internal/restorable: add Hint to optimize drawImageHistoryItem size

image.go

@@ -26,6 +26,7 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicscommand"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
+	"github.com/hajimehoshi/ebiten/v2/internal/restorable"
 	"github.com/hajimehoshi/ebiten/v2/internal/shaderir"
 	"github.com/hajimehoshi/ebiten/v2/internal/ui"
 )
@@ -266,7 +267,7 @@ func (i *Image) DrawImage(img *Image, options *DrawImageOptions) {
 		})
 	}
 
-	i.image.DrawTriangles(srcs, vs, is, blend, i.adjustedBounds(), [graphics.ShaderSrcImageCount]image.Rectangle{img.adjustedBounds()}, shader.shader, i.tmpUniforms, graphicsdriver.FillRuleFillAll, canSkipMipmap(geoM, filter), false)
+	i.image.DrawTriangles(srcs, vs, is, blend, i.adjustedBounds(), [graphics.ShaderSrcImageCount]image.Rectangle{img.adjustedBounds()}, shader.shader, i.tmpUniforms, graphicsdriver.FillRuleFillAll, canSkipMipmap(geoM, filter), false, restorable.HintNone)
 }
 
 // Vertex represents a vertex passed to DrawTriangles.
@@ -550,7 +551,7 @@ func (i *Image) DrawTriangles(vertices []Vertex, indices []uint16, img *Image, o
 		})
 	}
 
-	i.image.DrawTriangles(srcs, vs, is, blend, i.adjustedBounds(), [graphics.ShaderSrcImageCount]image.Rectangle{img.adjustedBounds()}, shader.shader, i.tmpUniforms, graphicsdriver.FillRule(options.FillRule), filter != builtinshader.FilterLinear, options.AntiAlias)
+	i.image.DrawTriangles(srcs, vs, is, blend, i.adjustedBounds(), [graphics.ShaderSrcImageCount]image.Rectangle{img.adjustedBounds()}, shader.shader, i.tmpUniforms, graphicsdriver.FillRule(options.FillRule), filter != builtinshader.FilterLinear, options.AntiAlias, restorable.HintNone)
 }
 
 // DrawTrianglesShaderOptions represents options for DrawTrianglesShader.
@@ -722,7 +723,7 @@ func (i *Image) DrawTrianglesShader(vertices []Vertex, indices []uint16, shader
 	i.tmpUniforms = i.tmpUniforms[:0]
 	i.tmpUniforms = shader.appendUniforms(i.tmpUniforms, options.Uniforms)
 
-	i.image.DrawTriangles(imgs, vs, is, blend, i.adjustedBounds(), srcRegions, shader.shader, i.tmpUniforms, graphicsdriver.FillRule(options.FillRule), true, options.AntiAlias)
+	i.image.DrawTriangles(imgs, vs, is, blend, i.adjustedBounds(), srcRegions, shader.shader, i.tmpUniforms, graphicsdriver.FillRule(options.FillRule), true, options.AntiAlias, restorable.HintNone)
 }
 
 // DrawRectShaderOptions represents options for DrawRectShader.
@@ -855,7 +856,7 @@ func (i *Image) DrawRectShader(width, height int, shader *Shader, options *DrawR
 	i.tmpUniforms = i.tmpUniforms[:0]
 	i.tmpUniforms = shader.appendUniforms(i.tmpUniforms, options.Uniforms)
 
-	i.image.DrawTriangles(imgs, vs, is, blend, i.adjustedBounds(), srcRegions, shader.shader, i.tmpUniforms, graphicsdriver.FillRuleFillAll, true, false)
+	i.image.DrawTriangles(imgs, vs, is, blend, i.adjustedBounds(), srcRegions, shader.shader, i.tmpUniforms, graphicsdriver.FillRuleFillAll, true, false, restorable.HintNone)
 }
 
 // SubImage returns an image representing the portion of the image p visible through r.

internal/atlas/image.go

@@ -157,6 +157,7 @@ const (
 	ImageTypeScreen
 
 	// ImageTypeVolatile is a volatile image that is cleared every frame.
+	// A volatile image is also unmanaged.
 	ImageTypeVolatile
 
 	// ImageTypeUnmanaged is an unmanaged image that is not on an atlas.
@@ -284,7 +285,7 @@ func (i *Image) ensureIsolatedFromSource(backends []*backend) {
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, i.width, i.height)
 
-	newI.drawTriangles([graphics.ShaderSrcImageCount]*Image{i}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	newI.drawTriangles([graphics.ShaderSrcImageCount]*Image{i}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintOverwriteDstRegion)
 	newI.moveTo(i)
 }
 
@@ -314,7 +315,7 @@ func (i *Image) putOnSourceBackend() {
 	graphics.QuadVerticesFromDstAndSrc(vs, 0, 0, w, h, 0, 0, w, h, 1, 1, 1, 1)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, i.width, i.height)
-	newI.drawTriangles([graphics.ShaderSrcImageCount]*Image{i}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	newI.drawTriangles([graphics.ShaderSrcImageCount]*Image{i}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintOverwriteDstRegion)
 
 	newI.moveTo(i)
 	i.usedAsSourceCount = 0
@@ -346,7 +347,7 @@ func (i *Image) regionWithPadding() image.Rectangle {
 //	5: Color G
 //	6: Color B
 //	7: Color Y
-func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule) {
+func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule, hint restorable.Hint) {
 	backendsM.Lock()
 	defer backendsM.Unlock()
 
@@ -359,15 +360,15 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertice
 		copy(us, uniforms)
 
 		appendDeferred(func() {
-			i.drawTriangles(srcs, vs, is, blend, dstRegion, srcRegions, shader, us, fillRule)
+			i.drawTriangles(srcs, vs, is, blend, dstRegion, srcRegions, shader, us, fillRule, hint)
 		})
 		return
 	}
 
-	i.drawTriangles(srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule)
+	i.drawTriangles(srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule, hint)
 }
 
-func (i *Image) drawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule) {
+func (i *Image) drawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule, hint restorable.Hint) {
 	backends := make([]*backend, 0, len(srcs))
 	for _, src := range srcs {
 		if src == nil {
@@ -448,7 +449,7 @@ func (i *Image) drawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertice
 		imgs[i] = src.backend.restorable
 	}
 
-	i.backend.restorable.DrawTriangles(imgs, vertices, indices, blend, dstRegion, srcRegions, shader.ensureShader(), uniforms, fillRule)
+	i.backend.restorable.DrawTriangles(imgs, vertices, indices, blend, dstRegion, srcRegions, shader.ensureShader(), uniforms, fillRule, hint)
 
 	for _, src := range srcs {
 		if src == nil {

internal/atlas/image_test.go

@@ -25,6 +25,7 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/internal/atlas"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
+	"github.com/hajimehoshi/ebiten/v2/internal/restorable"
 	t "github.com/hajimehoshi/ebiten/v2/internal/testing"
 	"github.com/hajimehoshi/ebiten/v2/internal/ui"
 )
@@ -102,7 +103,7 @@ func TestEnsureIsolatedFromSourceBackend(t *testing.T) {
 	vs := quadVertices(size/2, size/2, size/4, size/4, 1)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, size, size)
-	img4.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img4.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	if got, want := img4.IsOnSourceBackendForTesting(), false; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
@@ -110,7 +111,7 @@ func TestEnsureIsolatedFromSourceBackend(t *testing.T) {
 	// img5 is not allocated now, but is allocated at DrawTriangles.
 	vs = quadVertices(0, 0, size/2, size/2, 1)
 	dr = image.Rect(0, 0, size/2, size/2)
-	img3.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img5}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img3.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img5}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	if got, want := img3.IsOnSourceBackendForTesting(), false; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
@@ -144,7 +145,7 @@ func TestEnsureIsolatedFromSourceBackend(t *testing.T) {
 	// Check further drawing doesn't cause panic.
 	// This bug was fixed by 03dcd948.
 	vs = quadVertices(0, 0, size/2, size/2, 1)
-	img4.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img4.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 }
 
 func TestReputOnSourceBackend(t *testing.T) {
@@ -188,7 +189,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 	// Render onto img1. The count should not matter.
 	for i := 0; i < 5; i++ {
 		vs := quadVertices(size, size, 0, 0, 1)
-		img1.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		img1.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 		if got, want := img1.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -200,7 +201,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 	for i := 0; i < atlas.BaseCountToPutOnSourceBackend*2; i++ {
 		atlas.PutImagesOnSourceBackendForTesting()
 		vs := quadVertices(size, size, 0, 0, 1)
-		img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 		if got, want := img1.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -208,7 +209,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 	// Finally, img1 is on a source backend.
 	atlas.PutImagesOnSourceBackendForTesting()
 	vs := quadVertices(size, size, 0, 0, 1)
-	img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	if got, want := img1.IsOnSourceBackendForTesting(), true; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
@@ -237,7 +238,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 	}
 
 	vs = quadVertices(size, size, 0, 0, 1)
-	img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	if got, want := img1.IsOnSourceBackendForTesting(), true; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
@@ -267,7 +268,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 	// Use img1 as a render target again. The count should not matter.
 	for i := 0; i < 5; i++ {
 		vs := quadVertices(size, size, 0, 0, 1)
-		img1.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		img1.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 		if got, want := img1.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -279,7 +280,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 		atlas.PutImagesOnSourceBackendForTesting()
 		img1.WritePixels(make([]byte, 4*size*size), image.Rect(0, 0, size, size))
 		vs := quadVertices(size, size, 0, 0, 1)
-		img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 		if got, want := img1.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -288,7 +289,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 
 	// img1 is not on an atlas due to WritePixels.
 	vs = quadVertices(size, size, 0, 0, 1)
-	img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	if got, want := img1.IsOnSourceBackendForTesting(), false; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
@@ -297,7 +298,7 @@ func TestReputOnSourceBackend(t *testing.T) {
 	for i := 0; i < atlas.BaseCountToPutOnSourceBackend*2; i++ {
 		atlas.PutImagesOnSourceBackendForTesting()
 		vs := quadVertices(size, size, 0, 0, 1)
-		img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img3}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 		if got, want := img3.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -400,7 +401,7 @@ func TestWritePixelsAfterDrawTriangles(t *testing.T) {
 	vs := quadVertices(w, h, 0, 0, 1)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	dst.WritePixels(pix, image.Rect(0, 0, w, h))
 
 	pix = make([]byte, 4*w*h)
@@ -447,7 +448,7 @@ func TestSmallImages(t *testing.T) {
 	vs := quadVertices(w, h, 0, 0, 1)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	pix = make([]byte, 4*w*h)
 	ok, err := dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h))
@@ -494,7 +495,7 @@ func TestLongImages(t *testing.T) {
 	vs := quadVertices(w, h, 0, 0, scale)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, dstW, dstH)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	pix = make([]byte, 4*dstW*dstH)
 	ok, err := dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, dstW, dstH))
@@ -610,7 +611,7 @@ func TestDeallocatedAndReputOnSourceBackend(t *testing.T) {
 	vs := quadVertices(size, size, 0, 0, 1)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, size, size)
-	src.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	src.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	if got, want := src.IsOnSourceBackendForTesting(), false; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
@@ -619,7 +620,7 @@ func TestDeallocatedAndReputOnSourceBackend(t *testing.T) {
 	for i := 0; i < atlas.BaseCountToPutOnSourceBackend/2; i++ {
 		atlas.PutImagesOnSourceBackendForTesting()
 		vs := quadVertices(size, size, 0, 0, 1)
-		dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 		if got, want := src.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -653,7 +654,7 @@ func TestImageIsNotReputOnSourceBackendWithoutUsingAsSource(t *testing.T) {
 	// Call DrawTriangles multiple times.
 	// The number of DrawTriangles doesn't matter as long as these are called in one frame.
 	for i := 0; i < 2; i++ {
-		src2.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		src2.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	}
 	if got, want := src2.IsOnSourceBackendForTesting(), false; got != want {
 		t.Errorf("got: %v, want: %v", got, want)
@@ -672,7 +673,7 @@ func TestImageIsNotReputOnSourceBackendWithoutUsingAsSource(t *testing.T) {
 	for i := 0; i < atlas.BaseCountToPutOnSourceBackend; i++ {
 		atlas.PutImagesOnSourceBackendForTesting()
 		vs := quadVertices(size, size, 0, 0, 1)
-		dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src2}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 		if got, want := src2.IsOnSourceBackendForTesting(), false; got != want {
 			t.Errorf("got: %v, want: %v", got, want)
 		}
@@ -798,14 +799,14 @@ func TestDestinationCountOverflow(t *testing.T) {
 
 	// Use dst0 as a destination for a while.
 	for i := 0; i < 31; i++ {
-		dst0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		dst0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 		atlas.PutImagesOnSourceBackendForTesting()
 	}
 
 	// Use dst0 as a source for a while.
 	// As dst0 is used as a destination too many times (31 is a maximum), dst0's backend should never be a source backend.
 	for i := 0; i < 100; i++ {
-		dst1.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{dst0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		dst1.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{dst0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 		atlas.PutImagesOnSourceBackendForTesting()
 		if dst0.IsOnSourceBackendForTesting() {
 			t.Errorf("dst0 cannot be on a source backend: %d", i)
@@ -831,7 +832,7 @@ func TestIteratingImagesToPutOnSourceBackend(t *testing.T) {
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
 	for _, img := range srcs {
-		img.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		img.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	}
 	atlas.PutImagesOnSourceBackendForTesting()
 
@@ -839,7 +840,7 @@ func TestIteratingImagesToPutOnSourceBackend(t *testing.T) {
 	// Check iterating the registered image works correctly.
 	for i := 0; i < 100; i++ {
 		for _, src := range srcs {
-			dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+			dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 		}
 		atlas.PutImagesOnSourceBackendForTesting()
 	}
@@ -887,7 +888,7 @@ func TestDallocateUnmanagedImageBackends(t *testing.T) {
 	vs := quadVertices(w, h, 0, 0, 1)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img0.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{img1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	// Get the difference of the number of backends before and after the images are deallocated.
 	c := atlas.BackendCountForTesting()

internal/atlas/shader_test.go

@@ -23,6 +23,7 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/internal/atlas"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
+	"github.com/hajimehoshi/ebiten/v2/internal/restorable"
 	etesting "github.com/hajimehoshi/ebiten/v2/internal/testing"
 	"github.com/hajimehoshi/ebiten/v2/internal/ui"
 )
@@ -37,12 +38,12 @@ func TestShaderFillTwice(t *testing.T) {
 	dr := image.Rect(0, 0, w, h)
 	g := ui.Get().GraphicsDriverForTesting()
 	s0 := atlas.NewShader(etesting.ShaderProgramFill(0xff, 0xff, 0xff, 0xff), "")
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s0, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s0, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	// Vertices must be recreated (#1755)
 	vs = quadVertices(w, h, 0, 0, 1)
 	s1 := atlas.NewShader(etesting.ShaderProgramFill(0x80, 0x80, 0x80, 0xff), "")
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s1, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s1, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	pix := make([]byte, 4*w*h)
 	ok, err := dst.ReadPixels(g, pix, image.Rect(0, 0, w, h))
@@ -69,11 +70,11 @@ func TestImageDrawTwice(t *testing.T) {
 	vs := quadVertices(w, h, 0, 0, 1)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	// Vertices must be recreated (#1755)
 	vs = quadVertices(w, h, 0, 0, 1)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{src1}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	pix := make([]byte, 4*w*h)
 	ok, err := dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h))
@@ -97,7 +98,7 @@ func TestGCShader(t *testing.T) {
 	vs := quadVertices(w, h, 0, 0, 1)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*atlas.Image{}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	// Ensure other objects are GCed, as GC appends deferred functions for collected objects.
 	ensureGC()

internal/buffered/image.go

@@ -196,7 +196,7 @@ func (i *Image) WritePixels(pix []byte, region image.Rectangle) {
 // DrawTriangles draws the src image with the given vertices.
 //
 // Copying vertices and indices is the caller's responsibility.
-func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *atlas.Shader, uniforms []uint32, fillRule graphicsdriver.FillRule) {
+func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *atlas.Shader, uniforms []uint32, fillRule graphicsdriver.FillRule, hint restorable.Hint) {
 	for _, src := range srcs {
 		if i == src {
 			panic("buffered: Image.DrawTriangles: source images must be different from the receiver")
@@ -218,7 +218,7 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertice
 		imgs[i] = img.img
 	}
 
-	i.img.DrawTriangles(imgs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule)
+	i.img.DrawTriangles(imgs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule, hint)
 
 	// After rendering, the pixel cache is no longer valid.
 	i.pixels = nil
@@ -311,7 +311,7 @@ func (i *Image) syncPixelsIfNeeded() {
 	srcs := [graphics.ShaderSrcImageCount]*atlas.Image{whiteImage.img}
 	dr := image.Rect(0, 0, i.width, i.height)
 	blend := graphicsdriver.BlendCopy
-	i.img.DrawTriangles(srcs, vs, is, blend, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	i.img.DrawTriangles(srcs, vs, is, blend, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	// TODO: Use clear if Go 1.21 is available.
 	for pos := range i.dotsBuffer {

internal/buffered/image_test.go

@@ -22,6 +22,7 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/internal/buffered"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
+	"github.com/hajimehoshi/ebiten/v2/internal/restorable"
 	t "github.com/hajimehoshi/ebiten/v2/internal/testing"
 	"github.com/hajimehoshi/ebiten/v2/internal/ui"
 )
@@ -56,7 +57,7 @@ func TestUnsyncedPixels(t *testing.T) {
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, 16, 16)
 	sr := [graphics.ShaderSrcImageCount]image.Rectangle{image.Rect(0, 0, 16, 16)}
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*buffered.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, sr, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*buffered.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, sr, atlas.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	// Check the result is correct.
 	var got [4]byte

internal/mipmap/mipmap.go

@@ -23,6 +23,7 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/internal/buffered"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
+	"github.com/hajimehoshi/ebiten/v2/internal/restorable"
 )
 
 func canUseMipmap(imageType atlas.ImageType) bool {
@@ -65,7 +66,7 @@ func (m *Mipmap) ReadPixels(graphicsDriver graphicsdriver.Graphics, pixels []byt
 	return m.orig.ReadPixels(graphicsDriver, pixels, region)
 }
 
-func (m *Mipmap) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Mipmap, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *atlas.Shader, uniforms []uint32, fillRule graphicsdriver.FillRule, canSkipMipmap bool) {
+func (m *Mipmap) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Mipmap, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *atlas.Shader, uniforms []uint32, fillRule graphicsdriver.FillRule, canSkipMipmap bool, hint restorable.Hint) {
 	if len(indices) == 0 {
 		return
 	}
@@ -123,7 +124,7 @@ func (m *Mipmap) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Mipmap, verti
 		imgs[i] = src.orig
 	}
 
-	m.orig.DrawTriangles(imgs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule)
+	m.orig.DrawTriangles(imgs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule, hint)
 	m.deallocateMipmaps()
 }
 
@@ -184,7 +185,7 @@ func (m *Mipmap) level(level int) *buffered.Image {
 	s := buffered.NewImage(w2, h2, m.imageType)
 
 	dstRegion := image.Rect(0, 0, w2, h2)
-	s.DrawTriangles([graphics.ShaderSrcImageCount]*buffered.Image{src}, vs, is, graphicsdriver.BlendCopy, dstRegion, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.LinearFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	s.DrawTriangles([graphics.ShaderSrcImageCount]*buffered.Image{src}, vs, is, graphicsdriver.BlendCopy, dstRegion, [graphics.ShaderSrcImageCount]image.Rectangle{}, atlas.LinearFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintOverwriteDstRegion)
 	m.setImg(level, s)
 
 	return m.imgs[level]

internal/restorable/image.go

@@ -109,6 +109,18 @@ const (
 	ImageTypeVolatile
 )
 
+// Hint is a hint to optimize the info to restore the image.
+type Hint int
+
+const (
+	// HintNone indicates that there is no hint.
+	HintNone Hint = iota
+
+	// HintOverwriteDstRegion indicates that the destination region is overwritten.
+	// HintOverwriteDstRegion helps to reduce the size of the draw-image history.
+	HintOverwriteDstRegion
+)
+
 // Image represents an image that can be restored when GL context is lost.
 type Image struct {
 	image *graphicscommand.Image
@@ -194,7 +206,7 @@ func (i *Image) Extend(width, height int) *Image {
 	graphics.QuadVerticesFromDstAndSrc(vs, 0, 0, float32(sw), float32(sh), 0, 0, float32(sw), float32(sh), 1, 1, 1, 1)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, sw, sh)
-	newImg.DrawTriangles(srcs, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	newImg.DrawTriangles(srcs, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, HintOverwriteDstRegion)
 	i.Dispose()
 
 	return newImg
@@ -316,7 +328,7 @@ func (i *Image) WritePixels(pixels *graphics.ManagedBytes, region image.Rectangl
 //	5: Color G
 //	6: Color B
 //	7: Color Y
-func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule) {
+func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule, hint Hint) {
 	if len(vertices) == 0 {
 		return
 	}
@@ -338,7 +350,8 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertice
 	if srcstale || !needsRestoration() || !i.needsRestoration() || i.stale {
 		i.makeStale(dstRegion)
 	} else {
-		i.appendDrawTrianglesHistory(srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule)
+		// TODO: Consider overwritten.
+		i.appendDrawTrianglesHistory(srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule, hint)
 	}
 
 	var imgs [graphics.ShaderSrcImageCount]*graphicscommand.Image
@@ -352,7 +365,7 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertice
 }
 
 // appendDrawTrianglesHistory appends a draw-image history item to the image.
-func (i *Image) appendDrawTrianglesHistory(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule) {
+func (i *Image) appendDrawTrianglesHistory(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule, hint Hint) {
 	if i.stale || !i.needsRestoration() {
 		panic("restorable: an image must not be stale or need restoration at appendDrawTrianglesHistory")
 	}
@@ -360,6 +373,24 @@ func (i *Image) appendDrawTrianglesHistory(srcs [graphics.ShaderSrcImageCount]*I
 		panic("restorable: appendDrawTrianglesHistory must not be called when AlwaysReadPixelsFromGPU() returns true")
 	}
 
+	// If the command overwrites the destination region, remove the history items that are in the region.
+	if hint == HintOverwriteDstRegion {
+		for idx, c := range i.drawTrianglesHistory {
+			if c.dstRegion.In(dstRegion) {
+				i.drawTrianglesHistory[idx] = nil
+			}
+		}
+		var n int
+		for _, c := range i.drawTrianglesHistory {
+			if c == nil {
+				continue
+			}
+			i.drawTrianglesHistory[n] = c
+			n++
+		}
+		i.drawTrianglesHistory = i.drawTrianglesHistory[:n]
+	}
+
 	// TODO: Would it be possible to merge draw image history items?
 	const maxDrawTrianglesHistoryCount = 1024
 	if len(i.drawTrianglesHistory)+1 > maxDrawTrianglesHistoryCount {

internal/restorable/images_test.go

@@ -140,7 +140,7 @@ func TestRestoreChain(t *testing.T) {
 		vs := quadVertices(1, 1, 0, 0)
 		is := graphics.QuadIndices()
 		dr := image.Rect(0, 0, 1, 1)
-		imgs[i+1].DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{imgs[i]}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		imgs[i+1].DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{imgs[i]}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	}
 	if err := restorable.ResolveStaleImages(ui.Get().GraphicsDriverForTesting()); err != nil {
 		t.Fatal(err)
@@ -183,10 +183,10 @@ func TestRestoreChain2(t *testing.T) {
 
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	imgs[8].DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{imgs[7]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	imgs[8].DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{imgs[7]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
-	imgs[9].DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{imgs[8]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	imgs[9].DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{imgs[8]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	for i := 0; i < 7; i++ {
-		imgs[i+1].DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{imgs[i]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+		imgs[i+1].DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{imgs[i]}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	}
 
 	if err := restorable.ResolveStaleImages(ui.Get().GraphicsDriverForTesting()); err != nil {
@@ -227,10 +227,10 @@ func TestRestoreOverrideSource(t *testing.T) {
 	img1.WritePixels(bytesToManagedBytes([]byte{clr0.R, clr0.G, clr0.B, clr0.A}), image.Rect(0, 0, w, h))
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	img2.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img1}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img2.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img1}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
-	img3.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img2}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img3.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img2}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	img0.WritePixels(bytesToManagedBytes([]byte{clr1.R, clr1.G, clr1.B, clr1.A}), image.Rect(0, 0, w, h))
-	img1.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img0}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img1.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img0}, quadVertices(w, h, 0, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	if err := restorable.ResolveStaleImages(ui.Get().GraphicsDriverForTesting()); err != nil {
 		t.Fatal(err)
 	}
@@ -310,23 +310,23 @@ func TestRestoreComplexGraph(t *testing.T) {
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
 	vs := quadVertices(w, h, 0, 0)
-	img3.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img3.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	vs = quadVertices(w, h, 1, 0)
-	img3.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img1}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img3.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img1}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	vs = quadVertices(w, h, 1, 0)
-	img4.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img1}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img4.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img1}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	vs = quadVertices(w, h, 2, 0)
-	img4.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img2}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img4.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img2}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	vs = quadVertices(w, h, 0, 0)
-	img5.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img5.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	vs = quadVertices(w, h, 0, 0)
-	img6.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img6.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	vs = quadVertices(w, h, 1, 0)
-	img6.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img4}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img6.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img4}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	vs = quadVertices(w, h, 0, 0)
-	img7.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img2}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img7.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img2}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	vs = quadVertices(w, h, 2, 0)
-	img7.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img7.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img3}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	if err := restorable.ResolveStaleImages(ui.Get().GraphicsDriverForTesting()); err != nil {
 		t.Fatal(err)
 	}
@@ -419,8 +419,8 @@ func TestRestoreRecursive(t *testing.T) {
 	}()
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	img1.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img0}, quadVertices(w, h, 1, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img1.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img0}, quadVertices(w, h, 1, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
-	img0.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img1}, quadVertices(w, h, 1, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img0.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img1}, quadVertices(w, h, 1, 0), is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	if err := restorable.ResolveStaleImages(ui.Get().GraphicsDriverForTesting()); err != nil {
 		t.Fatal(err)
 	}
@@ -519,7 +519,7 @@ func TestDrawTrianglesAndWritePixels(t *testing.T) {
 	vs := quadVertices(1, 1, 0, 0)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, 2, 1)
-	img1.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img1.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	img1.WritePixels(bytesToManagedBytes([]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}), image.Rect(0, 0, 2, 1))
 
 	if err := restorable.ResolveStaleImages(ui.Get().GraphicsDriverForTesting()); err != nil {
@@ -557,8 +557,8 @@ func TestDispose(t *testing.T) {
 
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, 1, 1)
-	img1.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img2}, quadVertices(1, 1, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img1.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img2}, quadVertices(1, 1, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
-	img0.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img1}, quadVertices(1, 1, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img0.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img1}, quadVertices(1, 1, 0, 0), is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	img1.Dispose()
 
 	if err := restorable.ResolveStaleImages(ui.Get().GraphicsDriverForTesting()); err != nil {
@@ -667,7 +667,7 @@ func TestWritePixelsOnly(t *testing.T) {
 	vs := quadVertices(1, 1, 0, 0)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, 1, 1)
-	img1.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img1.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{img0}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	img0.WritePixels(bytesToManagedBytes([]byte{5, 6, 7, 8}), image.Rect(0, 0, 1, 1))
 
 	// BasePixelsForTesting is available without GPU accessing.
@@ -721,7 +721,7 @@ func TestReadPixelsFromVolatileImage(t *testing.T) {
 	vs := quadVertices(1, 1, 0, 0)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	// Read the pixels. If the implementation is correct, dst tries to read its pixels from GPU due to being
 	// stale.
@@ -745,7 +745,7 @@ func TestAllowWritePixelsAfterDrawTriangles(t *testing.T) {
 	vs := quadVertices(w, h, 0, 0)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	dst.WritePixels(bytesToManagedBytes(make([]byte, 4*w*h)), image.Rect(0, 0, w, h))
 	// WritePixels for a whole image doesn't panic.
 }
@@ -764,7 +764,7 @@ func TestAllowWritePixelsForPartAfterDrawTriangles(t *testing.T) {
 	vs := quadVertices(w, h, 0, 0)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	dst.WritePixels(bytesToManagedBytes(make([]byte, 4*2*2)), image.Rect(0, 0, 2, 2))
 	// WritePixels for a part of image doesn't panic.
 
@@ -858,7 +858,7 @@ func TestDrawTrianglesAndExtend(t *testing.T) {
 	vs := quadVertices(w, h, 0, 0)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	orig.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	orig.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	extended := orig.Extend(w*2, h*2) // After this, orig is already disposed.
 
 	result := make([]byte, 4*(w*2)*(h*2))
@@ -908,7 +908,7 @@ func TestMutateSlices(t *testing.T) {
 	is := make([]uint32, len(graphics.QuadIndices()))
 	copy(is, graphics.QuadIndices())
 	dr := image.Rect(0, 0, w, h)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	for i := range vs {
 		vs[i] = 0
 	}
@@ -1100,7 +1100,7 @@ func TestDrawTrianglesAndReadPixels(t *testing.T) {
 	vs := quadVertices(w, h, 0, 0)
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	pix := make([]byte, 4*w*h)
 	if err := dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h)); err != nil {
@@ -1124,7 +1124,7 @@ func TestWritePixelsAndDrawTriangles(t *testing.T) {
 	vs := quadVertices(1, 1, 1, 0)
 	is := graphics.QuadIndices()
 	dr := image.Rect(1, 0, 2, 1)
-	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	// Get the pixels.
 	pix := make([]byte, 4*2*1)
@@ -1138,3 +1138,36 @@ func TestWritePixelsAndDrawTriangles(t *testing.T) {
 		t.Errorf("got: %v, want: %v", got, want)
 	}
 }
+
+func TestOverwriteDstRegion(t *testing.T) {
+	const w, h = 1, 1
+	src0 := restorable.NewImage(w, h, restorable.ImageTypeRegular)
+	src1 := restorable.NewImage(w, h, restorable.ImageTypeRegular)
+	dst := restorable.NewImage(w, h, restorable.ImageTypeRegular)
+
+	src0.WritePixels(bytesToManagedBytes([]byte{0x40, 0x40, 0x40, 0x40}), image.Rect(0, 0, 1, 1))
+	src1.WritePixels(bytesToManagedBytes([]byte{0x80, 0x80, 0x80, 0x80}), image.Rect(0, 0, 1, 1))
+
+	vs := quadVertices(w, h, 0, 0)
+	is := graphics.QuadIndices()
+	dr := image.Rect(0, 0, w, h)
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src0}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
+	// This tests that HintOverwriteDstRegion removes the previous DrawTriangles.
+	// In practice, BlendCopy should be used instead of BlendSourceOver in this case.
+	dst.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{src1}, vs, is, graphicsdriver.BlendSourceOver, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintOverwriteDstRegion)
+
+	if err := restorable.ResolveStaleImages(ui.Get().GraphicsDriverForTesting()); err != nil {
+		t.Fatal(err)
+	}
+	if err := restorable.RestoreIfNeeded(ui.Get().GraphicsDriverForTesting()); err != nil {
+		t.Fatal(err)
+	}
+
+	pix := make([]byte, 4*w*h)
+	if err := dst.ReadPixels(ui.Get().GraphicsDriverForTesting(), pix, image.Rect(0, 0, w, h)); err != nil {
+		t.Fatal(err)
+	}
+	if got, want := (color.RGBA{R: pix[0], G: pix[1], B: pix[2], A: pix[3]}), (color.RGBA{R: 0x80, G: 0x80, B: 0x80, A: 0x80}); !sameColors(got, want, 1) {
+		t.Errorf("got: %v, want: %v", got, want)
+	}
+}

internal/restorable/shader_test.go

@@ -46,7 +46,7 @@ func clearImage(img *restorable.Image, w, h int) {
 	}
 	is := graphics.QuadIndices()
 	dr := image.Rect(0, 0, w, h)
-	img.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{emptyImage}, vs, is, graphicsdriver.BlendClear, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll)
+	img.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{emptyImage}, vs, is, graphicsdriver.BlendClear, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, restorable.NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 }
 
 func TestShader(t *testing.T) {
@@ -55,7 +55,7 @@ func TestShader(t *testing.T) {
 
 	s := restorable.NewShader(etesting.ShaderProgramFill(0xff, 0, 0, 0xff), "")
 	dr := image.Rect(0, 0, 1, 1)
-	img.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s, nil, graphicsdriver.FillRuleFillAll)
+	img.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	if err := restorable.ResolveStaleImages(ui.Get().GraphicsDriverForTesting()); err != nil {
 		t.Fatal(err)
@@ -85,7 +85,7 @@ func TestShaderChain(t *testing.T) {
 	s := restorable.NewShader(etesting.ShaderProgramImages(1), "")
 	for i := 0; i < num-1; i++ {
 		dr := image.Rect(0, 0, 1, 1)
-		imgs[i+1].DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{imgs[i]}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s, nil, graphicsdriver.FillRuleFillAll)
+		imgs[i+1].DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{imgs[i]}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 	}
 
 	if err := restorable.ResolveStaleImages(ui.Get().GraphicsDriverForTesting()); err != nil {
@@ -117,7 +117,7 @@ func TestShaderMultipleSources(t *testing.T) {
 
 	s := restorable.NewShader(etesting.ShaderProgramImages(3), "")
 	dr := image.Rect(0, 0, 1, 1)
-	dst.DrawTriangles(srcs, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles(srcs, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	// Clear one of the sources after DrawTriangles. dst should not be affected.
 	clearImage(srcs[0], 1, 1)
@@ -154,7 +154,7 @@ func TestShaderMultipleSourcesOnOneTexture(t *testing.T) {
 		image.Rect(1, 0, 2, 1),
 		image.Rect(2, 0, 3, 1),
 	}
-	dst.DrawTriangles(srcs, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, srcRegions, s, nil, graphicsdriver.FillRuleFillAll)
+	dst.DrawTriangles(srcs, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, srcRegions, s, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	// Clear one of the sources after DrawTriangles. dst should not be affected.
 	clearImage(srcs[0], 3, 1)
@@ -179,7 +179,7 @@ func TestShaderDispose(t *testing.T) {
 
 	s := restorable.NewShader(etesting.ShaderProgramFill(0xff, 0, 0, 0xff), "")
 	dr := image.Rect(0, 0, 1, 1)
-	img.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s, nil, graphicsdriver.FillRuleFillAll)
+	img.DrawTriangles([graphics.ShaderSrcImageCount]*restorable.Image{}, quadVertices(1, 1, 0, 0), graphics.QuadIndices(), graphicsdriver.BlendCopy, dr, [graphics.ShaderSrcImageCount]image.Rectangle{}, s, nil, graphicsdriver.FillRuleFillAll, restorable.HintNone)
 
 	// Dispose the shader. This should invalidate all the images using this shader i.e., all the images become
 	// stale.

internal/ui/image.go

@@ -23,6 +23,7 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
 	"github.com/hajimehoshi/ebiten/v2/internal/mipmap"
+	"github.com/hajimehoshi/ebiten/v2/internal/restorable"
 )
 
 // panicOnErrorOnReadingPixels indicates whether reading pixels panics on an error or not.
@@ -77,7 +78,7 @@ func (i *Image) Deallocate() {
 	i.mipmap.Deallocate()
 }
 
-func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule, canSkipMipmap bool, antialias bool) {
+func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertices []float32, indices []uint32, blend graphicsdriver.Blend, dstRegion image.Rectangle, srcRegions [graphics.ShaderSrcImageCount]image.Rectangle, shader *Shader, uniforms []uint32, fillRule graphicsdriver.FillRule, canSkipMipmap bool, antialias bool, hint restorable.Hint) {
 	if i.modifyCallback != nil {
 		i.modifyCallback()
 	}
@@ -113,7 +114,7 @@ func (i *Image) DrawTriangles(srcs [graphics.ShaderSrcImageCount]*Image, vertice
 		srcMipmaps[i] = src.mipmap
 	}
 
-	i.mipmap.DrawTriangles(srcMipmaps, vertices, indices, blend, dstRegion, srcRegions, shader.shader, uniforms, fillRule, canSkipMipmap)
+	i.mipmap.DrawTriangles(srcMipmaps, vertices, indices, blend, dstRegion, srcRegions, shader.shader, uniforms, fillRule, canSkipMipmap, hint)
 }
 
 func (i *Image) WritePixels(pix []byte, region image.Rectangle) {
@@ -183,7 +184,7 @@ func (i *Image) Fill(r, g, b, a float32, region image.Rectangle) {
 		blend = graphicsdriver.BlendSourceOver
 	}
 	// i.lastBlend is updated in DrawTriangles.
-	i.DrawTriangles(srcs, i.tmpVerticesForFill, is, blend, region, [graphics.ShaderSrcImageCount]image.Rectangle{}, NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, true, false)
+	i.DrawTriangles(srcs, i.tmpVerticesForFill, is, blend, region, [graphics.ShaderSrcImageCount]image.Rectangle{}, NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, true, false, restorable.HintOverwriteDstRegion)
 }
 
 type bigOffscreenImage struct {
@@ -252,7 +253,7 @@ func (i *bigOffscreenImage) drawTriangles(srcs [graphics.ShaderSrcImageCount]*Im
 			1, 1, 1, 1)
 		is := graphics.QuadIndices()
 		dstRegion := image.Rect(0, 0, i.region.Dx()*bigOffscreenScale, i.region.Dy()*bigOffscreenScale)
-		i.image.DrawTriangles(srcs, i.tmpVerticesForCopying, is, graphicsdriver.BlendCopy, dstRegion, [graphics.ShaderSrcImageCount]image.Rectangle{}, NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, true, false)
+		i.image.DrawTriangles(srcs, i.tmpVerticesForCopying, is, graphicsdriver.BlendCopy, dstRegion, [graphics.ShaderSrcImageCount]image.Rectangle{}, NearestFilterShader, nil, graphicsdriver.FillRuleFillAll, true, false, restorable.HintOverwriteDstRegion)
 	}
 
 	for idx := 0; idx < len(vertices); idx += graphics.VertexFloatCount {
@@ -268,7 +269,7 @@ func (i *bigOffscreenImage) drawTriangles(srcs [graphics.ShaderSrcImageCount]*Im
 	dstRegion.Max.X *= bigOffscreenScale
 	dstRegion.Max.Y *= bigOffscreenScale
 
-	i.image.DrawTriangles(srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule, canSkipMipmap, false)
+	i.image.DrawTriangles(srcs, vertices, indices, blend, dstRegion, srcRegions, shader, uniforms, fillRule, canSkipMipmap, false, restorable.HintNone)
 	i.dirty = true
 }
 
@@ -297,10 +298,12 @@ func (i *bigOffscreenImage) flush() {
 	is := graphics.QuadIndices()
 	dstRegion := i.region
 	blend := graphicsdriver.BlendSourceOver
+	hint := restorable.HintNone
 	if i.blend != graphicsdriver.BlendSourceOver {
 		blend = graphicsdriver.BlendCopy
+		hint = restorable.HintOverwriteDstRegion
 	}
-	i.orig.DrawTriangles(srcs, i.tmpVerticesForFlushing, is, blend, dstRegion, [graphics.ShaderSrcImageCount]image.Rectangle{}, LinearFilterShader, nil, graphicsdriver.FillRuleFillAll, true, false)
+	i.orig.DrawTriangles(srcs, i.tmpVerticesForFlushing, is, blend, dstRegion, [graphics.ShaderSrcImageCount]image.Rectangle{}, LinearFilterShader, nil, graphicsdriver.FillRuleFillAll, true, false, hint)
 
 	i.image.clear()
 	i.dirty = false