Enum Binding

pub enum Binding {
    BuiltIn(BuiltIn),
    Location {
        location: u32,
        second_blend_source: bool,
        interpolation: Option<Interpolation>,
        sampling: Option<Sampling>,
    },
}

Available on crate feature unstable-wgpu-24 only.

Describes how an input/output variable is to be bound.

Variants

BuiltIn(BuiltIn)

Built-in shader variable.

Location

Indexed location.

Values passed from the Vertex stage to the Fragment stage must have their interpolation defaulted (i.e. not None) by the front end as appropriate for that language.

For other stages, we permit interpolations even though they’re ignored. When a front end is parsing a struct type, it usually doesn’t know what stages will be using it for IO, so it’s easiest if it can apply the defaults to anything with a Location binding, just in case.

For anything other than floating-point scalars and vectors, the interpolation must be Flat.

Fields

location: u32

second_blend_source: bool

Indicates the 2nd input to the blender when dual-source blending.

interpolation: Option<Interpolation>

sampling: Option<Sampling>

Implementations

impl Binding

pub fn apply_default_interpolation(&mut self, ty: &TypeInner)

Apply the usual default interpolation for ty to binding.

This function is a utility front ends may use to satisfy the Naga IR’s requirement, meant to ensure that input languages’ policies have been applied appropriately, that all I/O Bindings from the vertex shader to the fragment shader must have non-None interpolation values.

All the shader languages Naga supports have similar rules: perspective-correct, center-sampled interpolation is the default for any binding that can vary, and everything else either defaults to flat, or requires an explicit flat qualifier/attribute/what-have-you.

If binding is not a Location binding, or if its interpolation is already set, then make no changes. Otherwise, set binding’s interpolation and sampling to reasonable defaults depending on ty, the type of the value being interpolated:

• If ty is a floating-point scalar, vector, or matrix type, then default to Perspective interpolation and Center sampling.

• If ty is an integral scalar or vector, then default to Flat interpolation, which has no associated sampling.

• For any other types, make no change. Such types are not permitted as user-defined IO values, and will probably be flagged by the verifier

When structs appear in input or output types, each member ought to have its own Binding, so structs are simply covered by the third case.

impl Binding

pub const fn to_built_in(&self) -> Option<BuiltIn>

Trait Implementations

impl Clone for Binding

fn clone(&self) -> Binding

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Binding

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Hash for Binding

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Binding

fn eq(&self, other: &Binding) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Binding

impl StructuralPartialEq for Binding