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
// Copyright (c) 2016 The vulkano developers
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or http://opensource.org/licenses/MIT>,
// at your option. All files in the project carrying such
// notice may not be copied, modified, or distributed except
// according to those terms.

//! How to retrieve data from an image within a shader.
//!
//! When you retrieve data from an image, you have to pass the coordinates of the pixel you want
//! to retrieve. The implementation then performs various calculations, and these operations are
//! what the `Sampler` struct describes.
//!
//! Sampling is a very complex topic but that hasn't changed much since the beginnings of 3D
//! rendering. Documentation here is missing, but any tutorial about OpenGL or DirectX can teach
//! you how it works.
//!
//! # Examples
//!
//! A simple sampler for most usages:
//!
//! ```
//! use vulkano::sampler::Sampler;
//!
//! # let device: std::sync::Arc<vulkano::device::Device> = return;
//! let _sampler = Sampler::simple_repeat_linear_no_mipmap(device.clone());
//! ```
//!
//! More detailed sampler creation:
//!
//! ```
//! use vulkano::sampler;
//!
//! # let device: std::sync::Arc<vulkano::device::Device> = return;
//! let _sampler = sampler::Sampler::new(device.clone(), sampler::Filter::Linear,
//!                                      sampler::Filter::Linear,
//!                                      sampler::MipmapMode::Nearest,
//!                                      sampler::SamplerAddressMode::Repeat,
//!                                      sampler::SamplerAddressMode::Repeat,
//!                                      sampler::SamplerAddressMode::Repeat, 1.0, 1.0,
//!                                      0.0, 100.0).unwrap();;
//! ```
//!
//! # About border colors
//!
//! One of the possible values of `SamplerAddressMode` and `UnnormalizedSamplerAddressMode` is
//! `ClampToBorder`. This value indicates that accessing an image outside of its range must return
//! the specified color.
//!
//! However this comes with restrictions. When using a floating-point border color, the sampler can
//! only be used with floating-point or depth image views. When using an integer border color, the
//! sampler can only be used with integer or stencil image views. In addition to this, you can't
//! use an opaque black border color with an image view that uses components swizzling.
//!
//! > **Note**: The reason for this restriction about opaque black borders is that the value of the
//! > alpha is 1.0 while the value of the color components is 0.0. In the other border colors, the
//! > value of all the components is the same.
//!
//! Samplers that don't use `ClampToBorder` are not concerned by these restrictions.
//!
// FIXME: restrictions aren't checked yet

use std::error;
use std::fmt;
use std::mem;
use std::ptr;
use std::sync::Arc;

use Error;
use OomError;
use VulkanObject;
use check_errors;
use device::Device;
use device::DeviceOwned;
use vk;

pub use pipeline::depth_stencil::Compare;

/// Describes how to retrieve data from an image within a shader.
pub struct Sampler {
    sampler: vk::Sampler,
    device: Arc<Device>,
    compare_mode: bool,
    unnormalized: bool,
    usable_with_float_formats: bool,
    usable_with_int_formats: bool,
    usable_with_swizzling: bool,
}

impl Sampler {
    /// Shortcut for creating a sampler with linear sampling, linear mipmaps, and with the repeat
    /// mode for borders.
    ///
    /// Useful for prototyping, but can also be used in real projects.
    ///
    /// # Panic
    ///
    /// - Panics if out of memory or the maximum number of samplers has exceeded.
    ///
    #[inline]
    pub fn simple_repeat_linear(device: Arc<Device>) -> Arc<Sampler> {
        Sampler::new(device,
                     Filter::Linear,
                     Filter::Linear,
                     MipmapMode::Linear,
                     SamplerAddressMode::Repeat,
                     SamplerAddressMode::Repeat,
                     SamplerAddressMode::Repeat,
                     0.0,
                     1.0,
                     0.0,
                     1_000.0)
            .unwrap()
    }

    /// Shortcut for creating a sampler with linear sampling, that only uses the main level of
    /// images, and with the repeat mode for borders.
    ///
    /// Useful for prototyping, but can also be used in real projects.
    ///
    /// # Panic
    ///
    /// - Panics if out of memory or the maximum number of samplers has exceeded.
    ///
    #[inline]
    pub fn simple_repeat_linear_no_mipmap(device: Arc<Device>) -> Arc<Sampler> {
        Sampler::new(device,
                     Filter::Linear,
                     Filter::Linear,
                     MipmapMode::Nearest,
                     SamplerAddressMode::Repeat,
                     SamplerAddressMode::Repeat,
                     SamplerAddressMode::Repeat,
                     0.0,
                     1.0,
                     0.0,
                     1.0)
            .unwrap()
    }

    /// Creates a new `Sampler` with the given behavior.
    ///
    /// `mag_filter` and `min_filter` define how the implementation should sample from the image
    /// when it is respectively larger and smaller than the original.
    ///
    /// `mipmap_mode` defines how the implementation should choose which mipmap to use.
    ///
    /// `address_u`, `address_v` and `address_w` define how the implementation should behave when
    /// sampling outside of the texture coordinates range `[0.0, 1.0]`.
    ///
    /// `mip_lod_bias` is a value to add to .
    ///
    /// `max_anisotropy` must be greater than or equal to 1.0. If greater than 1.0, the
    /// implementation will use anisotropic filtering. Using a value greater than 1.0 requires
    /// the `sampler_anisotropy` feature to be enabled when creating the device.
    ///
    /// `min_lod` and `max_lod` are respectively the minimum and maximum mipmap level to use.
    /// `max_lod` must always be greater than or equal to `min_lod`.
    ///
    /// # Panic
    ///
    /// - Panics if multiple `ClampToBorder` values are passed and the border color is different.
    /// - Panics if `max_anisotropy < 1.0`.
    /// - Panics if `min_lod > max_lod`.
    ///
    #[inline(always)]
    pub fn new(device: Arc<Device>, mag_filter: Filter, min_filter: Filter,
               mipmap_mode: MipmapMode, address_u: SamplerAddressMode,
               address_v: SamplerAddressMode, address_w: SamplerAddressMode, mip_lod_bias: f32,
               max_anisotropy: f32, min_lod: f32, max_lod: f32)
               -> Result<Arc<Sampler>, SamplerCreationError> {
        Sampler::new_impl(device,
                          mag_filter,
                          min_filter,
                          mipmap_mode,
                          address_u,
                          address_v,
                          address_w,
                          mip_lod_bias,
                          max_anisotropy,
                          min_lod,
                          max_lod,
                          None)
    }

    /// Creates a new `Sampler` with the given behavior.
    ///
    /// Contrary to `new`, this creates a sampler that is used to compare depth values.
    ///
    /// A sampler like this can only operate on depth or depth-stencil textures. Instead of
    /// returning the value of the texture, this sampler will return a value between 0.0 and 1.0
    /// indicating how much the reference value (passed by the shader) compares to the value in the
    /// texture.
    ///
    /// Note that it doesn't make sense to create a compare-mode sampler with an integer border
    /// color, as such a sampler would be unusable.
    ///
    /// # Panic
    ///
    /// Same panic reasons as `new`.
    ///
    #[inline(always)]
    pub fn compare(device: Arc<Device>, mag_filter: Filter, min_filter: Filter,
                   mipmap_mode: MipmapMode, address_u: SamplerAddressMode,
                   address_v: SamplerAddressMode, address_w: SamplerAddressMode,
                   mip_lod_bias: f32, max_anisotropy: f32, min_lod: f32, max_lod: f32,
                   compare: Compare)
                   -> Result<Arc<Sampler>, SamplerCreationError> {
        Sampler::new_impl(device,
                          mag_filter,
                          min_filter,
                          mipmap_mode,
                          address_u,
                          address_v,
                          address_w,
                          mip_lod_bias,
                          max_anisotropy,
                          min_lod,
                          max_lod,
                          Some(compare))
    }

    fn new_impl(device: Arc<Device>, mag_filter: Filter, min_filter: Filter,
                mipmap_mode: MipmapMode, address_u: SamplerAddressMode,
                address_v: SamplerAddressMode, address_w: SamplerAddressMode, mip_lod_bias: f32,
                max_anisotropy: f32, min_lod: f32, max_lod: f32, compare: Option<Compare>)
                -> Result<Arc<Sampler>, SamplerCreationError> {
        assert!(max_anisotropy >= 1.0);
        assert!(min_lod <= max_lod);

        // Check max anisotropy.
        if max_anisotropy > 1.0 {
            if !device.enabled_features().sampler_anisotropy {
                return Err(SamplerCreationError::SamplerAnisotropyFeatureNotEnabled);
            }

            let limit = device.physical_device().limits().max_sampler_anisotropy();
            if max_anisotropy > limit {
                return Err(SamplerCreationError::AnisotropyLimitExceeded {
                               requested: max_anisotropy,
                               maximum: limit,
                           });
            }
        }

        // Check mip_lod_bias value.
        {
            let limit = device.physical_device().limits().max_sampler_lod_bias();
            if mip_lod_bias > limit {
                return Err(SamplerCreationError::MipLodBiasLimitExceeded {
                               requested: mip_lod_bias,
                               maximum: limit,
                           });
            }
        }

        // Check MirrorClampToEdge extension support
        if [address_u, address_v, address_w]
            .iter()
            .any(|&mode| mode == SamplerAddressMode::MirrorClampToEdge)
        {
            if !device.loaded_extensions().khr_sampler_mirror_clamp_to_edge {
                return Err(SamplerCreationError::SamplerMirrorClampToEdgeExtensionNotEnabled);
            }
        }

        // Handling border color.
        let border_color = address_u.border_color();
        let border_color = match (border_color, address_v.border_color()) {
            (Some(b1), Some(b2)) => {
                assert_eq!(b1, b2);
                Some(b1)
            },
            (None, b) => b,
            (b, None) => b,
        };
        let border_color = match (border_color, address_w.border_color()) {
            (Some(b1), Some(b2)) => {
                assert_eq!(b1, b2);
                Some(b1)
            },
            (None, b) => b,
            (b, None) => b,
        };

        let vk = device.pointers();
        let sampler = unsafe {
            let infos = vk::SamplerCreateInfo {
                sType: vk::STRUCTURE_TYPE_SAMPLER_CREATE_INFO,
                pNext: ptr::null(),
                flags: 0, // reserved
                magFilter: mag_filter as u32,
                minFilter: min_filter as u32,
                mipmapMode: mipmap_mode as u32,
                addressModeU: address_u.to_vk(),
                addressModeV: address_v.to_vk(),
                addressModeW: address_w.to_vk(),
                mipLodBias: mip_lod_bias,
                anisotropyEnable: if max_anisotropy > 1.0 {
                    vk::TRUE
                } else {
                    vk::FALSE
                },
                maxAnisotropy: max_anisotropy,
                compareEnable: if compare.is_some() {
                    vk::TRUE
                } else {
                    vk::FALSE
                },
                compareOp: compare.map(|c| c as u32).unwrap_or(0),
                minLod: min_lod,
                maxLod: max_lod,
                borderColor: border_color.map(|b| b as u32).unwrap_or(0),
                unnormalizedCoordinates: vk::FALSE,
            };

            let mut output = mem::uninitialized();
            check_errors(vk.CreateSampler(device.internal_object(),
                                          &infos,
                                          ptr::null(),
                                          &mut output))?;
            output
        };

        Ok(Arc::new(Sampler {
                        sampler: sampler,
                        device: device.clone(),
                        compare_mode: compare.is_some(),
                        unnormalized: false,
                        usable_with_float_formats: match border_color {
                            Some(BorderColor::FloatTransparentBlack) => true,
                            Some(BorderColor::FloatOpaqueBlack) => true,
                            Some(BorderColor::FloatOpaqueWhite) => true,
                            Some(_) => false,
                            None => true,
                        },
                        usable_with_int_formats: compare.is_none() &&
                            match border_color {
                                Some(BorderColor::IntTransparentBlack) => true,
                                Some(BorderColor::IntOpaqueBlack) => true,
                                Some(BorderColor::IntOpaqueWhite) => true,
                                Some(_) => false,
                                None => true,
                            },
                        usable_with_swizzling: match border_color {
                            Some(BorderColor::FloatOpaqueBlack) => false,
                            Some(BorderColor::IntOpaqueBlack) => false,
                            _ => true,
                        },
                    }))
    }

    /// Creates a sampler with unnormalized coordinates. This means that texture coordinates won't
    /// range between `0.0` and `1.0` but use plain pixel offsets.
    ///
    /// Using an unnormalized sampler adds a few restrictions:
    ///
    /// - It can only be used with non-array 1D or 2D images.
    /// - It can only be used with images with a single mipmap.
    /// - Projection and offsets can't be used by shaders. Only the first mipmap can be accessed.
    ///
    /// # Panic
    ///
    /// - Panics if multiple `ClampToBorder` values are passed and the border color is different.
    ///
    pub fn unnormalized(device: Arc<Device>, filter: Filter,
                        address_u: UnnormalizedSamplerAddressMode,
                        address_v: UnnormalizedSamplerAddressMode)
                        -> Result<Arc<Sampler>, SamplerCreationError> {
        let vk = device.pointers();

        let border_color = address_u.border_color();
        let border_color = match (border_color, address_v.border_color()) {
            (Some(b1), Some(b2)) => {
                assert_eq!(b1, b2);
                Some(b1)
            },
            (None, b) => b,
            (b, None) => b,
        };

        let sampler = unsafe {
            let infos = vk::SamplerCreateInfo {
                sType: vk::STRUCTURE_TYPE_SAMPLER_CREATE_INFO,
                pNext: ptr::null(),
                flags: 0, // reserved
                magFilter: filter as u32,
                minFilter: filter as u32,
                mipmapMode: vk::SAMPLER_MIPMAP_MODE_NEAREST,
                addressModeU: address_u.to_vk(),
                addressModeV: address_v.to_vk(),
                addressModeW: vk::SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE, // unused by the impl
                mipLodBias: 0.0,
                anisotropyEnable: vk::FALSE,
                maxAnisotropy: 1.0,
                compareEnable: vk::FALSE,
                compareOp: vk::COMPARE_OP_NEVER,
                minLod: 0.0,
                maxLod: 0.0,
                borderColor: border_color.map(|b| b as u32).unwrap_or(0),
                unnormalizedCoordinates: vk::TRUE,
            };

            let mut output = mem::uninitialized();
            check_errors(vk.CreateSampler(device.internal_object(),
                                          &infos,
                                          ptr::null(),
                                          &mut output))?;
            output
        };

        Ok(Arc::new(Sampler {
                        sampler: sampler,
                        device: device.clone(),
                        compare_mode: false,
                        unnormalized: true,
                        usable_with_float_formats: match border_color {
                            Some(BorderColor::FloatTransparentBlack) => true,
                            Some(BorderColor::FloatOpaqueBlack) => true,
                            Some(BorderColor::FloatOpaqueWhite) => true,
                            Some(_) => false,
                            None => true,
                        },
                        usable_with_int_formats: match border_color {
                            Some(BorderColor::IntTransparentBlack) => true,
                            Some(BorderColor::IntOpaqueBlack) => true,
                            Some(BorderColor::IntOpaqueWhite) => true,
                            Some(_) => false,
                            None => true,
                        },
                        usable_with_swizzling: match border_color {
                            Some(BorderColor::FloatOpaqueBlack) => false,
                            Some(BorderColor::IntOpaqueBlack) => false,
                            _ => true,
                        },
                    }))
    }

    /// Returns true if the sampler is a compare-mode sampler.
    #[inline]
    pub fn compare_mode(&self) -> bool {
        self.compare_mode
    }

    /// Returns true if the sampler is unnormalized.
    #[inline]
    pub fn is_unnormalized(&self) -> bool {
        self.unnormalized
    }

    /// Returns true if the sampler can be used with floating-point image views. See the
    /// documentation of the `sampler` module for more info.
    #[inline]
    pub fn usable_with_float_formats(&self) -> bool {
        self.usable_with_float_formats
    }

    /// Returns true if the sampler can be used with integer image views. See the documentation of
    /// the `sampler` module for more info.
    #[inline]
    pub fn usable_with_int_formats(&self) -> bool {
        self.usable_with_int_formats
    }

    /// Returns true if the sampler can be used with image views that have non-identity swizzling.
    /// See the documentation of the `sampler` module for more info.
    #[inline]
    pub fn usable_with_swizzling(&self) -> bool {
        self.usable_with_swizzling
    }
}

unsafe impl DeviceOwned for Sampler {
    #[inline]
    fn device(&self) -> &Arc<Device> {
        &self.device
    }
}

unsafe impl VulkanObject for Sampler {
    type Object = vk::Sampler;

    const TYPE: vk::DebugReportObjectTypeEXT = vk::DEBUG_REPORT_OBJECT_TYPE_SAMPLER_EXT;

    #[inline]
    fn internal_object(&self) -> vk::Sampler {
        self.sampler
    }
}

impl fmt::Debug for Sampler {
    #[inline]
    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
        write!(fmt, "<Vulkan sampler {:?}>", self.sampler)
    }
}

impl Drop for Sampler {
    #[inline]
    fn drop(&mut self) {
        unsafe {
            let vk = self.device.pointers();
            vk.DestroySampler(self.device.internal_object(), self.sampler, ptr::null());
        }
    }
}

/// Describes how the color of each pixel should be determined.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
#[repr(u32)]
pub enum Filter {
    /// The four pixels whose center surround the requested coordinates are taken, then their
    /// values are interpolated.
    Linear = vk::FILTER_LINEAR,

    /// The pixel whose center is nearest to the requested coordinates is taken from the source
    /// and its value is returned as-is.
    Nearest = vk::FILTER_NEAREST,
}

/// Describes which mipmap from the source to use.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
#[repr(u32)]
pub enum MipmapMode {
    /// Use the mipmap whose dimensions are the nearest to the dimensions of the destination.
    Nearest = vk::SAMPLER_MIPMAP_MODE_NEAREST,

    /// Take the mipmap whose dimensions are no greater than that of the destination together
    /// with the next higher level mipmap, calculate the value for both, and interpolate them.
    Linear = vk::SAMPLER_MIPMAP_MODE_LINEAR,
}

/// How the sampler should behave when it needs to access a pixel that is out of range of the
/// texture.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub enum SamplerAddressMode {
    /// Repeat the texture. In other words, the pixel at coordinate `x + 1.0` is the same as the
    /// one at coordinate `x`.
    Repeat,

    /// Repeat the texture but mirror it at every repetition. In other words, the pixel at
    /// coordinate `x + 1.0` is the same as the one at coordinate `1.0 - x`.
    MirroredRepeat,

    /// The coordinates are clamped to the valid range. Coordinates below 0.0 have the same value
    /// as coordinate 0.0. Coordinates over 1.0 have the same value as coordinate 1.0.
    ClampToEdge,

    /// Any pixel out of range is considered to be part of the "border" of the image, which has a
    /// specific color of your choice.
    ///
    /// Note that if you use `ClampToBorder` multiple times, they must all have the same border
    /// color.
    ClampToBorder(BorderColor),

    /// Similar to `MirroredRepeat`, except that coordinates are clamped to the range
    /// `[-1.0, 1.0]`.
    MirrorClampToEdge,
}

impl SamplerAddressMode {
    #[inline]
    fn to_vk(self) -> vk::SamplerAddressMode {
        match self {
            SamplerAddressMode::Repeat => vk::SAMPLER_ADDRESS_MODE_REPEAT,
            SamplerAddressMode::MirroredRepeat => vk::SAMPLER_ADDRESS_MODE_MIRRORED_REPEAT,
            SamplerAddressMode::ClampToEdge => vk::SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE,
            SamplerAddressMode::ClampToBorder(_) => vk::SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER,
            SamplerAddressMode::MirrorClampToEdge => vk::SAMPLER_ADDRESS_MODE_MIRROR_CLAMP_TO_EDGE,
        }
    }

    #[inline]
    fn border_color(self) -> Option<BorderColor> {
        match self {
            SamplerAddressMode::ClampToBorder(c) => Some(c),
            _ => None,
        }
    }
}

/// How the sampler should behave when it needs to access a pixel that is out of range of the
/// texture.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
#[repr(u32)]
pub enum UnnormalizedSamplerAddressMode {
    /// The coordinates are clamped to the valid range. Coordinates below 0 have the same value
    /// as coordinate 0. Coordinates over *size of texture* have the same value as coordinate
    /// *size of texture*.
    ClampToEdge,

    /// Any pixel out of range is considered to be part of the "border" of the image, which has a
    /// specific color of your choice.
    ///
    /// Note that if you use `ClampToBorder` multiple times, they must all have the same border
    /// color.
    ClampToBorder(BorderColor),
}

impl UnnormalizedSamplerAddressMode {
    #[inline]
    fn to_vk(self) -> vk::SamplerAddressMode {
        match self {
            UnnormalizedSamplerAddressMode::ClampToEdge => vk::SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE,
            UnnormalizedSamplerAddressMode::ClampToBorder(_) => {
                vk::SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER
            },
        }
    }

    #[inline]
    fn border_color(self) -> Option<BorderColor> {
        match self {
            UnnormalizedSamplerAddressMode::ClampToEdge => None,
            UnnormalizedSamplerAddressMode::ClampToBorder(c) => Some(c),
        }
    }
}

/// The color to use for the border of an image.
///
/// Only relevant if you use `ClampToBorder`.
///
/// Using a border color restricts the sampler to either floating-point images or integer images.
/// See the documentation of the `sampler` module for more info.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
#[repr(u32)]
pub enum BorderColor {
    /// The value `(0.0, 0.0, 0.0, 0.0)`. Can only be used with floating-point images.
    FloatTransparentBlack = vk::BORDER_COLOR_FLOAT_TRANSPARENT_BLACK,

    /// The value `(0, 0, 0, 0)`. Can only be used with integer images.
    IntTransparentBlack = vk::BORDER_COLOR_INT_TRANSPARENT_BLACK,

    /// The value `(0.0, 0.0, 0.0, 1.0)`. Can only be used with floating-point identity-swizzled
    /// images.
    FloatOpaqueBlack = vk::BORDER_COLOR_FLOAT_OPAQUE_BLACK,

    /// The value `(0, 0, 0, 1)`. Can only be used with integer identity-swizzled images.
    IntOpaqueBlack = vk::BORDER_COLOR_INT_OPAQUE_BLACK,

    /// The value `(1.0, 1.0, 1.0, 1.0)`. Can only be used with floating-point images.
    FloatOpaqueWhite = vk::BORDER_COLOR_FLOAT_OPAQUE_WHITE,

    /// The value `(1, 1, 1, 1)`. Can only be used with integer images.
    IntOpaqueWhite = vk::BORDER_COLOR_INT_OPAQUE_WHITE,
}

/// Error that can happen when creating an instance.
#[derive(Clone, Debug, PartialEq)]
pub enum SamplerCreationError {
    /// Not enough memory.
    OomError(OomError),

    /// Too many sampler objects have been created. You must destroy some before creating new ones.
    /// Note the specs guarantee that at least 4000 samplers can exist simultaneously.
    TooManyObjects,

    /// Using an anisotropy greater than 1.0 requires enabling the `sampler_anisotropy` feature
    /// when creating the device.
    SamplerAnisotropyFeatureNotEnabled,

    /// The requested anisotropy level exceeds the device's limits.
    AnisotropyLimitExceeded {
        /// The value that was requested.
        requested: f32,
        /// The maximum supported value.
        maximum: f32,
    },

    /// The requested mip lod bias exceeds the device's limits.
    MipLodBiasLimitExceeded {
        /// The value that was requested.
        requested: f32,
        /// The maximum supported value.
        maximum: f32,
    },

    /// Using `MirrorClampToEdge` requires enabling the `VK_KHR_sampler_mirror_clamp_to_edge`
    /// extension when creating the device.
    SamplerMirrorClampToEdgeExtensionNotEnabled,
}

impl error::Error for SamplerCreationError {
    #[inline]
    fn description(&self) -> &str {
        match *self {
            SamplerCreationError::OomError(_) => "not enough memory available",
            SamplerCreationError::TooManyObjects => "too many simultaneous sampler objects",
            SamplerCreationError::SamplerAnisotropyFeatureNotEnabled =>
                "the `sampler_anisotropy` feature is not enabled",
            SamplerCreationError::AnisotropyLimitExceeded { .. } => "anisotropy limit exceeded",
            SamplerCreationError::MipLodBiasLimitExceeded { .. } => "mip lod bias limit exceeded",
            SamplerCreationError::SamplerMirrorClampToEdgeExtensionNotEnabled =>
                "the device extension `VK_KHR_sampler_mirror_clamp_to_edge` is not enabled",
        }
    }

    #[inline]
    fn cause(&self) -> Option<&dyn error::Error> {
        match *self {
            SamplerCreationError::OomError(ref err) => Some(err),
            _ => None,
        }
    }
}

impl fmt::Display for SamplerCreationError {
    #[inline]
    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
        write!(fmt, "{}", error::Error::description(self))
    }
}

impl From<OomError> for SamplerCreationError {
    #[inline]
    fn from(err: OomError) -> SamplerCreationError {
        SamplerCreationError::OomError(err)
    }
}

impl From<Error> for SamplerCreationError {
    #[inline]
    fn from(err: Error) -> SamplerCreationError {
        match err {
            err @ Error::OutOfHostMemory => SamplerCreationError::OomError(OomError::from(err)),
            err @ Error::OutOfDeviceMemory => SamplerCreationError::OomError(OomError::from(err)),
            Error::TooManyObjects => SamplerCreationError::TooManyObjects,
            _ => panic!("unexpected error: {:?}", err),
        }
    }
}

#[cfg(test)]
mod tests {
    use sampler;

    #[test]
    fn create_regular() {
        let (device, queue) = gfx_dev_and_queue!();

        let s = sampler::Sampler::new(device,
                                      sampler::Filter::Linear,
                                      sampler::Filter::Linear,
                                      sampler::MipmapMode::Nearest,
                                      sampler::SamplerAddressMode::Repeat,
                                      sampler::SamplerAddressMode::Repeat,
                                      sampler::SamplerAddressMode::Repeat,
                                      1.0,
                                      1.0,
                                      0.0,
                                      2.0)
            .unwrap();
        assert!(!s.compare_mode());
        assert!(!s.is_unnormalized());
    }

    #[test]
    fn create_compare() {
        let (device, queue) = gfx_dev_and_queue!();

        let s = sampler::Sampler::compare(device,
                                          sampler::Filter::Linear,
                                          sampler::Filter::Linear,
                                          sampler::MipmapMode::Nearest,
                                          sampler::SamplerAddressMode::Repeat,
                                          sampler::SamplerAddressMode::Repeat,
                                          sampler::SamplerAddressMode::Repeat,
                                          1.0,
                                          1.0,
                                          0.0,
                                          2.0,
                                          sampler::Compare::Less)
            .unwrap();

        assert!(s.compare_mode());
        assert!(!s.is_unnormalized());
    }

    #[test]
    fn create_unnormalized() {
        let (device, queue) = gfx_dev_and_queue!();

        let s =
            sampler::Sampler::unnormalized(device,
                                           sampler::Filter::Linear,
                                           sampler::UnnormalizedSamplerAddressMode::ClampToEdge,
                                           sampler::UnnormalizedSamplerAddressMode::ClampToEdge)
                .unwrap();

        assert!(!s.compare_mode());
        assert!(s.is_unnormalized());
    }

    #[test]
    fn simple_repeat_linear() {
        let (device, queue) = gfx_dev_and_queue!();
        let _ = sampler::Sampler::simple_repeat_linear(device);
    }

    #[test]
    fn simple_repeat_linear_no_mipmap() {
        let (device, queue) = gfx_dev_and_queue!();
        let _ = sampler::Sampler::simple_repeat_linear_no_mipmap(device);
    }

    #[test]
    fn min_lod_inferior() {
        let (device, queue) = gfx_dev_and_queue!();

        assert_should_panic!({
                                 let _ = sampler::Sampler::new(device,
                                                               sampler::Filter::Linear,
                                                               sampler::Filter::Linear,
                                                               sampler::MipmapMode::Nearest,
                                                               sampler::SamplerAddressMode::Repeat,
                                                               sampler::SamplerAddressMode::Repeat,
                                                               sampler::SamplerAddressMode::Repeat,
                                                               1.0,
                                                               1.0,
                                                               5.0,
                                                               2.0);
                             });
    }

    #[test]
    fn max_anisotropy() {
        let (device, queue) = gfx_dev_and_queue!();

        assert_should_panic!({
                                 let _ = sampler::Sampler::new(device,
                                                               sampler::Filter::Linear,
                                                               sampler::Filter::Linear,
                                                               sampler::MipmapMode::Nearest,
                                                               sampler::SamplerAddressMode::Repeat,
                                                               sampler::SamplerAddressMode::Repeat,
                                                               sampler::SamplerAddressMode::Repeat,
                                                               1.0,
                                                               0.5,
                                                               0.0,
                                                               2.0);
                             });
    }

    #[test]
    fn different_borders() {
        let (device, queue) = gfx_dev_and_queue!();

        let b1 = sampler::BorderColor::IntTransparentBlack;
        let b2 = sampler::BorderColor::FloatOpaqueWhite;

        assert_should_panic!({
            let _ = sampler::Sampler::new(device,
                                          sampler::Filter::Linear,
                                          sampler::Filter::Linear,
                                          sampler::MipmapMode::Nearest,
                                          sampler::SamplerAddressMode::ClampToBorder(b1),
                                          sampler::SamplerAddressMode::ClampToBorder(b2),
                                          sampler::SamplerAddressMode::Repeat,
                                          1.0,
                                          1.0,
                                          5.0,
                                          2.0);
        });
    }

    #[test]
    fn anisotropy_feature() {
        let (device, queue) = gfx_dev_and_queue!();

        let r = sampler::Sampler::new(device,
                                      sampler::Filter::Linear,
                                      sampler::Filter::Linear,
                                      sampler::MipmapMode::Nearest,
                                      sampler::SamplerAddressMode::Repeat,
                                      sampler::SamplerAddressMode::Repeat,
                                      sampler::SamplerAddressMode::Repeat,
                                      1.0,
                                      2.0,
                                      0.0,
                                      2.0);

        match r {
            Err(sampler::SamplerCreationError::SamplerAnisotropyFeatureNotEnabled) => (),
            _ => panic!(),
        }
    }

    #[test]
    fn anisotropy_limit() {
        let (device, queue) = gfx_dev_and_queue!(sampler_anisotropy);

        let r = sampler::Sampler::new(device,
                                      sampler::Filter::Linear,
                                      sampler::Filter::Linear,
                                      sampler::MipmapMode::Nearest,
                                      sampler::SamplerAddressMode::Repeat,
                                      sampler::SamplerAddressMode::Repeat,
                                      sampler::SamplerAddressMode::Repeat,
                                      1.0,
                                      100000000.0,
                                      0.0,
                                      2.0);

        match r {
            Err(sampler::SamplerCreationError::AnisotropyLimitExceeded { .. }) => (),
            _ => panic!(),
        }
    }

    #[test]
    fn mip_lod_bias_limit() {
        let (device, queue) = gfx_dev_and_queue!();

        let r = sampler::Sampler::new(device,
                                      sampler::Filter::Linear,
                                      sampler::Filter::Linear,
                                      sampler::MipmapMode::Nearest,
                                      sampler::SamplerAddressMode::Repeat,
                                      sampler::SamplerAddressMode::Repeat,
                                      sampler::SamplerAddressMode::Repeat,
                                      100000000.0,
                                      1.0,
                                      0.0,
                                      2.0);

        match r {
            Err(sampler::SamplerCreationError::MipLodBiasLimitExceeded { .. }) => (),
            _ => panic!(),
        }
    }

    #[test]
    fn sampler_mirror_clamp_to_edge_extension() {
        let (device, queue) = gfx_dev_and_queue!();

        let r = sampler::Sampler::new(device,
                                      sampler::Filter::Linear,
                                      sampler::Filter::Linear,
                                      sampler::MipmapMode::Nearest,
                                      sampler::SamplerAddressMode::MirrorClampToEdge,
                                      sampler::SamplerAddressMode::MirrorClampToEdge,
                                      sampler::SamplerAddressMode::MirrorClampToEdge,
                                      1.0,
                                      1.0,
                                      0.0,
                                      2.0);

        match r {
            Err(sampler::SamplerCreationError::SamplerMirrorClampToEdgeExtensionNotEnabled) => (),
            _ => panic!(),
        }
    }
}