使用Visual Studio SDK制作GLSL词法着色插件

使用Visual Studio SDK制作GLSL词法着色插件

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我们在Visual Studio上开发OpenGL ES项目时，避免不了写Shader。这时在vs里直接编辑shader就会显得很方便。但是vs默认是不支持GLSL的语法着色的，我们只好自己动手创造。最简单的实现自定义语法着色的方法就是创建一个VSIX插件包，我们只需要安装Visual Studio SDK，使用内置的模版就可以构建一个插件项目。

1. 安装Visual Studio SDK

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在http://www.microsoft.com/en-us/download/details.aspx?id=40758下载最新的Visual Studio 2013 SDK。

双击安装，一路next即可。

安装完毕后我们可以在新建项目->模版->C#中看到“扩展性”这一条目，这些就是开发插件用的模版了。

2. 创建插件项目

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新建项目，在扩展性标签中，选择Editor Classifier模版，命名为ShaderEditor，点击确定。

Visual Studio为我们生成了如下几个文件。

ShaderEditorFormat.cs文件的默认代码如下：

     [Export(typeof(EditorFormatDefinition))]
     [ClassificationType(ClassificationTypeNames = "ShaderEditor")]
     [Name("ShaderEditor")]
     [UserVisible(true)] //this should be visible to the end user
     [Order(Before = Priority.Default)] //set the priority to be after the default classifiers
     internal sealed class ShaderEditorFormat : ClassificationFormatDefinition {
         /// <summary>
         /// Defines the visual format for the "ShaderEditor" classification type
         /// </summary>
         public ShaderEditorFormat() {
             this.DisplayName = "ShaderEditor"; //human readable version of the name
             this.BackgroundColor = Colors.BlueViolet;
             this.TextDecorations = System.Windows.TextDecorations.Underline;
         }
     }

这段代码定义了一个名为"ShaderEditor"的着色类型，编译工程并运行，我们可以在Visual Studio实验实例的工具->选项->字体和颜色中找到一个名为"ShaderEditor"的条目。同时我们会发现所有文本文件的颜色都变成了Colors.BlueViolet并带上了下划线。修改this.DisplayName = "ShaderEditor"的内容，可以改变在字体和颜色中显示的名字。下面的格式设置可以任意修改成喜欢的样式，但要注意在这里的格式只是插件首次安装时的默认设置，这些条目和其它着色选项一样，都可以被用户任意更改。

3. 创建GLSL的着色类型

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我们已经了解了如何将着色类型添加到Visual Studio，现在修改ShaderEditorFormat.cs，添加我们的着色类型。

     [Export(typeof(EditorFormatDefinition))]
     [ClassificationType(ClassificationTypeNames = "GLSLText")]
     [Name("GLSLText")]
     [UserVisible(true)]
     [Order(Before = Priority.Default)]
     internal sealed class GLSLTextFormatDefinition : ClassificationFormatDefinition {
         public GLSLTextFormatDefinition() {
             this.DisplayName = "GLSL文本";
             this.ForegroundColor = Colors.Brown;
         }
     }

     [Export(typeof(EditorFormatDefinition))]
     [ClassificationType(ClassificationTypeNames = "GLSLIdentifier")]
     [Name("GLSLIdentifier")]
     [UserVisible(true)]
     [Order(Before = Priority.Default)]
     internal sealed class GLSLIdentifierFormatDefinition : ClassificationFormatDefinition {
         public GLSLIdentifierFormatDefinition() {
             this.DisplayName = "GLSL标识符";
             this.ForegroundColor = Colors.Brown;
         }
     }

     [Export(typeof(EditorFormatDefinition))]
     [ClassificationType(ClassificationTypeNames = "GLSLComment")]
     [Name("GLSLComment")]
     [UserVisible(true)]
     [Order(Before = Priority.Default)]
     internal sealed class GLSLCommentFormatDefinition : ClassificationFormatDefinition {
         public GLSLCommentFormatDefinition() {
             this.DisplayName = "GLSL注释";
             this.ForegroundColor = Colors.DarkGray;
         }
     }

     [Export(typeof(EditorFormatDefinition))]
     [ClassificationType(ClassificationTypeNames = "GLSLKeyword")]
     [Name("GLSLKeyword")]
     [UserVisible(true)]
     [Order(Before = Priority.Default)]
     internal sealed class GLSLKeywordFormatDefinition : ClassificationFormatDefinition {
         public GLSLKeywordFormatDefinition() {
             this.DisplayName = "GLSL关键字";
             this.ForegroundColor = Colors.Blue;
         }
     }

     [Export(typeof(EditorFormatDefinition))]
     [ClassificationType(ClassificationTypeNames = "GLSLClass")]
     [Name("GLSLClass")]
     [UserVisible(true)]
     [Order(Before = Priority.Default)]
     internal sealed class GLSLClassFormatDefinition : ClassificationFormatDefinition {
         public GLSLClassFormatDefinition() {
             this.DisplayName = "GLSL类型";
             this.ForegroundColor = Colors.Green;
         }
     }

     [Export(typeof(EditorFormatDefinition))]
     [ClassificationType(ClassificationTypeNames = "GLSLQualifier")]
     [Name("GLSLQualifier")]
     [UserVisible(true)]
     [Order(Before = Priority.Default)]
     internal sealed class GLSLQualifierFormatDefinition : ClassificationFormatDefinition {
         public GLSLQualifierFormatDefinition() {
             this.DisplayName = "GLSL限定符";
             this.ForegroundColor = Colors.Pink;
         }
     }

     [Export(typeof(EditorFormatDefinition))]
     [ClassificationType(ClassificationTypeNames = "GLSLVariable")]
     [Name("GLSLVariable")]
     [UserVisible(true)]
     [Order(Before = Priority.Default)]
     internal sealed class GLSLVariableFormatDefinition : ClassificationFormatDefinition {
         public GLSLVariableFormatDefinition() {
             this.DisplayName = "GLSL系统变量";
             this.ForegroundColor = Colors.DarkOrange;
         }
     }

     [Export(typeof(EditorFormatDefinition))]
     [ClassificationType(ClassificationTypeNames = "GLSLFunction")]
     [Name("GLSLFunction")]
     [UserVisible(true)]
     [Order(Before = Priority.Default)]
     internal sealed class GLSLFunctionFormatDefinition : ClassificationFormatDefinition {
         public GLSLFunctionFormatDefinition() {
             this.DisplayName = "GLSL系统函数";
             this.ForegroundColor = Colors.DarkTurquoise;
         }
     }

4. 导出着色类型

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Editor Classifier使用了MEF框架，关于MEF的具体细节，请参考MSDN的相关文档。

我们需要注意的是，在MEF中，光定义了着色类型还不够，我们需要导出一个ClassificationTypeDefinition，才能在系统中生效。

打开ShaderEditorType.cs，我们看到系统生成的代码如下：

     internal static class ShaderEditorClassificationDefinition {
         [Export(typeof(ClassificationTypeDefinition))]
         [Name("ShaderEditor")]
         internal static ClassificationTypeDefinition ShaderEditorType = null;
     }

这里的Name与之前默认生成的ShaderEditor相同，同理，我们将这里的代码修改成方才定义的类型

     internal static class ShaderEditorClassificationDefinition {
         [Export(typeof(ClassificationTypeDefinition))]
         [Name("GLSLText")]
         internal static ClassificationTypeDefinition GLSLTextType = null;

         [Export(typeof(ClassificationTypeDefinition))]
         [Name("GLSLIdentifier")]
         internal static ClassificationTypeDefinition GLSLIdentifierType = null;

         [Export(typeof(ClassificationTypeDefinition))]
         [Name("GLSLComment")]
         internal static ClassificationTypeDefinition GLSLCommentType = null;

         [Export(typeof(ClassificationTypeDefinition))]
         [Name("GLSLKeyword")]
         internal static ClassificationTypeDefinition GLSLKeywordType = null;

         [Export(typeof(ClassificationTypeDefinition))]
         [Name("GLSLClass")]
         internal static ClassificationTypeDefinition GLSLClassType = null;

         [Export(typeof(ClassificationTypeDefinition))]
         [Name("GLSLQualifier")]
         internal static ClassificationTypeDefinition GLSLQualifierType = null;

         [Export(typeof(ClassificationTypeDefinition))]
         [Name("GLSLVariable")]
         internal static ClassificationTypeDefinition GLSLVariableType = null;

         [Export(typeof(ClassificationTypeDefinition))]
         [Name("GLSLFunction")]
         internal static ClassificationTypeDefinition GLSLFunctionType = null;
     }

5. 关联文件类型

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打开ShaderEditor.cs

     [Export(typeof(IClassifierProvider))]
     [ContentType("text")]
     internal class ShaderEditorProvider : IClassifierProvider {
         [Import]
         internal IClassificationTypeRegistryService ClassificationRegistry = null; // Set via MEF

         public IClassifier GetClassifier(ITextBuffer buffer) {
             return buffer.Properties.GetOrCreateSingletonProperty<ShaderEditor>(delegate { return new ShaderEditor(ClassificationRegistry); });
         }
     }

代码ContentType("text")创建了一个Provider并将它们对所有text类型的文件生效。

GLSL主要的文件扩展名为.vsh和.fsh，为了只对这两个扩展名生效，我们需要自定义一个ContentType，并创建两个扩展名关联。将上述代码修改为：

     [Export(typeof(ITaggerProvider))]
     [ContentType("glsl")]
     [TagType(typeof(ClassificationTag))]
     internal sealed class GLSLClassifierProvider : ITaggerProvider {

         [Export]
         [Name("glsl")]
         [BaseDefinition("code")]
         internal static ContentTypeDefinition GLSLContentType = null;

         [Export]
         [FileExtension(".vsh")]
         [ContentType("glsl")]
         internal static FileExtensionToContentTypeDefinition GLSLVshType = null;

         [Export]
         [FileExtension(".fsh")]
         [ContentType("glsl")]
         internal static FileExtensionToContentTypeDefinition GLSLFshType = null;

         [Import]
         internal IClassificationTypeRegistryService classificationTypeRegistry = null;

         [Import]
         internal IBufferTagAggregatorFactoryService aggregatorFactory = null;

         public ITagger<T> CreateTagger<T>(ITextBuffer buffer) where T : ITag {
             return new GLSLClassifier(buffer, classificationTypeRegistry) as ITagger<T>;
         }
     }

这样我们就创建了只针对vsh和fsh文件生效的Editor。

6. 使用gplex进行词法分析

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我们需要使用词法分析扫描器来实现具体的着色功能，gplex可以为我们生成C#语言的扫描器，下载地址：

http://gplex.codeplex.com/

解压后在binaries文件夹下找到gplex.exe，把它拷贝到项目的根目录下。

在项目根目录下新建一个GLSL文件夹，新建GLSLLexer.lex文件。并把它们添加到proj中。

在proj上右键->属性，在生成事件选项卡中，在预先生成事件命令行中输入

cd $(ProjectDir)GLSL\
$(ProjectDir)\gplex GLSLLexer

打开GLSLLexer.lex，写入以下代码：

 %option unicode, codepage:raw

 %{
         // User code is all now in ScanHelper.cs
 %}

 %namespace Shane
 %option verbose, summary, noparser, nofiles, unicode

 %{
     public int nextToken() { return yylex(); }
     public int getPos() { return yypos; }
     public int getLength() { return yyleng; }
 %}

 //=============================================================
 //=============================================================

 number ([-])+
 chars [A-Za-z]
 cstring [A-Za-z_]
 blank " "
 delim [ \t\n]
 word {chars}+
 singleLineComment "//"[^\n]*
 multiLineComment "/*"[^*]*\*(\*|([^*/]([^*])*\*))*\/

 comment {multiLineComment}|{singleLineComment}
 class bool|int|float|bvec|ivec|vec|vec2|vec3|vec4|mat2|mat3|mat4|sampler1D|sampler2D|sampler3D|samplerCube|sampler1DShadow|sampler2DShadow
 keyword return|if|else|while|do|for|foreach|break|continue|switch|case|default|goto|class|struct|enum|extern|interface|namespace|public|static|this|volatile|using|in|out|true|false
 qualifier const|attribute|uniform|varying
 systemVariable gl_BackColor|gl_BackLightModelProduct|gl_BackLightProduct|gl_BackMaterial|gl_BackSecondaryColor|gl_ClipPlane|gl_ClipVertex|gl_Color|gl_DepthRange|gl_DepthRangeParameters|gl_EyePlaneQ|gl_EyePlaneR|gl_EyePlaneS|gl_EyePlaneT|gl_Fog|gl_FogCoord|gl_FogFragCoord|gl_FogParameters|gl_FragColor|gl_FragCoord|gl_FragData|gl_FragDepth|gl_FrontColor|gl_FrontFacing|gl_FrontLightModelProduct|gl_FrontLightProduct|gl_FrontMaterial|gl_FrontSecondaryColor|gl_LightModel|gl_LightModelParameters|gl_LightModelProducts|gl_LightProducts|gl_LightSource|gl_LightSourceParameters|gl_MaterialParameters|gl_MaxClipPlanes|gl_MaxCombinedTextureImageUnits|gl_MaxDrawBuffers|gl_MaxFragmentUniformComponents|gl_MaxLights|gl_MaxTextureCoords|gl_MaxTextureImageUnits|gl_MaxTextureUnits|gl_MaxVaryingFloats|gl_MaxVertexAttribs|gl_MaxVertexTextureImageUnits|gl_MaxVertexUniformComponents|gl_ModelViewMatrix|gl_ModelViewMatrixInverse|gl_ModelViewMatrixInverseTranspose|gl_ModelViewMatrixTranspose|gl_ModelViewProjectionMatrix|gl_ModelViewProjectionMatrixInverse|gl_ModelViewProjectionMatrixInverseTranspose|gl_ModelViewProjectionMatrixTranspose|gl_MultiTexCoord0|gl_MultiTexCoord1|gl_MultiTexCoord10|gl_MultiTexCoord11|gl_MultiTexCoord2|gl_MultiTexCoord3|gl_MultiTexCoord4|gl_MultiTexCoord5|gl_MultiTexCoord6|gl_MultiTexCoord7|gl_MultiTexCoord8|gl_MultiTexCoord9|gl_Normal|gl_NormalMatrix|gl_NormalScale|gl_ObjectPlaneQ|gl_ObjectPlaneR|gl_ObjectPlaneS|gl_ObjectPlaneT|gl_Point|gl_PointParameters|gl_PointSize|gl_Position|gl_ProjectionMatrix|gl_ProjectionMatrixInverse|gl_ProjectionMatrixInverseTranspose|gl_ProjectionMatrixTranspose|gl_SecondaryColor|gl_TexCoord|gl_TextureEnvColor|gl_TextureMatrix|gl_TextureMatrixInverse|gl_TextureMatrixInverseTranspose|gl_TextureMatrixTranspose|gl_Vertex
 systemFunction radians|degress|sin|cos|tan|asin|acos|atan|pow|exp|log|exp2|log2|sqrt|inversesqrt|abs|sign|floor|ceil|fract|mod|min|max|clamp|mix|step|smoothstep|length|distance|dot|cross|normalize|faceforward|reflect|matrixCompMult|lessThan|lessThanEqual|greaterThan|greaterThanEqual|equal|notEqual|any|all|not|texture2D|texture2DProj|texture2DLod|texture2DProjLod|textureCube|textureCubeLod
 identifier {cstring}+{number}*[{cstring}@]*{number}*

 %%

 {keyword}            return (int)GLSLTokenType.Keyword;
 {class}                return (int)GLSLTokenType.Class;
 {qualifier}            return (int)GLSLTokenType.Qualifier;
 {systemVariable}    return (int)GLSLTokenType.SystemVariable;
 {systemFunction}    return (int)GLSLTokenType.SystemFunction;
 {identifier}        return (int)GLSLTokenType.Identifier;
 {comment}            return (int)GLSLTokenType.Comment;

 %%

保存并关闭，这时生成一下项目，我们会看到在GLSL目录下生成了GLSLLexer.cs文件，同样把这个文件添加到proj中。

7. 处理扫描结果

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接下来我们要在ShaderEditor.cs中处理我们的扫描结果，并最终对匹配的代码行进行着色。

首先删除默认创建的ShaderEditor类。

添加一个GLSLToken枚举，这个枚举就是GLSLLexer.cs返回的枚举类型，它用来通知我们当前的语句块是哪个类型。

代码如下：

     public enum GLSLTokenType {
         Text = ,
         Keyword,
         Comment,
         Identifier,
         Class,
         Qualifier,
         SystemVariable,
         SystemFunction
     }

创建我们自己的ShaderEditor类，代码如下：

     internal sealed class GLSLClassifier : ITagger<ClassificationTag> {
         internal GLSLClassifier(ITextBuffer buffer, IClassificationTypeRegistryService typeService) {
             textBuffer = buffer;
             typeDic = new Dictionary<GLSLTokenType, IClassificationType>();
             typeDic[GLSLTokenType.Text] = typeService.GetClassificationType("GLSLText");
             typeDic[GLSLTokenType.Identifier] = typeService.GetClassificationType("GLSLIdentifier");
             typeDic[GLSLTokenType.Keyword] = typeService.GetClassificationType("GLSLKeyword");
             typeDic[GLSLTokenType.Class] = typeService.GetClassificationType("GLSLClass");
             typeDic[GLSLTokenType.Comment] = typeService.GetClassificationType("GLSLComment");
             typeDic[GLSLTokenType.Qualifier] = typeService.GetClassificationType("GLSLQualifier");
             typeDic[GLSLTokenType.SystemVariable] = typeService.GetClassificationType("GLSLVariable");
             typeDic[GLSLTokenType.SystemFunction] = typeService.GetClassificationType("GLSLFunction");
         }

         public event EventHandler<SnapshotSpanEventArgs> TagsChanged {
             add { }
             remove { }
         }

         public IEnumerable<ITagSpan<ClassificationTag>> GetTags(NormalizedSnapshotSpanCollection spans) {
             IClassificationType classification = typeDic[GLSLTokenType.Text];
             string text = spans[].Snapshot.GetText();
             yield return new TagSpan<ClassificationTag>(
                 new SnapshotSpan(spans[].Snapshot, new Span(, text.Length)),
                 new ClassificationTag(classification));
             scanner.SetSource(text, );
             int tok;
             do {
                 tok = scanner.nextToken();
                 int pos = scanner.getPos();
                 int len = scanner.getLength();
                 int total = text.Length;
                 if (pos <  || len <  || pos > total) {
                     continue;
                 }
                 if (pos + len > total) {
                     len = total - pos;
                 }
                 if (typeDic.TryGetValue((GLSLTokenType)tok, out classification)) {
                     yield return new TagSpan<ClassificationTag>(
                         new SnapshotSpan(spans[].Snapshot, new Span(pos, len)),
                         new ClassificationTag(classification));
                 }
             } while (tok > (int)Tokens.EOF);
         }

         ITextBuffer textBuffer;
         IDictionary<GLSLTokenType, IClassificationType> typeDic;
         Scanner scanner = new Scanner();
     }

TagsChanged事件保证在代码发生改变时实时刷新编辑器。

构造方法中，通过typeService.GetClassificationType("GLSLIdentifier")取得我们定义的实例，并把它们和枚举关联起来，

GetClassificationType的参数传入着色类型的Name。

GetTags方法是由系统调用的迭代方法，yield return new TagSpan<ClassificationTag>()返回我们的着色对象，即可实现着色效果。

编译并运行，可以看到vsh和fsh已经有了语法着色了。

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