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An OpenGL function pointer loader for the Rust Programming Language.

gl = "0.5.2"

Basic usage

You can import the pointer style loader and type aliases like so:

extern crate gl;
// include the OpenGL type aliases
use gl::types::*;

You must load the function pointers into their respective function pointers using the load_with function. You must supply a loader function from your context library, This is how it would look using [glfw-rs] (

// the supplied function must be of the type:
// `&fn(symbol: &str) -> Option<extern "C" fn()>`
// `window` is a glfw::Window
gl::load_with(|s| window.get_proc_address(s));

// loading a specific function pointer
gl::Viewport::load_with(|s| window.get_proc_address(s));

Calling a function that has not been loaded will result in a failure like: panic!("gl::Viewport was not loaded"), which avoids a segfault. This feature does not cause any run time overhead because the failing functions are assigned only when load_with is called.

// accessing an enum

// calling a function
gl::DrawArrays(gl::TRIANGLES, 0, 3);

// functions that take pointers are unsafe
unsafe {  gl::ShaderSource(shader, 1, &c_str, std::ptr::null()) };

Each function pointer has an associated boolean value allowing you to check if a function has been loaded at run time. The function accesses a corresponding global boolean that is set when load_with is called, so there shouldn't be much overhead.

if gl::Viewport::is_loaded() {
    // do something...



  • Update crate metadata


  • Upgrade khronos_api to v1.0.0


  • Use glutin for examples
  • Use raw::c_void for GLvoid