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
impl super::AdapterShared {
    pub(super) fn describe_texture_format(
        &self,
        texture_format: wgt::TextureFormat,
    ) -> super::TextureFormatDesc {
        use wgt::TextureFormat as Tf;
        use wgt::{AstcBlock, AstcChannel};

        let (internal, external, data_type) = match texture_format {
            Tf::R8Unorm => (glow::R8, glow::RED, glow::UNSIGNED_BYTE),
            Tf::R8Snorm => (glow::R8_SNORM, glow::RED, glow::BYTE),
            Tf::R8Uint => (glow::R8UI, glow::RED_INTEGER, glow::UNSIGNED_BYTE),
            Tf::R8Sint => (glow::R8I, glow::RED_INTEGER, glow::BYTE),
            Tf::R16Uint => (glow::R16UI, glow::RED_INTEGER, glow::UNSIGNED_SHORT),
            Tf::R16Sint => (glow::R16I, glow::RED_INTEGER, glow::SHORT),
            Tf::R16Unorm => (glow::R16, glow::RED, glow::UNSIGNED_SHORT),
            Tf::R16Snorm => (glow::R16_SNORM, glow::RED, glow::SHORT),
            Tf::R16Float => (glow::R16F, glow::RED, glow::HALF_FLOAT),
            Tf::Rg8Unorm => (glow::RG8, glow::RG, glow::UNSIGNED_BYTE),
            Tf::Rg8Snorm => (glow::RG8_SNORM, glow::RG, glow::BYTE),
            Tf::Rg8Uint => (glow::RG8UI, glow::RG_INTEGER, glow::UNSIGNED_BYTE),
            Tf::Rg8Sint => (glow::RG8I, glow::RG_INTEGER, glow::BYTE),
            Tf::R32Uint => (glow::R32UI, glow::RED_INTEGER, glow::UNSIGNED_INT),
            Tf::R32Sint => (glow::R32I, glow::RED_INTEGER, glow::INT),
            Tf::R32Float => (glow::R32F, glow::RED, glow::FLOAT),
            Tf::Rg16Uint => (glow::RG16UI, glow::RG_INTEGER, glow::UNSIGNED_SHORT),
            Tf::Rg16Sint => (glow::RG16I, glow::RG_INTEGER, glow::SHORT),
            Tf::Rg16Unorm => (glow::RG16, glow::RG, glow::UNSIGNED_SHORT),
            Tf::Rg16Snorm => (glow::RG16_SNORM, glow::RG, glow::SHORT),
            Tf::Rg16Float => (glow::RG16F, glow::RG, glow::HALF_FLOAT),
            Tf::Rgba8Unorm => (glow::RGBA8, glow::RGBA, glow::UNSIGNED_BYTE),
            Tf::Rgba8UnormSrgb => (glow::SRGB8_ALPHA8, glow::RGBA, glow::UNSIGNED_BYTE),
            Tf::Bgra8UnormSrgb => (glow::SRGB8_ALPHA8, glow::BGRA, glow::UNSIGNED_BYTE), //TODO?
            Tf::Rgba8Snorm => (glow::RGBA8_SNORM, glow::RGBA, glow::BYTE),
            Tf::Bgra8Unorm => (glow::RGBA8, glow::BGRA, glow::UNSIGNED_BYTE), //TODO?
            Tf::Rgba8Uint => (glow::RGBA8UI, glow::RGBA_INTEGER, glow::UNSIGNED_BYTE),
            Tf::Rgba8Sint => (glow::RGBA8I, glow::RGBA_INTEGER, glow::BYTE),
            Tf::Rgb10a2Uint => (
                glow::RGB10_A2UI,
                glow::RGBA_INTEGER,
                glow::UNSIGNED_INT_2_10_10_10_REV,
            ),
            Tf::Rgb10a2Unorm => (
                glow::RGB10_A2,
                glow::RGBA,
                glow::UNSIGNED_INT_2_10_10_10_REV,
            ),
            Tf::Rg11b10Ufloat => (
                glow::R11F_G11F_B10F,
                glow::RGB,
                glow::UNSIGNED_INT_10F_11F_11F_REV,
            ),
            Tf::Rg32Uint => (glow::RG32UI, glow::RG_INTEGER, glow::UNSIGNED_INT),
            Tf::Rg32Sint => (glow::RG32I, glow::RG_INTEGER, glow::INT),
            Tf::Rg32Float => (glow::RG32F, glow::RG, glow::FLOAT),
            Tf::Rgba16Uint => (glow::RGBA16UI, glow::RGBA_INTEGER, glow::UNSIGNED_SHORT),
            Tf::Rgba16Sint => (glow::RGBA16I, glow::RGBA_INTEGER, glow::SHORT),
            Tf::Rgba16Unorm => (glow::RGBA16, glow::RGBA, glow::UNSIGNED_SHORT),
            Tf::Rgba16Snorm => (glow::RGBA16_SNORM, glow::RGBA, glow::SHORT),
            Tf::Rgba16Float => (glow::RGBA16F, glow::RGBA, glow::HALF_FLOAT),
            Tf::Rgba32Uint => (glow::RGBA32UI, glow::RGBA_INTEGER, glow::UNSIGNED_INT),
            Tf::Rgba32Sint => (glow::RGBA32I, glow::RGBA_INTEGER, glow::INT),
            Tf::Rgba32Float => (glow::RGBA32F, glow::RGBA, glow::FLOAT),
            Tf::Stencil8 => (
                glow::STENCIL_INDEX8,
                glow::STENCIL_INDEX,
                glow::UNSIGNED_BYTE,
            ),
            Tf::Depth16Unorm => (
                glow::DEPTH_COMPONENT16,
                glow::DEPTH_COMPONENT,
                glow::UNSIGNED_SHORT,
            ),
            Tf::Depth32Float => (glow::DEPTH_COMPONENT32F, glow::DEPTH_COMPONENT, glow::FLOAT),
            Tf::Depth32FloatStencil8 => (
                glow::DEPTH32F_STENCIL8,
                glow::DEPTH_STENCIL,
                glow::FLOAT_32_UNSIGNED_INT_24_8_REV,
            ),
            Tf::Depth24Plus => (
                glow::DEPTH_COMPONENT24,
                glow::DEPTH_COMPONENT,
                glow::UNSIGNED_INT,
            ),
            Tf::Depth24PlusStencil8 => (
                glow::DEPTH24_STENCIL8,
                glow::DEPTH_STENCIL,
                glow::UNSIGNED_INT_24_8,
            ),
            Tf::NV12 => unreachable!(),
            Tf::Rgb9e5Ufloat => (glow::RGB9_E5, glow::RGB, glow::UNSIGNED_INT_5_9_9_9_REV),
            Tf::Bc1RgbaUnorm => (glow::COMPRESSED_RGBA_S3TC_DXT1_EXT, glow::RGBA, 0),
            Tf::Bc1RgbaUnormSrgb => (glow::COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT, glow::RGBA, 0),
            Tf::Bc2RgbaUnorm => (glow::COMPRESSED_RGBA_S3TC_DXT3_EXT, glow::RGBA, 0),
            Tf::Bc2RgbaUnormSrgb => (glow::COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT, glow::RGBA, 0),
            Tf::Bc3RgbaUnorm => (glow::COMPRESSED_RGBA_S3TC_DXT5_EXT, glow::RGBA, 0),
            Tf::Bc3RgbaUnormSrgb => (glow::COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT, glow::RGBA, 0),
            Tf::Bc4RUnorm => (glow::COMPRESSED_RED_RGTC1, glow::RED, 0),
            Tf::Bc4RSnorm => (glow::COMPRESSED_SIGNED_RED_RGTC1, glow::RED, 0),
            Tf::Bc5RgUnorm => (glow::COMPRESSED_RG_RGTC2, glow::RG, 0),
            Tf::Bc5RgSnorm => (glow::COMPRESSED_SIGNED_RG_RGTC2, glow::RG, 0),
            Tf::Bc6hRgbUfloat => (glow::COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT, glow::RGB, 0),
            Tf::Bc6hRgbFloat => (glow::COMPRESSED_RGB_BPTC_SIGNED_FLOAT, glow::RGB, 0),
            Tf::Bc7RgbaUnorm => (glow::COMPRESSED_RGBA_BPTC_UNORM, glow::RGBA, 0),
            Tf::Bc7RgbaUnormSrgb => (glow::COMPRESSED_SRGB_ALPHA_BPTC_UNORM, glow::RGBA, 0),
            Tf::Etc2Rgb8Unorm => (glow::COMPRESSED_RGB8_ETC2, glow::RGB, 0),
            Tf::Etc2Rgb8UnormSrgb => (glow::COMPRESSED_SRGB8_ETC2, glow::RGB, 0),
            Tf::Etc2Rgb8A1Unorm => (
                glow::COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2,
                glow::RGBA,
                0,
            ),
            Tf::Etc2Rgb8A1UnormSrgb => (
                glow::COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2,
                glow::RGBA,
                0,
            ),
            Tf::Etc2Rgba8Unorm => (glow::COMPRESSED_RGBA8_ETC2_EAC, glow::RGBA, 0),
            Tf::Etc2Rgba8UnormSrgb => (glow::COMPRESSED_SRGB8_ALPHA8_ETC2_EAC, glow::RGBA, 0),
            Tf::EacR11Unorm => (glow::COMPRESSED_R11_EAC, glow::RED, 0),
            Tf::EacR11Snorm => (glow::COMPRESSED_SIGNED_R11_EAC, glow::RED, 0),
            Tf::EacRg11Unorm => (glow::COMPRESSED_RG11_EAC, glow::RG, 0),
            Tf::EacRg11Snorm => (glow::COMPRESSED_SIGNED_RG11_EAC, glow::RG, 0),
            Tf::Astc { block, channel } => match channel {
                AstcChannel::Unorm | AstcChannel::Hdr => match block {
                    AstcBlock::B4x4 => (glow::COMPRESSED_RGBA_ASTC_4x4_KHR, glow::RGBA, 0),
                    AstcBlock::B5x4 => (glow::COMPRESSED_RGBA_ASTC_5x4_KHR, glow::RGBA, 0),
                    AstcBlock::B5x5 => (glow::COMPRESSED_RGBA_ASTC_5x5_KHR, glow::RGBA, 0),
                    AstcBlock::B6x5 => (glow::COMPRESSED_RGBA_ASTC_6x5_KHR, glow::RGBA, 0),
                    AstcBlock::B6x6 => (glow::COMPRESSED_RGBA_ASTC_6x6_KHR, glow::RGBA, 0),
                    AstcBlock::B8x5 => (glow::COMPRESSED_RGBA_ASTC_8x5_KHR, glow::RGBA, 0),
                    AstcBlock::B8x6 => (glow::COMPRESSED_RGBA_ASTC_8x6_KHR, glow::RGBA, 0),
                    AstcBlock::B8x8 => (glow::COMPRESSED_RGBA_ASTC_8x8_KHR, glow::RGBA, 0),
                    AstcBlock::B10x5 => (glow::COMPRESSED_RGBA_ASTC_10x5_KHR, glow::RGBA, 0),
                    AstcBlock::B10x6 => (glow::COMPRESSED_RGBA_ASTC_10x6_KHR, glow::RGBA, 0),
                    AstcBlock::B10x8 => (glow::COMPRESSED_RGBA_ASTC_10x8_KHR, glow::RGBA, 0),
                    AstcBlock::B10x10 => (glow::COMPRESSED_RGBA_ASTC_10x10_KHR, glow::RGBA, 0),
                    AstcBlock::B12x10 => (glow::COMPRESSED_RGBA_ASTC_12x10_KHR, glow::RGBA, 0),
                    AstcBlock::B12x12 => (glow::COMPRESSED_RGBA_ASTC_12x12_KHR, glow::RGBA, 0),
                },
                AstcChannel::UnormSrgb => match block {
                    AstcBlock::B4x4 => (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR, glow::RGBA, 0),
                    AstcBlock::B5x4 => (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_5x4_KHR, glow::RGBA, 0),
                    AstcBlock::B5x5 => (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_5x5_KHR, glow::RGBA, 0),
                    AstcBlock::B6x5 => (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_6x5_KHR, glow::RGBA, 0),
                    AstcBlock::B6x6 => (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_6x6_KHR, glow::RGBA, 0),
                    AstcBlock::B8x5 => (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_8x5_KHR, glow::RGBA, 0),
                    AstcBlock::B8x6 => (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_8x6_KHR, glow::RGBA, 0),
                    AstcBlock::B8x8 => (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_8x8_KHR, glow::RGBA, 0),
                    AstcBlock::B10x5 => {
                        (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_10x5_KHR, glow::RGBA, 0)
                    }
                    AstcBlock::B10x6 => {
                        (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR, glow::RGBA, 0)
                    }
                    AstcBlock::B10x8 => {
                        (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_10x8_KHR, glow::RGBA, 0)
                    }
                    AstcBlock::B10x10 => {
                        (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR, glow::RGBA, 0)
                    }
                    AstcBlock::B12x10 => {
                        (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_12x10_KHR, glow::RGBA, 0)
                    }
                    AstcBlock::B12x12 => {
                        (glow::COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR, glow::RGBA, 0)
                    }
                },
            },
        };

        super::TextureFormatDesc {
            internal,
            external,
            data_type,
        }
    }
}

pub(super) fn describe_vertex_format(vertex_format: wgt::VertexFormat) -> super::VertexFormatDesc {
    use super::VertexAttribKind as Vak;
    use wgt::VertexFormat as Vf;

    let (element_count, element_format, attrib_kind) = match vertex_format {
        Vf::Unorm8 => (1, glow::UNSIGNED_BYTE, Vak::Float),
        Vf::Snorm8 => (1, glow::BYTE, Vak::Float),
        Vf::Uint8 => (1, glow::UNSIGNED_BYTE, Vak::Integer),
        Vf::Sint8 => (1, glow::BYTE, Vak::Integer),
        Vf::Unorm8x2 => (2, glow::UNSIGNED_BYTE, Vak::Float),
        Vf::Snorm8x2 => (2, glow::BYTE, Vak::Float),
        Vf::Uint8x2 => (2, glow::UNSIGNED_BYTE, Vak::Integer),
        Vf::Sint8x2 => (2, glow::BYTE, Vak::Integer),
        Vf::Unorm8x4 => (4, glow::UNSIGNED_BYTE, Vak::Float),
        Vf::Snorm8x4 => (4, glow::BYTE, Vak::Float),
        Vf::Uint8x4 => (4, glow::UNSIGNED_BYTE, Vak::Integer),
        Vf::Sint8x4 => (4, glow::BYTE, Vak::Integer),
        Vf::Unorm16 => (1, glow::UNSIGNED_SHORT, Vak::Float),
        Vf::Snorm16 => (1, glow::SHORT, Vak::Float),
        Vf::Uint16 => (1, glow::UNSIGNED_SHORT, Vak::Integer),
        Vf::Sint16 => (1, glow::SHORT, Vak::Integer),
        Vf::Float16 => (1, glow::HALF_FLOAT, Vak::Float),
        Vf::Unorm16x2 => (2, glow::UNSIGNED_SHORT, Vak::Float),
        Vf::Snorm16x2 => (2, glow::SHORT, Vak::Float),
        Vf::Uint16x2 => (2, glow::UNSIGNED_SHORT, Vak::Integer),
        Vf::Sint16x2 => (2, glow::SHORT, Vak::Integer),
        Vf::Float16x2 => (2, glow::HALF_FLOAT, Vak::Float),
        Vf::Unorm16x4 => (4, glow::UNSIGNED_SHORT, Vak::Float),
        Vf::Snorm16x4 => (4, glow::SHORT, Vak::Float),
        Vf::Uint16x4 => (4, glow::UNSIGNED_SHORT, Vak::Integer),
        Vf::Sint16x4 => (4, glow::SHORT, Vak::Integer),
        Vf::Float16x4 => (4, glow::HALF_FLOAT, Vak::Float),
        Vf::Uint32 => (1, glow::UNSIGNED_INT, Vak::Integer),
        Vf::Sint32 => (1, glow::INT, Vak::Integer),
        Vf::Float32 => (1, glow::FLOAT, Vak::Float),
        Vf::Uint32x2 => (2, glow::UNSIGNED_INT, Vak::Integer),
        Vf::Sint32x2 => (2, glow::INT, Vak::Integer),
        Vf::Float32x2 => (2, glow::FLOAT, Vak::Float),
        Vf::Uint32x3 => (3, glow::UNSIGNED_INT, Vak::Integer),
        Vf::Sint32x3 => (3, glow::INT, Vak::Integer),
        Vf::Float32x3 => (3, glow::FLOAT, Vak::Float),
        Vf::Uint32x4 => (4, glow::UNSIGNED_INT, Vak::Integer),
        Vf::Sint32x4 => (4, glow::INT, Vak::Integer),
        Vf::Float32x4 => (4, glow::FLOAT, Vak::Float),
        Vf::Unorm10_10_10_2 => (4, glow::UNSIGNED_INT_10_10_10_2, Vak::Float),
        Vf::Unorm8x4Bgra => (glow::BGRA as i32, glow::UNSIGNED_BYTE, Vak::Float),
        Vf::Float64 | Vf::Float64x2 | Vf::Float64x3 | Vf::Float64x4 => unimplemented!(),
    };

    super::VertexFormatDesc {
        element_count,
        element_format,
        attrib_kind,
    }
}

pub fn map_filter_modes(
    min: wgt::FilterMode,
    mag: wgt::FilterMode,
    mip: wgt::FilterMode,
) -> (u32, u32) {
    use wgt::FilterMode as Fm;

    let mag_filter = match mag {
        Fm::Nearest => glow::NEAREST,
        Fm::Linear => glow::LINEAR,
    };

    let min_filter = match (min, mip) {
        (Fm::Nearest, Fm::Nearest) => glow::NEAREST_MIPMAP_NEAREST,
        (Fm::Nearest, Fm::Linear) => glow::NEAREST_MIPMAP_LINEAR,
        (Fm::Linear, Fm::Nearest) => glow::LINEAR_MIPMAP_NEAREST,
        (Fm::Linear, Fm::Linear) => glow::LINEAR_MIPMAP_LINEAR,
    };

    (min_filter, mag_filter)
}

pub fn map_address_mode(mode: wgt::AddressMode) -> u32 {
    match mode {
        wgt::AddressMode::Repeat => glow::REPEAT,
        wgt::AddressMode::MirrorRepeat => glow::MIRRORED_REPEAT,
        wgt::AddressMode::ClampToEdge => glow::CLAMP_TO_EDGE,
        wgt::AddressMode::ClampToBorder => glow::CLAMP_TO_BORDER,
        //wgt::AddressMode::MirrorClamp => glow::MIRROR_CLAMP_TO_EDGE,
    }
}

pub fn map_compare_func(fun: wgt::CompareFunction) -> u32 {
    use wgt::CompareFunction as Cf;
    match fun {
        Cf::Never => glow::NEVER,
        Cf::Less => glow::LESS,
        Cf::LessEqual => glow::LEQUAL,
        Cf::Equal => glow::EQUAL,
        Cf::GreaterEqual => glow::GEQUAL,
        Cf::Greater => glow::GREATER,
        Cf::NotEqual => glow::NOTEQUAL,
        Cf::Always => glow::ALWAYS,
    }
}

pub fn map_primitive_topology(topology: wgt::PrimitiveTopology) -> u32 {
    use wgt::PrimitiveTopology as Pt;
    match topology {
        Pt::PointList => glow::POINTS,
        Pt::LineList => glow::LINES,
        Pt::LineStrip => glow::LINE_STRIP,
        Pt::TriangleList => glow::TRIANGLES,
        Pt::TriangleStrip => glow::TRIANGLE_STRIP,
    }
}

pub(super) fn map_primitive_state(state: &wgt::PrimitiveState) -> super::PrimitiveState {
    super::PrimitiveState {
        //Note: we are flipping the front face, so that
        // the Y-flip in the generated GLSL keeps the same visibility.
        // See `naga::back::glsl::WriterFlags::ADJUST_COORDINATE_SPACE`.
        front_face: match state.front_face {
            wgt::FrontFace::Cw => glow::CCW,
            wgt::FrontFace::Ccw => glow::CW,
        },
        cull_face: match state.cull_mode {
            Some(wgt::Face::Front) => glow::FRONT,
            Some(wgt::Face::Back) => glow::BACK,
            None => 0,
        },
        unclipped_depth: state.unclipped_depth,
        polygon_mode: match state.polygon_mode {
            wgt::PolygonMode::Fill => glow::FILL,
            wgt::PolygonMode::Line => glow::LINE,
            wgt::PolygonMode::Point => glow::POINT,
        },
    }
}

pub fn _map_view_dimension(dim: wgt::TextureViewDimension) -> u32 {
    use wgt::TextureViewDimension as Tvd;
    match dim {
        Tvd::D1 | Tvd::D2 => glow::TEXTURE_2D,
        Tvd::D2Array => glow::TEXTURE_2D_ARRAY,
        Tvd::Cube => glow::TEXTURE_CUBE_MAP,
        Tvd::CubeArray => glow::TEXTURE_CUBE_MAP_ARRAY,
        Tvd::D3 => glow::TEXTURE_3D,
    }
}

fn map_stencil_op(operation: wgt::StencilOperation) -> u32 {
    use wgt::StencilOperation as So;
    match operation {
        So::Keep => glow::KEEP,
        So::Zero => glow::ZERO,
        So::Replace => glow::REPLACE,
        So::Invert => glow::INVERT,
        So::IncrementClamp => glow::INCR,
        So::DecrementClamp => glow::DECR,
        So::IncrementWrap => glow::INCR_WRAP,
        So::DecrementWrap => glow::DECR_WRAP,
    }
}

fn map_stencil_ops(face: &wgt::StencilFaceState) -> super::StencilOps {
    super::StencilOps {
        pass: map_stencil_op(face.pass_op),
        fail: map_stencil_op(face.fail_op),
        depth_fail: map_stencil_op(face.depth_fail_op),
    }
}

pub(super) fn map_stencil(state: &wgt::StencilState) -> super::StencilState {
    super::StencilState {
        front: super::StencilSide {
            function: map_compare_func(state.front.compare),
            mask_read: state.read_mask,
            mask_write: state.write_mask,
            reference: 0,
            ops: map_stencil_ops(&state.front),
        },
        back: super::StencilSide {
            function: map_compare_func(state.back.compare),
            mask_read: state.read_mask,
            mask_write: state.write_mask,
            reference: 0,
            ops: map_stencil_ops(&state.back),
        },
    }
}

fn map_blend_factor(factor: wgt::BlendFactor) -> u32 {
    use wgt::BlendFactor as Bf;
    match factor {
        Bf::Zero => glow::ZERO,
        Bf::One => glow::ONE,
        Bf::Src => glow::SRC_COLOR,
        Bf::OneMinusSrc => glow::ONE_MINUS_SRC_COLOR,
        Bf::Dst => glow::DST_COLOR,
        Bf::OneMinusDst => glow::ONE_MINUS_DST_COLOR,
        Bf::SrcAlpha => glow::SRC_ALPHA,
        Bf::OneMinusSrcAlpha => glow::ONE_MINUS_SRC_ALPHA,
        Bf::DstAlpha => glow::DST_ALPHA,
        Bf::OneMinusDstAlpha => glow::ONE_MINUS_DST_ALPHA,
        Bf::Constant => glow::CONSTANT_COLOR,
        Bf::OneMinusConstant => glow::ONE_MINUS_CONSTANT_COLOR,
        Bf::SrcAlphaSaturated => glow::SRC_ALPHA_SATURATE,
        Bf::Src1 => glow::SRC1_COLOR,
        Bf::OneMinusSrc1 => glow::ONE_MINUS_SRC1_COLOR,
        Bf::Src1Alpha => glow::SRC1_ALPHA,
        Bf::OneMinusSrc1Alpha => glow::ONE_MINUS_SRC1_ALPHA,
    }
}

fn map_blend_component(component: &wgt::BlendComponent) -> super::BlendComponent {
    super::BlendComponent {
        src: map_blend_factor(component.src_factor),
        dst: map_blend_factor(component.dst_factor),
        equation: match component.operation {
            wgt::BlendOperation::Add => glow::FUNC_ADD,
            wgt::BlendOperation::Subtract => glow::FUNC_SUBTRACT,
            wgt::BlendOperation::ReverseSubtract => glow::FUNC_REVERSE_SUBTRACT,
            wgt::BlendOperation::Min => glow::MIN,
            wgt::BlendOperation::Max => glow::MAX,
        },
    }
}

pub(super) fn map_blend(blend: &wgt::BlendState) -> super::BlendDesc {
    super::BlendDesc {
        color: map_blend_component(&blend.color),
        alpha: map_blend_component(&blend.alpha),
    }
}

pub(super) fn map_storage_access(access: wgt::StorageTextureAccess) -> u32 {
    match access {
        wgt::StorageTextureAccess::ReadOnly => glow::READ_ONLY,
        wgt::StorageTextureAccess::WriteOnly => glow::WRITE_ONLY,
        wgt::StorageTextureAccess::ReadWrite => glow::READ_WRITE,
    }
}

pub(super) fn is_layered_target(target: u32) -> bool {
    match target {
        glow::TEXTURE_2D | glow::TEXTURE_CUBE_MAP => false,
        glow::TEXTURE_2D_ARRAY | glow::TEXTURE_CUBE_MAP_ARRAY | glow::TEXTURE_3D => true,
        _ => unreachable!(),
    }
}