internal/shaderlister: add go:embeddedshader directive for embedded files

Updates #3157

examples/flappy/crt.go

@@ -14,6 +14,8 @@
 
 //go:build ignore
 
+//ebitengine:embeddedshader
+
 //kage:unit pixels
 
 // Reference: a public domain CRT effect

examples/shader/chromaticaberration.go

@@ -14,6 +14,8 @@
 
 //go:build ignore
 
+//ebitengine:embeddedshader
+
 //kage:unit pixels
 
 package main

examples/shader/default.go

@@ -14,6 +14,8 @@
 
 //go:build ignore
 
+//ebitengine:embeddedshader
+
 //kage:unit pixels
 
 package main

examples/shader/dissolve.go

@@ -14,6 +14,8 @@
 
 //go:build ignore
 
+//ebitengine:embeddedshader
+
 //kage:unit pixels
 
 package main

examples/shader/lighting.go

@@ -14,7 +14,8 @@
 
 //go:build ignore
 
-// Specify the 'pixel' mode.
+//ebitengine:embeddedshader
+
 //kage:unit pixels
 
 package main

examples/shader/radialblur.go

@@ -14,6 +14,8 @@
 
 //go:build ignore
 
+//ebitengine:embeddedshader
+
 //kage:unit pixels
 
 package main

examples/shader/texel.go

@@ -14,6 +14,8 @@
 
 //go:build ignore
 
+//ebitengine:embeddedshader
+
 //kage:unit pixels
 
 package main

examples/shader/water.go

@@ -14,6 +14,8 @@
 
 //go:build ignore
 
+//ebitengine:embeddedshader
+
 //kage:unit pixels
 
 package main

internal/shaderlister/main.go

@@ -94,7 +94,7 @@ func xmain() error {
 	}
 
 	pkgs, err := packages.Load(&packages.Config{
-		Mode: packages.NeedName | packages.NeedImports | packages.NeedDeps | packages.NeedTypes | packages.NeedSyntax | packages.NeedTypesInfo,
+		Mode: packages.NeedName | packages.NeedImports | packages.NeedDeps | packages.NeedTypes | packages.NeedSyntax | packages.NeedTypesInfo | packages.NeedEmbedFiles,
 	}, flag.Args()...)
 	if err != nil {
 		return err
@@ -124,7 +124,11 @@ func xmain() error {
 		}
 
 		origN := len(shaders)
-		shaders = appendShaderSources(shaders, pkg)
+		shaders, err = appendShaderSources(shaders, pkg)
+		if err != nil {
+			visitErr = err
+			return false
+		}
 
 		// Add source hashes.
 		for i := range shaders[origN:] {
@@ -175,20 +179,26 @@ func isStandardImportPath(path string) bool {
 	return !strings.Contains(head, ".")
 }
 
-const directive = "ebitengine:shader"
+const (
+	shaderDirective         = "ebitengine:shader"
+	embeddedShaderDirective = "ebitengine:embeddedshader"
+)
 
-var reDirective = regexp.MustCompile(`(?m)^\s*//` + regexp.QuoteMeta(directive))
+var (
+	reShaderDirective         = regexp.MustCompile(`(?m)^\s*//` + regexp.QuoteMeta(shaderDirective))
+	reEmbeddedShaderDirective = regexp.MustCompile(`(?m)^\s*//` + regexp.QuoteMeta(embeddedShaderDirective))
+)
 
 func hasShaderDirectiveInComment(commentGroup *ast.CommentGroup) bool {
 	for _, line := range commentGroup.List {
-		if reDirective.MatchString(line.Text) {
+		if reShaderDirective.MatchString(line.Text) {
 			return true
 		}
 	}
 	return false
 }
 
-func appendShaderSources(shaders []Shader, pkg *packages.Package) []Shader {
+func appendShaderSources(shaders []Shader, pkg *packages.Package) ([]Shader, error) {
 	topLevelDecls := map[ast.Decl]struct{}{}
 	for _, file := range pkg.Syntax {
 		for _, decl := range file.Decls {
@@ -220,7 +230,7 @@ func appendShaderSources(shaders []Shader, pkg *packages.Package) []Shader {
 				if genDecl.Lparen != token.NoPos {
 					if genDecl.Doc != nil && hasShaderDirectiveInComment(genDecl.Doc) {
 						pos := pkg.Fset.Position(genDecl.Doc.Pos())
-						slog.Warn(fmt.Sprintf("misplaced %s directive", directive),
+						slog.Warn(fmt.Sprintf("misplaced %s directive", shaderDirective),
 							"package", pkg.PkgPath,
 							"file", pos.Filename,
 							"line", pos.Line,
@@ -268,7 +278,7 @@ func appendShaderSources(shaders []Shader, pkg *packages.Package) []Shader {
 
 			if !isTopLevelDecl(genDecl) {
 				pos := pkg.Fset.Position(docPos)
-				slog.Warn(fmt.Sprintf("misplaced %s directive", directive),
+				slog.Warn(fmt.Sprintf("misplaced %s directive", shaderDirective),
 					"package", pkg.PkgPath,
 					"file", pos.Filename,
 					"line", pos.Line,
@@ -279,7 +289,7 @@ func appendShaderSources(shaders []Shader, pkg *packages.Package) []Shader {
 			// Avoid multiple names like `const a, b = "foo", "bar"` to avoid confusions.
 			if len(spec.Names) != 1 {
 				pos := pkg.Fset.Position(docPos)
-				slog.Warn(fmt.Sprintf("%s cannot apply to multiple declarations", directive),
+				slog.Warn(fmt.Sprintf("%s cannot apply to multiple declarations", shaderDirective),
 					"package", pkg.PkgPath,
 					"file", pos.Filename,
 					"line", pos.Line,
@@ -293,7 +303,7 @@ func appendShaderSources(shaders []Shader, pkg *packages.Package) []Shader {
 			c, ok := def.(*types.Const)
 			if !ok {
 				pos := pkg.Fset.Position(docPos)
-				slog.Warn(fmt.Sprintf("%s cannot apply to %s", directive, objectTypeString(def)),
+				slog.Warn(fmt.Sprintf("%s cannot apply to %s", shaderDirective, objectTypeString(def)),
 					"package", pkg.PkgPath,
 					"file", pos.Filename,
 					"line", pos.Line,
@@ -305,7 +315,7 @@ func appendShaderSources(shaders []Shader, pkg *packages.Package) []Shader {
 			val := c.Val()
 			if val.Kind() != constant.String {
 				pos := pkg.Fset.Position(docPos)
-				slog.Warn(fmt.Sprintf("%s cannot apply to const type of %s", directive, val.Kind()),
+				slog.Warn(fmt.Sprintf("%s cannot apply to const type of %s", shaderDirective, val.Kind()),
 					"package", pkg.PkgPath,
 					"file", pos.Filename,
 					"line", pos.Line,
@@ -325,7 +335,22 @@ func appendShaderSources(shaders []Shader, pkg *packages.Package) []Shader {
 		}
 	})
 
-	return shaders
+	for _, file := range pkg.EmbedFiles {
+		content, err := os.ReadFile(file)
+		if err != nil {
+			return nil, err
+		}
+		if !reEmbeddedShaderDirective.Match(content) {
+			continue
+		}
+		shaders = append(shaders, Shader{
+			Package: pkg.PkgPath,
+			File:    file,
+			Source:  string(content),
+		})
+	}
+
+	return shaders, nil
 }
 
 func objectTypeString(obj types.Object) string {

internal/shaderlister/shaderlister_test.go

@@ -19,6 +19,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"os/exec"
+	"regexp"
 	"slices"
 	"strings"
 	"testing"
@@ -58,29 +59,47 @@ func TestRun(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	slices.SortFunc(shaders, func(s1, s2 shader) int {
+	type filteredShader struct {
-		return cmp.Compare(s1.Source, s2.Source)
+		shader         shader
+		filteredSource string
+	}
+
+	re := regexp.MustCompile(`shader \d+`)
+	var filteredShaders []filteredShader
+	for _, s := range shaders {
+		m := re.FindAllString(s.Source, 1)
+		if len(m) != 1 {
+			t.Fatalf("invalid source: %q", s.Source)
+		}
+		filteredShaders = append(filteredShaders, filteredShader{
+			shader:         s,
+			filteredSource: m[0],
+		})
+	}
+
+	slices.SortFunc(filteredShaders, func(s1, s2 filteredShader) int {
+		return cmp.Compare(s1.filteredSource, s2.filteredSource)
 	})
 
-	if got, want := len(shaders), 6; got != want {
+	if got, want := len(filteredShaders), 9; got != want {
 		t.Fatalf("len(shaders): got: %d, want: %d", got, want)
 	}
 
-	for i, s := range shaders {
+	for i, s := range filteredShaders {
-		if s.Package == "" {
+		if s.shader.Package == "" {
 			t.Errorf("s.Package is empty: %v", s)
 		}
-		if s.File == "" {
+		if s.shader.File == "" {
 			t.Errorf("s.File is empty: %v", s)
 		}
-		hash, err := graphics.CalcSourceHash([]byte(s.Source))
+		hash, err := graphics.CalcSourceHash([]byte(s.shader.Source))
 		if err != nil {
 			t.Fatal(err)
 		}
-		if got, want := s.SourceHash, hash.String(); got != want {
+		if got, want := s.shader.SourceHash, hash.String(); got != want {
 			t.Errorf("s.SourceHash: got: %q, want: %q", got, want)
 		}
-		if got, want := s.Source, fmt.Sprintf("shader %d", i+1); got != want {
+		if got, want := s.filteredSource, fmt.Sprintf("shader %d", i+1); got != want {
 			t.Errorf("s.Source: got: %q, want: %q", got, want)
 		}
 	}

internal/shaderlister/shaderlistertest/def.go

@@ -14,7 +14,11 @@
 
 package shaderlistertest
 
-import "github.com/hajimehoshi/ebiten/v2/internal/shaderlister/shaderlistertest2"
+import (
+	"embed"
+
+	"github.com/hajimehoshi/ebiten/v2/internal/shaderlister/shaderlistertest2"
+)
 
 //ebitengine:shader
 const _ = "shader 1"
@@ -66,3 +70,9 @@ const (
 	//ebitengine:shader
 	_, _ = "ignored", "ignored again" // multiple consts are ignored to avoid confusion.
 )
+
+//go:embed *kage.go
+var embed_go []byte
+
+//go:embed resource
+var embed2_go embed.FS

internal/shaderlister/shaderlistertest/embed2_kage.go

@@ -0,0 +1,21 @@
+// Copyright 2025 The Ebitengine 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.
+
+//go:build ignore
+
+//ebitengine:embeddedshader
+
+package main
+
+// shader 8

internal/shaderlister/shaderlistertest/embed_kage.go

@@ -0,0 +1,21 @@
+// Copyright 2025 The Ebitengine 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.
+
+//go:build ignore
+
+//ebitengine:embeddedshader
+
+package main
+
+// shader 7

internal/shaderlister/shaderlistertest/embed_notkage.go

@@ -0,0 +1,21 @@
+// Copyright 2025 The Ebitengine 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.
+
+//go:build ignore
+
+// This file lacks the directive `ebitengine:embeddedshader`, so this is not considered as a shader file by shaderlister.
+
+package main
+
+// shader 0

internal/shaderlister/shaderlistertest/resource/embed_kage.go

@@ -0,0 +1,21 @@
+// Copyright 2025 The Ebitengine 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.
+
+//go:build ignore
+
+//ebitengine:embeddedshader
+
+package main
+
+// shader 9

internal/shaderlister/shaderlistertest/resource/embed_notkage.go

@@ -0,0 +1,21 @@
+// Copyright 2025 The Ebitengine 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.
+
+//go:build ignore
+
+// This file lacks the directive `ebitengine:embeddedshader`, so this is not considered as a shader file by shaderlister.
+
+package main
+
+// shader 0