GDShader LSP

A high-performance, standalone Language Server Protocol (LSP) implementation for the Godot Shading Language (.gdshader), developed in C++20.

GDShader LSP provides enterprise-grade code intelligence, strict semantic analysis, and real-time diagnostics for Godot shaders. It is designed to be editor-agnostic, integrating seamlessly into VSCode, Neovim, Emacs, or directly into the Godot Engine via GDExtension.

For information on changes per version, see CHANGELOG.md.

Key Features

Advanced Static Analysis & Type Checking

Unlike basic syntax highlighters, GDShader LSP performs full semantic analysis of your shader code:

• Strict Type Validation: comprehensive checking for vector swizzling, matrix operations, and implicit type conversions.
• Scope & Shadowing: Accurate detection of variable shadowing, scope leakage, and uninitialized variables.
• Control Flow Analysis: Detection of unreachable code, missing return statements, and invalid discard usage in specific processor stages.
• Constructor Validation: Overload resolution for functions and type constructors (e.g., vec3, mat4).

Modular Preprocessor Support

Full support for complex project structures using an AST-aware preprocessor:

• #include Resolution: Resolves dependencies via a Virtual File System, supporting both relative paths and Godot res:// paths.
• Cross-File Symbol Linking: Functions, structs, and constants defined in included files are fully resolved, typed, and available for autocompletion.
• Macro Support: Handles #define, #ifdef, #elif, and #endif branching, ensuring that only active code paths are analyzed.

LSP Capabilities

• Code Completion: Context-aware suggestions for built-ins, struct members, vector swizzles (.xyz), and user-defined symbols.
• Signature Help: Parameter hints and overload information for built-in and user functions.
• Hover Documentation: Type information and documentation for symbols.
• Go to Definition: Jump to variables, structs, and included files.
• Document Symbols: hierarchical outline view of the shader structure.
• Semantic Highlighting: precise token coloring based on symbol roles (uniforms, consts, varyings).

Architecture & Performance

GDShader LSP is built for speed and low latency.

• Virtual File System: The server maintains a "Split-Brain" architecture, prioritizing in-memory dirty buffers from the editor while lazily loading dependencies from disk.
• Performance Metrics: Internal stress tests on 5,000+ line shader files with deep include hierarchies demonstrate a full analysis pipeline (Client → Server → Client) latency of < 25ms.
• Memory Management: The architecture utilizes standard C++ allocators efficiently. Given that shader translation units are typically small, this approach provides the optimal balance between code maintainability and runtime performance without the overhead of complex arena allocators.

Compatibility & Versioning

The GDShader language evolves with every Godot Engine release (adding new built-ins, changing keywords, etc.). To ensure strict semantic accuracy, GDShader LSP releases are pinned to specific Godot versions.

We follow a "Main is Latest" strategy:

• The main branch always tracks the latest stable version of Godot.
• Previous Godot versions are supported via long-lived support/ branches.

LSP Version	Godot Version	Git Branch
v0.3.x (Upcoming)	Godot 4.6	main
v0.2.x (Current)	Godot 4.5	support/4.5

Note: If you are building from source, ensure you checkout the branch matching your project's Godot version.

Building from Source

This project uses SCons as its build system.

Prerequisites

• C++ Compiler: GCC, Clang, or MSVC supporting C++20.
• SCons: Install via Python (pip install scons).
• LSP build: You need to build the LSP Framework library for your platform.

Building LSP Framework

This project expects the LSP Framework to be located at extern/lsp-framework. You must compile the framework for your target platform and ensure the build artifacts are located in the specific directories expected by the SConstruct script:

• Linux: extern/lsp-framework/build_linux
• Windows: extern/lsp-framework/build_windows
• macOS: extern/lsp-framework/build_macos

Ensure your directory structure looks like this before compiling the main project:

extern/
└── lsp-framework/
    ├── build_linux/    # Contains liblsp.a for Linux
    ├── build_windows/  # Contains lsp.lib for Windows
    └── build_macos/    # Contains liblsp.a (Universal Binary) for macOS

Linux

cd extern/lsp-framework
cmake -B build_linux -DCMAKE_BUILD_TYPE=Release
cmake --build build_linux

Windows

Use this if you are compiling with MinGW (as expected by the SConstruct configuration).

cd extern/lsp-framework
cmake -B build_windows -G "MinGW Makefiles" -DCMAKE_BUILD_TYPE=Release
cmake --build build_windows

Macos

To support both Intel and Apple Silicon Macs, build a universal binary using the architectural flags.

cd extern/lsp-framework

cmake -B build_macos \
    -DCMAKE_OSX_ARCHITECTURES="x86_64;arm64" \
    -DCMAKE_BUILD_TYPE=Release

cmake --build build_macos

Compilation

To build the standalone LSP executable:

scons platform=<platform> target=<debug/release>

Supported Platforms:

• linux
• windows
• macos

The binary will be output to bin/.

Configuration (VSCode Example)

To use this with VSCode, you can use a generic LSP client extension (like glsl-canvas or a custom configuration).

{
    "godot_shader_lsp.serverPath": "/path/to/bin/gdshader-lsp-release",
    "godot_shader_lsp.trace.server": "verbose"
}

Note: A dedicated VSCode extension wrapper is NOT planned. Feel free to implement one!

Roadmap

This project is currently in Alpha. While the core analysis engine is robust, the following features are planned:

• Code Actions: Quick fixes for common errors (e.g., "Did you mean...?").
• Formatting: AST-based code formatting (textDocument/formatting).
• Rename Refactoring: Project-wide symbol renaming.
• Find References: Locate all usages of a symbol across the project.

Contributing

Contributions are welcome! Please submit Pull Requests or open Issues to discuss planned features.

License

Copyright 2026 5cump1

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.