internal/ui: use -overlay to provide the implementation for Nintendo Switch

Updates #2372

internal/gamepad/gamepad_nintendosdk.cpp

@@ -20,9 +20,7 @@
 
 extern "C" void ebitengine_UpdateGamepads() {}
 
-extern "C" int ebitengine_GetGamepadCount() {
+extern "C" int ebitengine_GetGamepadCount() { return 0; }
-  return 0;
-}
 
 extern "C" void ebitengine_GetGamepads(struct Gamepad *gamepads) {}
 

internal/nintendosdk/nintendosdk.go

@@ -32,10 +32,6 @@ package nintendosdk
 // void EbitenGetScreenSize(int* width, int* height);
 // void EbitenBeginFrame();
 // void EbitenEndFrame();
-//
-// // Input
-// int EbitenGetTouchNum();
-// void EbitenGetTouches(struct Touch* touches);
 import "C"
 
 type Touch struct {
@@ -61,27 +57,3 @@ func BeginFrame() {
 func EndFrame() {
 	C.EbitenEndFrame()
 }
-
-var cTouches []C.struct_Touch
-
-func AppendTouches(touches []Touch) []Touch {
-	n := int(C.EbitenGetTouchNum())
-	cTouches = cTouches[:0]
-	if cap(cTouches) < n {
-		cTouches = append(cTouches, make([]C.struct_Touch, n)...)
-	} else {
-		cTouches = cTouches[:n]
-	}
-	if n > 0 {
-		C.EbitenGetTouches(&cTouches[0])
-	}
-
-	for _, t := range cTouches {
-		touches = append(touches, Touch{
-			ID: int(t.id),
-			X:  int(t.x),
-			Y:  int(t.y),
-		})
-	}
-	return touches
-}

internal/ui/input_nintendosdk.cpp

@@ -0,0 +1,25 @@
+// Copyright 2023 The Ebitengine Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build nintendosdk
+
+// The actual implementaiton will be provided by -overlay.
+
+#include "input_nintendosdk.h"
+
+extern "C" void ebitengine_UpdateTouches() {}
+
+extern "C" int ebitengine_GetTouchCount() { return 0; }
+
+extern "C" void ebitengine_GetTouches(struct Touch *touches) {}

internal/ui/input_nintendosdk.go

@@ -16,22 +16,33 @@
 
 package ui
 
-import (
+// #cgo !darwin LDFLAGS: -Wl,-unresolved-symbols=ignore-all
-	"github.com/hajimehoshi/ebiten/v2/internal/nintendosdk"
+// #cgo darwin LDFLAGS: -Wl,-undefined,dynamic_lookup
-)
+//
+// #include "input_nintendosdk.h"
+import "C"
 
 func (u *userInterfaceImpl) updateInputState() {
+	C.ebitengine_UpdateTouches()
+
 	u.nativeTouches = u.nativeTouches[:0]
-	u.nativeTouches = nintendosdk.AppendTouches(u.nativeTouches)
+	if n := int(C.ebitengine_GetTouchCount()); n > 0 {
+		if cap(u.nativeTouches) < n {
+			u.nativeTouches = make([]C.struct_Touch, n)
+		} else {
+			u.nativeTouches = u.nativeTouches[:n]
+		}
+		C.ebitengine_GetTouches(&u.nativeTouches[0])
+	}
 
 	for i := range u.inputState.Touches {
 		u.inputState.Touches[i].Valid = false
 	}
 	for i, t := range u.nativeTouches {
-		x, y := u.context.clientPositionToLogicalPosition(float64(t.X), float64(t.Y), deviceScaleFactor)
+		x, y := u.context.clientPositionToLogicalPosition(float64(t.x), float64(t.y), deviceScaleFactor)
 		u.inputState.Touches[i] = Touch{
 			Valid: true,
-			ID:    TouchID(t.ID),
+			ID:    TouchID(t.id),
 			X:     int(x),
 			Y:     int(y),
 		}

internal/ui/input_nintendosdk.h

@@ -0,0 +1,33 @@
+// Copyright 2023 The Ebitengine Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build nintendosdk
+
+struct Touch {
+  int id;
+  int x;
+  int y;
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void ebitengine_UpdateTouches();
+int ebitengine_GetTouchCount();
+void ebitengine_GetTouches(struct Touch* touches);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif

internal/ui/ui_nintendosdk.go

@@ -16,6 +16,9 @@
 
 package ui
 
+// #include "input_nintendosdk.h"
+import "C"
+
 import (
 	"runtime"
 
@@ -55,7 +58,7 @@ type userInterfaceImpl struct {
 
 	context       *context
 	inputState    InputState
-	nativeTouches []nintendosdk.Touch
+	nativeTouches []C.struct_Touch
 }
 
 func (u *userInterfaceImpl) Run(game Game, options *RunOptions) error {