Add LazyCanvas

example/main.go

@@ -13,7 +13,6 @@ import (
 	"github.com/hajimehoshi/go-ebiten/ui/cocoa"
 	"os"
 	"runtime"
-	"sync"
 	"time"
 )
 
@@ -60,25 +59,13 @@ func main() {
 	var ui ebiten.UI = cocoa.New(screenWidth, screenHeight, screenScale, title)
 	ui.InitTextures(game.InitTextures)
 
-	lock := sync.Mutex{}
+	drawing := make(chan *graphics.LazyCanvas)
 	go func() {
-		frameTime := time.Duration(int64(time.Second) / int64(fps))
-		tick := time.Tick(frameTime)
-		for {
-			<-tick
-			func() {
-				lock.Lock()
-				defer lock.Unlock()
-				game.Update()
-			}()
-		}
-	}()
-
 		inputStateUpdated := ui.ObserveInputStateUpdated()
 		screenSizeUpdated := ui.ObserveScreenSizeUpdated()
-	for {
-		ui.PollEvents()
-	events:
+
+		frameTime := time.Duration(int64(time.Second) / int64(fps))
+		tick := time.Tick(frameTime)
 		for {
 			select {
 			case e, ok := <-inputStateUpdated:
@@ -101,14 +88,21 @@ func main() {
 					}
 				}
 				screenSizeUpdated = ui.ObserveScreenSizeUpdated()
-			default:
-				break events
+			case <-tick:
+				game.Update()
+			case canvas := <-drawing:
+				game.Draw(canvas)
+				drawing <- canvas
 			}
 		}
+	}()
+
+	for {
+		ui.PollEvents()
 		ui.Draw(func(c graphics.Canvas) {
-			lock.Lock()
-			defer lock.Unlock()
-			game.Draw(c)
+			drawing <- graphics.NewLazyCanvas()
+			canvas := <-drawing
+			canvas.Flush(c)
 		})
 	}
 }

graphics/canvas.go

@@ -0,0 +1,102 @@
+package graphics
+
+import (
+	"github.com/hajimehoshi/go-ebiten/graphics/matrix"
+)
+
+type Canvas interface {
+	Clear()
+	Fill(r, g, b uint8)
+	DrawTexture(id TextureId,
+		geometryMatrix matrix.Geometry,
+		colorMatrix matrix.Color)
+	DrawRenderTarget(id RenderTargetId,
+		geometryMatrix matrix.Geometry,
+		colorMatrix matrix.Color)
+	DrawTextureParts(id TextureId,
+		parts []TexturePart,
+		geometryMatrix matrix.Geometry,
+		colorMatrix matrix.Color)
+	DrawRenderTargetParts(id RenderTargetId,
+		parts []TexturePart,
+		geometryMatrix matrix.Geometry,
+		colorMatrix matrix.Color)
+
+	ResetOffscreen()
+	SetOffscreen(id RenderTargetId)
+}
+
+type LazyCanvas struct {
+	funcs []func(Canvas)
+}
+
+func NewLazyCanvas() *LazyCanvas {
+	return &LazyCanvas{
+		funcs: []func(Canvas){},
+	}
+}
+
+func (c *LazyCanvas) Flush(actual Canvas) {
+	for _, f := range c.funcs {
+		f(actual)
+	}
+	c.funcs = []func(Canvas){}
+}
+
+func (c *LazyCanvas) Clear() {
+	c.funcs = append(c.funcs, func(actual Canvas) {
+		actual.Clear()
+	})
+}
+
+func (c *LazyCanvas) Fill(r, g, b uint8) {
+	c.funcs = append(c.funcs, func(actual Canvas) {
+		actual.Fill(r, g, b)
+	})
+}
+
+func (c *LazyCanvas) DrawTexture(id TextureId,
+	geometryMatrix matrix.Geometry,
+	colorMatrix matrix.Color) {
+	c.funcs = append(c.funcs, func(actual Canvas) {
+		actual.DrawTexture(id, geometryMatrix, colorMatrix)
+	})
+}
+
+func (c *LazyCanvas) DrawRenderTarget(id RenderTargetId,
+	geometryMatrix matrix.Geometry,
+	colorMatrix matrix.Color) {
+	c.funcs = append(c.funcs, func(actual Canvas) {
+		actual.DrawRenderTarget(id, geometryMatrix, colorMatrix)
+	})
+}
+
+func (c *LazyCanvas) DrawTextureParts(id TextureId,
+	parts []TexturePart,
+	geometryMatrix matrix.Geometry,
+	colorMatrix matrix.Color) {
+	c.funcs = append(c.funcs, func(actual Canvas) {
+		actual.DrawTextureParts(id, parts, geometryMatrix, colorMatrix)
+	})
+}
+
+func (c *LazyCanvas) DrawRenderTargetParts(id RenderTargetId,
+	parts []TexturePart,
+	geometryMatrix matrix.Geometry,
+	colorMatrix matrix.Color) {
+	c.funcs = append(c.funcs, func(actual Canvas) {
+		actual.DrawRenderTargetParts(id, parts, geometryMatrix, colorMatrix)
+	})
+}
+
+func (c *LazyCanvas) ResetOffscreen() {
+	c.funcs = append(c.funcs, func(actual Canvas) {
+		actual.ResetOffscreen()
+	})
+}
+
+func (c *LazyCanvas) SetOffscreen(id RenderTargetId) {
+	c.funcs = append(c.funcs, func(actual Canvas) {
+		actual.SetOffscreen(id)
+	})
+}

graphics/graphics.go

@@ -1,7 +1,6 @@
 package graphics
 
 import (
-	"github.com/hajimehoshi/go-ebiten/graphics/matrix"
 	"image"
 )
 
@@ -18,28 +17,6 @@ type TexturePart struct {
 	Source    Rect
 }
 
-type Canvas interface {
-	Clear()
-	Fill(r, g, b uint8)
-	DrawTexture(id TextureId,
-		geometryMatrix matrix.Geometry,
-		colorMatrix matrix.Color)
-	DrawRenderTarget(id RenderTargetId,
-		geometryMatrix matrix.Geometry,
-		colorMatrix matrix.Color)
-	DrawTextureParts(id TextureId,
-		parts []TexturePart,
-		geometryMatrix matrix.Geometry,
-		colorMatrix matrix.Color)
-	DrawRenderTargetParts(id RenderTargetId,
-		parts []TexturePart,
-		geometryMatrix matrix.Geometry,
-		colorMatrix matrix.Color)
-
-	ResetOffscreen()
-	SetOffscreen(id RenderTargetId)
-}
-
 type TextureFactory interface {
 	CreateRenderTarget(width, height int) (RenderTargetId, error)
 	CreateTextureFromImage(img image.Image) (TextureId, error)

graphics/matrix/affine.go

@@ -1,12 +1,12 @@
 package matrix
 
-type Affine interface {
+type affine interface {
 	Dim() int
 	element(i, j int) float64
 	setElement(i, j int, element float64)
 }
 
-func isIdentity(matrix Affine) bool {
+func isIdentity(matrix affine) bool {
 	dim := matrix.Dim()
 	for i := 0; i < dim-1; i++ {
 		for j := 0; j < dim; j++ {
@@ -21,7 +21,7 @@ func isIdentity(matrix Affine) bool {
 	return true
 }
 
-func mul(lhs, rhs, result Affine) {
+func mul(lhs, rhs, result affine) {
 	dim := lhs.Dim()
 	if dim != rhs.Dim() {
 		panic("diffrent-sized matrices can't be multiplied")