generate glenum, link glenum, add source gen for text regex

tools/StgSharp.GenerateGL/README.md

@@ -21,7 +21,7 @@ show command glBindBuffer
 target summary
 families list Vertex
 families show VertexAttributeP
-generate
+generate all
 list files
 preview OpenGLFunction.v4_1.g.cs
 ```
@@ -29,9 +29,21 @@ preview OpenGLFunction.v4_1.g.cs
 Generate directly into an existing directory:
 
 ```powershell
-dotnet run --project tools/StgSharp.GenerateGL/StgSharp.GenerateGL.csproj -- generate src/StgSharp.Graphics/OpenGL/Generated
+dotnet run --project tools/StgSharp.GenerateGL/StgSharp.GenerateGL.csproj -- generate all src/StgSharp.Graphics/OpenGL/Generated
 ```
 
+Generation targets are explicit:
+
+```text
+generate api [output-directory]   # function tables and managed forwarding APIs
+generate enum [output-directory]  # glConst and strongly typed enum groups
+generate all [output-directory]   # both sets
+```
+
+The API files reference the generated enum types. Use `generate all` for a clean output
+directory; use `generate api` when refreshing an output tree that already contains the enum
+files.
+
 Without a directory, `generate` retains its output in the current CLI session. With a directory:
 
 - the directory must already exist and be writable;
@@ -47,6 +59,7 @@ Use a directory dedicated to generated source files.
 gl.xml
   -> lossless XML and registry models
   -> desktop OpenGL 4.6 Core projection
+  -> GLenum/GLbitfield semantic group projection
   -> function-family and scalar/vector relation analysis
   -> managed API filters
   -> C# naming and signature validation
@@ -59,6 +72,7 @@ The target projection removes GLES and ARB/NV/EXT extension entry points. It ret
 Generated files:
 
 - `glconst.cs`: core constants;
+- `GlEnums.g.cs`: strongly typed enum groups referenced by Core Profile parameters and return values;
 - `OpenglContext.g.cs`: the function-pointer table with native names and ABI types;
 - `glContextShadow.g.cs`: an identically ordered `nint` table used while loading native entry points;
 - `OpenGLFunction.Base.g.cs`: APIs introduced through OpenGL 3.2 and retained in the target profile;
@@ -134,6 +148,10 @@ Renaming never changes the native target. For example, `VertexAttributeInteger(.
 ## Type rules
 
 - `gl.xml` typedefs map to equivalent C# ABI types; the generator does not emit separate type aliases;
+- `GLenum` and `GLbitfield` declarations with one unambiguous registry group use the generated enum type in public APIs;
+- enum pointers preserve their pointer shape (for example, `GLenum*` becomes `DebugSource*`) and are cast back to the native `uint*` representation at the forwarding boundary;
+- enum return values are converted from the native `uint` representation before being returned;
+- declarations with missing or conflicting enum group metadata remain on their ABI type;
 - a `GLuint` is converted to `GlHandle` only when object class and parameter semantics identify it as an object handle;
 - handle arrays use `Span<GlHandle>` or `ReadOnlySpan<GlHandle>`;
 - `OpenGLFunction` stores an `OpenglContext*` and forwards through `__context->glFunction(...)`;
@@ -141,6 +159,8 @@ Renaming never changes the native target. For example, `VertexAttributeInteger(.
 
 A `T*` alone does not determine whether a managed API should use `Span<T>`, `ReadOnlySpan<T>`, `out T`, or a return value. Future pointer improvements should be implemented as family-specific filters validated with `len`, parameter direction, and OpenGL state semantics.
 
+Raw managed forwards are omitted when a safer handwritten public API owns the command. In particular, `glShaderSource` remains in `OpenglContext` for ABI loading, while `OpenGLFunction` exposes the handwritten `ReadOnlySpan<byte>` and `string` overloads instead of a generated `byte**` signature.
+
 ## Documentation comments
 
 Every generated public method contains: