Add internal/monogame

Updates #1078

internal/monogame/monogame.go

@@ -0,0 +1,68 @@
+// Copyright 2020 The Ebiten 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.
+
+// +build js
+
+package monogame
+
+import (
+	"runtime"
+	"syscall/js"
+)
+
+// TODO: Update this
+const temporaryNamespace = "Go2DotNet.Example.Rotate"
+
+type UpdateDrawer interface {
+	Update() error
+	Draw() error
+}
+
+type Game struct {
+	v      js.Value
+	update js.Func
+	draw   js.Func
+}
+
+func (g *Game) Run() {
+	// Methods named *FromGo is defined to avoid ambiguous matches of methods.
+	g.v.Call("RunFromGo")
+}
+
+func (g *Game) Dispose() {
+	runtime.SetFinalizer(g, nil)
+	g.update.Release()
+	g.draw.Release()
+}
+
+type RenderTarget2D js.Value
+
+func NewGame(ud UpdateDrawer) *Game {
+	update := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		return ud.Update()
+	})
+
+	draw := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		return ud.Draw()
+	})
+
+	v := js.Global().Get(".net").Get(temporaryNamespace+".GoGame").New(update, draw)
+	g := &Game{
+		v:      v,
+		update: update,
+		draw:   draw,
+	}
+	runtime.SetFinalizer(g, (*Game).Dispose)
+	return g
+}

internal/uidriver/monogame/ui.go

@@ -17,16 +17,13 @@
 package monogame
 
 import (
-	"syscall/js"
-
 	"github.com/hajimehoshi/ebiten/internal/driver"
-	"github.com/hajimehoshi/ebiten/internal/graphicsdriver/monogame"
+	graphics "github.com/hajimehoshi/ebiten/internal/graphicsdriver/monogame"
+	"github.com/hajimehoshi/ebiten/internal/monogame"
 )
 
-// TODO: Update this
-const temporaryNamespace = "Go2DotNet.Example.Rotate"
-
 type UI struct {
+	game *monogame.Game
 }
 
 var theUI = &UI{}
@@ -36,17 +33,11 @@ func Get() *UI {
 }
 
 func (*UI) Run(context driver.UIContext) error {
-	update := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
-		return context.Update()
-	})
-	defer update.Release()
+	g := monogame.NewGame(context)
+	defer g.Dispose()
 
-	draw := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
-		return context.Draw()
-	})
-	defer draw.Release()
-
-	js.Global().Get(".net").Get(temporaryNamespace+".GoGameRunner").Call("Run", update, draw)
+	theUI.game = g
+	g.Run()
 	return nil
 }
 
@@ -122,5 +113,5 @@ func (*UI) Window() driver.Window {
 }
 
 func (*UI) Graphics() driver.Graphics {
-	return monogame.Get()
+	return graphics.Get()
 }