Add GraphicsContext.PushOffscreen / PopOffscreen (#21)

ebitenutil/debugprint.go

@@ -34,7 +34,7 @@ func DebugPrint(ga ebiten.GameContext, gr ebiten.GraphicsContext, str string) {
 	defaultDebugPrintState.DebugPrint(ga, gr, str)
 }
 
-func (d *debugPrintState) drawText(gr ebiten.GraphicsContext, str string, x, y int) {
+func (d *debugPrintState) drawText(gr ebiten.GraphicsContext, str string, x, y int, clr color.Color) {
 	parts := []ebiten.TexturePart{}
 	locationX, locationY := 0, 0
 	for _, c := range str {
@@ -54,12 +54,11 @@ func (d *debugPrintState) drawText(gr ebiten.GraphicsContext, str string, x, y i
 		})
 		locationX += assets.TextImageCharWidth
 	}
-	geo := ebiten.GeometryMatrixI()
+	geom := ebiten.GeometryMatrixI()
-	geo.Translate(float64(x)+1, float64(y))
+	geom.Translate(float64(x)+1, float64(y))
-	clr := ebiten.ColorMatrixI()
+	clrm := ebiten.ColorMatrixI()
-	// TODO: Is this color OK?
+	clrm.Scale(clr)
-	clr.Scale(color.RGBA{0x80, 0x80, 0x80, 0xff})
+	gr.Texture(d.textTexture).Draw(parts, geom, clrm)
-	gr.Texture(d.textTexture).Draw(parts, geo, clr)
 }
 
 func (d *debugPrintState) DebugPrint(ga ebiten.GameContext, gr ebiten.GraphicsContext, str string) {
@@ -81,5 +80,6 @@ func (d *debugPrintState) DebugPrint(ga ebiten.GameContext, gr ebiten.GraphicsCo
 			panic(err)
 		}
 	}
-	d.drawText(gr, str, 0, d.y)
+	d.drawText(gr, str, 1, d.y+1, &color.RGBA{0x00, 0x00, 0x00, 0x80})
+	d.drawText(gr, str, 0, d.y, &color.RGBA{0xff, 0xff, 0xff, 0xff})
 }

example/blocks/scenemanager.go

@@ -66,16 +66,17 @@ func (s *SceneManager) Draw(context ebiten.GraphicsContext, textures *Textures)
 		return
 	}
 	from := textures.GetRenderTarget("scene_manager_transition_from")
-	context.SetOffscreen(from)
+	context.PushOffscreen(from)
 	context.Clear()
 	s.current.Draw(context, textures)
+	context.PopOffscreen()
 
 	to := textures.GetRenderTarget("scene_manager_transition_to")
-	context.SetOffscreen(to)
+	context.PushOffscreen(to)
 	context.Clear()
 	s.next.Draw(context, textures)
+	context.PopOffscreen()
 
-	context.ResetOffscreen()
 	color := ebiten.ColorMatrixI()
 	ebiten.DrawWhole(
 		context.RenderTarget(from),

example/paint.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"github.com/hajimehoshi/ebiten"
 	"github.com/hajimehoshi/ebiten/ebitenutil"
 	"github.com/hajimehoshi/ebiten/runner"
@@ -35,12 +36,14 @@ func (g *Game) Draw(gr ebiten.GraphicsContext) error {
 		if err != nil {
 			return err
 		}
-		gr.SetOffscreen(g.canvasRenderTarget)
+		gr.PushOffscreen(g.canvasRenderTarget)
 		gr.Fill(0xff, 0xff, 0xff)
+		gr.PopOffscreen()
 	}
-	gr.ResetOffscreen()
 	ebiten.DrawWhole(gr.RenderTarget(g.canvasRenderTarget), screenWidth, screenHeight, ebiten.GeometryMatrixI(), ebiten.ColorMatrixI())
-	ebitenutil.DebugPrint(g.gameContext, gr, "Hello\nWorld!")
+
+	mx, my := g.gameContext.CursorPosition()
+	ebitenutil.DebugPrint(g.gameContext, gr, fmt.Sprintf("(%d, %d)", mx, my))
 	return nil
 }
 

graphics.go

@@ -50,8 +50,8 @@ type GraphicsContext interface {
 	Fill(r, g, b uint8)
 	Texture(id TextureID) Drawer
 	RenderTarget(id RenderTargetID) Drawer
-	ResetOffscreen()
+	PushOffscreen(id RenderTargetID)
-	SetOffscreen(id RenderTargetID)
+	PopOffscreen()
 }
 
 // Filter represents the type of filter to be used when a texture or a render

internal/glfw/canvas.go

@@ -26,6 +26,7 @@ import (
 
 type canvas struct {
 	window          *glfw.Window
+	scale           int
 	graphicsContext *opengl.GraphicsContext
 	input           input
 	funcs           chan func()
@@ -86,7 +87,7 @@ func (c *canvas) use(f func()) {
 }
 
 func (c *canvas) update() {
-	c.input.update(c.window)
+	c.input.update(c.window, c.scale)
 }
 
 func (c *canvas) IsKeyPressed(key ebiten.Key) bool {

internal/glfw/context.go

@@ -58,15 +58,15 @@ func (c *graphicsContext) RenderTarget(id ebiten.RenderTargetID) (d ebiten.Drawe
 	return
 }
 
-func (c *graphicsContext) ResetOffscreen() {
+func (c *graphicsContext) PopOffscreen() {
 	c.canvas.use(func() {
-		c.canvas.graphicsContext.ResetOffscreen()
+		c.canvas.graphicsContext.PopOffscreen()
 	})
 }
 
-func (c *graphicsContext) SetOffscreen(id ebiten.RenderTargetID) {
+func (c *graphicsContext) PushOffscreen(id ebiten.RenderTargetID) {
 	c.canvas.use(func() {
-		c.canvas.graphicsContext.SetOffscreen(id)
+		c.canvas.graphicsContext.PushOffscreen(id)
 	})
 }
 

internal/glfw/input.go

@@ -49,7 +49,7 @@ var glfwKeyCodeToKey = map[glfw.Key]ebiten.Key{
 	glfw.KeyDown:  ebiten.KeyDown,
 }
 
-func (i *input) update(window *glfw.Window) {
+func (i *input) update(window *glfw.Window, scale int) {
 	for g, u := range glfwKeyCodeToKey {
 		i.keyPressed[u] = window.GetKey(g) == glfw.Press
 	}
@@ -57,6 +57,6 @@ func (i *input) update(window *glfw.Window) {
 		i.mouseButtonPressed[b] = window.GetMouseButton(glfw.MouseButton(b)) == glfw.Press
 	}
 	x, y := window.GetCursorPosition()
-	i.cursorX = int(math.Floor(x))
+	i.cursorX = int(math.Floor(x)) / scale
-	i.cursorY = int(math.Floor(y))
+	i.cursorY = int(math.Floor(y)) / scale
 }

internal/glfw/ui.go

@@ -46,6 +46,7 @@ func (u *UI) Start(game ebiten.Game, width, height, scale int, title string) err
 
 	c := &canvas{
 		window:    window,
+		scale:     scale,
 		funcs:     make(chan func()),
 		funcsDone: make(chan struct{}),
 	}

internal/opengl/context.go

@@ -33,27 +33,29 @@ func Initialize(screenWidth, screenHeight, screenScale int) (*GraphicsContext, e
 	}
 
 	// The defualt framebuffer should be 0.
-	c.defaultId = idsInstance.addRenderTarget(&renderTarget{
+	c.defaultID = idsInstance.addRenderTarget(&renderTarget{
 		width:  screenWidth * screenScale,
 		height: screenHeight * screenScale,
 		flipY:  true,
 	})
 
 	var err error
-	c.screenId, err = idsInstance.createRenderTarget(screenWidth, screenHeight, ebiten.FilterNearest)
+	c.screenID, err = idsInstance.createRenderTarget(screenWidth, screenHeight, ebiten.FilterNearest)
 	if err != nil {
 		return nil, err
 	}
-	c.ResetOffscreen()
+
+	// TODO: This is a special stack only for clearing. Can we change this?
+	c.currentIDs = []ebiten.RenderTargetID{c.screenID}
 	c.Clear()
 
 	return c, nil
 }
 
 type GraphicsContext struct {
-	screenId     ebiten.RenderTargetID
+	screenID     ebiten.RenderTargetID
-	defaultId    ebiten.RenderTargetID
+	defaultID    ebiten.RenderTargetID
-	currentId    ebiten.RenderTargetID
+	currentIDs   []ebiten.RenderTargetID
 	screenWidth  int
 	screenHeight int
 	screenScale  int
@@ -63,7 +65,7 @@ var _ ebiten.GraphicsContext = new(GraphicsContext)
 
 func (c *GraphicsContext) dispose() {
 	// NOTE: Now this method is not used anywhere.
-	idsInstance.deleteRenderTarget(c.screenId)
+	idsInstance.deleteRenderTarget(c.screenID)
 }
 
 func (c *GraphicsContext) Clear() {
@@ -71,7 +73,7 @@ func (c *GraphicsContext) Clear() {
 }
 
 func (c *GraphicsContext) Fill(r, g, b uint8) {
-	idsInstance.fillRenderTarget(c.currentId, r, g, b)
+	idsInstance.fillRenderTarget(c.currentIDs[len(c.currentIDs)-1], r, g, b)
 }
 
 func (c *GraphicsContext) Texture(id ebiten.TextureID) ebiten.Drawer {
@@ -82,27 +84,28 @@ func (c *GraphicsContext) RenderTarget(id ebiten.RenderTargetID) ebiten.Drawer {
 	return &textureWithContext{idsInstance.toTexture(id), c}
 }
 
-func (c *GraphicsContext) ResetOffscreen() {
+func (c *GraphicsContext) PushOffscreen(renderTargetID ebiten.RenderTargetID) {
-	c.currentId = c.screenId
+	c.currentIDs = append(c.currentIDs, renderTargetID)
 }
 
-func (c *GraphicsContext) SetOffscreen(renderTargetId ebiten.RenderTargetID) {
+func (c *GraphicsContext) PopOffscreen() {
-	c.currentId = renderTargetId
+	c.currentIDs = c.currentIDs[:len(c.currentIDs)-1]
 }
 
 func (c *GraphicsContext) PreUpdate() {
-	c.ResetOffscreen()
+	c.currentIDs = []ebiten.RenderTargetID{c.defaultID}
+	c.PushOffscreen(c.screenID)
 	c.Clear()
 }
 
 func (c *GraphicsContext) PostUpdate() {
-	c.SetOffscreen(c.defaultId)
+	c.PopOffscreen()
 	c.Clear()
 
 	scale := float64(c.screenScale)
 	geo := ebiten.GeometryMatrixI()
 	geo.Scale(scale, scale)
-	ebiten.DrawWhole(c.RenderTarget(c.screenId), c.screenWidth, c.screenHeight, geo, ebiten.ColorMatrixI())
+	ebiten.DrawWhole(c.RenderTarget(c.screenID), c.screenWidth, c.screenHeight, geo, ebiten.ColorMatrixI())
 
 	gl.Flush()
 }
@@ -113,5 +116,6 @@ type textureWithContext struct {
 }
 
 func (t *textureWithContext) Draw(parts []ebiten.TexturePart, geo ebiten.GeometryMatrix, color ebiten.ColorMatrix) {
-	idsInstance.drawTexture(t.context.currentId, t.id, parts, geo, color)
+	currentID := t.context.currentIDs[len(t.context.currentIDs)-1]
+	idsInstance.drawTexture(currentID, t.id, parts, geo, color)
 }