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//! `enable …;` extensions in WGSL.
//!
//! The focal point of this module is the [`EnableExtension`] API.
use crate::front::wgsl::{Error, Result};
use crate::Span;
use alloc::boxed::Box;
/// Tracks the status of every enable-extension known to Naga.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct EnableExtensions {
dual_source_blending: bool,
/// Whether `enable f16;` was written earlier in the shader module.
f16: bool,
clip_distances: bool,
}
impl EnableExtensions {
pub(crate) const fn empty() -> Self {
Self {
f16: false,
dual_source_blending: false,
clip_distances: false,
}
}
/// Add an enable-extension to the set requested by a module.
pub(crate) fn add(&mut self, ext: ImplementedEnableExtension) {
let field = match ext {
ImplementedEnableExtension::DualSourceBlending => &mut self.dual_source_blending,
ImplementedEnableExtension::F16 => &mut self.f16,
ImplementedEnableExtension::ClipDistances => &mut self.clip_distances,
};
*field = true;
}
/// Query whether an enable-extension tracked here has been requested.
pub(crate) const fn contains(&self, ext: ImplementedEnableExtension) -> bool {
match ext {
ImplementedEnableExtension::DualSourceBlending => self.dual_source_blending,
ImplementedEnableExtension::F16 => self.f16,
ImplementedEnableExtension::ClipDistances => self.clip_distances,
}
}
}
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 {
Implemented(ImplementedEnableExtension),
Unimplemented(UnimplementedEnableExtension),
}
impl From<ImplementedEnableExtension> for EnableExtension {
fn from(value: ImplementedEnableExtension) -> Self {
Self::Implemented(value)
}
}
impl EnableExtension {
const F16: &'static str = "f16";
const CLIP_DISTANCES: &'static str = "clip_distances";
const DUAL_SOURCE_BLENDING: &'static str = "dual_source_blending";
const SUBGROUPS: &'static str = "subgroups";
/// Convert from a sentinel word in WGSL into its associated [`EnableExtension`], if possible.
pub(crate) fn from_ident(word: &str, span: Span) -> Result<Self> {
Ok(match word {
Self::F16 => Self::Implemented(ImplementedEnableExtension::F16),
Self::CLIP_DISTANCES => Self::Implemented(ImplementedEnableExtension::ClipDistances),
Self::DUAL_SOURCE_BLENDING => {
Self::Implemented(ImplementedEnableExtension::DualSourceBlending)
}
Self::SUBGROUPS => Self::Unimplemented(UnimplementedEnableExtension::Subgroups),
_ => return Err(Box::new(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 {
ImplementedEnableExtension::DualSourceBlending => Self::DUAL_SOURCE_BLENDING,
ImplementedEnableExtension::F16 => Self::F16,
ImplementedEnableExtension::ClipDistances => Self::CLIP_DISTANCES,
},
Self::Unimplemented(kind) => match kind {
UnimplementedEnableExtension::Subgroups => Self::SUBGROUPS,
},
}
}
}
/// A variant of [`EnableExtension::Implemented`].
#[derive(Clone, Copy, Debug, Hash, Eq, PartialEq)]
pub enum ImplementedEnableExtension {
/// Enables `f16`/`half` primitive support in all shader languages.
///
/// In the WGSL standard, this corresponds to [`enable f16;`].
///
F16,
/// Enables the `blend_src` attribute in WGSL.
///
/// In the WGSL standard, this corresponds to [`enable dual_source_blending;`].
///
DualSourceBlending,
/// Enables the `clip_distances` variable in WGSL.
///
/// In the WGSL standard, this corresponds to [`enable clip_distances;`].
///
ClipDistances,
}
/// A variant of [`EnableExtension::Unimplemented`].
#[derive(Clone, Copy, Debug, Hash, Eq, PartialEq)]
pub enum UnimplementedEnableExtension {
/// Enables subgroup built-ins in all languages.
///
/// In the WGSL standard, this corresponds to [`enable subgroups;`].
///
Subgroups,
}
impl UnimplementedEnableExtension {
pub(crate) const fn tracking_issue_num(self) -> u16 {
match self {
Self::Subgroups => 5555,
}
}
}