naga/common/wgsl/
to_wgsl.rs

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1//! Generating WGSL source code for Naga IR types.
2
3use alloc::format;
4use alloc::string::{String, ToString};
5
6/// Types that can return the WGSL source representation of their
7/// values as a `'static` string.
8///
9/// This trait is specifically for types whose WGSL forms are simple
10/// enough that they can always be returned as a static string.
11///
12/// - If only some values have a WGSL representation, consider
13///   implementing [`TryToWgsl`] instead.
14///
15/// - If a type's WGSL form requires dynamic formatting, so that
16///   returning a `&'static str` isn't feasible, consider implementing
17///   [`core::fmt::Display`] on some wrapper type instead.
18pub trait ToWgsl: Sized {
19    /// Return WGSL source code representation of `self`.
20    fn to_wgsl(self) -> &'static str;
21}
22
23/// Types that may be able to return the WGSL source representation
24/// for their values as a `'static` string.
25///
26/// This trait is specifically for types whose values are either
27/// simple enough that their WGSL form can be represented a static
28/// string, or aren't representable in WGSL at all.
29///
30/// - If all values in the type have `&'static str` representations in
31///   WGSL, consider implementing [`ToWgsl`] instead.
32///
33/// - If a type's WGSL form requires dynamic formatting, so that
34///   returning a `&'static str` isn't feasible, consider implementing
35///   [`core::fmt::Display`] on some wrapper type instead.
36pub trait TryToWgsl: Sized {
37    /// Return the WGSL form of `self` as a `'static` string.
38    ///
39    /// If `self` doesn't have a representation in WGSL (standard or
40    /// as extended by Naga), then return `None`.
41    fn try_to_wgsl(self) -> Option<&'static str>;
42
43    /// What kind of WGSL thing `Self` represents.
44    const DESCRIPTION: &'static str;
45
46    /// Return the WGSL form of `self` as appropriate for diagnostics.
47    ///
48    /// If `self` can be expressed in WGSL, return that form as a
49    /// [`String`]. Otherwise, return some representation of `self`
50    /// that is appropriate for use in diagnostic messages.
51    ///
52    /// The default implementation of this function falls back to
53    /// `self`'s [`Debug`] form.
54    ///
55    /// [`Debug`]: core::fmt::Debug
56    fn to_wgsl_for_diagnostics(self) -> String
57    where
58        Self: core::fmt::Debug + Copy,
59    {
60        match self.try_to_wgsl() {
61            Some(static_string) => static_string.to_string(),
62            None => format!("{{non-WGSL {} {self:?}}}", Self::DESCRIPTION),
63        }
64    }
65}
66
67impl TryToWgsl for crate::MathFunction {
68    const DESCRIPTION: &'static str = "math function";
69
70    fn try_to_wgsl(self) -> Option<&'static str> {
71        use crate::MathFunction as Mf;
72
73        Some(match self {
74            Mf::Abs => "abs",
75            Mf::Min => "min",
76            Mf::Max => "max",
77            Mf::Clamp => "clamp",
78            Mf::Saturate => "saturate",
79            Mf::Cos => "cos",
80            Mf::Cosh => "cosh",
81            Mf::Sin => "sin",
82            Mf::Sinh => "sinh",
83            Mf::Tan => "tan",
84            Mf::Tanh => "tanh",
85            Mf::Acos => "acos",
86            Mf::Asin => "asin",
87            Mf::Atan => "atan",
88            Mf::Atan2 => "atan2",
89            Mf::Asinh => "asinh",
90            Mf::Acosh => "acosh",
91            Mf::Atanh => "atanh",
92            Mf::Radians => "radians",
93            Mf::Degrees => "degrees",
94            Mf::Ceil => "ceil",
95            Mf::Floor => "floor",
96            Mf::Round => "round",
97            Mf::Fract => "fract",
98            Mf::Trunc => "trunc",
99            Mf::Modf => "modf",
100            Mf::Frexp => "frexp",
101            Mf::Ldexp => "ldexp",
102            Mf::Exp => "exp",
103            Mf::Exp2 => "exp2",
104            Mf::Log => "log",
105            Mf::Log2 => "log2",
106            Mf::Pow => "pow",
107            Mf::Dot => "dot",
108            Mf::Dot4I8Packed => "dot4I8Packed",
109            Mf::Dot4U8Packed => "dot4U8Packed",
110            Mf::Cross => "cross",
111            Mf::Distance => "distance",
112            Mf::Length => "length",
113            Mf::Normalize => "normalize",
114            Mf::FaceForward => "faceForward",
115            Mf::Reflect => "reflect",
116            Mf::Refract => "refract",
117            Mf::Sign => "sign",
118            Mf::Fma => "fma",
119            Mf::Mix => "mix",
120            Mf::Step => "step",
121            Mf::SmoothStep => "smoothstep",
122            Mf::Sqrt => "sqrt",
123            Mf::InverseSqrt => "inverseSqrt",
124            Mf::Transpose => "transpose",
125            Mf::Determinant => "determinant",
126            Mf::QuantizeToF16 => "quantizeToF16",
127            Mf::CountTrailingZeros => "countTrailingZeros",
128            Mf::CountLeadingZeros => "countLeadingZeros",
129            Mf::CountOneBits => "countOneBits",
130            Mf::ReverseBits => "reverseBits",
131            Mf::ExtractBits => "extractBits",
132            Mf::InsertBits => "insertBits",
133            Mf::FirstTrailingBit => "firstTrailingBit",
134            Mf::FirstLeadingBit => "firstLeadingBit",
135            Mf::Pack4x8snorm => "pack4x8snorm",
136            Mf::Pack4x8unorm => "pack4x8unorm",
137            Mf::Pack2x16snorm => "pack2x16snorm",
138            Mf::Pack2x16unorm => "pack2x16unorm",
139            Mf::Pack2x16float => "pack2x16float",
140            Mf::Pack4xI8 => "pack4xI8",
141            Mf::Pack4xU8 => "pack4xU8",
142            Mf::Pack4xI8Clamp => "pack4xI8Clamp",
143            Mf::Pack4xU8Clamp => "pack4xU8Clamp",
144            Mf::Unpack4x8snorm => "unpack4x8snorm",
145            Mf::Unpack4x8unorm => "unpack4x8unorm",
146            Mf::Unpack2x16snorm => "unpack2x16snorm",
147            Mf::Unpack2x16unorm => "unpack2x16unorm",
148            Mf::Unpack2x16float => "unpack2x16float",
149            Mf::Unpack4xI8 => "unpack4xI8",
150            Mf::Unpack4xU8 => "unpack4xU8",
151
152            // Non-standard math functions.
153            Mf::Inverse | Mf::Outer => return None,
154        })
155    }
156}
157
158impl TryToWgsl for crate::BuiltIn {
159    const DESCRIPTION: &'static str = "builtin value";
160
161    fn try_to_wgsl(self) -> Option<&'static str> {
162        use crate::BuiltIn as Bi;
163        Some(match self {
164            Bi::Position { .. } => "position",
165            Bi::ViewIndex => "view_index",
166            Bi::InstanceIndex => "instance_index",
167            Bi::VertexIndex => "vertex_index",
168            Bi::ClipDistance => "clip_distances",
169            Bi::FragDepth => "frag_depth",
170            Bi::FrontFacing => "front_facing",
171            Bi::PrimitiveIndex => "primitive_index",
172            Bi::Barycentric => "barycentric",
173            Bi::SampleIndex => "sample_index",
174            Bi::SampleMask => "sample_mask",
175            Bi::GlobalInvocationId => "global_invocation_id",
176            Bi::LocalInvocationId => "local_invocation_id",
177            Bi::LocalInvocationIndex => "local_invocation_index",
178            Bi::WorkGroupId => "workgroup_id",
179            Bi::NumWorkGroups => "num_workgroups",
180            Bi::NumSubgroups => "num_subgroups",
181            Bi::SubgroupId => "subgroup_id",
182            Bi::SubgroupSize => "subgroup_size",
183            Bi::SubgroupInvocationId => "subgroup_invocation_id",
184
185            // Non-standard built-ins.
186            Bi::BaseInstance
187            | Bi::BaseVertex
188            | Bi::CullDistance
189            | Bi::PointSize
190            | Bi::DrawID
191            | Bi::PointCoord
192            | Bi::WorkGroupSize
193            | Bi::CullPrimitive
194            | Bi::TriangleIndices
195            | Bi::LineIndices
196            | Bi::MeshTaskSize
197            | Bi::PointIndex => return None,
198        })
199    }
200}
201
202impl ToWgsl for crate::Interpolation {
203    fn to_wgsl(self) -> &'static str {
204        match self {
205            crate::Interpolation::Perspective => "perspective",
206            crate::Interpolation::Linear => "linear",
207            crate::Interpolation::Flat => "flat",
208        }
209    }
210}
211
212impl ToWgsl for crate::Sampling {
213    fn to_wgsl(self) -> &'static str {
214        match self {
215            crate::Sampling::Center => "center",
216            crate::Sampling::Centroid => "centroid",
217            crate::Sampling::Sample => "sample",
218            crate::Sampling::First => "first",
219            crate::Sampling::Either => "either",
220        }
221    }
222}
223
224impl ToWgsl for crate::StorageFormat {
225    fn to_wgsl(self) -> &'static str {
226        use crate::StorageFormat as Sf;
227
228        match self {
229            Sf::R8Unorm => "r8unorm",
230            Sf::R8Snorm => "r8snorm",
231            Sf::R8Uint => "r8uint",
232            Sf::R8Sint => "r8sint",
233            Sf::R16Uint => "r16uint",
234            Sf::R16Sint => "r16sint",
235            Sf::R16Float => "r16float",
236            Sf::Rg8Unorm => "rg8unorm",
237            Sf::Rg8Snorm => "rg8snorm",
238            Sf::Rg8Uint => "rg8uint",
239            Sf::Rg8Sint => "rg8sint",
240            Sf::R32Uint => "r32uint",
241            Sf::R32Sint => "r32sint",
242            Sf::R32Float => "r32float",
243            Sf::Rg16Uint => "rg16uint",
244            Sf::Rg16Sint => "rg16sint",
245            Sf::Rg16Float => "rg16float",
246            Sf::Rgba8Unorm => "rgba8unorm",
247            Sf::Rgba8Snorm => "rgba8snorm",
248            Sf::Rgba8Uint => "rgba8uint",
249            Sf::Rgba8Sint => "rgba8sint",
250            Sf::Bgra8Unorm => "bgra8unorm",
251            Sf::Rgb10a2Uint => "rgb10a2uint",
252            Sf::Rgb10a2Unorm => "rgb10a2unorm",
253            Sf::Rg11b10Ufloat => "rg11b10ufloat",
254            Sf::R64Uint => "r64uint",
255            Sf::Rg32Uint => "rg32uint",
256            Sf::Rg32Sint => "rg32sint",
257            Sf::Rg32Float => "rg32float",
258            Sf::Rgba16Uint => "rgba16uint",
259            Sf::Rgba16Sint => "rgba16sint",
260            Sf::Rgba16Float => "rgba16float",
261            Sf::Rgba32Uint => "rgba32uint",
262            Sf::Rgba32Sint => "rgba32sint",
263            Sf::Rgba32Float => "rgba32float",
264            Sf::R16Unorm => "r16unorm",
265            Sf::R16Snorm => "r16snorm",
266            Sf::Rg16Unorm => "rg16unorm",
267            Sf::Rg16Snorm => "rg16snorm",
268            Sf::Rgba16Unorm => "rgba16unorm",
269            Sf::Rgba16Snorm => "rgba16snorm",
270        }
271    }
272}
273
274impl TryToWgsl for crate::Scalar {
275    const DESCRIPTION: &'static str = "scalar type";
276
277    fn try_to_wgsl(self) -> Option<&'static str> {
278        use crate::Scalar;
279
280        Some(match self {
281            Scalar::F16 => "f16",
282            Scalar::F32 => "f32",
283            Scalar::F64 => "f64",
284            Scalar::I32 => "i32",
285            Scalar::U32 => "u32",
286            Scalar::I64 => "i64",
287            Scalar::U64 => "u64",
288            Scalar::BOOL => "bool",
289            _ => return None,
290        })
291    }
292
293    fn to_wgsl_for_diagnostics(self) -> String {
294        match self.try_to_wgsl() {
295            Some(static_string) => static_string.to_string(),
296            None => match self.kind {
297                crate::ScalarKind::Sint
298                | crate::ScalarKind::Uint
299                | crate::ScalarKind::Float
300                | crate::ScalarKind::Bool => format!("{{non-WGSL scalar {self:?}}}"),
301                crate::ScalarKind::AbstractInt => "{AbstractInt}".to_string(),
302                crate::ScalarKind::AbstractFloat => "{AbstractFloat}".to_string(),
303            },
304        }
305    }
306}
307
308impl ToWgsl for crate::ImageDimension {
309    fn to_wgsl(self) -> &'static str {
310        use crate::ImageDimension as IDim;
311
312        match self {
313            IDim::D1 => "1d",
314            IDim::D2 => "2d",
315            IDim::D3 => "3d",
316            IDim::Cube => "cube",
317        }
318    }
319}
320
321/// Return the WGSL address space and access mode strings for `space`.
322///
323/// Why don't we implement [`ToWgsl`] for [`AddressSpace`]?
324///
325/// In WGSL, the full form of a pointer type is `ptr<AS, T, AM>`, where:
326/// - `AS` is the address space,
327/// - `T` is the store type, and
328/// - `AM` is the access mode.
329///
330/// Since the type `T` intervenes between the address space and the
331/// access mode, there isn't really any individual WGSL grammar
332/// production that corresponds to an [`AddressSpace`], so [`ToWgsl`]
333/// is too simple-minded for this case.
334///
335/// Furthermore, we want to write `var<AS[, AM]>` for most address
336/// spaces, but we want to just write `var foo: T` for handle types.
337///
338/// [`AddressSpace`]: crate::AddressSpace
339pub const fn address_space_str(
340    space: crate::AddressSpace,
341) -> (Option<&'static str>, Option<&'static str>) {
342    use crate::AddressSpace as As;
343
344    (
345        Some(match space {
346            As::Private => "private",
347            As::Uniform => "uniform",
348            As::Storage { access } => {
349                if access.contains(crate::StorageAccess::ATOMIC) {
350                    return (Some("storage"), Some("atomic"));
351                } else if access.contains(crate::StorageAccess::STORE) {
352                    return (Some("storage"), Some("read_write"));
353                } else {
354                    "storage"
355                }
356            }
357            As::PushConstant => "push_constant",
358            As::WorkGroup => "workgroup",
359            As::Handle => return (None, None),
360            As::Function => "function",
361            As::TaskPayload => return (None, None),
362        }),
363        None,
364    )
365}
naga/common/wgsl/to_wgsl.rs

naga/common/wgsl/
to_wgsl.rs
