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1 // SPDX-License-Identifier: Apache-2.0
2 // ----------------------------------------------------------------------------
3 // Copyright 2020-2024 Arm Limited
4 //
5 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
6 // use this file except in compliance with the License. You may obtain a copy
7 // of the License at:
8 //
9 //     http://www.apache.org/licenses/LICENSE-2.0
10 //
11 // Unless required by applicable law or agreed to in writing, software
12 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
13 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
14 // License for the specific language governing permissions and limitations
15 // under the License.
16 // ----------------------------------------------------------------------------
17 
18 /**
19  * @brief The core astcenc codec library interface.
20  *
21  * This interface is the entry point to the core astcenc codec. It aims to be easy to use for
22  * non-experts, but also to allow experts to have fine control over the compressor heuristics if
23  * needed. The core codec only handles compression and decompression, transferring all inputs and
24  * outputs via memory buffers. To catch obvious input/output buffer sizing issues, which can cause
25  * security and stability problems, all transfer buffers are explicitly sized.
26  *
27  * While the aim is that we keep this interface mostly stable, it should be viewed as a mutable
28  * interface tied to a specific source version. We are not trying to maintain backwards
29  * compatibility across codec versions.
30  *
31  * The API state management is based around an explicit context object, which is the context for all
32  * allocated memory resources needed to compress and decompress a single image. A context can be
33  * used to sequentially compress multiple images using the same configuration, allowing setup
34  * overheads to be amortized over multiple images, which is particularly important when images are
35  * small.
36  *
37  * Multi-threading can be used two ways.
38  *
39  *     * An application wishing to process multiple images in parallel can allocate multiple
40  *       contexts and assign each context to a thread.
41  *     * An application wishing to process a single image in using multiple threads can configure
42  *       contexts for multi-threaded use, and invoke astcenc_compress/decompress() once per thread
43  *       for faster processing. The caller is responsible for creating the worker threads, and
44  *       synchronizing between images.
45  *
46  * Extended instruction set support
47  * ================================
48  *
49  * This library supports use of extended instruction sets, such as SSE4.1 and AVX2. These are
50  * enabled at compile time when building the library. There is no runtime checking in the core
51  * library that the instruction sets used are actually available. Checking compatibility is the
52  * responsibility of the calling code.
53  *
54  * Threading
55  * =========
56  *
57  * In pseudo-code, the usage for manual user threading looks like this:
58  *
59  *     // Configure the compressor run
60  *     astcenc_config my_config;
61  *     astcenc_config_init(..., &my_config);
62  *
63  *     // Power users can tweak <my_config> settings here ...
64  *
65  *     // Allocate working state given config and thread_count
66  *     astcenc_context* my_context;
67  *     astcenc_context_alloc(&my_config, thread_count, &my_context);
68  *
69  *     // Compress each image using these config settings
70  *     foreach image:
71  *         // For each thread in the thread pool
72  *         for i in range(0, thread_count):
73  *             astcenc_compress_image(my_context, &my_input, my_output, i);
74  *
75  *         astcenc_compress_reset(my_context);
76  *
77  *     // Clean up
78  *     astcenc_context_free(my_context);
79  *
80  * Images
81  * ======
82  *
83  * The codec supports compressing single images, which can be either 2D images or volumetric 3D
84  * images. Calling code is responsible for any handling of aggregate types, such as mipmap chains,
85  * texture arrays, or sliced 3D textures.
86  *
87  * Images are passed in as an astcenc_image structure. Inputs can be either 8-bit unorm, 16-bit
88  * half-float, or 32-bit float, as indicated by the data_type field.
89  *
90  * Images can be any dimension; there is no requirement to be a multiple of the ASTC block size.
91  *
92  * Data is always passed in as 4 color components, and accessed as an array of 2D image slices. Data
93  * within an image slice is always tightly packed without padding. Addressing looks like this:
94  *
95  *     data[z_coord][y_coord * x_dim * 4 + x_coord * 4    ]   // Red
96  *     data[z_coord][y_coord * x_dim * 4 + x_coord * 4 + 1]   // Green
97  *     data[z_coord][y_coord * x_dim * 4 + x_coord * 4 + 2]   // Blue
98  *     data[z_coord][y_coord * x_dim * 4 + x_coord * 4 + 3]   // Alpha
99  *
100  * Common compressor usage
101  * =======================
102  *
103  * One of the most important things for coding image quality is to align the input data component
104  * count with the ASTC color endpoint mode. This avoids wasting bits encoding components you don't
105  * actually need in the endpoint colors.
106  *
107  *         | Input data   | Encoding swizzle | Sampling swizzle |
108  *         | ------------ | ---------------- | ---------------- |
109  *         | 1 component  | RRR1             | .[rgb]           |
110  *         | 2 components | RRRG             | .[rgb]a          |
111  *         | 3 components | RGB1             | .rgb             |
112  *         | 4 components | RGBA             | .rgba            |
113  *
114  * The 1 and 2 component modes recommend sampling from "g" to recover the luminance value as this
115  * provide best compatibility with other texture formats where the green component may be stored at
116  * higher precision than the others, such as RGB565. For ASTC any of the RGB components can be used;
117  * the luminance endpoint component will be returned for all three.
118  *
119  * When using the normal map compression mode ASTC will store normals as a two component X+Y map.
120  * Input images must contain unit-length normalized and should be passed in using a two component
121  * swizzle. The astcenc command line tool defaults to an RRRG swizzle, but some developers prefer
122  * to use GGGR for compatability with BC5n which will work just as well. The Z component can be
123  * recovered programmatically in shader code, using knowledge that the vector is unit length and
124  * that Z must be positive for a tangent-space normal map.
125  *
126  * Decompress-only usage
127  * =====================
128  *
129  * For some use cases it is useful to have a cut-down context and/or library which supports
130  * decompression but not compression.
131  *
132  * A context can be made decompress-only using the ASTCENC_FLG_DECOMPRESS_ONLY flag when the context
133  * is allocated. These contexts have lower dynamic memory footprint than a full context.
134  *
135  * The entire library can be made decompress-only by building the files with the define
136  * ASTCENC_DECOMPRESS_ONLY set. In this build the context will be smaller, and the library will
137  * exclude the functionality which is only needed for compression. This reduces the binary size by
138  * ~180KB. For these builds contexts must be created with the ASTCENC_FLG_DECOMPRESS_ONLY flag.
139  *
140  * Note that context structures returned by a library built as decompress-only are incompatible with
141  * a library built with compression included, and visa versa, as they have different sizes and
142  * memory layout.
143  *
144  * Self-decompress-only usage
145  * ==========================
146  *
147  * ASTC is a complex format with a large search space. The parts of this search space that are
148  * searched is determined by heuristics that are, in part, tied to the quality level used when
149  * creating the context.
150  *
151  * A normal context is capable of decompressing any ASTC texture, including those generated by other
152  * compressors with unknown heuristics. This is the most flexible implementation, but forces the
153  * data tables used by the codec to include entries that are not needed during compression. This
154  * can slow down context creation by a significant amount, especially for the faster compression
155  * modes where few data table entries are actually used. To optimize this use case the context can
156  * be created with the ASTCENC_FLG_SELF_DECOMPRESS_ONLY flag. This tells the compressor that it will
157  * only be asked to decompress images that it compressed itself, allowing the data tables to
158  * exclude entries that are not needed by the current compression configuration. This reduces the
159  * size of the context data tables in memory and improves context creation performance. Note that,
160  * as of the 3.6 release, this flag no longer affects compression performance.
161  *
162  * Using this flag while attempting to decompress an valid image which was created by another
163  * compressor, or even another astcenc compressor version or configuration, may result in blocks
164  * returning as solid magenta or NaN value error blocks.
165  */
166 
167 #ifndef ASTCENC_INCLUDED
168 #define ASTCENC_INCLUDED
169 
170 #include <cstddef>
171 #include <cstdint>
172 #if defined(__aarch64__)
173 	#define ASTCENC_NEON 1
174 #else
175 	#define ASTCENC_NEON 0
176 #endif
177 
178 enum QualityProfile {
179 	HIGH_QUALITY_PROFILE = 0, // default profile
180 	HIGH_SPEED_PROFILE,
181 	CUSTOMIZED_PROFILE
182 };
183 
184 static const int HIGH_SPEED_PROFILE_BLOCK_MODE = 67; // keep openSource type, example
185 static const int BYTE_MASK = 0xFF;
186 
187 #define QUALITY_CONTROL (1)
188 #if QUALITY_CONTROL
189 enum ComponentRGBA {
190 	R_COM = 0,
191 	G_COM,
192 	B_COM,
193 	A_COM,
194 	RGBA_COM
195 };
196 #endif
197 
198 #if defined(ASTCENC_DYNAMIC_LIBRARY)
199 	#if defined(_MSC_VER)
200 		#define ASTCENC_PUBLIC extern "C" __declspec(dllexport)
201 	#else
202 		#define ASTCENC_PUBLIC extern "C" __attribute__ ((visibility ("default")))
203 	#endif
204 #else
205 	#define ASTCENC_PUBLIC
206 #endif
207 
208 /* ============================================================================
209     Data declarations
210 ============================================================================ */
211 
212 /**
213  * @brief An opaque structure; see astcenc_internal.h for definition.
214  */
215 struct astcenc_context;
216 
217 /**
218  * @brief A codec API error code.
219  */
220 enum astcenc_error {
221 	/** @brief The call was successful. */
222 	ASTCENC_SUCCESS = 0,
223 	/** @brief The call failed due to low memory, or undersized I/O buffers. */
224 	ASTCENC_ERR_OUT_OF_MEM,
225 	/** @brief The call failed due to the build using fast math. */
226 	ASTCENC_ERR_BAD_CPU_FLOAT,
227 	/** @brief The call failed due to an out-of-spec parameter. */
228 	ASTCENC_ERR_BAD_PARAM,
229 	/** @brief The call failed due to an out-of-spec block size. */
230 	ASTCENC_ERR_BAD_BLOCK_SIZE,
231 	/** @brief The call failed due to an out-of-spec color profile. */
232 	ASTCENC_ERR_BAD_PROFILE,
233 	/** @brief The call failed due to an out-of-spec quality value. */
234 	ASTCENC_ERR_BAD_QUALITY,
235 	/** @brief The call failed due to an out-of-spec component swizzle. */
236 	ASTCENC_ERR_BAD_SWIZZLE,
237 	/** @brief The call failed due to an out-of-spec flag set. */
238 	ASTCENC_ERR_BAD_FLAGS,
239 	/** @brief The call failed due to the context not supporting the operation. */
240 	ASTCENC_ERR_BAD_CONTEXT,
241 	/** @brief The call failed due to unimplemented functionality. */
242 	ASTCENC_ERR_NOT_IMPLEMENTED,
243 	/** @brief The call failed due to an out-of-spec decode mode flag set. */
244 	ASTCENC_ERR_BAD_DECODE_MODE,
245 #if defined(ASTCENC_DIAGNOSTICS)
246 	/** @brief The call failed due to an issue with diagnostic tracing. */
247 	ASTCENC_ERR_DTRACE_FAILURE,
248 #endif
249 #if QUALITY_CONTROL
250 	ASTCENC_ERR_BAD_QUALITY_CHECK,
251 #endif
252 #ifdef ASTC_CUSTOMIZED_ENABLE
253 	ASTCENC_ERR_DLOPEN_FAILED
254 #endif
255 };
256 
257 /**
258  * @brief A codec color profile.
259  */
260 enum astcenc_profile {
261 	/** @brief The LDR sRGB color profile. */
262 	ASTCENC_PRF_LDR_SRGB = 0,
263 	/** @brief The LDR linear color profile. */
264 	ASTCENC_PRF_LDR,
265 	/** @brief The HDR RGB with LDR alpha color profile. */
266 	ASTCENC_PRF_HDR_RGB_LDR_A,
267 	/** @brief The HDR RGBA color profile. */
268 	ASTCENC_PRF_HDR
269 };
270 
271 /** @brief The fastest, lowest quality, search preset. */
272 static const float ASTCENC_PRE_FASTEST = 0.0f;
273 
274 /** @brief The fast search preset. */
275 static const float ASTCENC_PRE_FAST = 10.0f;
276 
277 /** @brief The medium quality search preset. */
278 static const float ASTCENC_PRE_MEDIUM = 60.0f;
279 
280 /** @brief The thorough quality search preset. */
281 static const float ASTCENC_PRE_THOROUGH = 98.0f;
282 
283 /** @brief The thorough quality search preset. */
284 static const float ASTCENC_PRE_VERYTHOROUGH = 99.0f;
285 
286 /** @brief The exhaustive, highest quality, search preset. */
287 static const float ASTCENC_PRE_EXHAUSTIVE = 100.0f;
288 
289 /**
290  * @brief A codec component swizzle selector.
291  */
292 enum astcenc_swz
293 {
294 	/** @brief Select the red component. */
295 	ASTCENC_SWZ_R = 0,
296 	/** @brief Select the green component. */
297 	ASTCENC_SWZ_G = 1,
298 	/** @brief Select the blue component. */
299 	ASTCENC_SWZ_B = 2,
300 	/** @brief Select the alpha component. */
301 	ASTCENC_SWZ_A = 3,
302 	/** @brief Use a constant zero component. */
303 	ASTCENC_SWZ_0 = 4,
304 	/** @brief Use a constant one component. */
305 	ASTCENC_SWZ_1 = 5,
306 	/** @brief Use a reconstructed normal vector Z component. */
307 	ASTCENC_SWZ_Z = 6
308 };
309 
310 /**
311  * @brief A texel component swizzle.
312  */
313 struct astcenc_swizzle
314 {
315 	/** @brief The red component selector. */
316 	astcenc_swz r;
317 	/** @brief The green component selector. */
318 	astcenc_swz g;
319 	/** @brief The blue component selector. */
320 	astcenc_swz b;
321 	/** @brief The alpha component selector. */
322 	astcenc_swz a;
323 };
324 
325 /**
326  * @brief A texel component data format.
327  */
328 enum astcenc_type
329 {
330 	/** @brief Unorm 8-bit data per component. */
331 	ASTCENC_TYPE_U8 = 0,
332 	/** @brief 16-bit float per component. */
333 	ASTCENC_TYPE_F16 = 1,
334 	/** @brief 32-bit float per component. */
335 	ASTCENC_TYPE_F32 = 2
336 };
337 
338 /**
339  * @brief Function pointer type for compression progress reporting callback.
340  */
341 extern "C" typedef void (*astcenc_progress_callback)(float);
342 
343 /**
344  * @brief Enable normal map compression.
345  *
346  * Input data will be treated a two component normal map, storing X and Y, and the codec will
347  * optimize for angular error rather than simple linear PSNR. In this mode the input swizzle should
348  * be e.g. rrrg (the default ordering for ASTC normals on the command line) or gggr (the ordering
349  * used by BC5n).
350  */
351 static const unsigned int ASTCENC_FLG_MAP_NORMAL          = 1 << 0;
352 
353 /**
354  * @brief Enable compression heuristics that assume use of decode_unorm8 decode mode.
355  *
356  * The decode_unorm8 decode mode rounds differently to the decode_fp16 decode mode, so enabling this
357  * flag during compression will allow the compressor to use the correct rounding when selecting
358  * encodings. This will improve the compressed image quality if your application is using the
359  * decode_unorm8 decode mode, but will reduce image quality if using decode_fp16.
360  *
361  * Note that LDR_SRGB images will always use decode_unorm8 for the RGB channels, irrespective of
362  * this setting.
363  */
364 static const unsigned int ASTCENC_FLG_USE_DECODE_UNORM8        = 1 << 1;
365 
366 /**
367  * @brief Enable alpha weighting.
368  *
369  * The input alpha value is used for transparency, so errors in the RGB components are weighted by
370  * the transparency level. This allows the codec to more accurately encode the alpha value in areas
371  * where the color value is less significant.
372  */
373 static const unsigned int ASTCENC_FLG_USE_ALPHA_WEIGHT     = 1 << 2;
374 
375 /**
376  * @brief Enable perceptual error metrics.
377  *
378  * This mode enables perceptual compression mode, which will optimize for perceptual error rather
379  * than best PSNR. Only some input modes support perceptual error metrics.
380  */
381 static const unsigned int ASTCENC_FLG_USE_PERCEPTUAL       = 1 << 3;
382 
383 /**
384  * @brief Create a decompression-only context.
385  *
386  * This mode disables support for compression. This enables context allocation to skip some
387  * transient buffer allocation, resulting in lower memory usage.
388  */
389 static const unsigned int ASTCENC_FLG_DECOMPRESS_ONLY      = 1 << 4;
390 
391 /**
392  * @brief Create a self-decompression context.
393  *
394  * This mode configures the compressor so that it is only guaranteed to be able to decompress images
395  * that were actually created using the current context. This is the common case for compression use
396  * cases, and setting this flag enables additional optimizations, but does mean that the context
397  * cannot reliably decompress arbitrary ASTC images.
398  */
399 static const unsigned int ASTCENC_FLG_SELF_DECOMPRESS_ONLY = 1 << 5;
400 
401 /**
402  * @brief Enable RGBM map compression.
403  *
404  * Input data will be treated as HDR data that has been stored in an LDR RGBM-encoded wrapper
405  * format. Data must be preprocessed by the user to be in LDR RGBM format before calling the
406  * compression function, this flag is only used to control the use of RGBM-specific heuristics and
407  * error metrics.
408  *
409  * IMPORTANT: The ASTC format is prone to bad failure modes with unconstrained RGBM data; very small
410  * M values can round to zero due to quantization and result in black or white pixels. It is highly
411  * recommended that the minimum value of M used in the encoding is kept above a lower threshold (try
412  * 16 or 32). Applying this threshold reduces the number of very dark colors that can be
413  * represented, but is still higher precision than 8-bit LDR.
414  *
415  * When this flag is set the value of @c rgbm_m_scale in the context must be set to the RGBM scale
416  * factor used during reconstruction. This defaults to 5 when in RGBM mode.
417  *
418  * It is recommended that the value of @c cw_a_weight is set to twice the value of the multiplier
419  * scale, ensuring that the M value is accurately encoded. This defaults to 10 when in RGBM mode,
420  * matching the default scale factor.
421  */
422 static const unsigned int ASTCENC_FLG_MAP_RGBM             = 1 << 6;
423 
424 /**
425  * @brief The bit mask of all valid flags.
426  */
427 static const unsigned int ASTCENC_ALL_FLAGS =
428                               ASTCENC_FLG_MAP_NORMAL |
429                               ASTCENC_FLG_MAP_RGBM |
430                               ASTCENC_FLG_USE_ALPHA_WEIGHT |
431                               ASTCENC_FLG_USE_PERCEPTUAL |
432                               ASTCENC_FLG_USE_DECODE_UNORM8 |
433                               ASTCENC_FLG_DECOMPRESS_ONLY |
434                               ASTCENC_FLG_SELF_DECOMPRESS_ONLY;
435 
436 /**
437  * @brief The config structure.
438  *
439  * This structure will initially be populated by a call to astcenc_config_init, but power users may
440  * modify it before calling astcenc_context_alloc. See astcenccli_toplevel_help.cpp for full user
441  * documentation of the power-user settings.
442  *
443  * Note for any settings which are associated with a specific color component, the value in the
444  * config applies to the component that exists after any compression data swizzle is applied.
445  */
446 struct astcenc_config
447 {
448 	/** @brief The color profile. */
449 	astcenc_profile profile;
450 
451 	/** @brief The set of set flags. */
452 	unsigned int flags;
453 
454 	/** @brief The ASTC block size X dimension. */
455 	unsigned int block_x;
456 
457 	/** @brief The ASTC block size Y dimension. */
458 	unsigned int block_y;
459 
460 	/** @brief The ASTC block size Z dimension. */
461 	unsigned int block_z;
462 
463 	/** @brief The red component weight scale for error weighting (-cw). */
464 	float cw_r_weight;
465 
466 	/** @brief The green component weight scale for error weighting (-cw). */
467 	float cw_g_weight;
468 
469 	/** @brief The blue component weight scale for error weighting (-cw). */
470 	float cw_b_weight;
471 
472 	/** @brief The alpha component weight scale for error weighting (-cw). */
473 	float cw_a_weight;
474 
475 	/**
476 	 * @brief The radius for any alpha-weight scaling (-a).
477 	 *
478 	 * It is recommended that this is set to 1 when using FLG_USE_ALPHA_WEIGHT on a texture that
479 	 * will be sampled using linear texture filtering to minimize color bleed out of transparent
480 	 * texels that are adjacent to non-transparent texels.
481 	 */
482 	unsigned int a_scale_radius;
483 
484 	/** @brief The RGBM scale factor for the shared multiplier (-rgbm). */
485 	float rgbm_m_scale;
486 
487 	/**
488 	 * @brief The maximum number of partitions searched (-partitioncountlimit).
489 	 *
490 	 * Valid values are between 1 and 4.
491 	 */
492 	unsigned int tune_partition_count_limit;
493 
494 	/**
495 	 * @brief The maximum number of partitions searched (-2partitionindexlimit).
496 	 *
497 	 * Valid values are between 1 and 1024.
498 	 */
499 	unsigned int tune_2partition_index_limit;
500 
501 	/**
502 	 * @brief The maximum number of partitions searched (-3partitionindexlimit).
503 	 *
504 	 * Valid values are between 1 and 1024.
505 	 */
506 	unsigned int tune_3partition_index_limit;
507 
508 	/**
509 	 * @brief The maximum number of partitions searched (-4partitionindexlimit).
510 	 *
511 	 * Valid values are between 1 and 1024.
512 	 */
513 	unsigned int tune_4partition_index_limit;
514 
515 	/**
516 	 * @brief The maximum centile for block modes searched (-blockmodelimit).
517 	 *
518 	 * Valid values are between 1 and 100.
519 	 */
520 	unsigned int tune_block_mode_limit;
521 
522 	/**
523 	 * @brief The maximum iterative refinements applied (-refinementlimit).
524 	 *
525 	 * Valid values are between 1 and N; there is no technical upper limit
526 	 * but little benefit is expected after N=4.
527 	 */
528 	unsigned int tune_refinement_limit;
529 
530 	/**
531 	 * @brief The number of trial candidates per mode search (-candidatelimit).
532 	 *
533 	 * Valid values are between 1 and TUNE_MAX_TRIAL_CANDIDATES.
534 	 */
535 	unsigned int tune_candidate_limit;
536 
537 	/**
538 	 * @brief The number of trial partitionings per search (-2partitioncandidatelimit).
539 	 *
540 	 * Valid values are between 1 and TUNE_MAX_PARTITIONING_CANDIDATES.
541 	 */
542 	unsigned int tune_2partitioning_candidate_limit;
543 
544 	/**
545 	 * @brief The number of trial partitionings per search (-3partitioncandidatelimit).
546 	 *
547 	 * Valid values are between 1 and TUNE_MAX_PARTITIONING_CANDIDATES.
548 	 */
549 	unsigned int tune_3partitioning_candidate_limit;
550 
551 	/**
552 	 * @brief The number of trial partitionings per search (-4partitioncandidatelimit).
553 	 *
554 	 * Valid values are between 1 and TUNE_MAX_PARTITIONING_CANDIDATES.
555 	 */
556 	unsigned int tune_4partitioning_candidate_limit;
557 
558 	/**
559 	 * @brief The dB threshold for stopping block search (-dblimit).
560 	 *
561 	 * This option is ineffective for HDR textures.
562 	 */
563 	float tune_db_limit;
564 
565 	/**
566 	 * @brief The amount of MSE overshoot needed to early-out trials.
567 	 *
568 	 * The first early-out is for 1 partition, 1 plane trials, where we try a minimal encode using
569 	 * the high probability block modes. This can short-cut compression for simple blocks.
570 	 *
571 	 * The second early-out is for refinement trials, where we can exit refinement once quality is
572 	 * reached.
573 	 */
574 	float tune_mse_overshoot;
575 
576 	/**
577 	 * @brief The threshold for skipping 3.1/4.1 trials (-2partitionlimitfactor).
578 	 *
579 	 * This option is further scaled for normal maps, so it skips less often.
580 	 */
581 	float tune_2partition_early_out_limit_factor;
582 
583 	/**
584 	 * @brief The threshold for skipping 4.1 trials (-3partitionlimitfactor).
585 	 *
586 	 * This option is further scaled for normal maps, so it skips less often.
587 	 */
588 	float tune_3partition_early_out_limit_factor;
589 
590 	/**
591 	 * @brief The threshold for skipping two weight planes (-2planelimitcorrelation).
592 	 *
593 	 * This option is ineffective for normal maps.
594 	 */
595 	float tune_2plane_early_out_limit_correlation;
596 
597 	/**
598 	 * @brief The config enable for the mode0 fast-path search.
599 	 *
600 	 * If this is set to TUNE_MIN_TEXELS_MODE0 or higher then the early-out fast mode0
601 	 * search is enabled. This option is ineffective for 3D block sizes.
602 	 */
603 	float tune_search_mode0_enable;
604 
605 	/**
606 	 * @brief The progress callback, can be @c nullptr.
607 	 *
608 	 * If this is specified the codec will peridocially report progress for
609 	 * compression as a percentage between 0 and 100. The callback is called from one
610 	 * of the compressor threads, so doing significant work in the callback will
611 	 * reduce compression performance.
612 	 */
613 	astcenc_progress_callback progress_callback;
614 
615 #if defined(ASTCENC_DIAGNOSTICS)
616 	/**
617 	 * @brief The path to save the diagnostic trace data to.
618 	 *
619 	 * This option is not part of the public API, and requires special builds
620 	 * of the library.
621 	 */
622 	const char* trace_file_path;
623 #endif
624 	QualityProfile privateProfile;
625 };
626 
627 /**
628  * @brief An uncompressed 2D or 3D image.
629  *
630  * 3D image are passed in as an array of 2D slices. Each slice has identical
631  * size and color format.
632  */
633 struct astcenc_image
634 {
635 	/** @brief The stride dimension of the image, in texels. */
636 	unsigned int dim_stride;
637 
638 	/** @brief The X dimension of the image, in texels. */
639 	unsigned int dim_x;
640 
641 	/** @brief The Y dimension of the image, in texels. */
642 	unsigned int dim_y;
643 
644 	/** @brief The Z dimension of the image, in texels. */
645 	unsigned int dim_z;
646 
647 	/** @brief The data type per component. */
648 	astcenc_type data_type;
649 
650 	/** @brief The array of 2D slices, of length @c dim_z. */
651 	void** data;
652 };
653 
654 /**
655  * @brief A block encoding metadata query result.
656  *
657  * If the block is an error block or a constant color block or an error block all fields other than
658  * the profile, block dimensions, and error/constant indicator will be zero.
659  */
660 struct astcenc_block_info
661 {
662 	/** @brief The block encoding color profile. */
663 	astcenc_profile profile;
664 
665 	/** @brief The number of texels in the X dimension. */
666 	unsigned int block_x;
667 
668 	/** @brief The number of texels in the Y dimension. */
669 	unsigned int block_y;
670 
671 	/** @brief The number of texel in the Z dimension. */
672 	unsigned int block_z;
673 
674 	/** @brief The number of texels in the block. */
675 	unsigned int texel_count;
676 
677 	/** @brief True if this block is an error block. */
678 	bool is_error_block;
679 
680 	/** @brief True if this block is a constant color block. */
681 	bool is_constant_block;
682 
683 	/** @brief True if this block is an HDR block. */
684 	bool is_hdr_block;
685 
686 	/** @brief True if this block uses two weight planes. */
687 	bool is_dual_plane_block;
688 
689 	/** @brief The number of partitions if not constant color. */
690 	unsigned int partition_count;
691 
692 	/** @brief The partition index if 2 - 4 partitions used. */
693 	unsigned int partition_index;
694 
695 	/** @brief The component index of the second plane if dual plane. */
696 	unsigned int dual_plane_component;
697 
698 	/** @brief The color endpoint encoding mode for each partition. */
699 	unsigned int color_endpoint_modes[4];
700 
701 	/** @brief The number of color endpoint quantization levels. */
702 	unsigned int color_level_count;
703 
704 	/** @brief The number of weight quantization levels. */
705 	unsigned int weight_level_count;
706 
707 	/** @brief The number of weights in the X dimension. */
708 	unsigned int weight_x;
709 
710 	/** @brief The number of weights in the Y dimension. */
711 	unsigned int weight_y;
712 
713 	/** @brief The number of weights in the Z dimension. */
714 	unsigned int weight_z;
715 
716 	/** @brief The unpacked color endpoints for each partition. */
717 	float color_endpoints[4][2][4];
718 
719 	/** @brief The per-texel interpolation weights for the block. */
720 	float weight_values_plane1[216];
721 
722 	/** @brief The per-texel interpolation weights for the block. */
723 	float weight_values_plane2[216];
724 
725 	/** @brief The per-texel partition assignments for the block. */
726 	uint8_t partition_assignment[216];
727 };
728 
729 /**
730  * Populate a codec config based on default settings.
731  *
732  * Power users can edit the returned config struct to fine tune before allocating the context.
733  *
734  * @param      profile   Color profile.
735  * @param      block_x   ASTC block size X dimension.
736  * @param      block_y   ASTC block size Y dimension.
737  * @param      block_z   ASTC block size Z dimension.
738  * @param      quality   Search quality preset / effort level. Either an
739  *                       @c ASTCENC_PRE_* value, or a effort level between 0
740  *                       and 100. Performance is not linear between 0 and 100.
741 
742  * @param      flags     A valid set of @c ASTCENC_FLG_* flag bits.
743  * @param[out] config    Output config struct to populate.
744  *
745  * @return @c ASTCENC_SUCCESS on success, or an error if the inputs are invalid
746  * either individually, or in combination.
747  */
748 ASTCENC_PUBLIC astcenc_error astcenc_config_init(
749 	astcenc_profile profile,
750 	unsigned int block_x,
751 	unsigned int block_y,
752 	unsigned int block_z,
753 	float quality,
754 	unsigned int flags,
755 	astcenc_config* config);
756 
757 /**
758  * @brief Allocate a new codec context based on a config.
759  *
760  * This function allocates all of the memory resources and threads needed by the codec. This can be
761  * slow, so it is recommended that contexts are reused to serially compress or decompress multiple
762  * images to amortize setup cost.
763  *
764  * Contexts can be allocated to support only decompression using the @c ASTCENC_FLG_DECOMPRESS_ONLY
765  * flag when creating the configuration. The compression functions will fail if invoked. For a
766  * decompress-only library build the @c ASTCENC_FLG_DECOMPRESS_ONLY flag must be set when creating
767  * any context.
768  *
769  * @param[in]  config         Codec config.
770  * @param      thread_count   Thread count to configure for.
771  * @param[out] context        Location to store an opaque context pointer.
772  *
773  * @return @c ASTCENC_SUCCESS on success, or an error if context creation failed.
774  */
775 ASTCENC_PUBLIC astcenc_error astcenc_context_alloc(
776 	const astcenc_config* config,
777 	unsigned int thread_count,
778 	astcenc_context** context);
779 
780 /**
781  * @brief Compress an image.
782  *
783  * A single context can only compress or decompress a single image at a time.
784  *
785  * For a context configured for multi-threading, any set of the N threads can call this function.
786  * Work will be dynamically scheduled across the threads available. Each thread must have a unique
787  * @c thread_index.
788  *
789  * @param         context        Codec context.
790  * @param[in,out] image          An input image, in 2D slices.
791  * @param         swizzle        Compression data swizzle, applied before compression.
792  * @param[out]    data_out       Pointer to output data array.
793  * @param         data_len       Length of the output data array.
794  * @param         thread_index   Thread index [0..N-1] of calling thread.
795  *
796  * @return @c ASTCENC_SUCCESS on success, or an error if compression failed.
797  */
798 ASTCENC_PUBLIC astcenc_error astcenc_compress_image(
799 	astcenc_context* context,
800 	astcenc_image* image,
801 	const astcenc_swizzle* swizzle,
802 	uint8_t* data_out,
803 	size_t data_len,
804 #if QUALITY_CONTROL
805 	bool calQualityEnable,
806 	int32_t *mse[RGBA_COM],
807 #endif
808 	unsigned int thread_index);
809 
810 /**
811  * @brief Reset the codec state for a new compression.
812  *
813  * The caller is responsible for synchronizing threads in the worker thread pool. This function must
814  * only be called when all threads have exited the @c astcenc_compress_image() function for image N,
815  * but before any thread enters it for image N + 1.
816  *
817  * Calling this is not required (but won't hurt), if the context is created for single threaded use.
818  *
819  * @param context   Codec context.
820  *
821  * @return @c ASTCENC_SUCCESS on success, or an error if reset failed.
822  */
823 ASTCENC_PUBLIC astcenc_error astcenc_compress_reset(
824 	astcenc_context* context);
825 
826 /**
827  * @brief Decompress an image.
828  *
829  * @param         context        Codec context.
830  * @param[in]     data           Pointer to compressed data.
831  * @param         data_len       Length of the compressed data, in bytes.
832  * @param[in,out] image_out      Output image.
833  * @param         swizzle        Decompression data swizzle, applied after decompression.
834  * @param         thread_index   Thread index [0..N-1] of calling thread.
835  *
836  * @return @c ASTCENC_SUCCESS on success, or an error if decompression failed.
837  */
838 ASTCENC_PUBLIC astcenc_error astcenc_decompress_image(
839 	astcenc_context* context,
840 	const uint8_t* data,
841 	size_t data_len,
842 	astcenc_image* image_out,
843 	const astcenc_swizzle* swizzle,
844 	unsigned int thread_index);
845 
846 /**
847  * @brief Reset the codec state for a new decompression.
848  *
849  * The caller is responsible for synchronizing threads in the worker thread pool. This function must
850  * only be called when all threads have exited the @c astcenc_decompress_image() function for image
851  * N, but before any thread enters it for image N + 1.
852  *
853  * Calling this is not required (but won't hurt), if the context is created for single threaded use.
854  *
855  * @param context   Codec context.
856  *
857  * @return @c ASTCENC_SUCCESS on success, or an error if reset failed.
858  */
859 ASTCENC_PUBLIC astcenc_error astcenc_decompress_reset(
860 	astcenc_context* context);
861 
862 /**
863  * Free the compressor context.
864  *
865  * @param context   The codec context.
866  */
867 ASTCENC_PUBLIC void astcenc_context_free(
868 	astcenc_context* context);
869 
870 /**
871  * @brief Provide a high level summary of a block's encoding.
872  *
873  * This feature is primarily useful for codec developers but may be useful for developers building
874  * advanced content packaging pipelines.
875  *
876  * @param context   Codec context.
877  * @param data      One block of compressed ASTC data.
878  * @param info      The output info structure to populate.
879  *
880  * @return @c ASTCENC_SUCCESS if the block was decoded, or an error otherwise. Note that this
881  *         function will return success even if the block itself was an error block encoding, as the
882  *         decode was correctly handled.
883  */
884 ASTCENC_PUBLIC astcenc_error astcenc_get_block_info(
885 	astcenc_context* context,
886 	const uint8_t data[16],
887 	astcenc_block_info* info);
888 
889 /**
890  * @brief Get a printable string for specific status code.
891  *
892  * @param status   The status value.
893  *
894  * @return A human readable nul-terminated string.
895  */
896 ASTCENC_PUBLIC const char* astcenc_get_error_string(
897 	astcenc_error status);
898 
899 #endif
900