internal/atlas: always use DrawTriangles at putOnAtlas

DrawTriangles was introduced at #1508, and apparently there is no
reason we should use ReplacePixels here. So, simplify the logic by
using only DrawTriangles.

internal/atlas/image.go

@@ -341,37 +341,18 @@ func (i *Image) putOnAtlas(graphicsDriver graphicsdriver.Graphics) error {
 
 	newI := NewImage(i.width, i.height, ImageTypeRegular)
 
-	if restorable.NeedsRestoring() {
+	// If the underlying graphics driver doesn't require restoring from the context lost, just a regular
-		// If the underlying graphics driver requires restoring from the context lost, the pixel data is
+	// rendering works.
-		// needed. An image on an atlas must have its complete pixel data in this case.
+	w, h := float32(i.width), float32(i.height)
-		pixels := make([]byte, 4*i.width*i.height)
+	vs := graphics.QuadVertices(0, 0, w, h, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1)
-		for y := 0; y < i.height; y++ {
+	is := graphics.QuadIndices()
-			for x := 0; x < i.width; x++ {
+	dr := graphicsdriver.Region{
-				r, g, b, a, err := i.at(graphicsDriver, x+i.paddingSize(), y+i.paddingSize())
+		X:      0,
-				if err != nil {
+		Y:      0,
-					return err
+		Width:  w,
-				}
+		Height: h,
-				pixels[4*(i.width*y+x)] = r
-				pixels[4*(i.width*y+x)+1] = g
-				pixels[4*(i.width*y+x)+2] = b
-				pixels[4*(i.width*y+x)+3] = a
-			}
-		}
-		newI.replacePixels(pixels, nil)
-	} else {
-		// If the underlying graphics driver doesn't require restoring from the context lost, just a regular
-		// rendering works.
-		w, h := float32(i.width), float32(i.height)
-		vs := graphics.QuadVertices(0, 0, w, h, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1)
-		is := graphics.QuadIndices()
-		dr := graphicsdriver.Region{
-			X:      0,
-			Y:      0,
-			Width:  w,
-			Height: h,
-		}
-		newI.drawTriangles([graphics.ShaderImageNum]*Image{i}, vs, is, affine.ColorMIdentity{}, graphicsdriver.CompositeModeCopy, graphicsdriver.FilterNearest, graphicsdriver.AddressUnsafe, dr, graphicsdriver.Region{}, [graphics.ShaderImageNum - 1][2]float32{}, nil, nil, false, true)
 	}
+	newI.drawTriangles([graphics.ShaderImageNum]*Image{i}, vs, is, affine.ColorMIdentity{}, graphicsdriver.CompositeModeCopy, graphicsdriver.FilterNearest, graphicsdriver.AddressUnsafe, dr, graphicsdriver.Region{}, [graphics.ShaderImageNum - 1][2]float32{}, nil, nil, false, true)
 
 	newI.moveTo(i)
 	i.usedAsSourceCount = 0

internal/restorable/image.go

@@ -127,7 +127,7 @@ func ensureEmptyImage() *Image {
 		return emptyImage
 	}
 
-	// Initialize the empty image lazily. Some functions like NeedsRestoring might not work at the initial phase.
+	// Initialize the empty image lazily. Some functions like needsRestoring might not work at the initial phase.
 
 	// w and h are the empty image's size. They indicate the 1x1 image with 1px padding around.
 	const w, h = 3, 3
@@ -299,7 +299,7 @@ func (i *Image) ReplacePixels(pixels []byte, mask []byte, x, y, width, height in
 		i.image.ReplacePixels(make([]byte, 4*width*height), nil, x, y, width, height)
 	}
 
-	if !NeedsRestoring() || !i.needsRestoring() {
+	if !needsRestoring() || !i.needsRestoring() {
 		i.makeStale()
 		return
 	}
@@ -373,7 +373,7 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderImageNum]*Image, offsets [gra
 		}
 	}
 
-	if srcstale || !NeedsRestoring() || !i.needsRestoring() {
+	if srcstale || !needsRestoring() || !i.needsRestoring() {
 		i.makeStale()
 	} else {
 		i.appendDrawTrianglesHistory(srcs, offsets, vertices, indices, colorm, mode, filter, address, dstRegion, srcRegion, shader, uniforms, evenOdd)
@@ -498,7 +498,7 @@ func (i *Image) readPixelsFromGPU(graphicsDriver graphicsdriver.Graphics) error
 
 // resolveStale resolves the image's 'stale' state.
 func (i *Image) resolveStale(graphicsDriver graphicsdriver.Graphics) error {
-	if !NeedsRestoring() {
+	if !needsRestoring() {
 		return nil
 	}
 	if !i.needsRestoring() {

internal/restorable/images.go

@@ -29,8 +29,8 @@ var forceRestoring = false
 
 var needsRestoringByGraphicsDriver bool
 
-// NeedsRestoring reports whether restoring process works or not.
+// needsRestoring reports whether restoring process works or not.
-func NeedsRestoring() bool {
+func needsRestoring() bool {
 	return forceRestoring || needsRestoringByGraphicsDriver
 }
 
@@ -70,7 +70,7 @@ func ResolveStaleImages(graphicsDriver graphicsdriver.Graphics) error {
 	if err := graphicscommand.FlushCommands(graphicsDriver); err != nil {
 		return err
 	}
-	if !NeedsRestoring() {
+	if !needsRestoring() {
 		return nil
 	}
 	return theImages.resolveStaleImages(graphicsDriver)
@@ -80,7 +80,7 @@ func ResolveStaleImages(graphicsDriver graphicsdriver.Graphics) error {
 //
 // Restoring means to make all *graphicscommand.Image objects have their textures and framebuffers.
 func RestoreIfNeeded(graphicsDriver graphicsdriver.Graphics) error {
-	if !NeedsRestoring() {
+	if !needsRestoring() {
 		return nil
 	}
 
@@ -195,7 +195,7 @@ func (i *images) makeStaleIfDependingOnShader(shader *Shader) {
 //
 // Restoring means to make all *graphicscommand.Image objects have their textures and framebuffers.
 func (i *images) restore(graphicsDriver graphicsdriver.Graphics) error {
-	if !NeedsRestoring() {
+	if !needsRestoring() {
 		panic("restorable: restore cannot be called when restoring is disabled")
 	}