Refactoring

example/game.go

@@ -14,8 +14,18 @@ var TexturePaths = map[string]string{
 	"text":   "images/text.png",
 }
 
+type Size struct {
+	Width  int
+	Height int
+}
+
+var RenderTargetSizes = map[string]Size{
+	"whole": Size{256, 254},
+}
+
 type drawInfo struct {
 	textures      map[string]graphics.TextureId
+	renderTargets map[string]graphics.RenderTargetId
 	inputStr      string
 	textureX      int
 	textureY      int
@@ -41,6 +51,7 @@ func NewGame() *Game {
 		counter:    0,
 		drawInfo: drawInfo{
 			textures:      map[string]graphics.TextureId{},
+			renderTargets: map[string]graphics.RenderTargetId{},
 			textureX:      0,
 			textureY:      0,
 			textureAngle:  0,
@@ -56,11 +67,32 @@ func (game *Game) OnTextureCreated(e graphics.TextureCreatedEvent) {
 	game.textures[e.Tag.(string)] = e.Id
 }
 
+func (game *Game) OnRenderTargetCreated(e graphics.RenderTargetCreatedEvent) {
+	if e.Error != nil {
+		panic(e.Error)
+	}
+	game.renderTargets[e.Tag.(string)] = e.Id
+}
+
 func (game *Game) OnInputStateUpdated(e ui.InputStateUpdatedEvent) {
 	game.inputX, game.inputY = e.X, e.Y
 }
 
+func (game *Game) isInitialized() bool {
+	if len(game.drawInfo.textures) < len(TexturePaths) {
+		return false
+	}
+	if len(game.drawInfo.renderTargets) < len(RenderTargetSizes) {
+		return false
+	}
+	return true
+}
+
 func (game *Game) Update() {
+	if !game.isInitialized() {
+		return
+	}
+
 	const textureWidth = 57
 	const textureHeight = 26
 
@@ -78,27 +110,37 @@ func (game *Game) Update() {
 	}
 	game.drawInfo.textureAngle = 2 * math.Pi * float64(game.counter) / 600
 
-	game.drawInfo.textureGeo = matrix.IdentityGeometry()
+	geo := matrix.IdentityGeometry()
+	geo.Translate(-textureWidth/2, -textureHeight/2)
+	geo.Rotate(game.drawInfo.textureAngle)
+	geo.Translate(textureWidth/2, textureHeight/2)
+	geo.Translate(float64(game.textureX), float64(game.textureY))
 
-	game.drawInfo.textureGeo.Translate(-textureWidth/2, -textureHeight/2)
+	game.drawInfo.textureGeo = geo
-	game.drawInfo.textureGeo.Rotate(game.drawInfo.textureAngle)
-	game.drawInfo.textureGeo.Translate(textureWidth/2, textureHeight/2)
-
-	game.drawInfo.textureGeo.Translate(float64(game.textureX), float64(game.textureY))
 
 	// Update for the next frame.
 	game.inputPrevX, game.inputPrevY = game.inputX, game.inputY
 }
 
 func (game *Game) Draw(g graphics.Canvas) {
-	if len(game.drawInfo.textures) < len(TexturePaths) {
+	if !game.isInitialized() {
 		return
 	}
 
-	g.Fill(128, 128, 255)
+	whole := game.drawInfo.renderTargets["whole"]
+	g.SetOffscreen(whole)
+
+	g.Fill(0x40, 0x60, 0xb0)
 	game.drawTexture(g, game.drawInfo.textureGeo, matrix.IdentityColor())
 	game.drawText(g, game.drawInfo.inputStr, 6, 6, &color.RGBA{0x0, 0x0, 0x0, 0x80})
 	game.drawText(g, game.drawInfo.inputStr, 5, 5, color.White)
+
+	g.ResetOffscreen()
+	g.DrawRenderTarget(whole, matrix.IdentityGeometry(), matrix.IdentityColor())
+	wholeGeo := matrix.IdentityGeometry()
+	wholeGeo.Scale(0.25, 0.25)
+	wholeGeo.Translate(256*3/4, 240*3/4)
+	g.DrawRenderTarget(whole, wholeGeo, matrix.IdentityColor())
 }
 
 func (game *Game) drawText(g graphics.Canvas, text string, x, y int, clr color.Color) {

example/main.go

@@ -42,6 +42,7 @@ func main() {
 	var u UI = cocoa.New(screenWidth, screenHeight, screenScale, title)
 
 	textureCreated := u.TextureCreated()
+	renderTargetCreated := u.RenderTargetCreated()
 	inputStateUpdated := u.InputStateUpdated()
 	screenSizeUpdated := u.ScreenSizeUpdated()
 
@@ -57,6 +58,14 @@ func main() {
 		}()
 	}
 
+	for tag, size := range RenderTargetSizes {
+		tag := tag
+		size := size
+		go func() {
+			u.CreateRenderTarget(tag, size.Width, size.Height)
+		}()
+	}
+
 	drawing := make(chan *graphics.LazyCanvas)
 	go func() {
 		game := NewGame()
@@ -64,18 +73,12 @@ func main() {
 		tick := time.Tick(frameTime)
 		for {
 			select {
-			case e, ok := <-textureCreated:
+			case e := <-textureCreated:
-				if ok {
 				game.OnTextureCreated(e)
-				} else {
+			case e := <-renderTargetCreated:
-					textureCreated = nil
+				game.OnRenderTargetCreated(e)
-				}
+			case e := <-inputStateUpdated:
-			case e, ok := <-inputStateUpdated:
-				if ok {
 				game.OnInputStateUpdated(e)
-				} else {
-					inputStateUpdated = nil
-				}
 			case _, ok := <-screenSizeUpdated:
 				if ok {
 					// Do nothing

ui/cocoa/mainloop.c

@@ -66,8 +66,6 @@ void* CreateWindow(size_t width, size_t height, const char* title, void* glConte
   return window;
 }
 
-static BOOL initialBoot = YES;
-
 void PollEvents(void) {
   for (;;) {
     NSEvent* event = [NSApp nextEventMatchingMask:NSAnyEventMask
@@ -79,6 +77,7 @@ void PollEvents(void) {
     }
     [NSApp sendEvent:event];
   }
+  static BOOL initialBoot = YES;
   if (initialBoot) {
     [NSApp activateIgnoringOtherApps:YES];
     initialBoot = NO;