ebiten: add FilterPixelated

Closes #2826

examples/filter/main.go

@@ -19,6 +19,7 @@ import (
 	"image"
 	_ "image/png"
 	"log"
+	"math"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
@@ -35,27 +36,40 @@ var (
 )
 
 type Game struct {
+	counter int
 }
 
 func (g *Game) Update() error {
+	g.counter++
 	return nil
 }
 
 func (g *Game) Draw(screen *ebiten.Image) {
-	ebitenutil.DebugPrint(screen, "Nearest Filter (default) VS Linear Filter")
+	scale := 2*math.Sin(float64(g.counter%360)*math.Pi/180) + 4
+
+	ebitenutil.DebugPrintAt(screen, "Nearest Filter (default) and Linear Filter", 16, 16)
 
 	op := &ebiten.DrawImageOptions{}
-	op.GeoM.Scale(4, 4)
+	op.GeoM.Scale(scale, scale)
 	op.GeoM.Translate(64, 64)
 	// By default, nearest filter is used.
 	screen.DrawImage(ebitenImage, op)
 
 	op = &ebiten.DrawImageOptions{}
-	op.GeoM.Scale(4, 4)
+	op.GeoM.Scale(scale, scale)
-	op.GeoM.Translate(64, 64+240)
+	op.GeoM.Translate(64+240, 64)
 	// Specify linear filter.
 	op.Filter = ebiten.FilterLinear
 	screen.DrawImage(ebitenImage, op)
+
+	ebitenutil.DebugPrintAt(screen, "Pixelated Filter", 16, 16+200)
+
+	op = &ebiten.DrawImageOptions{}
+	op.GeoM.Scale(scale, scale)
+	op.GeoM.Translate(64, 64+200)
+	// Specify pixelated filter.
+	op.Filter = ebiten.FilterPixelated
+	screen.DrawImage(ebitenImage, op)
 }
 
 func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {

gameforui.go

@@ -15,10 +15,8 @@
 package ebiten
 
 import (
-	"fmt"
 	"image"
 	"math"
-	"sync"
 	"sync/atomic"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/atlas"
@@ -131,25 +129,12 @@ func (g *gameForUI) DrawFinalScreen(scale, offsetX, offsetY float64) {
 	DefaultDrawFinalScreen(g.screen, g.offscreen, geoM)
 }
 
-var (
-	theScreenShader     *Shader
-	theScreenShaderOnce sync.Once
-)
-
 // DefaultDrawFinalScreen is the default implementation of [FinalScreenDrawer.DrawFinalScreen],
 // used when a [Game] doesn't implement [FinalScreenDrawer].
 //
 // You can use DefaultDrawFinalScreen when you need the default implementation of [FinalScreenDrawer.DrawFinalScreen]
 // in your implementation of [FinalScreenDrawer], for example.
 func DefaultDrawFinalScreen(screen FinalScreen, offscreen *Image, geoM GeoM) {
-	theScreenShaderOnce.Do(func() {
-		s, err := newShader([]byte(builtinshader.ScreenShaderSource), "screen")
-		if err != nil {
-			panic(fmt.Sprintf("ebiten: compiling the screen shader failed: %v", err))
-		}
-		theScreenShader = s
-	})
-
 	scale := geoM.Element(0, 0)
 	switch {
 	case !screenFilterEnabled.Load(), math.Floor(scale) == scale:
@@ -166,6 +151,7 @@ func DefaultDrawFinalScreen(screen FinalScreen, offscreen *Image, geoM GeoM) {
 		op.Images[0] = offscreen
 		op.GeoM = geoM
 		w, h := offscreen.Bounds().Dx(), offscreen.Bounds().Dy()
-		screen.DrawRectShader(w, h, theScreenShader, op)
+		screenShader := builtinShader(builtinshader.FilterPixelated, builtinshader.AddressUnsafe, false)
+		screen.DrawRectShader(w, h, screenShader, op)
 	}
 }

graphics.go

@@ -28,6 +28,10 @@ const (
 
 	// FilterLinear represents linear filter
 	FilterLinear Filter = Filter(builtinshader.FilterLinear)
+
+	// FilterPixelated represents a pixelated filter.
+	// FilterPixelated is similar to FilterNearest, but it preserves the pixelated appearance even when scaled to non-integer sizes.
+	FilterPixelated Filter = Filter(builtinshader.FilterPixelated)
 )
 
 // GraphicsLibrary represents graphics libraries supported by the engine.

internal/builtinshader/defs.go

@@ -39,19 +39,37 @@ const _ = "//kage:unit pixels\n\npackage main\n\n\n\n\nfunc adjustSrcPosForAddre
 const _ = "//kage:unit pixels\n\npackage main\n\n\nvar ColorMBody mat4\nvar ColorMTranslation vec4\n\n\n\nfunc adjustSrcPosForAddressRepeat(p vec2) vec2 {\n\torigin := imageSrc0Origin()\n\tsize := imageSrc0Size()\n\treturn mod(p - origin, size) + origin\n}\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\tclr := imageSrc0At(adjustSrcPosForAddressRepeat(srcPos))\n\n\n\n\n\t// Un-premultiply alpha.\n\t// When the alpha is 0, 1-sign(alpha) is 1.0, which means division does nothing.\n\tclr.rgb /= clr.a + (1-sign(clr.a))\n\t// Apply the clr matrix.\n\tclr = (ColorMBody * clr) + ColorMTranslation\n\t// Premultiply alpha\n\tclr.rgb *= clr.a\n\t// Apply the color scale.\n\tclr *= color\n\t// Clamp the output.\n\tclr.rgb = min(clr.rgb, clr.a)\n\n\n\treturn clr\n}\n\n"
 
 //ebitengine:shader
-const _ = "//kage:unit pixels\n\npackage main\n\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\n\n\tc0 := imageSrc0UnsafeAt(p0)\n\tc1 := imageSrc0UnsafeAt(vec2(p1.x, p0.y))\n\tc2 := imageSrc0UnsafeAt(vec2(p0.x, p1.y))\n\tc3 := imageSrc0UnsafeAt(p1)\n\n\n\trate := fract(p1)\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Apply the color scale.\n\tclr *= color\n\n\n\treturn clr\n}\n\n"
+const _ = "//kage:unit pixels\n\npackage main\n\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\n\n\n\tc0 := imageSrc0UnsafeAt(p0)\n\tc1 := imageSrc0UnsafeAt(vec2(p1.x, p0.y))\n\tc2 := imageSrc0UnsafeAt(vec2(p0.x, p1.y))\n\tc3 := imageSrc0UnsafeAt(p1)\n\n\n\n\trate := fract(p1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Apply the color scale.\n\tclr *= color\n\n\n\treturn clr\n}\n\n"
 
 //ebitengine:shader
-const _ = "//kage:unit pixels\n\npackage main\n\n\nvar ColorMBody mat4\nvar ColorMTranslation vec4\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\n\n\tc0 := imageSrc0UnsafeAt(p0)\n\tc1 := imageSrc0UnsafeAt(vec2(p1.x, p0.y))\n\tc2 := imageSrc0UnsafeAt(vec2(p0.x, p1.y))\n\tc3 := imageSrc0UnsafeAt(p1)\n\n\n\trate := fract(p1)\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Un-premultiply alpha.\n\t// When the alpha is 0, 1-sign(alpha) is 1.0, which means division does nothing.\n\tclr.rgb /= clr.a + (1-sign(clr.a))\n\t// Apply the clr matrix.\n\tclr = (ColorMBody * clr) + ColorMTranslation\n\t// Premultiply alpha\n\tclr.rgb *= clr.a\n\t// Apply the color scale.\n\tclr *= color\n\t// Clamp the output.\n\tclr.rgb = min(clr.rgb, clr.a)\n\n\n\treturn clr\n}\n\n"
+const _ = "//kage:unit pixels\n\npackage main\n\n\nvar ColorMBody mat4\nvar ColorMTranslation vec4\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\n\n\n\tc0 := imageSrc0UnsafeAt(p0)\n\tc1 := imageSrc0UnsafeAt(vec2(p1.x, p0.y))\n\tc2 := imageSrc0UnsafeAt(vec2(p0.x, p1.y))\n\tc3 := imageSrc0UnsafeAt(p1)\n\n\n\n\trate := fract(p1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Un-premultiply alpha.\n\t// When the alpha is 0, 1-sign(alpha) is 1.0, which means division does nothing.\n\tclr.rgb /= clr.a + (1-sign(clr.a))\n\t// Apply the clr matrix.\n\tclr = (ColorMBody * clr) + ColorMTranslation\n\t// Premultiply alpha\n\tclr.rgb *= clr.a\n\t// Apply the color scale.\n\tclr *= color\n\t// Clamp the output.\n\tclr.rgb = min(clr.rgb, clr.a)\n\n\n\treturn clr\n}\n\n"
 
 //ebitengine:shader
-const _ = "//kage:unit pixels\n\npackage main\n\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\trate := fract(p1)\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Apply the color scale.\n\tclr *= color\n\n\n\treturn clr\n}\n\n"
+const _ = "//kage:unit pixels\n\npackage main\n\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\n\trate := fract(p1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Apply the color scale.\n\tclr *= color\n\n\n\treturn clr\n}\n\n"
 
 //ebitengine:shader
-const _ = "//kage:unit pixels\n\npackage main\n\n\nvar ColorMBody mat4\nvar ColorMTranslation vec4\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\trate := fract(p1)\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Un-premultiply alpha.\n\t// When the alpha is 0, 1-sign(alpha) is 1.0, which means division does nothing.\n\tclr.rgb /= clr.a + (1-sign(clr.a))\n\t// Apply the clr matrix.\n\tclr = (ColorMBody * clr) + ColorMTranslation\n\t// Premultiply alpha\n\tclr.rgb *= clr.a\n\t// Apply the color scale.\n\tclr *= color\n\t// Clamp the output.\n\tclr.rgb = min(clr.rgb, clr.a)\n\n\n\treturn clr\n}\n\n"
+const _ = "//kage:unit pixels\n\npackage main\n\n\nvar ColorMBody mat4\nvar ColorMTranslation vec4\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\n\trate := fract(p1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Un-premultiply alpha.\n\t// When the alpha is 0, 1-sign(alpha) is 1.0, which means division does nothing.\n\tclr.rgb /= clr.a + (1-sign(clr.a))\n\t// Apply the clr matrix.\n\tclr = (ColorMBody * clr) + ColorMTranslation\n\t// Premultiply alpha\n\tclr.rgb *= clr.a\n\t// Apply the color scale.\n\tclr *= color\n\t// Clamp the output.\n\tclr.rgb = min(clr.rgb, clr.a)\n\n\n\treturn clr\n}\n\n"
 
 //ebitengine:shader
-const _ = "//kage:unit pixels\n\npackage main\n\n\n\n\nfunc adjustSrcPosForAddressRepeat(p vec2) vec2 {\n\torigin := imageSrc0Origin()\n\tsize := imageSrc0Size()\n\treturn mod(p - origin, size) + origin\n}\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\tp0 = adjustSrcPosForAddressRepeat(p0)\n\tp1 = adjustSrcPosForAddressRepeat(p1)\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\trate := fract(p1)\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Apply the color scale.\n\tclr *= color\n\n\n\treturn clr\n}\n\n"
+const _ = "//kage:unit pixels\n\npackage main\n\n\n\n\nfunc adjustSrcPosForAddressRepeat(p vec2) vec2 {\n\torigin := imageSrc0Origin()\n\tsize := imageSrc0Size()\n\treturn mod(p - origin, size) + origin\n}\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\n\tp0 = adjustSrcPosForAddressRepeat(p0)\n\tp1 = adjustSrcPosForAddressRepeat(p1)\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\n\trate := fract(p1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Apply the color scale.\n\tclr *= color\n\n\n\treturn clr\n}\n\n"
 
 //ebitengine:shader
-const _ = "//kage:unit pixels\n\npackage main\n\n\nvar ColorMBody mat4\nvar ColorMTranslation vec4\n\n\n\nfunc adjustSrcPosForAddressRepeat(p vec2) vec2 {\n\torigin := imageSrc0Origin()\n\tsize := imageSrc0Size()\n\treturn mod(p - origin, size) + origin\n}\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\tp0 = adjustSrcPosForAddressRepeat(p0)\n\tp1 = adjustSrcPosForAddressRepeat(p1)\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\trate := fract(p1)\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Un-premultiply alpha.\n\t// When the alpha is 0, 1-sign(alpha) is 1.0, which means division does nothing.\n\tclr.rgb /= clr.a + (1-sign(clr.a))\n\t// Apply the clr matrix.\n\tclr = (ColorMBody * clr) + ColorMTranslation\n\t// Premultiply alpha\n\tclr.rgb *= clr.a\n\t// Apply the color scale.\n\tclr *= color\n\t// Clamp the output.\n\tclr.rgb = min(clr.rgb, clr.a)\n\n\n\treturn clr\n}\n\n"
+const _ = "//kage:unit pixels\n\npackage main\n\n\nvar ColorMBody mat4\nvar ColorMTranslation vec4\n\n\n\nfunc adjustSrcPosForAddressRepeat(p vec2) vec2 {\n\torigin := imageSrc0Origin()\n\tsize := imageSrc0Size()\n\treturn mod(p - origin, size) + origin\n}\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\tp0 := srcPos - 1/2.0\n\tp1 := srcPos + 1/2.0\n\n\n\n\tp0 = adjustSrcPosForAddressRepeat(p0)\n\tp1 = adjustSrcPosForAddressRepeat(p1)\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\n\trate := fract(p1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Un-premultiply alpha.\n\t// When the alpha is 0, 1-sign(alpha) is 1.0, which means division does nothing.\n\tclr.rgb /= clr.a + (1-sign(clr.a))\n\t// Apply the clr matrix.\n\tclr = (ColorMBody * clr) + ColorMTranslation\n\t// Premultiply alpha\n\tclr.rgb *= clr.a\n\t// Apply the color scale.\n\tclr *= color\n\t// Clamp the output.\n\tclr.rgb = min(clr.rgb, clr.a)\n\n\n\treturn clr\n}\n\n"
+
+//ebitengine:shader
+const _ = "//kage:unit pixels\n\npackage main\n\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\t// inversedScale is the size of the region on the source image.\n\t// The size is the inverse of the geometry-matrix scale.\n\tinversedScale := vec2(abs(dfdx(srcPos.x)), abs(dfdy(srcPos.y)))\n\t// Cap the inversedScale to 1 as dfdx/dfdy is not accurate on some machines (#3182).\n\tinversedScale = min(inversedScale, vec2(1))\n\tp0 := srcPos - inversedScale/2.0\n\tp1 := srcPos + inversedScale/2.0\n\n\n\n\n\n\tc0 := imageSrc0UnsafeAt(p0)\n\tc1 := imageSrc0UnsafeAt(vec2(p1.x, p0.y))\n\tc2 := imageSrc0UnsafeAt(vec2(p0.x, p1.y))\n\tc3 := imageSrc0UnsafeAt(p1)\n\n\n\n\trate := clamp(fract(p1)/inversedScale, 0, 1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Apply the color scale.\n\tclr *= color\n\n\n\treturn clr\n}\n\n"
+
+//ebitengine:shader
+const _ = "//kage:unit pixels\n\npackage main\n\n\nvar ColorMBody mat4\nvar ColorMTranslation vec4\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\t// inversedScale is the size of the region on the source image.\n\t// The size is the inverse of the geometry-matrix scale.\n\tinversedScale := vec2(abs(dfdx(srcPos.x)), abs(dfdy(srcPos.y)))\n\t// Cap the inversedScale to 1 as dfdx/dfdy is not accurate on some machines (#3182).\n\tinversedScale = min(inversedScale, vec2(1))\n\tp0 := srcPos - inversedScale/2.0\n\tp1 := srcPos + inversedScale/2.0\n\n\n\n\n\n\tc0 := imageSrc0UnsafeAt(p0)\n\tc1 := imageSrc0UnsafeAt(vec2(p1.x, p0.y))\n\tc2 := imageSrc0UnsafeAt(vec2(p0.x, p1.y))\n\tc3 := imageSrc0UnsafeAt(p1)\n\n\n\n\trate := clamp(fract(p1)/inversedScale, 0, 1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Un-premultiply alpha.\n\t// When the alpha is 0, 1-sign(alpha) is 1.0, which means division does nothing.\n\tclr.rgb /= clr.a + (1-sign(clr.a))\n\t// Apply the clr matrix.\n\tclr = (ColorMBody * clr) + ColorMTranslation\n\t// Premultiply alpha\n\tclr.rgb *= clr.a\n\t// Apply the color scale.\n\tclr *= color\n\t// Clamp the output.\n\tclr.rgb = min(clr.rgb, clr.a)\n\n\n\treturn clr\n}\n\n"
+
+//ebitengine:shader
+const _ = "//kage:unit pixels\n\npackage main\n\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\t// inversedScale is the size of the region on the source image.\n\t// The size is the inverse of the geometry-matrix scale.\n\tinversedScale := vec2(abs(dfdx(srcPos.x)), abs(dfdy(srcPos.y)))\n\t// Cap the inversedScale to 1 as dfdx/dfdy is not accurate on some machines (#3182).\n\tinversedScale = min(inversedScale, vec2(1))\n\tp0 := srcPos - inversedScale/2.0\n\tp1 := srcPos + inversedScale/2.0\n\n\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\n\trate := clamp(fract(p1)/inversedScale, 0, 1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Apply the color scale.\n\tclr *= color\n\n\n\treturn clr\n}\n\n"
+
+//ebitengine:shader
+const _ = "//kage:unit pixels\n\npackage main\n\n\nvar ColorMBody mat4\nvar ColorMTranslation vec4\n\n\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\t// inversedScale is the size of the region on the source image.\n\t// The size is the inverse of the geometry-matrix scale.\n\tinversedScale := vec2(abs(dfdx(srcPos.x)), abs(dfdy(srcPos.y)))\n\t// Cap the inversedScale to 1 as dfdx/dfdy is not accurate on some machines (#3182).\n\tinversedScale = min(inversedScale, vec2(1))\n\tp0 := srcPos - inversedScale/2.0\n\tp1 := srcPos + inversedScale/2.0\n\n\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\n\trate := clamp(fract(p1)/inversedScale, 0, 1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Un-premultiply alpha.\n\t// When the alpha is 0, 1-sign(alpha) is 1.0, which means division does nothing.\n\tclr.rgb /= clr.a + (1-sign(clr.a))\n\t// Apply the clr matrix.\n\tclr = (ColorMBody * clr) + ColorMTranslation\n\t// Premultiply alpha\n\tclr.rgb *= clr.a\n\t// Apply the color scale.\n\tclr *= color\n\t// Clamp the output.\n\tclr.rgb = min(clr.rgb, clr.a)\n\n\n\treturn clr\n}\n\n"
+
+//ebitengine:shader
+const _ = "//kage:unit pixels\n\npackage main\n\n\n\n\nfunc adjustSrcPosForAddressRepeat(p vec2) vec2 {\n\torigin := imageSrc0Origin()\n\tsize := imageSrc0Size()\n\treturn mod(p - origin, size) + origin\n}\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\t// inversedScale is the size of the region on the source image.\n\t// The size is the inverse of the geometry-matrix scale.\n\tinversedScale := vec2(abs(dfdx(srcPos.x)), abs(dfdy(srcPos.y)))\n\t// Cap the inversedScale to 1 as dfdx/dfdy is not accurate on some machines (#3182).\n\tinversedScale = min(inversedScale, vec2(1))\n\tp0 := srcPos - inversedScale/2.0\n\tp1 := srcPos + inversedScale/2.0\n\n\n\n\tp0 = adjustSrcPosForAddressRepeat(p0)\n\tp1 = adjustSrcPosForAddressRepeat(p1)\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\n\trate := clamp(fract(p1)/inversedScale, 0, 1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Apply the color scale.\n\tclr *= color\n\n\n\treturn clr\n}\n\n"
+
+//ebitengine:shader
+const _ = "//kage:unit pixels\n\npackage main\n\n\nvar ColorMBody mat4\nvar ColorMTranslation vec4\n\n\n\nfunc adjustSrcPosForAddressRepeat(p vec2) vec2 {\n\torigin := imageSrc0Origin()\n\tsize := imageSrc0Size()\n\treturn mod(p - origin, size) + origin\n}\n\n\nfunc Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {\n\n\n\t// inversedScale is the size of the region on the source image.\n\t// The size is the inverse of the geometry-matrix scale.\n\tinversedScale := vec2(abs(dfdx(srcPos.x)), abs(dfdy(srcPos.y)))\n\t// Cap the inversedScale to 1 as dfdx/dfdy is not accurate on some machines (#3182).\n\tinversedScale = min(inversedScale, vec2(1))\n\tp0 := srcPos - inversedScale/2.0\n\tp1 := srcPos + inversedScale/2.0\n\n\n\n\tp0 = adjustSrcPosForAddressRepeat(p0)\n\tp1 = adjustSrcPosForAddressRepeat(p1)\n\n\n\n\tc0 := imageSrc0At(p0)\n\tc1 := imageSrc0At(vec2(p1.x, p0.y))\n\tc2 := imageSrc0At(vec2(p0.x, p1.y))\n\tc3 := imageSrc0At(p1)\n\n\n\n\trate := clamp(fract(p1)/inversedScale, 0, 1)\n\n\tclr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)\n\n\n\n\t// Un-premultiply alpha.\n\t// When the alpha is 0, 1-sign(alpha) is 1.0, which means division does nothing.\n\tclr.rgb /= clr.a + (1-sign(clr.a))\n\t// Apply the clr matrix.\n\tclr = (ColorMBody * clr) + ColorMTranslation\n\t// Premultiply alpha\n\tclr.rgb *= clr.a\n\t// Apply the color scale.\n\tclr *= color\n\t// Clamp the output.\n\tclr.rgb = min(clr.rgb, clr.a)\n\n\n\treturn clr\n}\n\n"

internal/builtinshader/shader.go

@@ -29,9 +29,10 @@ type Filter int
 const (
 	FilterNearest Filter = iota
 	FilterLinear
+	FilterPixelated
 )
 
-const FilterCount = 2
+const FilterCount = 3
 
 type Address int
 
@@ -79,9 +80,19 @@ func Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {
 {{else if eq .Address .AddressRepeat}}
 	clr := imageSrc0At(adjustSrcPosForAddressRepeat(srcPos))
 {{end}}
-{{else if eq .Filter .FilterLinear}}
+{{else}}
+{{if eq .Filter .FilterLinear}}
 	p0 := srcPos - 1/2.0
 	p1 := srcPos + 1/2.0
+{{else if eq .Filter .FilterPixelated}}
+	// inversedScale is the size of the region on the source image.
+	// The size is the inverse of the geometry-matrix scale.
+	inversedScale := vec2(abs(dfdx(srcPos.x)), abs(dfdy(srcPos.y)))
+	// Cap the inversedScale to 1 as dfdx/dfdy is not accurate on some machines (#3182).
+	inversedScale = min(inversedScale, vec2(1))
+	p0 := srcPos - inversedScale/2.0
+	p1 := srcPos + inversedScale/2.0
+{{end}}
 
 {{if eq .Address .AddressRepeat}}
 	p0 = adjustSrcPosForAddressRepeat(p0)
@@ -100,7 +111,11 @@ func Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {
 	c3 := imageSrc0At(p1)
 {{end}}
 
+{{if eq .Filter .FilterLinear}}
 	rate := fract(p1)
+{{else if eq .Filter .FilterPixelated}}
+	rate := clamp(fract(p1)/inversedScale, 0, 1)
+{{end}}
 	clr := mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)
 {{end}}
 
@@ -146,6 +161,7 @@ func ShaderSource(filter Filter, address Address, useColorM bool) []byte {
 		Filter             Filter
 		FilterNearest      Filter
 		FilterLinear       Filter
+		FilterPixelated    Filter
 		Address            Address
 		AddressUnsafe      Address
 		AddressClampToZero Address
@@ -155,6 +171,7 @@ func ShaderSource(filter Filter, address Address, useColorM bool) []byte {
 		Filter:             filter,
 		FilterNearest:      FilterNearest,
 		FilterLinear:       FilterLinear,
+		FilterPixelated:    FilterPixelated,
 		Address:            address,
 		AddressUnsafe:      AddressUnsafe,
 		AddressClampToZero: AddressClampToZero,
@@ -169,28 +186,6 @@ func ShaderSource(filter Filter, address Address, useColorM bool) []byte {
 	return b
 }
 
-//ebitengine:shader
-const ScreenShaderSource = `//kage:unit pixels
-
-package main
-
-func Fragment(dstPos vec4, srcPos vec2) vec4 {
-	// Blend source colors in a square region, which size is 1/scale.
-	scale := imageDstSize()/imageSrc0Size()
-	p0 := srcPos - 1/2.0/scale
-	p1 := srcPos + 1/2.0/scale
-
-	// Texels must be in the source rect, so it is not necessary to check.
-	c0 := imageSrc0UnsafeAt(p0)
-	c1 := imageSrc0UnsafeAt(vec2(p1.x, p0.y))
-	c2 := imageSrc0UnsafeAt(vec2(p0.x, p1.y))
-	c3 := imageSrc0UnsafeAt(p1)
-
-	rate := clamp(fract(p1)*scale, 0, 1)
-	return mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y)
-}
-`
-
 //ebitengine:shader
 const ClearShaderSource = `//kage:unit pixels
 

shader.go

@@ -113,7 +113,8 @@ func builtinShader(filter builtinshader.Filter, address builtinshader.Address, u
 	}
 
 	var shader *Shader
-	if address == builtinshader.AddressUnsafe && !useColorM {
+	if (filter == builtinshader.FilterNearest || filter == builtinshader.FilterLinear) &&
+		address == builtinshader.AddressUnsafe && !useColorM {
 		switch filter {
 		case builtinshader.FilterNearest:
 			shader = &Shader{shader: ui.NearestFilterShader}
@@ -128,6 +129,8 @@ func builtinShader(filter builtinshader.Filter, address builtinshader.Address, u
 			name = "nearest"
 		case builtinshader.FilterLinear:
 			name = "linear"
+		case builtinshader.FilterPixelated:
+			name = "pixelated"
 		}
 		switch address {
 		case builtinshader.AddressClampToZero: