Add AsyncGraphicsContext; Use goroutines in the main routine

ebiten.go

@@ -30,29 +30,35 @@ type InputState struct {
 	Y        int
 }
 
-func OpenGLRun(game Game, ui UI, screenScale int, input chan InputState) {
-	ch := make(chan bool, 1)
+func OpenGLRun(game Game, ui UI, screenScale int, input <-chan InputState) {
+	deviceUpdate := make(chan bool)
+	commandSet := make(chan chan func(graphics.GraphicsContext))
+
 	graphicsDevice := opengl.NewDevice(
-		game.ScreenWidth(), game.ScreenHeight(), screenScale,
-		func(g graphics.GraphicsContext, offscreen graphics.Texture) {
-			ticket := <-ch
-			game.Draw(g, offscreen)
-			ch <- ticket
-		})
+		game.ScreenWidth(), game.ScreenHeight(), screenScale, deviceUpdate, commandSet)
+
+	game.Init(graphicsDevice.TextureFactory())
 
 	go func() {
 		frameTime := time.Duration(int64(time.Second) / int64(game.Fps()))
-		tick := time.Tick(frameTime)
+		updateTick := time.Tick(frameTime)
 		for {
-			<-tick
-			ticket := <-ch
-			inputState := <-input
-			game.Update(inputState)
-			ch <- ticket
+			select {
+			case <-updateTick:
+				inputState := <-input
+				game.Update(inputState)
+			case <-deviceUpdate:
+				commands := make(chan func(graphics.GraphicsContext))
+				commandSet <- commands
+				g := graphics.NewAsyncGraphicsContext(commands)
+				// TODO: graphicsDevice is shared by multiple goroutines.
+				game.Draw(g, graphicsDevice.OffscreenTexture())
+				close(commands)
+			}
 		}
 	}()
 
-	game.Init(graphicsDevice.TextureFactory())
-	ch <- true
+
+	// UI should be executed on the main thread.
 	ui.Run(graphicsDevice)
 }

graphics/async_graphics_context.go

@@ -0,0 +1,57 @@
+package graphics
+
+import (
+	"github.com/hajimehoshi/go.ebiten/graphics/matrix"
+	"image/color"
+)
+
+type AsyncGraphicsContext struct {
+	ch chan<- func(GraphicsContext)
+}
+
+func NewAsyncGraphicsContext(ch chan<- func(GraphicsContext)) *AsyncGraphicsContext {
+	return &AsyncGraphicsContext{
+		ch: ch,
+	}
+}
+
+func (g *AsyncGraphicsContext) Clear() {
+	g.ch <- func(g2 GraphicsContext) {
+		g2.Clear()
+	}
+}
+
+func (g *AsyncGraphicsContext) Fill(clr color.Color) {
+	g.ch <- func(g2 GraphicsContext) {
+		g2.Fill(clr)
+	}
+}
+
+func (g *AsyncGraphicsContext) DrawRect(rect Rect, clr color.Color) {
+	g.ch <- func(g2 GraphicsContext) {
+		g2.DrawRect(rect, clr)
+	}
+}
+
+func (g *AsyncGraphicsContext) DrawTexture(textureID TextureID,
+	geometryMatrix matrix.Geometry,
+	colorMatrix matrix.Color) {
+	g.ch <- func(g2 GraphicsContext) {
+		g2.DrawTexture(textureID, geometryMatrix, colorMatrix)
+	}
+}
+
+func (g *AsyncGraphicsContext) DrawTextureParts(textureID TextureID,
+	locations []TexturePart,
+	geometryMatrix matrix.Geometry,
+	colorMatrix matrix.Color) {
+	g.ch <- func(g2 GraphicsContext) {
+		g2.DrawTextureParts(textureID, locations, geometryMatrix, colorMatrix)
+	}
+}
+
+func (g *AsyncGraphicsContext) SetOffscreen(textureID TextureID) {
+	g.ch <- func(g2 GraphicsContext) {
+		g2.SetOffscreen(textureID)
+	}
+}

graphics/graphics.go

@@ -9,6 +9,7 @@ import (
 type Device interface {
 	Update()
 	TextureFactory() TextureFactory
+	OffscreenTexture() Texture
 }
 
 type Rect struct {
@@ -26,7 +27,7 @@ type TexturePart struct {
 
 type GraphicsContext interface {
 	Clear()
-	Fill(color color.Color)
+	Fill(clr color.Color)
 	DrawRect(rect Rect, clr color.Color)
 	DrawTexture(textureID TextureID,
 		geometryMatrix matrix.Geometry,

graphics/opengl/device.go

@@ -16,23 +16,32 @@ type Device struct {
 	screenScale      int
 	graphicsContext  *GraphicsContext
 	offscreenTexture graphics.Texture
-	drawFunc         func(graphics.GraphicsContext, graphics.Texture)
+	deviceUpdate     chan<- bool
+	commandSet       <-chan chan func(graphics.GraphicsContext)
 }
 
 func NewDevice(screenWidth, screenHeight, screenScale int,
-	drawFunc func(graphics.GraphicsContext, graphics.Texture)) *Device {
+	deviceUpdate chan<- bool,
+	commandSet <-chan chan func(graphics.GraphicsContext)) *Device {
+	graphicsContext := newGraphicsContext(screenWidth, screenHeight, screenScale)
+
 	device := &Device{
 		screenWidth:     screenWidth,
 		screenHeight:    screenHeight,
 		screenScale:     screenScale,
-		graphicsContext: newGraphicsContext(screenWidth, screenHeight, screenScale),
-		drawFunc:        drawFunc,
+		deviceUpdate:    deviceUpdate,
+		commandSet:      commandSet,
+		graphicsContext: graphicsContext,
 	}
 	device.offscreenTexture =
 		device.graphicsContext.NewTexture(screenWidth, screenHeight)
 	return device
 }
 
+func (device *Device) OffscreenTexture() graphics.Texture {
+	return device.offscreenTexture
+}
+
 func (device *Device) Update() {
 	g := device.graphicsContext
 	C.glEnable(C.GL_TEXTURE_2D)
@@ -40,7 +49,13 @@ func (device *Device) Update() {
 	C.glTexParameteri(C.GL_TEXTURE_2D, C.GL_TEXTURE_MAG_FILTER, C.GL_NEAREST)
 	g.SetOffscreen(device.offscreenTexture.ID)
 	g.Clear()
-	device.drawFunc(g, device.offscreenTexture)
+
+	device.deviceUpdate <- true
+	commands := <-device.commandSet
+	for command := range commands {
+		command(g)
+	}
+
 	g.flush()
 
 	C.glTexParameteri(C.GL_TEXTURE_2D, C.GL_TEXTURE_MIN_FILTER, C.GL_LINEAR)