wgpu_hal/noop/
mod.rs

1#![allow(unused_variables)]
2
3use alloc::{string::String, vec, vec::Vec};
4use core::{ptr, sync::atomic::Ordering, time::Duration};
5
6#[cfg(supports_64bit_atomics)]
7use core::sync::atomic::AtomicU64;
8#[cfg(not(supports_64bit_atomics))]
9use portable_atomic::AtomicU64;
10
11use crate::TlasInstance;
12
13mod buffer;
14pub use buffer::Buffer;
15mod command;
16pub use command::CommandBuffer;
17
18#[derive(Clone, Debug)]
19pub struct Api;
20pub struct Context;
21#[derive(Debug)]
22pub struct Encoder;
23#[derive(Debug)]
24pub struct Resource;
25
26#[derive(Debug)]
27pub struct Fence {
28    value: AtomicU64,
29}
30
31type DeviceResult<T> = Result<T, crate::DeviceError>;
32
33impl crate::Api for Api {
34    type Instance = Context;
35    type Surface = Context;
36    type Adapter = Context;
37    type Device = Context;
38
39    type Queue = Context;
40    type CommandEncoder = CommandBuffer;
41    type CommandBuffer = CommandBuffer;
42
43    type Buffer = Buffer;
44    type Texture = Resource;
45    type SurfaceTexture = Resource;
46    type TextureView = Resource;
47    type Sampler = Resource;
48    type QuerySet = Resource;
49    type Fence = Fence;
50    type AccelerationStructure = Resource;
51    type PipelineCache = Resource;
52
53    type BindGroupLayout = Resource;
54    type BindGroup = Resource;
55    type PipelineLayout = Resource;
56    type ShaderModule = Resource;
57    type RenderPipeline = Resource;
58    type ComputePipeline = Resource;
59}
60
61crate::impl_dyn_resource!(Buffer, CommandBuffer, Context, Fence, Resource);
62
63impl crate::DynAccelerationStructure for Resource {}
64impl crate::DynBindGroup for Resource {}
65impl crate::DynBindGroupLayout for Resource {}
66impl crate::DynBuffer for Buffer {}
67impl crate::DynCommandBuffer for CommandBuffer {}
68impl crate::DynComputePipeline for Resource {}
69impl crate::DynFence for Fence {}
70impl crate::DynPipelineCache for Resource {}
71impl crate::DynPipelineLayout for Resource {}
72impl crate::DynQuerySet for Resource {}
73impl crate::DynRenderPipeline for Resource {}
74impl crate::DynSampler for Resource {}
75impl crate::DynShaderModule for Resource {}
76impl crate::DynSurfaceTexture for Resource {}
77impl crate::DynTexture for Resource {}
78impl crate::DynTextureView for Resource {}
79
80impl core::borrow::Borrow<dyn crate::DynTexture> for Resource {
81    fn borrow(&self) -> &dyn crate::DynTexture {
82        self
83    }
84}
85
86impl crate::Instance for Context {
87    type A = Api;
88
89    unsafe fn init(desc: &crate::InstanceDescriptor) -> Result<Self, crate::InstanceError> {
90        let crate::InstanceDescriptor {
91            backend_options:
92                wgt::BackendOptions {
93                    noop: wgt::NoopBackendOptions { enable },
94                    ..
95                },
96            name: _,
97            flags: _,
98        } = *desc;
99        if enable {
100            Ok(Context)
101        } else {
102            Err(crate::InstanceError::new(String::from(
103                "noop backend disabled because NoopBackendOptions::enable is false",
104            )))
105        }
106    }
107    unsafe fn create_surface(
108        &self,
109        _display_handle: raw_window_handle::RawDisplayHandle,
110        _window_handle: raw_window_handle::RawWindowHandle,
111    ) -> Result<Context, crate::InstanceError> {
112        Ok(Context)
113    }
114    unsafe fn enumerate_adapters(
115        &self,
116        _surface_hint: Option<&Context>,
117    ) -> Vec<crate::ExposedAdapter<Api>> {
118        vec![crate::ExposedAdapter {
119            adapter: Context,
120            info: wgt::AdapterInfo {
121                name: String::from("noop wgpu backend"),
122                vendor: 0,
123                device: 0,
124                device_type: wgt::DeviceType::Cpu,
125                driver: String::from("wgpu"),
126                driver_info: String::new(),
127                backend: wgt::Backend::Noop,
128            },
129            features: wgt::Features::all(),
130            capabilities: CAPABILITIES,
131        }]
132    }
133}
134
135const CAPABILITIES: crate::Capabilities = {
136    /// Guaranteed to be no bigger than isize::MAX which is the maximum size of an allocation,
137    /// except on 16-bit platforms which we certainly don’t fit in.
138    const ALLOC_MAX_U32: u32 = i32::MAX as u32;
139
140    crate::Capabilities {
141        limits: wgt::Limits {
142            // All maximally permissive
143            max_texture_dimension_1d: ALLOC_MAX_U32,
144            max_texture_dimension_2d: ALLOC_MAX_U32,
145            max_texture_dimension_3d: ALLOC_MAX_U32,
146            max_texture_array_layers: ALLOC_MAX_U32,
147            max_bind_groups: ALLOC_MAX_U32,
148            max_bindings_per_bind_group: ALLOC_MAX_U32,
149            max_dynamic_uniform_buffers_per_pipeline_layout: ALLOC_MAX_U32,
150            max_dynamic_storage_buffers_per_pipeline_layout: ALLOC_MAX_U32,
151            max_sampled_textures_per_shader_stage: ALLOC_MAX_U32,
152            max_samplers_per_shader_stage: ALLOC_MAX_U32,
153            max_storage_buffers_per_shader_stage: ALLOC_MAX_U32,
154            max_storage_textures_per_shader_stage: ALLOC_MAX_U32,
155            max_uniform_buffers_per_shader_stage: ALLOC_MAX_U32,
156            max_binding_array_elements_per_shader_stage: ALLOC_MAX_U32,
157            max_binding_array_sampler_elements_per_shader_stage: ALLOC_MAX_U32,
158            max_uniform_buffer_binding_size: ALLOC_MAX_U32,
159            max_storage_buffer_binding_size: ALLOC_MAX_U32,
160            max_vertex_buffers: ALLOC_MAX_U32,
161            max_buffer_size: ALLOC_MAX_U32 as u64,
162            max_vertex_attributes: ALLOC_MAX_U32,
163            max_vertex_buffer_array_stride: ALLOC_MAX_U32,
164            min_uniform_buffer_offset_alignment: 1,
165            min_storage_buffer_offset_alignment: 1,
166            max_inter_stage_shader_components: ALLOC_MAX_U32,
167            max_color_attachments: ALLOC_MAX_U32,
168            max_color_attachment_bytes_per_sample: ALLOC_MAX_U32,
169            max_compute_workgroup_storage_size: ALLOC_MAX_U32,
170            max_compute_invocations_per_workgroup: ALLOC_MAX_U32,
171            max_compute_workgroup_size_x: ALLOC_MAX_U32,
172            max_compute_workgroup_size_y: ALLOC_MAX_U32,
173            max_compute_workgroup_size_z: ALLOC_MAX_U32,
174            max_compute_workgroups_per_dimension: ALLOC_MAX_U32,
175            min_subgroup_size: 1,
176            max_subgroup_size: ALLOC_MAX_U32,
177            max_push_constant_size: ALLOC_MAX_U32,
178            max_non_sampler_bindings: ALLOC_MAX_U32,
179        },
180        alignments: crate::Alignments {
181            // All maximally permissive
182            buffer_copy_offset: wgt::BufferSize::MIN,
183            buffer_copy_pitch: wgt::BufferSize::MIN,
184            uniform_bounds_check_alignment: wgt::BufferSize::MIN,
185            raw_tlas_instance_size: 0,
186            ray_tracing_scratch_buffer_alignment: 1,
187        },
188        downlevel: wgt::DownlevelCapabilities {
189            flags: wgt::DownlevelFlags::all(),
190            limits: wgt::DownlevelLimits {},
191            shader_model: wgt::ShaderModel::Sm5,
192        },
193    }
194};
195
196impl crate::Surface for Context {
197    type A = Api;
198
199    unsafe fn configure(
200        &self,
201        device: &Context,
202        config: &crate::SurfaceConfiguration,
203    ) -> Result<(), crate::SurfaceError> {
204        Ok(())
205    }
206
207    unsafe fn unconfigure(&self, device: &Context) {}
208
209    unsafe fn acquire_texture(
210        &self,
211        timeout: Option<Duration>,
212        fence: &Fence,
213    ) -> Result<Option<crate::AcquiredSurfaceTexture<Api>>, crate::SurfaceError> {
214        Ok(None)
215    }
216    unsafe fn discard_texture(&self, texture: Resource) {}
217}
218
219impl crate::Adapter for Context {
220    type A = Api;
221
222    unsafe fn open(
223        &self,
224        features: wgt::Features,
225        _limits: &wgt::Limits,
226        _memory_hints: &wgt::MemoryHints,
227    ) -> DeviceResult<crate::OpenDevice<Api>> {
228        Ok(crate::OpenDevice {
229            device: Context,
230            queue: Context,
231        })
232    }
233    unsafe fn texture_format_capabilities(
234        &self,
235        format: wgt::TextureFormat,
236    ) -> crate::TextureFormatCapabilities {
237        crate::TextureFormatCapabilities::empty()
238    }
239
240    unsafe fn surface_capabilities(&self, surface: &Context) -> Option<crate::SurfaceCapabilities> {
241        None
242    }
243
244    unsafe fn get_presentation_timestamp(&self) -> wgt::PresentationTimestamp {
245        wgt::PresentationTimestamp::INVALID_TIMESTAMP
246    }
247}
248
249impl crate::Queue for Context {
250    type A = Api;
251
252    unsafe fn submit(
253        &self,
254        command_buffers: &[&CommandBuffer],
255        surface_textures: &[&Resource],
256        (fence, fence_value): (&mut Fence, crate::FenceValue),
257    ) -> DeviceResult<()> {
258        // All commands are executed synchronously.
259        for cb in command_buffers {
260            // SAFETY: Caller is responsible for ensuring synchronization between commands and
261            // other mutations.
262            unsafe {
263                cb.execute();
264            }
265        }
266        fence.value.store(fence_value, Ordering::Release);
267        Ok(())
268    }
269    unsafe fn present(
270        &self,
271        surface: &Context,
272        texture: Resource,
273    ) -> Result<(), crate::SurfaceError> {
274        Ok(())
275    }
276
277    unsafe fn get_timestamp_period(&self) -> f32 {
278        1.0
279    }
280}
281
282impl crate::Device for Context {
283    type A = Api;
284
285    unsafe fn create_buffer(&self, desc: &crate::BufferDescriptor) -> DeviceResult<Buffer> {
286        Buffer::new(desc)
287    }
288
289    unsafe fn destroy_buffer(&self, buffer: Buffer) {}
290    unsafe fn add_raw_buffer(&self, _buffer: &Buffer) {}
291
292    unsafe fn map_buffer(
293        &self,
294        buffer: &Buffer,
295        range: crate::MemoryRange,
296    ) -> DeviceResult<crate::BufferMapping> {
297        // Safety: the `wgpu-core` validation layer will prevent any user-accessible aliasing
298        // mappings from being created, so we don’t need to perform any checks here, except for
299        // bounds checks on the range which are built into `get_slice_ptr()`.
300        Ok(crate::BufferMapping {
301            ptr: ptr::NonNull::new(buffer.get_slice_ptr(range).cast::<u8>()).unwrap(),
302            is_coherent: true,
303        })
304    }
305    unsafe fn unmap_buffer(&self, buffer: &Buffer) {}
306    unsafe fn flush_mapped_ranges<I>(&self, buffer: &Buffer, ranges: I) {}
307    unsafe fn invalidate_mapped_ranges<I>(&self, buffer: &Buffer, ranges: I) {}
308
309    unsafe fn create_texture(&self, desc: &crate::TextureDescriptor) -> DeviceResult<Resource> {
310        Ok(Resource)
311    }
312    unsafe fn destroy_texture(&self, texture: Resource) {}
313    unsafe fn add_raw_texture(&self, _texture: &Resource) {}
314
315    unsafe fn create_texture_view(
316        &self,
317        texture: &Resource,
318        desc: &crate::TextureViewDescriptor,
319    ) -> DeviceResult<Resource> {
320        Ok(Resource)
321    }
322    unsafe fn destroy_texture_view(&self, view: Resource) {}
323    unsafe fn create_sampler(&self, desc: &crate::SamplerDescriptor) -> DeviceResult<Resource> {
324        Ok(Resource)
325    }
326    unsafe fn destroy_sampler(&self, sampler: Resource) {}
327
328    unsafe fn create_command_encoder(
329        &self,
330        desc: &crate::CommandEncoderDescriptor<Context>,
331    ) -> DeviceResult<CommandBuffer> {
332        Ok(CommandBuffer::new())
333    }
334
335    unsafe fn create_bind_group_layout(
336        &self,
337        desc: &crate::BindGroupLayoutDescriptor,
338    ) -> DeviceResult<Resource> {
339        Ok(Resource)
340    }
341    unsafe fn destroy_bind_group_layout(&self, bg_layout: Resource) {}
342    unsafe fn create_pipeline_layout(
343        &self,
344        desc: &crate::PipelineLayoutDescriptor<Resource>,
345    ) -> DeviceResult<Resource> {
346        Ok(Resource)
347    }
348    unsafe fn destroy_pipeline_layout(&self, pipeline_layout: Resource) {}
349    unsafe fn create_bind_group(
350        &self,
351        desc: &crate::BindGroupDescriptor<Resource, Buffer, Resource, Resource, Resource>,
352    ) -> DeviceResult<Resource> {
353        Ok(Resource)
354    }
355    unsafe fn destroy_bind_group(&self, group: Resource) {}
356
357    unsafe fn create_shader_module(
358        &self,
359        desc: &crate::ShaderModuleDescriptor,
360        shader: crate::ShaderInput,
361    ) -> Result<Resource, crate::ShaderError> {
362        Ok(Resource)
363    }
364    unsafe fn destroy_shader_module(&self, module: Resource) {}
365    unsafe fn create_render_pipeline(
366        &self,
367        desc: &crate::RenderPipelineDescriptor<Resource, Resource, Resource>,
368    ) -> Result<Resource, crate::PipelineError> {
369        Ok(Resource)
370    }
371    unsafe fn create_mesh_pipeline(
372        &self,
373        desc: &crate::MeshPipelineDescriptor<
374            <Self::A as crate::Api>::PipelineLayout,
375            <Self::A as crate::Api>::ShaderModule,
376            <Self::A as crate::Api>::PipelineCache,
377        >,
378    ) -> Result<<Self::A as crate::Api>::RenderPipeline, crate::PipelineError> {
379        Ok(Resource)
380    }
381    unsafe fn destroy_render_pipeline(&self, pipeline: Resource) {}
382    unsafe fn create_compute_pipeline(
383        &self,
384        desc: &crate::ComputePipelineDescriptor<Resource, Resource, Resource>,
385    ) -> Result<Resource, crate::PipelineError> {
386        Ok(Resource)
387    }
388    unsafe fn destroy_compute_pipeline(&self, pipeline: Resource) {}
389    unsafe fn create_pipeline_cache(
390        &self,
391        desc: &crate::PipelineCacheDescriptor<'_>,
392    ) -> Result<Resource, crate::PipelineCacheError> {
393        Ok(Resource)
394    }
395    unsafe fn destroy_pipeline_cache(&self, cache: Resource) {}
396
397    unsafe fn create_query_set(
398        &self,
399        desc: &wgt::QuerySetDescriptor<crate::Label>,
400    ) -> DeviceResult<Resource> {
401        Ok(Resource)
402    }
403    unsafe fn destroy_query_set(&self, set: Resource) {}
404    unsafe fn create_fence(&self) -> DeviceResult<Fence> {
405        Ok(Fence {
406            value: AtomicU64::new(0),
407        })
408    }
409    unsafe fn destroy_fence(&self, fence: Fence) {}
410    unsafe fn get_fence_value(&self, fence: &Fence) -> DeviceResult<crate::FenceValue> {
411        Ok(fence.value.load(Ordering::Acquire))
412    }
413    unsafe fn wait(
414        &self,
415        fence: &Fence,
416        value: crate::FenceValue,
417        timeout_ms: u32,
418    ) -> DeviceResult<bool> {
419        // The relevant commands must have already been submitted, and noop-backend commands are
420        // executed synchronously, so there is no waiting — either it is already done,
421        // or this method was called incorrectly.
422        assert!(
423            fence.value.load(Ordering::Acquire) >= value,
424            "submission must have already been done"
425        );
426        Ok(true)
427    }
428
429    unsafe fn start_graphics_debugger_capture(&self) -> bool {
430        false
431    }
432    unsafe fn stop_graphics_debugger_capture(&self) {}
433    unsafe fn create_acceleration_structure(
434        &self,
435        desc: &crate::AccelerationStructureDescriptor,
436    ) -> DeviceResult<Resource> {
437        Ok(Resource)
438    }
439    unsafe fn get_acceleration_structure_build_sizes<'a>(
440        &self,
441        _desc: &crate::GetAccelerationStructureBuildSizesDescriptor<'a, Buffer>,
442    ) -> crate::AccelerationStructureBuildSizes {
443        Default::default()
444    }
445    unsafe fn get_acceleration_structure_device_address(
446        &self,
447        _acceleration_structure: &Resource,
448    ) -> wgt::BufferAddress {
449        Default::default()
450    }
451    unsafe fn destroy_acceleration_structure(&self, _acceleration_structure: Resource) {}
452
453    fn tlas_instance_to_bytes(&self, instance: TlasInstance) -> Vec<u8> {
454        vec![]
455    }
456
457    fn get_internal_counters(&self) -> wgt::HalCounters {
458        Default::default()
459    }
460}
wgpu_hal/noop/mod.rs

wgpu_hal/noop/
mod.rs
