Crate glslt

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 glsltcc.

Usage

Rust crate

The glslt crate manipulates syntax trees generated by the glsl crate (note that the fork currently used is https://github.com/vtavernier/glsl/tree/dev/).

use glslt::glsl_lang::ast::*;
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 = glslt::parse::parse_source_default(glsl_src).expect("failed to parse GLSLT source");

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

// Parse declarations
for decl in (tu.0).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();
glsl_lang::transpiler::glsl::show_translation_unit(
    &mut output_src,
    &tu,
    glsl_lang::transpiler::glsl::FormattingState::default(),
).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
unit.add_unit(translation_unit)

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

# Print the GLSL code
print(result.to_glsl())

Re-exports

pub use glsl_lang;

pub use transform::transform;

pub use transform::transform_min;

Modules

api	API wrapper module
glsl_ext	glsl_lang extensions
parse	Parsing utilities
transform	GLSLT transform utilities definitions

Enums

Error

GLSLT transform error type

Constants

PREFIX

Prefix for generated names for functions and captured parameters

Type Definitions

Result

GLSLT Result