An OpenGL function pointer loader for the Rust Programming Language.
toml
[dependencies]
gl = "0.6.0"
You can import the pointer style loader and type aliases like so:
rust
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]
(https://github.com/PistonDevelopers/glfw-rs):
``rust
// the supplied function must be of the type:
//&fn(symbol: &'static str) -> *const std::os::raw::cvoid
//window` is a glfw::Window
gl::loadwith(|s| window.getprocaddress(s) as *const _);
// loading a specific function pointer gl::Viewport::loadwith(|s| window.getproc_address(s) as *const _); ```
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.
```rust // 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.
rust
if gl::Viewport::is_loaded() {
// do something...
}
gl_generator v0.5.0khronos_api to v1.0.0glutin for examplesraw::c_void for GLvoid