// surfman/surfman/src/info.rs
//
//! OpenGL information.
use crate::Gl;
use crate::gl;
use std::ffi::CStr;
use std::os::raw::c_char;
/// The API (OpenGL or OpenGL ES).
#[derive(Clone, Copy, Debug, PartialEq)]
pub enum GLApi {
/// OpenGL (full or desktop OpenGL).
GL,
/// OpenGL ES (embedded OpenGL).
GLES,
}
/// Describes the OpenGL version that is requested when a context is created.
///
/// Since OpenGL and OpenGL ES have different version numbering schemes, the valid values here
/// depend on the value of `Device::gl_api()`.
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct GLVersion {
/// The major OpenGL version (e.g. 4 in 4.2).
pub major: u8,
/// The minor OpenGL version (e.g. 2 in 4.2).
pub minor: u8,
}
impl GLVersion {
/// Creates a GL version structure with the given major and minor version numbers.
#[inline]
pub fn new(major: u8, minor: u8) -> GLVersion {
GLVersion { major, minor }
}
#[allow(dead_code)]
pub(crate) fn current(gl: &Gl) -> GLVersion {
unsafe {
let version_string = gl.GetString(gl::VERSION) as *const c_char;
let version_string = CStr::from_ptr(version_string).to_string_lossy()
.trim_start_matches("OpenGL ES")
.trim_start()
.to_owned();
let mut version_string_iter = version_string.split(|c| c == '.' || c == ' ');
let major_version: u8 =
version_string_iter.next()
.expect("Where's the major GL version?")
.parse()
.expect("Couldn't parse the major GL version!");
let minor_version: u8 =
version_string_iter.next()
.expect("Where's the minor GL version?")
.parse()
.expect("Couldn't parse the minor GL version!");
GLVersion { major: major_version, minor: minor_version }
}
}
}