An OpenGL function pointer loader for the Rust Programming Language.
make
You can import the pointer style loader and type aliases like so:
extern crate gl;
// include the OpenGL type aliases
use gl::types::*;You can 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]
(https://github.com/bjz/glfw-rs):
// the supplied function must be of the type:
// `&fn(symbol: &str) -> Option<extern "C" fn()>`
gl::load_with(glfw::get_proc_address);
// loading a specific function pointer
gl::Viewport::load_with(glfw::get_proc_address);Calling a function that has not been loaded will result in a failure like:
fail!("gl::Viewport was not loaded"), which aviods 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
gl::RED_BITS;
// 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...
}The loader in gl.rs is generated using the [XML API Registry]
(http://www.opengl.org/discussion_boards/showthread.php/181927-New-XML-based-API-Registry-released?p=1251775).
If you would like to generate the loader yourself, please refer to the README
in the src/gen directory.
- Make the generator work properly GLX and WGL.