rsschermer / glsl_include_transformer.dart

Transformer preprocessor for include directives in GLSL shader files.

glsl_include_transformer.dart

Transformer preprocessor for include directives in .glsl shader files.

C-style include preprocessor directives are a basic way to reuse code snippets across multitple files. However, although OpenGL/WebGL implementations support most C-style preprocessor directives, include is a notable exception. This package adds support for include preprocessor directives through a Pub transformer that performs an additional preprocessing step at build time.

Usage

Add the glsl_include_transformer to the transformer list in your pubspec.yaml:

transformers:
  - glsl_include_transformer

This transformer will substitute include directives in .glsl files with the contents of the file they reference:

// Gets replaced with the contents of partials/my_shader_partial.glsl
#include "partials/my_shader_partial.glsl"

// Or alternatively, if you prefer angle brackets
#include <partials/my_shader_partial.glsl>

The include directive must reference a URI enclosed in double quotes or angle brackets. Unlike in C or C++ preprocessors there is no semantic difference between double quotes or angle brackets. The URI must be a relative URI (absolute URIs are not allowed):

// my_package/lib/shaders/my_shader.glsl

// Includes my_package|lib/shaders/partials/some_shader_partial.glsl
#include "partials/some_shader_partial.glsl"

A URI may reach into another package via the packages directory:

// my_package/lib/shaders/my_shader.glsl

// Includes some_package|lib/shaders/some_shader_partial.glsl
#include "../../packages/some_package/shaders/some_shader_partial.glsl"

You may only reference files in another package's lib directory. Note that URIs that reference another package should not contain a lib segment.