 	bool coreEnvironment(unsigned, void*);
 	return coreEnvironment(cmd, data);

pkg/emulator/libretro/nanoarch/naemulator.go

@@ -140,7 +140,7 @@ func (na *naEmulator) listenInput() {
 }
 
 func (na *naEmulator) LoadMeta(path string) config.EmulatorMeta {
-	coreLoad(na.meta.Path, na.meta.IsGlAllowed, na.meta.UsesLibCo, na.meta.Config)
+	coreLoad(na.meta)
 	coreLoadGame(path)
 	na.gamePath = path
 
@@ -206,6 +206,14 @@ func (na *naEmulator) LoadGame() error {
 	return nil
 }
 
+func (na *naEmulator) ToggleMultitap() error {
+	if na.roomID != "" {
+		toggleMultitap()
+	}
+
+	return nil
+}
+
 func (na *naEmulator) GetHashPath() string {
 	return util.GetSavePath(na.roomID)
 }

pkg/emulator/libretro/nanoarch/nanoarch.go

@@ -49,6 +49,7 @@ void* bridge_retro_get_memory_data(void *f, unsigned id);
 bool bridge_retro_serialize(void *f, void *data, size_t size);
 bool bridge_retro_unserialize(void *f, void *data, size_t size);
 size_t bridge_retro_serialize_size(void *f);
+void bridge_retro_set_controller_port_device(void *f, unsigned port, unsigned device);
 
 bool coreEnvironment_cgo(unsigned cmd, void *data);
 void coreVideoRefresh_cgo(void *data, unsigned width, unsigned height, size_t pitch);
@@ -100,6 +101,12 @@ var isGlAllowed bool
 var usesLibCo bool
 var coreConfig ConfigProperties
 
+var multitap struct {
+	supported bool
+	enabled   bool
+	value     C.unsigned
+}
+
 var systemDirectory = C.CString("./pkg/emulator/libretro/system")
 var saveDirectory = C.CString(".")
 var currentUser *C.char
@@ -131,6 +138,7 @@ type CloudEmulator interface {
 	LoadGame() error
 	GetHashPath() string
 	Close()
+	ToggleMultitap() error
 }
 
 //export coreVideoRefresh
@@ -328,6 +336,22 @@ func coreEnvironment(cmd C.unsigned, data unsafe.Pointer) C.bool {
 			return true
 		}
 		return false
+	case C.RETRO_ENVIRONMENT_SET_CONTROLLER_INFO:
+		if (multitap.supported) {
+			info := (*[100]C.struct_retro_controller_info)(data)
+			var i C.unsigned
+			for i = 0; unsafe.Pointer(info[i].types) != nil; i++ {
+				var j C.unsigned
+				types := (*[100]C.struct_retro_controller_description)(unsafe.Pointer(info[i].types))
+				for j = 0; j < info[i].num_types; j++ {
+					if (C.GoString(types[j].desc) == "Multitap") {
+						multitap.value = types[j].id
+						return true
+					}
+				}
+			}
+		}
+		return false
 	default:
 		//fmt.Println("[Env]: command not implemented", cmd)
 		return false
@@ -478,6 +502,7 @@ var retroGetMemoryData unsafe.Pointer
 var retroSerializeSize unsafe.Pointer
 var retroSerialize unsafe.Pointer
 var retroUnserialize unsafe.Pointer
+var retroSetControllerPortDevice unsafe.Pointer
 
 func loadFunction(handle unsafe.Pointer, name string) unsafe.Pointer {
 	cs := C.CString(name)
@@ -486,15 +511,19 @@ func loadFunction(handle unsafe.Pointer, name string) unsafe.Pointer {
 	return pointer
 }
 
-func coreLoad(pathNoExt string, isGlAllowedParam bool, usesLibCoParam bool, pathToCfg string) {
-	isGlAllowed = isGlAllowedParam
-	usesLibCo = usesLibCoParam
-	coreConfig = ScanConfigFile(pathToCfg)
+func coreLoad(meta config.EmulatorMeta) {
+	isGlAllowed = meta.IsGlAllowed
+	usesLibCo = meta.UsesLibCo
+	coreConfig = ScanConfigFile(meta.Config)
+
+	multitap.supported = meta.HasMultitap
+	multitap.enabled = false
+	multitap.value = 0
 
 	mu.Lock()
 	// Different OS requires different library, bruteforce till it finish
 	for _, ext := range config.EmulatorExtension {
-		pathWithExt := pathNoExt + ext
+		pathWithExt := meta.Path + ext
 		cs := C.CString(pathWithExt)
 		retroHandle = C.dlopen(cs, C.RTLD_LAZY)
 		C.free(unsafe.Pointer(cs))
@@ -505,7 +534,7 @@ func coreLoad(pathNoExt string, isGlAllowedParam bool, usesLibCoParam bool, path
 
 	if retroHandle == nil {
 		err := C.dlerror()
-		log.Fatalf("error loading %s, err %+v", pathNoExt, *err)
+		log.Fatalf("error loading %s, err %+v", meta.Path, *err)
 	}
 
 	retroInit = loadFunction(retroHandle, "retro_init")
@@ -525,6 +554,7 @@ func coreLoad(pathNoExt string, isGlAllowedParam bool, usesLibCoParam bool, path
 	retroSerializeSize = loadFunction(retroHandle, "retro_serialize_size")
 	retroSerialize = loadFunction(retroHandle, "retro_serialize")
 	retroUnserialize = loadFunction(retroHandle, "retro_unserialize")
+	retroSetControllerPortDevice = loadFunction(retroHandle, "retro_set_controller_port_device")
 
 	mu.Unlock()
 
@@ -650,6 +680,21 @@ func coreLoadGame(filename string) {
 	}
 }
 
+func toggleMultitap() {
+	if (multitap.supported && multitap.value != 0) {
+		// Official SNES games only support a single multitap device
+		// Most require it to be plugged in player 2 port
+		// And Snes9X requires it to be "plugged" after the game is loaded
+		// Control this from the browser since player 2 will stop working in some games if multitap is "plugged" in
+		if (multitap.enabled) {
+			C.bridge_retro_set_controller_port_device(retroSetControllerPortDevice, 1, C.RETRO_DEVICE_JOYPAD)
+		} else {
+			C.bridge_retro_set_controller_port_device(retroSetControllerPortDevice, 1, multitap.value)
+		}
+		multitap.enabled = !multitap.enabled
+	}
+}
+
 // serializeSize returns the amount of data the implementation requires to serialize
 // internal state (save states).
 // Between calls to retro_load_game() and retro_unload_game(), the

pkg/emulator/type.go

@@ -19,4 +19,6 @@ type CloudEmulator interface {
 	GetHashPath() string
 	// Close will be called when the game is done
 	Close()
+
+	ToggleMultitap() error
 }

pkg/worker/coordinator.go

@@ -265,6 +265,26 @@ func (h *Handler) RouteCoordinator() {
 			return req
 		})
 
+		oClient.Receive(
+			"multitap",
+			func(resp cws.WSPacket) (req cws.WSPacket) {
+				log.Println("Received a multitap toggle from coordinator")
+				req.ID = "multitap"
+				req.Data = "ok"
+				if resp.RoomID != "" {
+					room := h.getRoom(resp.RoomID)
+					err := room.ToggleMultitap()
+					if err != nil {
+						log.Println("[!] Could not toggle multitap state: ", err)
+						req.Data = "error"
+					}
+				} else {
+					req.Data = "error"
+				}
+
+				return req
+			})
+
 	oClient.Receive(
 		"terminateSession",
 		func(resp cws.WSPacket) (req cws.WSPacket) {

pkg/worker/room/room.go

@@ -375,6 +375,12 @@ func (r *Room) LoadGame() error {
 	return err
 }
 
+func (r *Room) ToggleMultitap() error {
+	err := r.director.ToggleMultitap()
+
+	return err
+}
+
 func (r *Room) EmptySessions() bool {
 	return len(r.rtcSessions) == 0
 }

web/js/controller.js

@@ -379,6 +379,11 @@
                             updatePlayerIndex(3);
                             break;
 
+                        // toggle multitap
+                        case KEY.MULTITAP:
+                            socket.toggleMultitap();
+                            break;
+
                         // quit
                         case KEY.QUIT:
                             input.poll().disable();

web/js/input/keyboard.js

@@ -31,6 +31,7 @@ const keyboard = (() => {
         72: KEY.HELP, // h
         220: KEY.STATS, // backslash
         84: KEY.DTOGGLE, // t
+        77: KEY.MULTITAP, // m
     };
 
     let dpadMode = true;

web/js/input/keys.js

@@ -28,5 +28,6 @@ const KEY = (() => {
         R2: 'r2',
         L3: 'l3',
         R3: 'r3',
+        MULTITAP: 'multitap',
     }
 })();

web/js/network/socket.js

@@ -114,6 +114,7 @@ const socket = (() => {
         "player_index": playerIndex
     });
     const quitGame = (roomId) => send({"id": "quit", "data": "", "room_id": roomId});
+    const toggleMultitap = () => send({"id": "multitap", "data": ""});
 
     return {
         init: init,
@@ -123,6 +124,7 @@ const socket = (() => {
         loadGame: loadGame,
         updatePlayerIndex: updatePlayerIndex,
         startGame: startGame,
-        quitGame: quitGame
+        quitGame: quitGame,
+        toggleMultitap: toggleMultitap,
     }
 })($, event, log);