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//! `enable …;` extensions in WGSL.
//!
//! The focal point of this module is the [`EnableExtension`] API.
use crate::{front::wgsl::error::Error, Span};
/// Tracks the status of every enable-extension known to Naga.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct EnableExtensions {}
impl EnableExtensions {
pub(crate) const fn empty() -> Self {
Self {}
}
/// Add an enable-extension to the set requested by a module.
#[allow(unreachable_code)]
pub(crate) fn add(&mut self, ext: ImplementedEnableExtension) {
let _field: &mut bool = match ext {};
*_field = true;
}
/// Query whether an enable-extension tracked here has been requested.
#[allow(unused)]
pub(crate) const fn contains(&self, ext: ImplementedEnableExtension) -> bool {
match ext {}
}
}
impl Default for EnableExtensions {
fn default() -> Self {
Self::empty()
}
}
/// An enable-extension not guaranteed to be present in all environments.
///
#[derive(Clone, Copy, Debug, Hash, Eq, PartialEq)]
pub enum EnableExtension {
#[allow(unused)]
Implemented(ImplementedEnableExtension),
Unimplemented(UnimplementedEnableExtension),
}
impl EnableExtension {
const F16: &'static str = "f16";
const CLIP_DISTANCES: &'static str = "clip_distances";
const DUAL_SOURCE_BLENDING: &'static str = "dual_source_blending";
/// Convert from a sentinel word in WGSL into its associated [`EnableExtension`], if possible.
pub(crate) fn from_ident(word: &str, span: Span) -> Result<Self, Error<'_>> {
Ok(match word {
Self::F16 => Self::Unimplemented(UnimplementedEnableExtension::F16),
Self::CLIP_DISTANCES => {
Self::Unimplemented(UnimplementedEnableExtension::ClipDistances)
}
Self::DUAL_SOURCE_BLENDING => {
Self::Unimplemented(UnimplementedEnableExtension::DualSourceBlending)
}
_ => return Err(Error::UnknownEnableExtension(span, word)),
})
}
/// Maps this [`EnableExtension`] into the sentinel word associated with it in WGSL.
pub const fn to_ident(self) -> &'static str {
match self {
Self::Implemented(kind) => match kind {},
Self::Unimplemented(kind) => match kind {
UnimplementedEnableExtension::F16 => Self::F16,
UnimplementedEnableExtension::ClipDistances => Self::CLIP_DISTANCES,
UnimplementedEnableExtension::DualSourceBlending => Self::DUAL_SOURCE_BLENDING,
},
}
}
}
/// A variant of [`EnableExtension::Implemented`].
#[derive(Clone, Copy, Debug, Hash, Eq, PartialEq)]
pub enum ImplementedEnableExtension {}
/// A variant of [`EnableExtension::Unimplemented`].
#[derive(Clone, Copy, Debug, Hash, Eq, PartialEq)]
pub enum UnimplementedEnableExtension {
/// Enables `f16`/`half` primitive support in all shader languages.
///
/// In the WGSL standard, this corresponds to [`enable f16;`].
///
F16,
/// Enables the `clip_distances` variable in WGSL.
///
/// In the WGSL standard, this corresponds to [`enable clip_distances;`].
///
ClipDistances,
/// Enables the `blend_src` attribute in WGSL.
///
/// In the WGSL standard, this corresponds to [`enable dual_source_blending;`].
///
DualSourceBlending,
}
impl UnimplementedEnableExtension {
pub(crate) const fn tracking_issue_num(self) -> u16 {
match self {
Self::F16 => 4384,
Self::ClipDistances => 6236,
Self::DualSourceBlending => 6402,
}
}
}