Crate glslt

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glslt is the main library that supports the GLSL Template compiler transforms. If you are building a system that relies on transforming GLSLT code, you’ll want to interact with this library directly instead of the command-line interface provided by glsltc.


Rust crate

The glslt crate manipulates syntax trees generated by the glsl-lang crate.

use glslt::glsl_lang::{ast::*, parse::IntoParseBuilderExt};
use glslt::transform::{Unit, TransformUnit};

let glsl_src = r#"
float sdf3d(in vec3 p);
float colort();

float sdSphere(vec3 p, float r) {
    return length(p) - r;

float opElongate(in sdf3d primitive, in colort C, in vec3 p, in colort D, in vec3 h) {
    vec3 q = p - clamp(p, -h, h);
    return C() * primitive(q) * D();

void mainImage(out vec4 fragColor, in vec2 fragCoord) {
    float sz = 5.;
    fragColor = vec4(vec3(opElongate(sdSphere(_p, sz), 1.0, vec3(fragCoord, 0.), 2.0, vec3(1., 2., 3.))), 1.0);

// Parse the GLSLT source code
let tu: TranslationUnit = glsl_src
    .expect("failed to parse GLSLT source")

// Create the transform unit
let mut unit = Unit::new();

// Parse declarations
for decl in tu.0.into_iter() {
    unit.parse_external_declaration(decl).expect("failed to parse declaration");

// Generate the result
let tu = unit.into_translation_unit().expect("failed to generate output");

// Transpile the syntax tree to GLSL source
let mut output_src = String::new();
    &mut output_src,
).expect("failed to generate GLSL");

Python library

If you installed the glslt library via pip install glslt or maturin develop, you may use the Python interface to the GLSLT compiler.

import glslt

# Parse the `sdf.glsl` file with `my-glsl-lib/include` being a system include
# directory for #include resolution
translation_unit = glslt.parse_files(["sdf.glsl"], ["my-glsl-lib/include"])

# Create a new minimizing transform unit
unit = glslt.MinUnit()

# Add the parsed declarations to the transform unit

# Get the output of the transform
result = unit.to_translation_unit(["mainImage"])

# Print the GLSL code





  • GLSLT transform error type


  • Prefix for generated names for functions and captured parameters

Type Aliases