1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
/*! This library describes the internal unsafe graphics abstraction API.
 *  It follows WebGPU for the most part, re-using wgpu-types,
 *  with the following deviations:
 *  - Fully unsafe: zero overhead, zero validation.
 *  - Compile-time backend selection via traits.
 *  - Objects are passed by references and returned by value. No IDs.
 *  - Mapping is persistent, with explicit synchronization.
 *  - Resource transitions are explicit.
 *  - All layouts are explicit. Binding model has compatibility.
 *
 *  General design direction is to follow the majority by the following weights:
 *  - wgpu-core: 1.5
 *  - primary backends (Vulkan/Metal/DX12): 1.0 each
 *  - secondary backends (DX11/GLES): 0.5 each
 */

#![allow(
    // for `if_then_panic` until it reaches stable
    unknown_lints,
    // We use loops for getting early-out of scope without closures.
    clippy::never_loop,
    // We don't use syntax sugar where it's not necessary.
    clippy::match_like_matches_macro,
    // Redundant matching is more explicit.
    clippy::redundant_pattern_matching,
    // Explicit lifetimes are often easier to reason about.
    clippy::needless_lifetimes,
    // No need for defaults in the internal types.
    clippy::new_without_default,
    // Matches are good and extendable, no need to make an exception here.
    clippy::single_match,
    // Push commands are more regular than macros.
    clippy::vec_init_then_push,
    // "if panic" is a good uniform construct.
    clippy::if_then_panic,
    // We unsafe impl `Send` for a reason.
    clippy::non_send_fields_in_send_ty,
    // TODO!
    clippy::missing_safety_doc,
)]
#![warn(
    trivial_casts,
    trivial_numeric_casts,
    unused_extern_crates,
    unused_qualifications,
    // We don't match on a reference, unless required.
    clippy::pattern_type_mismatch,
)]

#[cfg(all(feature = "metal", not(any(target_os = "macos", target_os = "ios"))))]
compile_error!("Metal API enabled on non-Apple OS. If your project is not using resolver=\"2\" in Cargo.toml, it should.");
#[cfg(all(feature = "dx12", not(windows)))]
compile_error!("DX12 API enabled on non-Windows OS. If your project is not using resolver=\"2\" in Cargo.toml, it should.");

#[cfg(all(feature = "dx11", windows))]
mod dx11;
#[cfg(all(feature = "dx12", windows))]
mod dx12;
mod empty;
#[cfg(all(feature = "gles"))]
mod gles;
#[cfg(all(feature = "metal"))]
mod metal;
#[cfg(feature = "vulkan")]
mod vulkan;

pub mod auxil;
pub mod api {
    #[cfg(feature = "dx11")]
    pub use super::dx11::Api as Dx11;
    #[cfg(feature = "dx12")]
    pub use super::dx12::Api as Dx12;
    pub use super::empty::Api as Empty;
    #[cfg(feature = "gles")]
    pub use super::gles::Api as Gles;
    #[cfg(feature = "metal")]
    pub use super::metal::Api as Metal;
    #[cfg(feature = "vulkan")]
    pub use super::vulkan::Api as Vulkan;
}

#[cfg(feature = "vulkan")]
pub use vulkan::UpdateAfterBindTypes;

use std::{
    borrow::Borrow,
    fmt,
    num::{NonZeroU32, NonZeroU8},
    ops::{Range, RangeInclusive},
    ptr::NonNull,
    sync::atomic::AtomicBool,
};

use bitflags::bitflags;
use thiserror::Error;

pub const MAX_ANISOTROPY: u8 = 16;
pub const MAX_BIND_GROUPS: usize = 8;
pub const MAX_VERTEX_BUFFERS: usize = 16;
pub const MAX_COLOR_ATTACHMENTS: usize = 8;
pub const MAX_MIP_LEVELS: u32 = 16;
/// Size of a single occlusion/timestamp query, when copied into a buffer, in bytes.
pub const QUERY_SIZE: wgt::BufferAddress = 8;

pub type Label<'a> = Option<&'a str>;
pub type MemoryRange = Range<wgt::BufferAddress>;
pub type FenceValue = u64;

#[derive(Clone, Debug, PartialEq, Error)]
pub enum DeviceError {
    #[error("out of memory")]
    OutOfMemory,
    #[error("device is lost")]
    Lost,
}

#[derive(Clone, Debug, PartialEq, Error)]
pub enum ShaderError {
    #[error("compilation failed: {0:?}")]
    Compilation(String),
    #[error(transparent)]
    Device(#[from] DeviceError),
}

#[derive(Clone, Debug, PartialEq, Error)]
pub enum PipelineError {
    #[error("linkage failed for stage {0:?}: {1}")]
    Linkage(wgt::ShaderStages, String),
    #[error("entry point for stage {0:?} is invalid")]
    EntryPoint(naga::ShaderStage),
    #[error(transparent)]
    Device(#[from] DeviceError),
}

#[derive(Clone, Debug, PartialEq, Error)]
pub enum SurfaceError {
    #[error("surface is lost")]
    Lost,
    #[error("surface is outdated, needs to be re-created")]
    Outdated,
    #[error(transparent)]
    Device(#[from] DeviceError),
    #[error("other reason: {0}")]
    Other(&'static str),
}

#[derive(Clone, Debug, PartialEq, Error)]
#[error("Not supported")]
pub struct InstanceError;

pub trait Api: Clone + Sized {
    type Instance: Instance<Self>;
    type Surface: Surface<Self>;
    type Adapter: Adapter<Self>;
    type Device: Device<Self>;

    type Queue: Queue<Self>;
    type CommandEncoder: CommandEncoder<Self>;
    type CommandBuffer: Send + Sync;

    type Buffer: fmt::Debug + Send + Sync + 'static;
    type Texture: fmt::Debug + Send + Sync + 'static;
    type SurfaceTexture: fmt::Debug + Send + Sync + Borrow<Self::Texture>;
    type TextureView: fmt::Debug + Send + Sync;
    type Sampler: fmt::Debug + Send + Sync;
    type QuerySet: fmt::Debug + Send + Sync;
    type Fence: fmt::Debug + Send + Sync;

    type BindGroupLayout: Send + Sync;
    type BindGroup: fmt::Debug + Send + Sync;
    type PipelineLayout: Send + Sync;
    type ShaderModule: fmt::Debug + Send + Sync;
    type RenderPipeline: Send + Sync;
    type ComputePipeline: Send + Sync;
}

pub trait Instance<A: Api>: Sized + Send + Sync {
    unsafe fn init(desc: &InstanceDescriptor) -> Result<Self, InstanceError>;
    unsafe fn create_surface(
        &self,
        rwh: &impl raw_window_handle::HasRawWindowHandle,
    ) -> Result<A::Surface, InstanceError>;
    unsafe fn destroy_surface(&self, surface: A::Surface);
    unsafe fn enumerate_adapters(&self) -> Vec<ExposedAdapter<A>>;
}

pub trait Surface<A: Api>: Send + Sync {
    unsafe fn configure(
        &mut self,
        device: &A::Device,
        config: &SurfaceConfiguration,
    ) -> Result<(), SurfaceError>;

    unsafe fn unconfigure(&mut self, device: &A::Device);

    /// Returns the next texture to be presented by the swapchain for drawing
    ///
    /// A `timeout` of `None` means to wait indefinitely, with no timeout.
    ///
    /// # Portability
    ///
    /// Some backends can't support a timeout when acquiring a texture and
    /// the timeout will be ignored.
    ///
    /// Returns `None` on timing out.
    unsafe fn acquire_texture(
        &mut self,
        timeout: Option<std::time::Duration>,
    ) -> Result<Option<AcquiredSurfaceTexture<A>>, SurfaceError>;
    unsafe fn discard_texture(&mut self, texture: A::SurfaceTexture);
}

pub trait Adapter<A: Api>: Send + Sync {
    unsafe fn open(
        &self,
        features: wgt::Features,
        limits: &wgt::Limits,
    ) -> Result<OpenDevice<A>, DeviceError>;

    /// Return the set of supported capabilities for a texture format.
    unsafe fn texture_format_capabilities(
        &self,
        format: wgt::TextureFormat,
    ) -> TextureFormatCapabilities;

    /// Returns the capabilities of working with a specified surface.
    ///
    /// `None` means presentation is not supported for it.
    unsafe fn surface_capabilities(&self, surface: &A::Surface) -> Option<SurfaceCapabilities>;
}

pub trait Device<A: Api>: Send + Sync {
    /// Exit connection to this logical device.
    unsafe fn exit(self, queue: A::Queue);
    /// Creates a new buffer.
    ///
    /// The initial usage is `BufferUses::empty()`.
    unsafe fn create_buffer(&self, desc: &BufferDescriptor) -> Result<A::Buffer, DeviceError>;
    unsafe fn destroy_buffer(&self, buffer: A::Buffer);
    //TODO: clarify if zero-sized mapping is allowed
    unsafe fn map_buffer(
        &self,
        buffer: &A::Buffer,
        range: MemoryRange,
    ) -> Result<BufferMapping, DeviceError>;
    unsafe fn unmap_buffer(&self, buffer: &A::Buffer) -> Result<(), DeviceError>;
    unsafe fn flush_mapped_ranges<I>(&self, buffer: &A::Buffer, ranges: I)
    where
        I: Iterator<Item = MemoryRange>;
    unsafe fn invalidate_mapped_ranges<I>(&self, buffer: &A::Buffer, ranges: I)
    where
        I: Iterator<Item = MemoryRange>;

    /// Creates a new texture.
    ///
    /// The initial usage for all subresources is `TextureUses::UNINITIALIZED`.
    unsafe fn create_texture(&self, desc: &TextureDescriptor) -> Result<A::Texture, DeviceError>;
    unsafe fn destroy_texture(&self, texture: A::Texture);
    unsafe fn create_texture_view(
        &self,
        texture: &A::Texture,
        desc: &TextureViewDescriptor,
    ) -> Result<A::TextureView, DeviceError>;
    unsafe fn destroy_texture_view(&self, view: A::TextureView);
    unsafe fn create_sampler(&self, desc: &SamplerDescriptor) -> Result<A::Sampler, DeviceError>;
    unsafe fn destroy_sampler(&self, sampler: A::Sampler);

    unsafe fn create_command_encoder(
        &self,
        desc: &CommandEncoderDescriptor<A>,
    ) -> Result<A::CommandEncoder, DeviceError>;
    unsafe fn destroy_command_encoder(&self, pool: A::CommandEncoder);

    /// Creates a bind group layout.
    unsafe fn create_bind_group_layout(
        &self,
        desc: &BindGroupLayoutDescriptor,
    ) -> Result<A::BindGroupLayout, DeviceError>;
    unsafe fn destroy_bind_group_layout(&self, bg_layout: A::BindGroupLayout);
    unsafe fn create_pipeline_layout(
        &self,
        desc: &PipelineLayoutDescriptor<A>,
    ) -> Result<A::PipelineLayout, DeviceError>;
    unsafe fn destroy_pipeline_layout(&self, pipeline_layout: A::PipelineLayout);
    unsafe fn create_bind_group(
        &self,
        desc: &BindGroupDescriptor<A>,
    ) -> Result<A::BindGroup, DeviceError>;
    unsafe fn destroy_bind_group(&self, group: A::BindGroup);

    unsafe fn create_shader_module(
        &self,
        desc: &ShaderModuleDescriptor,
        shader: ShaderInput,
    ) -> Result<A::ShaderModule, ShaderError>;
    unsafe fn destroy_shader_module(&self, module: A::ShaderModule);
    unsafe fn create_render_pipeline(
        &self,
        desc: &RenderPipelineDescriptor<A>,
    ) -> Result<A::RenderPipeline, PipelineError>;
    unsafe fn destroy_render_pipeline(&self, pipeline: A::RenderPipeline);
    unsafe fn create_compute_pipeline(
        &self,
        desc: &ComputePipelineDescriptor<A>,
    ) -> Result<A::ComputePipeline, PipelineError>;
    unsafe fn destroy_compute_pipeline(&self, pipeline: A::ComputePipeline);

    unsafe fn create_query_set(
        &self,
        desc: &wgt::QuerySetDescriptor<Label>,
    ) -> Result<A::QuerySet, DeviceError>;
    unsafe fn destroy_query_set(&self, set: A::QuerySet);
    unsafe fn create_fence(&self) -> Result<A::Fence, DeviceError>;
    unsafe fn destroy_fence(&self, fence: A::Fence);
    unsafe fn get_fence_value(&self, fence: &A::Fence) -> Result<FenceValue, DeviceError>;
    /// Calling wait with a lower value than the current fence value will immediately return.
    unsafe fn wait(
        &self,
        fence: &A::Fence,
        value: FenceValue,
        timeout_ms: u32,
    ) -> Result<bool, DeviceError>;

    unsafe fn start_capture(&self) -> bool;
    unsafe fn stop_capture(&self);
}

pub trait Queue<A: Api>: Send + Sync {
    /// Submits the command buffers for execution on GPU.
    ///
    /// Valid usage:
    /// - all of the command buffers were created from command pools
    ///   that are associated with this queue.
    /// - all of the command buffers had `CommadBuffer::finish()` called.
    unsafe fn submit(
        &mut self,
        command_buffers: &[&A::CommandBuffer],
        signal_fence: Option<(&mut A::Fence, FenceValue)>,
    ) -> Result<(), DeviceError>;
    unsafe fn present(
        &mut self,
        surface: &mut A::Surface,
        texture: A::SurfaceTexture,
    ) -> Result<(), SurfaceError>;
    unsafe fn get_timestamp_period(&self) -> f32;
}

/// Encoder for commands in command buffers.
/// Serves as a parent for all the encoded command buffers.
/// Works in bursts of action: one or more command buffers are recorded,
/// then submitted to a queue, and then it needs to be `reset_all()`.
pub trait CommandEncoder<A: Api>: Send + Sync {
    /// Begin encoding a new command buffer.
    unsafe fn begin_encoding(&mut self, label: Label) -> Result<(), DeviceError>;
    /// Discard currently recorded list, if any.
    unsafe fn discard_encoding(&mut self);
    unsafe fn end_encoding(&mut self) -> Result<A::CommandBuffer, DeviceError>;
    /// Reclaims all resources that are allocated for this encoder.
    /// Must get all of the produced command buffers back,
    /// and they must not be used by GPU at this moment.
    unsafe fn reset_all<I>(&mut self, command_buffers: I)
    where
        I: Iterator<Item = A::CommandBuffer>;

    unsafe fn transition_buffers<'a, T>(&mut self, barriers: T)
    where
        T: Iterator<Item = BufferBarrier<'a, A>>;

    unsafe fn transition_textures<'a, T>(&mut self, barriers: T)
    where
        T: Iterator<Item = TextureBarrier<'a, A>>;

    // copy operations

    unsafe fn clear_buffer(&mut self, buffer: &A::Buffer, range: MemoryRange);

    unsafe fn copy_buffer_to_buffer<T>(&mut self, src: &A::Buffer, dst: &A::Buffer, regions: T)
    where
        T: Iterator<Item = BufferCopy>;

    /// Copy from one texture to another.
    /// Works with a single array layer.
    /// Note: `dst` current usage has to be `TextureUses::COPY_DST`.
    /// Note: the copy extent is in physical size (rounded to the block size)
    unsafe fn copy_texture_to_texture<T>(
        &mut self,
        src: &A::Texture,
        src_usage: TextureUses,
        dst: &A::Texture,
        regions: T,
    ) where
        T: Iterator<Item = TextureCopy>;

    /// Copy from buffer to texture.
    /// Works with a single array layer.
    /// Note: `dst` current usage has to be `TextureUses::COPY_DST`.
    /// Note: the copy extent is in physical size (rounded to the block size)
    unsafe fn copy_buffer_to_texture<T>(&mut self, src: &A::Buffer, dst: &A::Texture, regions: T)
    where
        T: Iterator<Item = BufferTextureCopy>;

    /// Copy from texture to buffer.
    /// Works with a single array layer.
    /// Note: the copy extent is in physical size (rounded to the block size)
    unsafe fn copy_texture_to_buffer<T>(
        &mut self,
        src: &A::Texture,
        src_usage: TextureUses,
        dst: &A::Buffer,
        regions: T,
    ) where
        T: Iterator<Item = BufferTextureCopy>;

    // pass common

    /// Sets the bind group at `index` to `group`, assuming the layout
    /// of all the preceeding groups to be taken from `layout`.
    unsafe fn set_bind_group(
        &mut self,
        layout: &A::PipelineLayout,
        index: u32,
        group: &A::BindGroup,
        dynamic_offsets: &[wgt::DynamicOffset],
    );

    unsafe fn set_push_constants(
        &mut self,
        layout: &A::PipelineLayout,
        stages: wgt::ShaderStages,
        offset: u32,
        data: &[u32],
    );

    unsafe fn insert_debug_marker(&mut self, label: &str);
    unsafe fn begin_debug_marker(&mut self, group_label: &str);
    unsafe fn end_debug_marker(&mut self);

    // queries

    unsafe fn begin_query(&mut self, set: &A::QuerySet, index: u32);
    unsafe fn end_query(&mut self, set: &A::QuerySet, index: u32);
    unsafe fn write_timestamp(&mut self, set: &A::QuerySet, index: u32);
    unsafe fn reset_queries(&mut self, set: &A::QuerySet, range: Range<u32>);
    unsafe fn copy_query_results(
        &mut self,
        set: &A::QuerySet,
        range: Range<u32>,
        buffer: &A::Buffer,
        offset: wgt::BufferAddress,
        stride: wgt::BufferSize,
    );

    // render passes

    // Begins a render pass, clears all active bindings.
    unsafe fn begin_render_pass(&mut self, desc: &RenderPassDescriptor<A>);
    unsafe fn end_render_pass(&mut self);

    unsafe fn set_render_pipeline(&mut self, pipeline: &A::RenderPipeline);

    unsafe fn set_index_buffer<'a>(
        &mut self,
        binding: BufferBinding<'a, A>,
        format: wgt::IndexFormat,
    );
    unsafe fn set_vertex_buffer<'a>(&mut self, index: u32, binding: BufferBinding<'a, A>);
    unsafe fn set_viewport(&mut self, rect: &Rect<f32>, depth_range: Range<f32>);
    unsafe fn set_scissor_rect(&mut self, rect: &Rect<u32>);
    unsafe fn set_stencil_reference(&mut self, value: u32);
    unsafe fn set_blend_constants(&mut self, color: &[f32; 4]);

    unsafe fn draw(
        &mut self,
        start_vertex: u32,
        vertex_count: u32,
        start_instance: u32,
        instance_count: u32,
    );
    unsafe fn draw_indexed(
        &mut self,
        start_index: u32,
        index_count: u32,
        base_vertex: i32,
        start_instance: u32,
        instance_count: u32,
    );
    unsafe fn draw_indirect(
        &mut self,
        buffer: &A::Buffer,
        offset: wgt::BufferAddress,
        draw_count: u32,
    );
    unsafe fn draw_indexed_indirect(
        &mut self,
        buffer: &A::Buffer,
        offset: wgt::BufferAddress,
        draw_count: u32,
    );
    unsafe fn draw_indirect_count(
        &mut self,
        buffer: &A::Buffer,
        offset: wgt::BufferAddress,
        count_buffer: &A::Buffer,
        count_offset: wgt::BufferAddress,
        max_count: u32,
    );
    unsafe fn draw_indexed_indirect_count(
        &mut self,
        buffer: &A::Buffer,
        offset: wgt::BufferAddress,
        count_buffer: &A::Buffer,
        count_offset: wgt::BufferAddress,
        max_count: u32,
    );

    // compute passes

    // Begins a compute pass, clears all active bindings.
    unsafe fn begin_compute_pass(&mut self, desc: &ComputePassDescriptor);
    unsafe fn end_compute_pass(&mut self);

    unsafe fn set_compute_pipeline(&mut self, pipeline: &A::ComputePipeline);

    unsafe fn dispatch(&mut self, count: [u32; 3]);
    unsafe fn dispatch_indirect(&mut self, buffer: &A::Buffer, offset: wgt::BufferAddress);
}

bitflags!(
    /// Instance initialization flags.
    pub struct InstanceFlags: u32 {
        /// Generate debug information in shaders and objects.
        const DEBUG = 1 << 0;
        /// Enable validation, if possible.
        const VALIDATION = 1 << 1;
    }
);

bitflags!(
    /// Pipeline layout creation flags.
    pub struct PipelineLayoutFlags: u32 {
        /// Include support for base vertex/instance drawing.
        const BASE_VERTEX_INSTANCE = 1 << 0;
        /// Include support for num work groups builtin.
        const NUM_WORK_GROUPS = 1 << 1;
    }
);

bitflags!(
    /// Pipeline layout creation flags.
    pub struct BindGroupLayoutFlags: u32 {
        /// Allows for bind group binding arrays to be shorter than the array in the BGL.
        const PARTIALLY_BOUND = 1 << 0;
    }
);

bitflags!(
    /// Texture format capability flags.
    pub struct TextureFormatCapabilities: u32 {
        /// Format can be sampled.
        const SAMPLED = 1 << 0;
        /// Format can be sampled with a linear sampler.
        const SAMPLED_LINEAR = 1 << 1;
        /// Format can be sampled with a min/max reduction sampler.
        const SAMPLED_MINMAX = 1 << 2;

        /// Format can be used as storage with write-only access.
        const STORAGE = 1 << 3;
        /// Format can be used as storage with read and read/write access.
        const STORAGE_READ_WRITE = 1 << 4;
        /// Format can be used as storage with atomics.
        const STORAGE_ATOMIC = 1 << 5;

        /// Format can be used as color and input attachment.
        const COLOR_ATTACHMENT = 1 << 6;
        /// Format can be used as color (with blending) and input attachment.
        const COLOR_ATTACHMENT_BLEND = 1 << 7;
        /// Format can be used as depth-stencil and input attachment.
        const DEPTH_STENCIL_ATTACHMENT = 1 << 8;

        /// Format can be multisampled.
        const MULTISAMPLE = 1 << 9;
        /// Format can be used for render pass resolve targets.
        const MULTISAMPLE_RESOLVE = 1 << 10;

        /// Format can be copied from.
        const COPY_SRC = 1 << 11;
        /// Format can be copied to.
        const COPY_DST = 1 << 12;
    }
);

bitflags!(
    /// Texture format capability flags.
    pub struct FormatAspects: u8 {
        const COLOR = 1 << 0;
        const DEPTH = 1 << 1;
        const STENCIL = 1 << 2;
    }
);

impl From<wgt::TextureAspect> for FormatAspects {
    fn from(aspect: wgt::TextureAspect) -> Self {
        match aspect {
            wgt::TextureAspect::All => Self::all(),
            wgt::TextureAspect::DepthOnly => Self::DEPTH,
            wgt::TextureAspect::StencilOnly => Self::STENCIL,
        }
    }
}

impl From<wgt::TextureFormat> for FormatAspects {
    fn from(format: wgt::TextureFormat) -> Self {
        match format {
            wgt::TextureFormat::Depth32Float | wgt::TextureFormat::Depth24Plus => Self::DEPTH,
            wgt::TextureFormat::Depth32FloatStencil8
            | wgt::TextureFormat::Depth24PlusStencil8
            | wgt::TextureFormat::Depth24UnormStencil8 => Self::DEPTH | Self::STENCIL,
            _ => Self::COLOR,
        }
    }
}

bitflags!(
    pub struct MemoryFlags: u32 {
        const TRANSIENT = 1 << 0;
        const PREFER_COHERENT = 1 << 1;
    }
);

//TODO: it's not intuitive for the backends to consider `LOAD` being optional.

bitflags!(
    pub struct AttachmentOps: u8 {
        const LOAD = 1 << 0;
        const STORE = 1 << 1;
    }
);

bitflags::bitflags! {
    /// Similar to `wgt::BufferUsages` but for internal use.
    pub struct BufferUses: u16 {
        /// The argument to a read-only mapping.
        const MAP_READ = 1 << 0;
        /// The argument to a write-only mapping.
        const MAP_WRITE = 1 << 1;
        /// The source of a hardware copy.
        const COPY_SRC = 1 << 2;
        /// The destination of a hardware copy.
        const COPY_DST = 1 << 3;
        /// The index buffer used for drawing.
        const INDEX = 1 << 4;
        /// A vertex buffer used for drawing.
        const VERTEX = 1 << 5;
        /// A uniform buffer bound in a bind group.
        const UNIFORM = 1 << 6;
        /// A read-only storage buffer used in a bind group.
        const STORAGE_READ = 1 << 7;
        /// A read-write or write-only buffer used in a bind group.
        const STORAGE_READ_WRITE = 1 << 8;
        /// The indirect or count buffer in a indirect draw or dispatch.
        const INDIRECT = 1 << 9;
        /// The combination of states that a buffer may be in _at the same time_.
        const INCLUSIVE = Self::MAP_READ.bits | Self::COPY_SRC.bits |
            Self::INDEX.bits | Self::VERTEX.bits | Self::UNIFORM.bits |
            Self::STORAGE_READ.bits | Self::INDIRECT.bits;
        /// The combination of states that a buffer must exclusively be in.
        const EXCLUSIVE = Self::MAP_WRITE.bits | Self::COPY_DST.bits | Self::STORAGE_READ_WRITE.bits;
        /// The combination of all usages that the are guaranteed to be be ordered by the hardware.
        /// If a usage is ordered, then if the buffer state doesn't change between draw calls, there
        /// are no barriers needed for synchronization.
        const ORDERED = Self::INCLUSIVE.bits | Self::MAP_WRITE.bits;
    }
}

bitflags::bitflags! {
    /// Similar to `wgt::TextureUsages` but for internal use.
    pub struct TextureUses: u16 {
        /// The texture is in unknown state.
        const UNINITIALIZED = 1 << 0;
        /// Ready to present image to the surface.
        const PRESENT = 1 << 1;
        /// The source of a hardware copy.
        const COPY_SRC = 1 << 2;
        /// The destination of a hardware copy.
        const COPY_DST = 1 << 3;
        /// Read-only sampled or fetched resource.
        const RESOURCE = 1 << 4;
        /// The color target of a renderpass.
        const COLOR_TARGET = 1 << 5;
        /// Read-only depth stencil usage.
        const DEPTH_STENCIL_READ = 1 << 6;
        /// Read-write depth stencil usage
        const DEPTH_STENCIL_WRITE = 1 << 7;
        /// Read-only storage buffer usage. Corresponds to a UAV in d3d, so is exclusive, despite being read only.
        const STORAGE_READ = 1 << 8;
        /// Read-write or write-only storage buffer usage.
        const STORAGE_READ_WRITE = 1 << 9;
        /// The combination of states that a texture may be in _at the same time_.
        const INCLUSIVE = Self::COPY_SRC.bits | Self::RESOURCE.bits | Self::DEPTH_STENCIL_READ.bits;
        /// The combination of states that a texture must exclusively be in.
        const EXCLUSIVE = Self::COPY_DST.bits | Self::COLOR_TARGET.bits | Self::DEPTH_STENCIL_WRITE.bits | Self::STORAGE_READ.bits | Self::STORAGE_READ_WRITE.bits | Self::PRESENT.bits;
        /// The combination of all usages that the are guaranteed to be be ordered by the hardware.
        /// If a usage is ordered, then if the texture state doesn't change between draw calls, there
        /// are no barriers needed for synchronization.
        const ORDERED = Self::INCLUSIVE.bits | Self::COLOR_TARGET.bits | Self::DEPTH_STENCIL_WRITE.bits | Self::STORAGE_READ.bits;

        /// Flag used by the wgpu-core texture tracker to say a texture is in different states for every sub-resource
        const COMPLEX = 1 << 10;
        /// Flag used by the wgpu-core texture tracker to say that the tracker does not know the state of the sub-resource.
        /// This is different from UNINITIALIZED as that says the tracker does know, but the texture has not been initialized.
        const UNKNOWN = 1 << 11;
    }
}

#[derive(Clone, Debug)]
pub struct InstanceDescriptor<'a> {
    pub name: &'a str,
    pub flags: InstanceFlags,
}

#[derive(Clone, Debug)]
pub struct Alignments {
    /// The alignment of the start of the buffer used as a GPU copy source.
    pub buffer_copy_offset: wgt::BufferSize,
    /// The alignment of the row pitch of the texture data stored in a buffer that is
    /// used in a GPU copy operation.
    pub buffer_copy_pitch: wgt::BufferSize,
}

#[derive(Clone, Debug)]
pub struct Capabilities {
    pub limits: wgt::Limits,
    pub alignments: Alignments,
    pub downlevel: wgt::DownlevelCapabilities,
}

#[derive(Debug)]
pub struct ExposedAdapter<A: Api> {
    pub adapter: A::Adapter,
    pub info: wgt::AdapterInfo,
    pub features: wgt::Features,
    pub capabilities: Capabilities,
}

/// Describes information about what a `Surface`'s presentation capabilities are.
/// Fetch this with [Adapter::surface_capabilities].
#[derive(Debug, Clone)]
pub struct SurfaceCapabilities {
    /// List of supported texture formats.
    ///
    /// Must be at least one.
    pub formats: Vec<wgt::TextureFormat>,

    /// Range for the swap chain sizes.
    ///
    /// - `swap_chain_sizes.start` must be at least 1.
    /// - `swap_chain_sizes.end` must be larger or equal to `swap_chain_sizes.start`.
    pub swap_chain_sizes: RangeInclusive<u32>,

    /// Current extent of the surface, if known.
    pub current_extent: Option<wgt::Extent3d>,

    /// Range of supported extents.
    ///
    /// `current_extent` must be inside this range.
    pub extents: RangeInclusive<wgt::Extent3d>,

    /// Supported texture usage flags.
    ///
    /// Must have at least `TextureUses::COLOR_TARGET`
    pub usage: TextureUses,

    /// List of supported V-sync modes.
    ///
    /// Must be at least one.
    pub present_modes: Vec<wgt::PresentMode>,

    /// List of supported alpha composition modes.
    ///
    /// Must be at least one.
    pub composite_alpha_modes: Vec<CompositeAlphaMode>,
}

#[derive(Debug)]
pub struct AcquiredSurfaceTexture<A: Api> {
    pub texture: A::SurfaceTexture,
    /// The presentation configuration no longer matches
    /// the surface properties exactly, but can still be used to present
    /// to the surface successfully.
    pub suboptimal: bool,
}

#[derive(Debug)]
pub struct OpenDevice<A: Api> {
    pub device: A::Device,
    pub queue: A::Queue,
}

#[derive(Clone, Debug)]
pub struct BufferMapping {
    pub ptr: NonNull<u8>,
    pub is_coherent: bool,
}

#[derive(Clone, Debug)]
pub struct BufferDescriptor<'a> {
    pub label: Label<'a>,
    pub size: wgt::BufferAddress,
    pub usage: BufferUses,
    pub memory_flags: MemoryFlags,
}

#[derive(Clone, Debug)]
pub struct TextureDescriptor<'a> {
    pub label: Label<'a>,
    pub size: wgt::Extent3d,
    pub mip_level_count: u32,
    pub sample_count: u32,
    pub dimension: wgt::TextureDimension,
    pub format: wgt::TextureFormat,
    pub usage: TextureUses,
    pub memory_flags: MemoryFlags,
}

/// TextureView descriptor.
///
/// Valid usage:
///. - `format` has to be the same as `TextureDescriptor::format`
///. - `dimension` has to be compatible with `TextureDescriptor::dimension`
///. - `usage` has to be a subset of `TextureDescriptor::usage`
///. - `range` has to be a subset of parent texture
#[derive(Clone, Debug)]
pub struct TextureViewDescriptor<'a> {
    pub label: Label<'a>,
    pub format: wgt::TextureFormat,
    pub dimension: wgt::TextureViewDimension,
    pub usage: TextureUses,
    pub range: wgt::ImageSubresourceRange,
}

#[derive(Clone, Debug)]
pub struct SamplerDescriptor<'a> {
    pub label: Label<'a>,
    pub address_modes: [wgt::AddressMode; 3],
    pub mag_filter: wgt::FilterMode,
    pub min_filter: wgt::FilterMode,
    pub mipmap_filter: wgt::FilterMode,
    pub lod_clamp: Option<Range<f32>>,
    pub compare: Option<wgt::CompareFunction>,
    pub anisotropy_clamp: Option<NonZeroU8>,
    pub border_color: Option<wgt::SamplerBorderColor>,
}

/// BindGroupLayout descriptor.
///
/// Valid usage:
/// - `entries` are sorted by ascending `wgt::BindGroupLayoutEntry::binding`
#[derive(Clone, Debug)]
pub struct BindGroupLayoutDescriptor<'a> {
    pub label: Label<'a>,
    pub flags: BindGroupLayoutFlags,
    pub entries: &'a [wgt::BindGroupLayoutEntry],
}

#[derive(Clone, Debug)]
pub struct PipelineLayoutDescriptor<'a, A: Api> {
    pub label: Label<'a>,
    pub flags: PipelineLayoutFlags,
    pub bind_group_layouts: &'a [&'a A::BindGroupLayout],
    pub push_constant_ranges: &'a [wgt::PushConstantRange],
}

#[derive(Debug)]
pub struct BufferBinding<'a, A: Api> {
    pub buffer: &'a A::Buffer,
    pub offset: wgt::BufferAddress,
    pub size: Option<wgt::BufferSize>,
}

// Rust gets confused about the impl requirements for `A`
impl<A: Api> Clone for BufferBinding<'_, A> {
    fn clone(&self) -> Self {
        Self {
            buffer: self.buffer,
            offset: self.offset,
            size: self.size,
        }
    }
}

#[derive(Debug)]
pub struct TextureBinding<'a, A: Api> {
    pub view: &'a A::TextureView,
    pub usage: TextureUses,
}

// Rust gets confused about the impl requirements for `A`
impl<A: Api> Clone for TextureBinding<'_, A> {
    fn clone(&self) -> Self {
        Self {
            view: self.view,
            usage: self.usage,
        }
    }
}

#[derive(Clone, Debug)]
pub struct BindGroupEntry {
    pub binding: u32,
    pub resource_index: u32,
    pub count: u32,
}

/// BindGroup descriptor.
///
/// Valid usage:
///. - `entries` has to be sorted by ascending `BindGroupEntry::binding`
///. - `entries` has to have the same set of `BindGroupEntry::binding` as `layout`
///. - each entry has to be compatible with the `layout`
///. - each entry's `BindGroupEntry::resource_index` is within range
///    of the corresponding resource array, selected by the relevant
///    `BindGroupLayoutEntry`.
#[derive(Clone, Debug)]
pub struct BindGroupDescriptor<'a, A: Api> {
    pub label: Label<'a>,
    pub layout: &'a A::BindGroupLayout,
    pub buffers: &'a [BufferBinding<'a, A>],
    pub samplers: &'a [&'a A::Sampler],
    pub textures: &'a [TextureBinding<'a, A>],
    pub entries: &'a [BindGroupEntry],
}

#[derive(Clone, Debug)]
pub struct CommandEncoderDescriptor<'a, A: Api> {
    pub label: Label<'a>,
    pub queue: &'a A::Queue,
}

/// Naga shader module.
pub struct NagaShader {
    /// Shader module IR.
    pub module: naga::Module,
    /// Analysis information of the module.
    pub info: naga::valid::ModuleInfo,
}

// Custom implementation avoids the need to generate Debug impl code
// for the whole Naga module and info.
impl fmt::Debug for NagaShader {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        write!(formatter, "Naga shader")
    }
}

/// Shader input.
#[allow(clippy::large_enum_variant)]
pub enum ShaderInput<'a> {
    Naga(NagaShader),
    SpirV(&'a [u32]),
}

pub struct ShaderModuleDescriptor<'a> {
    pub label: Label<'a>,
    pub runtime_checks: bool,
}

/// Describes a programmable pipeline stage.
#[derive(Debug)]
pub struct ProgrammableStage<'a, A: Api> {
    /// The compiled shader module for this stage.
    pub module: &'a A::ShaderModule,
    /// The name of the entry point in the compiled shader. There must be a function that returns
    /// void with this name in the shader.
    pub entry_point: &'a str,
}

// Rust gets confused about the impl requirements for `A`
impl<A: Api> Clone for ProgrammableStage<'_, A> {
    fn clone(&self) -> Self {
        Self {
            module: self.module,
            entry_point: self.entry_point,
        }
    }
}

/// Describes a compute pipeline.
#[derive(Clone, Debug)]
pub struct ComputePipelineDescriptor<'a, A: Api> {
    pub label: Label<'a>,
    /// The layout of bind groups for this pipeline.
    pub layout: &'a A::PipelineLayout,
    /// The compiled compute stage and its entry point.
    pub stage: ProgrammableStage<'a, A>,
}

/// Describes how the vertex buffer is interpreted.
#[derive(Clone, Debug)]
pub struct VertexBufferLayout<'a> {
    /// The stride, in bytes, between elements of this buffer.
    pub array_stride: wgt::BufferAddress,
    /// How often this vertex buffer is "stepped" forward.
    pub step_mode: wgt::VertexStepMode,
    /// The list of attributes which comprise a single vertex.
    pub attributes: &'a [wgt::VertexAttribute],
}

/// Describes a render (graphics) pipeline.
#[derive(Clone, Debug)]
pub struct RenderPipelineDescriptor<'a, A: Api> {
    pub label: Label<'a>,
    /// The layout of bind groups for this pipeline.
    pub layout: &'a A::PipelineLayout,
    /// The format of any vertex buffers used with this pipeline.
    pub vertex_buffers: &'a [VertexBufferLayout<'a>],
    /// The vertex stage for this pipeline.
    pub vertex_stage: ProgrammableStage<'a, A>,
    /// The properties of the pipeline at the primitive assembly and rasterization level.
    pub primitive: wgt::PrimitiveState,
    /// The effect of draw calls on the depth and stencil aspects of the output target, if any.
    pub depth_stencil: Option<wgt::DepthStencilState>,
    /// The multi-sampling properties of the pipeline.
    pub multisample: wgt::MultisampleState,
    /// The fragment stage for this pipeline.
    pub fragment_stage: Option<ProgrammableStage<'a, A>>,
    /// The effect of draw calls on the color aspect of the output target.
    pub color_targets: &'a [Option<wgt::ColorTargetState>],
    /// If the pipeline will be used with a multiview render pass, this indicates how many array
    /// layers the attachments will have.
    pub multiview: Option<NonZeroU32>,
}

/// Specifies how the alpha channel of the textures should be handled during (martin mouv i step)
/// compositing.
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum CompositeAlphaMode {
    /// The alpha channel, if it exists, of the textures is ignored in the
    /// compositing process. Instead, the textures is treated as if it has a
    /// constant alpha of 1.0.
    Opaque,
    /// The alpha channel, if it exists, of the textures is respected in the
    /// compositing process. The non-alpha channels of the textures are
    /// expected to already be multiplied by the alpha channel by the
    /// application.
    PreMultiplied,
    /// The alpha channel, if it exists, of the textures is respected in the
    /// compositing process. The non-alpha channels of the textures are not
    /// expected to already be multiplied by the alpha channel by the
    /// application; instead, the compositor will multiply the non-alpha
    /// channels of the texture by the alpha channel during compositing.
    PostMultiplied,
}

#[derive(Debug, Clone)]
pub struct SurfaceConfiguration {
    /// Number of textures in the swap chain. Must be in
    /// `SurfaceCapabilities::swap_chain_size` range.
    pub swap_chain_size: u32,
    /// Vertical synchronization mode.
    pub present_mode: wgt::PresentMode,
    /// Alpha composition mode.
    pub composite_alpha_mode: CompositeAlphaMode,
    /// Format of the surface textures.
    pub format: wgt::TextureFormat,
    /// Requested texture extent. Must be in
    /// `SurfaceCapabilities::extents` range.
    pub extent: wgt::Extent3d,
    /// Allowed usage of surface textures,
    pub usage: TextureUses,
}

#[derive(Debug, Clone)]
pub struct Rect<T> {
    pub x: T,
    pub y: T,
    pub w: T,
    pub h: T,
}

#[derive(Debug, Clone)]
pub struct BufferBarrier<'a, A: Api> {
    pub buffer: &'a A::Buffer,
    pub usage: Range<BufferUses>,
}

#[derive(Debug, Clone)]
pub struct TextureBarrier<'a, A: Api> {
    pub texture: &'a A::Texture,
    pub range: wgt::ImageSubresourceRange,
    pub usage: Range<TextureUses>,
}

#[derive(Clone, Copy, Debug)]
pub struct BufferCopy {
    pub src_offset: wgt::BufferAddress,
    pub dst_offset: wgt::BufferAddress,
    pub size: wgt::BufferSize,
}

#[derive(Clone, Debug)]
pub struct TextureCopyBase {
    pub mip_level: u32,
    pub array_layer: u32,
    /// Origin within a texture.
    /// Note: for 1D and 2D textures, Z must be 0.
    pub origin: wgt::Origin3d,
    pub aspect: FormatAspects,
}

#[derive(Clone, Copy, Debug)]
pub struct CopyExtent {
    pub width: u32,
    pub height: u32,
    pub depth: u32,
}

#[derive(Clone, Debug)]
pub struct TextureCopy {
    pub src_base: TextureCopyBase,
    pub dst_base: TextureCopyBase,
    pub size: CopyExtent,
}

#[derive(Clone, Debug)]
pub struct BufferTextureCopy {
    pub buffer_layout: wgt::ImageDataLayout,
    pub texture_base: TextureCopyBase,
    pub size: CopyExtent,
}

#[derive(Debug)]
pub struct Attachment<'a, A: Api> {
    pub view: &'a A::TextureView,
    /// Contains either a single mutating usage as a target,
    /// or a valid combination of read-only usages.
    pub usage: TextureUses,
}

// Rust gets confused about the impl requirements for `A`
impl<A: Api> Clone for Attachment<'_, A> {
    fn clone(&self) -> Self {
        Self {
            view: self.view,
            usage: self.usage,
        }
    }
}

#[derive(Debug)]
pub struct ColorAttachment<'a, A: Api> {
    pub target: Attachment<'a, A>,
    pub resolve_target: Option<Attachment<'a, A>>,
    pub ops: AttachmentOps,
    pub clear_value: wgt::Color,
}

// Rust gets confused about the impl requirements for `A`
impl<A: Api> Clone for ColorAttachment<'_, A> {
    fn clone(&self) -> Self {
        Self {
            target: self.target.clone(),
            resolve_target: self.resolve_target.clone(),
            ops: self.ops,
            clear_value: self.clear_value,
        }
    }
}

#[derive(Clone, Debug)]
pub struct DepthStencilAttachment<'a, A: Api> {
    pub target: Attachment<'a, A>,
    pub depth_ops: AttachmentOps,
    pub stencil_ops: AttachmentOps,
    pub clear_value: (f32, u32),
}

#[derive(Clone, Debug)]
pub struct RenderPassDescriptor<'a, A: Api> {
    pub label: Label<'a>,
    pub extent: wgt::Extent3d,
    pub sample_count: u32,
    pub color_attachments: &'a [Option<ColorAttachment<'a, A>>],
    pub depth_stencil_attachment: Option<DepthStencilAttachment<'a, A>>,
    pub multiview: Option<NonZeroU32>,
}

#[derive(Clone, Debug)]
pub struct ComputePassDescriptor<'a> {
    pub label: Label<'a>,
}

/// Stores if any API validation error has occurred in this process
/// since it was last reset.
///
/// This is used for internal wgpu testing only and _must not_ be used
/// as a way to check for errors.
///
/// This works as a static because `cargo nextest` runs all of our
/// tests in separate processes, so each test gets its own canary.
///
/// This prevents the issue of one validation error terminating the
/// entire process.
pub static VALIDATION_CANARY: ValidationCanary = ValidationCanary {
    inner: AtomicBool::new(false),
};

/// Flag for internal testing.
pub struct ValidationCanary {
    inner: AtomicBool,
}

impl ValidationCanary {
    #[allow(dead_code)] // in some configurations this function is dead
    fn set(&self) {
        self.inner.store(true, std::sync::atomic::Ordering::SeqCst);
    }

    /// Returns true if any API validation error has occurred in this process
    /// since the last call to this function.
    pub fn get_and_reset(&self) -> bool {
        self.inner.swap(false, std::sync::atomic::Ordering::SeqCst)
    }
}

#[test]
fn test_default_limits() {
    let limits = wgt::Limits::default();
    assert!(limits.max_bind_groups <= MAX_BIND_GROUPS as u32);
}