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use core::fmt::{self, Debug, Display, Formatter};
#[cfg(doc)]
#[expect(unused_imports)]
use crate::validation::StageError;
/// Max shader I/O variable deductions for vertex shader output. Used by
/// [`StageError::TooManyUserDefinedVertexOutputs`] and
/// [`StageError::VertexOutputLocationTooLarge`].
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum MaxVertexShaderOutputDeduction {
/// When a pipeline's [`crate::pipeline::RenderPipelineDescriptor::primitive`] is set to
/// [`wgt::PrimitiveTopology::PointList`].
PointListPrimitiveTopology,
}
impl MaxVertexShaderOutputDeduction {
pub fn for_variables(self) -> u32 {
match self {
Self::PointListPrimitiveTopology => 1,
}
}
pub fn for_location(self) -> u32 {
match self {
Self::PointListPrimitiveTopology => 0,
}
}
}
/// Max shader I/O variable deductions for vertex shader output. Used by
/// [`StageError::TooManyUserDefinedFragmentInputs`] and
/// [`StageError::FragmentInputLocationTooLarge`].
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum MaxFragmentShaderInputDeduction {
InterStageBuiltIn(InterStageBuiltIn),
}
impl MaxFragmentShaderInputDeduction {
pub fn for_variables(self) -> u32 {
match self {
Self::InterStageBuiltIn(builtin) => match builtin {
InterStageBuiltIn::FrontFacing
| InterStageBuiltIn::SampleIndex
| InterStageBuiltIn::SampleMask
| InterStageBuiltIn::PrimitiveIndex
| InterStageBuiltIn::SubgroupInvocationId
| InterStageBuiltIn::SubgroupSize
| InterStageBuiltIn::ViewIndex
| InterStageBuiltIn::PointCoord => 1,
InterStageBuiltIn::Barycentric => 3,
InterStageBuiltIn::Position => 4,
},
}
}
pub fn from_inter_stage_builtin(builtin: naga::BuiltIn) -> Option<Self> {
use naga::BuiltIn;
Some(Self::InterStageBuiltIn(match builtin {
BuiltIn::FrontFacing => InterStageBuiltIn::FrontFacing,
BuiltIn::SampleIndex => InterStageBuiltIn::SampleIndex,
BuiltIn::SampleMask => InterStageBuiltIn::SampleMask,
BuiltIn::PrimitiveIndex => InterStageBuiltIn::PrimitiveIndex,
BuiltIn::SubgroupSize => InterStageBuiltIn::SubgroupSize,
BuiltIn::SubgroupInvocationId => InterStageBuiltIn::SubgroupInvocationId,
BuiltIn::PointCoord => InterStageBuiltIn::PointCoord,
BuiltIn::Barycentric => InterStageBuiltIn::Barycentric,
BuiltIn::Position { .. } => InterStageBuiltIn::Position,
BuiltIn::ViewIndex => InterStageBuiltIn::ViewIndex,
BuiltIn::BaseInstance
| BuiltIn::BaseVertex
| BuiltIn::ClipDistance
| BuiltIn::CullDistance
| BuiltIn::InstanceIndex
| BuiltIn::PointSize
| BuiltIn::VertexIndex
| BuiltIn::DrawID
| BuiltIn::FragDepth
| BuiltIn::GlobalInvocationId
| BuiltIn::LocalInvocationId
| BuiltIn::LocalInvocationIndex
| BuiltIn::WorkGroupId
| BuiltIn::WorkGroupSize
| BuiltIn::NumWorkGroups
| BuiltIn::NumSubgroups
| BuiltIn::SubgroupId
| BuiltIn::MeshTaskSize
| BuiltIn::CullPrimitive
| BuiltIn::PointIndex
| BuiltIn::LineIndices
| BuiltIn::TriangleIndices
| BuiltIn::VertexCount
| BuiltIn::Vertices
| BuiltIn::PrimitiveCount
| BuiltIn::Primitives => return None,
}))
}
}
/// A [`naga::BuiltIn`] that counts towards
/// a [`MaxFragmentShaderInputDeduction::InterStageBuiltIn`].
///
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum InterStageBuiltIn {
// Standard for WebGPU
FrontFacing,
SampleIndex,
SampleMask,
PrimitiveIndex,
SubgroupInvocationId,
SubgroupSize,
// Non-standard
PointCoord,
Barycentric,
Position,
ViewIndex,
}
pub(in crate::validation) fn display_deductions_as_optional_list<T>(
deductions: &[T],
accessor: fn(&T) -> u32,
) -> impl Display + '_
where
T: Debug,
{
struct DisplayFromFn<F>(F);
impl<F> Display for DisplayFromFn<F>
where
F: Fn(&mut Formatter<'_>) -> fmt::Result,
{
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
let Self(inner) = self;
inner(f)
}
}
DisplayFromFn(move |f: &mut Formatter<'_>| {
let relevant_deductions = deductions
.iter()
.map(|deduction| (deduction, accessor(deduction)))
.filter(|(_, effective_deduction)| *effective_deduction > 0);
if relevant_deductions.clone().next().is_some() {
writeln!(f, "; note that some deductions apply during validation:")?;
for deduction in deductions {
writeln!(f, "\n- {deduction:?}: {}", accessor(deduction))?;
}
}
Ok(())
})
}