crates/khronos-egl/examples/load-minimal.rs

extern crate khronos_egl as egl;
use egl::{EGL1_2, EGL1_4};
use std::sync::Arc;

fn main() {
	let minimal_egl =
		unsafe { Arc::new(egl::DynamicInstance::load().expect("unable to load libEGL.so.1")) };

	println!("EGL version is {}", minimal_egl.version());

	// Select the rendering API.
	if let Some(egl1_2) = minimal_egl.upcast::<EGL1_2>() {
		println!("selecting API");
		egl1_2
			.bind_api(egl::OPENGL_API)
			.expect("unable to select OpenGL API");
	}

	// Setup Open GL.
	gl::load_with(|name| minimal_egl.get_proc_address(name).unwrap() as *const std::ffi::c_void);

	match minimal_egl.upcast::<EGL1_4>() {
		Some(egl1_4) => foo_with_1_4(egl1_4),
		None => foo_without_1_4(&minimal_egl),
	}
}

fn foo_with_1_4<V: egl::api::EGL1_4>(_egl: &egl::Instance<V>) {
	println!("with 1.4");
	// do something that requires at least EGL 1.4.
}

fn foo_without_1_4<V>(_egl: &egl::Instance<V>) {
	println!("without 1.4");
	// do something without any specific EGL version (other that 1.0).
}