examples/shader: Add the radial blur example

Updates #1284

examples/resources/generate.go

@@ -34,6 +34,7 @@
 //go:generate file2byteslice -package=mascot -input=./images/mascot/out02.png -output=./images/mascot/out02.go -var=Out02_png
 //go:generate file2byteslice -package=mascot -input=./images/mascot/out03.png -output=./images/mascot/out03.go -var=Out03_png
 //go:generate file2byteslice -package=shader -input=./images/shader/gopher.png -output=./images/shader/gopher.go -var=Gopher_png
+//go:generate file2byteslice -package=shader -input=./images/shader/gopherbg.png -output=./images/shader/gopherbg.go -var=GopherBg_png
 //go:generate file2byteslice -package=shader -input=./images/shader/normal.png -output=./images/shader/normal.go -var=Normal_png
 //go:generate file2byteslice -package=platformer -input=./images/platformer/background.png -output=./images/platformer/background.go -var=Background_png
 //go:generate file2byteslice -package=platformer -input=./images/platformer/left.png -output=./images/platformer/left.go -var=Left_png

examples/resources/images/license.md

@@ -99,6 +99,24 @@ Read this article for more details: https://blog.golang.org/gopher
 https://corvussg.itch.io/2d-game-backgrounds
 ```
 
+## shader/gopher.png
+
+```
+The Go gopher was designed by Renee French. (http://reneefrench.blogspot.com/)
+The design is licensed under the Creative Commons 3.0 Attributions license.
+Read this article for more details: https://blog.golang.org/gopher
+```
+
+## shader/gopherbg.png
+
+```
+https://commons.wikimedia.org/wiki/File:Solna_Brick_wall_vilt_forband.jpg
+
+By Håkan Svensson Xauxa
+
+The Creative Commons Attribution-Share Alike 3.0 Unported license
+```
+
 ## Other image files
 
 ```

examples/shader/generate.go

@@ -16,3 +16,4 @@ package main
 
 //go:generate file2byteslice -package=main -input=default.go -output=default_go.go -var=default_go
 //go:generate file2byteslice -package=main -input=lighting.go -output=lighting_go.go -var=lighting_go
+//go:generate file2byteslice -package=main -input=radialblur.go -output=radialblur_go.go -var=radialblur_go

examples/shader/main.go

@@ -35,6 +35,7 @@ const (
 
 var (
 	gopherImage   *ebiten.Image
+	gopherBgImage *ebiten.Image
 	normalImage   *ebiten.Image
 )
 
@@ -55,6 +56,14 @@ func init() {
 	gopherImage, _ = ebiten.NewImageFromImage(img, ebiten.FilterDefault)
 }
 
+func init() {
+	img, _, err := image.Decode(bytes.NewReader(resources.GopherBg_png))
+	if err != nil {
+		log.Fatal(err)
+	}
+	gopherBgImage, _ = ebiten.NewImageFromImage(img, ebiten.FilterDefault)
+}
+
 func init() {
 	img, _, err := image.Decode(bytes.NewReader(resources.Normal_png))
 	if err != nil {
@@ -66,6 +75,7 @@ func init() {
 var shaderSrcs = [][]byte{
 	default_go,
 	lighting_go,
+	radialblur_go,
 }
 
 type Game struct {
@@ -114,6 +124,7 @@ func (g *Game) Draw(screen *ebiten.Image) {
 	}
 	op.Images[0] = gopherImage
 	op.Images[1] = normalImage
+	op.Images[2] = gopherBgImage
 	screen.DrawRectShader(w, h, s, op)
 
 	msg := "Press Up/Down to switch the shader."

examples/shader/radialblur.go

@@ -0,0 +1,40 @@
+// Copyright 2020 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build ignore
+
+package main
+
+var Time float
+var Cursor vec2
+
+func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
+	dir := normalize(position.xy - Cursor)
+	clr := texture2At(texCoord)
+
+	samples := [10]float{
+		-22, -14, -8, -4, -2, 2, 4, 8, 14, 22,
+	}
+	// TODO: Add len(samples)
+	sum := clr
+	for i := 0; i < 10; i++ {
+		// TODO: Consider the source region not to violate the region.
+		sum += texture2At(texCoord + dir*samples[i]/texture2Size())
+	}
+	sum /= 10 + 1
+
+	dist := distance(position.xy, Cursor)
+	t := clamp(dist/256, 0, 1)
+	return mix(clr, sum, t)
+}

examples/shader/radialblur_go.go

@@ -0,0 +1,6 @@
+// Code generated by file2byteslice. DO NOT EDIT.
+// (gofmt is fine after generating)
+
+package main
+
+var radialblur_go = []byte("// Copyright 2020 The Ebiten Authors\n//\n// Licensed under the Apache License, Version 2.0 (the \"License\");\n// you may not use this file except in compliance with the License.\n// You may obtain a copy of the License at\n//\n//     http://www.apache.org/licenses/LICENSE-2.0\n//\n// Unless required by applicable law or agreed to in writing, software\n// distributed under the License is distributed on an \"AS IS\" BASIS,\n// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n// See the License for the specific language governing permissions and\n// limitations under the License.\n\n// +build ignore\n\npackage main\n\nvar Time float\nvar Cursor vec2\n\nfunc Fragment(position vec4, texCoord vec2, color vec4) vec4 {\n\tdir := normalize(position.xy - Cursor)\n\tclr := texture2At(texCoord)\n\n\tsamples := [10]float{\n\t\t-22, -14, -8, -4, -2, 2, 4, 8, 14, 22,\n\t}\n\t// TODO: Add len(samples)\n\tsum := clr\n\tfor i := 0; i < 10; i++ {\n\t\t// TODO: Consider the source region not to violate the region.\n\t\tsum += texture2At(texCoord + dir*samples[i]/texture2Size())\n\t}\n\tsum /= 10 + 1\n\n\tdist := distance(position.xy, Cursor)\n\tt := clamp(dist/256, 0, 1)\n\treturn mix(clr, sum, t)\n}\n")