Crate gl46[−][src]

Makes the OpenGL 4.6 Core API (plus some extensions) available for use.

The crate’s interface is provided as a “struct” style loader. Construct a GlFns using an appropriate “gl_get_proc_address” function and then call its methods.

Cargo Features

track_caller: Enables the track_caller attribute on any function that can panic. Specifically, the extension functions of the struct loader might not be loaded, and if you call them when they’re not loaded you’ll get a panic.

GL must generally be dynamically loaded at runtime. This is done via a function which we’ll call “gl_get_proc_address”. The expected operation of this function is very simple: The caller passes in the pointer to a null-terminated string with the name of a GL function, and gl_get_proc_address returns the pointer to that function.

The way that you get an appropriate gl_get_proc_address function is platform dependent.

With Win32 you’d use wglGetProcAddress for any function from after OpenGL 1.1, and GetProcAddress on an open HMODULE to “OpenGL.dll” for any OpenGL function from either 1.1 or 1.0. That sounds silly, but it’s true.
With SDL2 you’d call SDL_GL_GetProcAddress, or the equivalent function within your SDL2 bindings.
With glutin you’d call Context::get_proc_address

The function to create a GLFns takes a &dyn Fn(*const u8) -> *const c_void. Note the &dyn part on the front. In addition to passing a closure to the constructor (|x| { ... }), you generally need to prefix your closure with a & to make it be a &dyn value. Like this:

use gl46::*;
let gl = unsafe { GlFns::load_from(&|u8_ptr| SDL_GL_GetProcAddress(u8_ptr.cast())).unwrap() };

It might seem a little silly, but it genuinely helps keep re-compile times down, and it’s just one extra & to write.

Inlining

This crate does not use the #[inline] attribute. If you want full inlining just turn on Link-Time Optimization in your cargo profile:

[profile.release]
lto = "thin"

Re-exports

pub use gl_core_types::*;

pub use gl_enumerations::*;

pub use gl_groups::*;

Modules

gl_command_types
gl_core_types
gl_enumerations
gl_groups

Structs

GlFns