virtualx-engine/thirdparty/astcenc/astcenc.h

860 lines
31 KiB
C++

// SPDX-License-Identifier: Apache-2.0
// ----------------------------------------------------------------------------
// Copyright 2020-2024 Arm Limited
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy
// of the License at:
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations
// under the License.
// ----------------------------------------------------------------------------
/**
* @brief The core astcenc codec library interface.
*
* This interface is the entry point to the core astcenc codec. It aims to be easy to use for
* non-experts, but also to allow experts to have fine control over the compressor heuristics if
* needed. The core codec only handles compression and decompression, transferring all inputs and
* outputs via memory buffers. To catch obvious input/output buffer sizing issues, which can cause
* security and stability problems, all transfer buffers are explicitly sized.
*
* While the aim is that we keep this interface mostly stable, it should be viewed as a mutable
* interface tied to a specific source version. We are not trying to maintain backwards
* compatibility across codec versions.
*
* The API state management is based around an explicit context object, which is the context for all
* allocated memory resources needed to compress and decompress a single image. A context can be
* used to sequentially compress multiple images using the same configuration, allowing setup
* overheads to be amortized over multiple images, which is particularly important when images are
* small.
*
* Multi-threading can be used two ways.
*
* * An application wishing to process multiple images in parallel can allocate multiple
* contexts and assign each context to a thread.
* * An application wishing to process a single image in using multiple threads can configure
* contexts for multi-threaded use, and invoke astcenc_compress/decompress() once per thread
* for faster processing. The caller is responsible for creating the worker threads, and
* synchronizing between images.
*
* Extended instruction set support
* ================================
*
* This library supports use of extended instruction sets, such as SSE4.1 and AVX2. These are
* enabled at compile time when building the library. There is no runtime checking in the core
* library that the instruction sets used are actually available. Checking compatibility is the
* responsibility of the calling code.
*
* Threading
* =========
*
* In pseudo-code, the usage for manual user threading looks like this:
*
* // Configure the compressor run
* astcenc_config my_config;
* astcenc_config_init(..., &my_config);
*
* // Power users can tweak <my_config> settings here ...
*
* // Allocate working state given config and thread_count
* astcenc_context* my_context;
* astcenc_context_alloc(&my_config, thread_count, &my_context);
*
* // Compress each image using these config settings
* foreach image:
* // For each thread in the thread pool
* for i in range(0, thread_count):
* astcenc_compress_image(my_context, &my_input, my_output, i);
*
* astcenc_compress_reset(my_context);
*
* // Clean up
* astcenc_context_free(my_context);
*
* Images
* ======
*
* The codec supports compressing single images, which can be either 2D images or volumetric 3D
* images. Calling code is responsible for any handling of aggregate types, such as mipmap chains,
* texture arrays, or sliced 3D textures.
*
* Images are passed in as an astcenc_image structure. Inputs can be either 8-bit unorm, 16-bit
* half-float, or 32-bit float, as indicated by the data_type field.
*
* Images can be any dimension; there is no requirement to be a multiple of the ASTC block size.
*
* Data is always passed in as 4 color components, and accessed as an array of 2D image slices. Data
* within an image slice is always tightly packed without padding. Addressing looks like this:
*
* data[z_coord][y_coord * x_dim * 4 + x_coord * 4 ] // Red
* data[z_coord][y_coord * x_dim * 4 + x_coord * 4 + 1] // Green
* data[z_coord][y_coord * x_dim * 4 + x_coord * 4 + 2] // Blue
* data[z_coord][y_coord * x_dim * 4 + x_coord * 4 + 3] // Alpha
*
* Common compressor usage
* =======================
*
* One of the most important things for coding image quality is to align the input data component
* count with the ASTC color endpoint mode. This avoids wasting bits encoding components you don't
* actually need in the endpoint colors.
*
* | Input data | Encoding swizzle | Sampling swizzle |
* | ------------ | ---------------- | ---------------- |
* | 1 component | RRR1 | .[rgb] |
* | 2 components | RRRG | .[rgb]a |
* | 3 components | RGB1 | .rgb |
* | 4 components | RGBA | .rgba |
*
* The 1 and 2 component modes recommend sampling from "g" to recover the luminance value as this
* provide best compatibility with other texture formats where the green component may be stored at
* higher precision than the others, such as RGB565. For ASTC any of the RGB components can be used;
* the luminance endpoint component will be returned for all three.
*
* When using the normal map compression mode ASTC will store normals as a two component X+Y map.
* Input images must contain unit-length normalized and should be passed in using a two component
* swizzle. The astcenc command line tool defaults to an RRRG swizzle, but some developers prefer
* to use GGGR for compatability with BC5n which will work just as well. The Z component can be
* recovered programmatically in shader code, using knowledge that the vector is unit length and
* that Z must be positive for a tangent-space normal map.
*
* Decompress-only usage
* =====================
*
* For some use cases it is useful to have a cut-down context and/or library which supports
* decompression but not compression.
*
* A context can be made decompress-only using the ASTCENC_FLG_DECOMPRESS_ONLY flag when the context
* is allocated. These contexts have lower dynamic memory footprint than a full context.
*
* The entire library can be made decompress-only by building the files with the define
* ASTCENC_DECOMPRESS_ONLY set. In this build the context will be smaller, and the library will
* exclude the functionality which is only needed for compression. This reduces the binary size by
* ~180KB. For these builds contexts must be created with the ASTCENC_FLG_DECOMPRESS_ONLY flag.
*
* Note that context structures returned by a library built as decompress-only are incompatible with
* a library built with compression included, and visa versa, as they have different sizes and
* memory layout.
*
* Self-decompress-only usage
* ==========================
*
* ASTC is a complex format with a large search space. The parts of this search space that are
* searched is determined by heuristics that are, in part, tied to the quality level used when
* creating the context.
*
* A normal context is capable of decompressing any ASTC texture, including those generated by other
* compressors with unknown heuristics. This is the most flexible implementation, but forces the
* data tables used by the codec to include entries that are not needed during compression. This
* can slow down context creation by a significant amount, especially for the faster compression
* modes where few data table entries are actually used. To optimize this use case the context can
* be created with the ASTCENC_FLG_SELF_DECOMPRESS_ONLY flag. This tells the compressor that it will
* only be asked to decompress images that it compressed itself, allowing the data tables to
* exclude entries that are not needed by the current compression configuration. This reduces the
* size of the context data tables in memory and improves context creation performance. Note that,
* as of the 3.6 release, this flag no longer affects compression performance.
*
* Using this flag while attempting to decompress an valid image which was created by another
* compressor, or even another astcenc compressor version or configuration, may result in blocks
* returning as solid magenta or NaN value error blocks.
*/
#ifndef ASTCENC_INCLUDED
#define ASTCENC_INCLUDED
#include <cstddef>
#include <cstdint>
#if defined(ASTCENC_DYNAMIC_LIBRARY)
#if defined(_MSC_VER)
#define ASTCENC_PUBLIC extern "C" __declspec(dllexport)
#else
#define ASTCENC_PUBLIC extern "C" __attribute__ ((visibility ("default")))
#endif
#else
#define ASTCENC_PUBLIC
#endif
/* ============================================================================
Data declarations
============================================================================ */
/**
* @brief An opaque structure; see astcenc_internal.h for definition.
*/
struct astcenc_context;
/**
* @brief A codec API error code.
*/
enum astcenc_error {
/** @brief The call was successful. */
ASTCENC_SUCCESS = 0,
/** @brief The call failed due to low memory, or undersized I/O buffers. */
ASTCENC_ERR_OUT_OF_MEM,
/** @brief The call failed due to the build using fast math. */
ASTCENC_ERR_BAD_CPU_FLOAT,
/** @brief The call failed due to an out-of-spec parameter. */
ASTCENC_ERR_BAD_PARAM,
/** @brief The call failed due to an out-of-spec block size. */
ASTCENC_ERR_BAD_BLOCK_SIZE,
/** @brief The call failed due to an out-of-spec color profile. */
ASTCENC_ERR_BAD_PROFILE,
/** @brief The call failed due to an out-of-spec quality value. */
ASTCENC_ERR_BAD_QUALITY,
/** @brief The call failed due to an out-of-spec component swizzle. */
ASTCENC_ERR_BAD_SWIZZLE,
/** @brief The call failed due to an out-of-spec flag set. */
ASTCENC_ERR_BAD_FLAGS,
/** @brief The call failed due to the context not supporting the operation. */
ASTCENC_ERR_BAD_CONTEXT,
/** @brief The call failed due to unimplemented functionality. */
ASTCENC_ERR_NOT_IMPLEMENTED,
/** @brief The call failed due to an out-of-spec decode mode flag set. */
ASTCENC_ERR_BAD_DECODE_MODE,
#if defined(ASTCENC_DIAGNOSTICS)
/** @brief The call failed due to an issue with diagnostic tracing. */
ASTCENC_ERR_DTRACE_FAILURE,
#endif
};
/**
* @brief A codec color profile.
*/
enum astcenc_profile {
/** @brief The LDR sRGB color profile. */
ASTCENC_PRF_LDR_SRGB = 0,
/** @brief The LDR linear color profile. */
ASTCENC_PRF_LDR,
/** @brief The HDR RGB with LDR alpha color profile. */
ASTCENC_PRF_HDR_RGB_LDR_A,
/** @brief The HDR RGBA color profile. */
ASTCENC_PRF_HDR
};
/** @brief The fastest, lowest quality, search preset. */
static const float ASTCENC_PRE_FASTEST = 0.0f;
/** @brief The fast search preset. */
static const float ASTCENC_PRE_FAST = 10.0f;
/** @brief The medium quality search preset. */
static const float ASTCENC_PRE_MEDIUM = 60.0f;
/** @brief The thorough quality search preset. */
static const float ASTCENC_PRE_THOROUGH = 98.0f;
/** @brief The thorough quality search preset. */
static const float ASTCENC_PRE_VERYTHOROUGH = 99.0f;
/** @brief The exhaustive, highest quality, search preset. */
static const float ASTCENC_PRE_EXHAUSTIVE = 100.0f;
/**
* @brief A codec component swizzle selector.
*/
enum astcenc_swz
{
/** @brief Select the red component. */
ASTCENC_SWZ_R = 0,
/** @brief Select the green component. */
ASTCENC_SWZ_G = 1,
/** @brief Select the blue component. */
ASTCENC_SWZ_B = 2,
/** @brief Select the alpha component. */
ASTCENC_SWZ_A = 3,
/** @brief Use a constant zero component. */
ASTCENC_SWZ_0 = 4,
/** @brief Use a constant one component. */
ASTCENC_SWZ_1 = 5,
/** @brief Use a reconstructed normal vector Z component. */
ASTCENC_SWZ_Z = 6
};
/**
* @brief A texel component swizzle.
*/
struct astcenc_swizzle
{
/** @brief The red component selector. */
astcenc_swz r;
/** @brief The green component selector. */
astcenc_swz g;
/** @brief The blue component selector. */
astcenc_swz b;
/** @brief The alpha component selector. */
astcenc_swz a;
};
/**
* @brief A texel component data format.
*/
enum astcenc_type
{
/** @brief Unorm 8-bit data per component. */
ASTCENC_TYPE_U8 = 0,
/** @brief 16-bit float per component. */
ASTCENC_TYPE_F16 = 1,
/** @brief 32-bit float per component. */
ASTCENC_TYPE_F32 = 2
};
/**
* @brief Function pointer type for compression progress reporting callback.
*/
extern "C" typedef void (*astcenc_progress_callback)(float);
/**
* @brief Enable normal map compression.
*
* Input data will be treated a two component normal map, storing X and Y, and the codec will
* optimize for angular error rather than simple linear PSNR. In this mode the input swizzle should
* be e.g. rrrg (the default ordering for ASTC normals on the command line) or gggr (the ordering
* used by BC5n).
*/
static const unsigned int ASTCENC_FLG_MAP_NORMAL = 1 << 0;
/**
* @brief Enable compression heuristics that assume use of decode_unorm8 decode mode.
*
* The decode_unorm8 decode mode rounds differently to the decode_fp16 decode mode, so enabling this
* flag during compression will allow the compressor to use the correct rounding when selecting
* encodings. This will improve the compressed image quality if your application is using the
* decode_unorm8 decode mode, but will reduce image quality if using decode_fp16.
*
* Note that LDR_SRGB images will always use decode_unorm8 for the RGB channels, irrespective of
* this setting.
*/
static const unsigned int ASTCENC_FLG_USE_DECODE_UNORM8 = 1 << 1;
/**
* @brief Enable alpha weighting.
*
* The input alpha value is used for transparency, so errors in the RGB components are weighted by
* the transparency level. This allows the codec to more accurately encode the alpha value in areas
* where the color value is less significant.
*/
static const unsigned int ASTCENC_FLG_USE_ALPHA_WEIGHT = 1 << 2;
/**
* @brief Enable perceptual error metrics.
*
* This mode enables perceptual compression mode, which will optimize for perceptual error rather
* than best PSNR. Only some input modes support perceptual error metrics.
*/
static const unsigned int ASTCENC_FLG_USE_PERCEPTUAL = 1 << 3;
/**
* @brief Create a decompression-only context.
*
* This mode disables support for compression. This enables context allocation to skip some
* transient buffer allocation, resulting in lower memory usage.
*/
static const unsigned int ASTCENC_FLG_DECOMPRESS_ONLY = 1 << 4;
/**
* @brief Create a self-decompression context.
*
* This mode configures the compressor so that it is only guaranteed to be able to decompress images
* that were actually created using the current context. This is the common case for compression use
* cases, and setting this flag enables additional optimizations, but does mean that the context
* cannot reliably decompress arbitrary ASTC images.
*/
static const unsigned int ASTCENC_FLG_SELF_DECOMPRESS_ONLY = 1 << 5;
/**
* @brief Enable RGBM map compression.
*
* Input data will be treated as HDR data that has been stored in an LDR RGBM-encoded wrapper
* format. Data must be preprocessed by the user to be in LDR RGBM format before calling the
* compression function, this flag is only used to control the use of RGBM-specific heuristics and
* error metrics.
*
* IMPORTANT: The ASTC format is prone to bad failure modes with unconstrained RGBM data; very small
* M values can round to zero due to quantization and result in black or white pixels. It is highly
* recommended that the minimum value of M used in the encoding is kept above a lower threshold (try
* 16 or 32). Applying this threshold reduces the number of very dark colors that can be
* represented, but is still higher precision than 8-bit LDR.
*
* When this flag is set the value of @c rgbm_m_scale in the context must be set to the RGBM scale
* factor used during reconstruction. This defaults to 5 when in RGBM mode.
*
* It is recommended that the value of @c cw_a_weight is set to twice the value of the multiplier
* scale, ensuring that the M value is accurately encoded. This defaults to 10 when in RGBM mode,
* matching the default scale factor.
*/
static const unsigned int ASTCENC_FLG_MAP_RGBM = 1 << 6;
/**
* @brief The bit mask of all valid flags.
*/
static const unsigned int ASTCENC_ALL_FLAGS =
ASTCENC_FLG_MAP_NORMAL |
ASTCENC_FLG_MAP_RGBM |
ASTCENC_FLG_USE_ALPHA_WEIGHT |
ASTCENC_FLG_USE_PERCEPTUAL |
ASTCENC_FLG_USE_DECODE_UNORM8 |
ASTCENC_FLG_DECOMPRESS_ONLY |
ASTCENC_FLG_SELF_DECOMPRESS_ONLY;
/**
* @brief The config structure.
*
* This structure will initially be populated by a call to astcenc_config_init, but power users may
* modify it before calling astcenc_context_alloc. See astcenccli_toplevel_help.cpp for full user
* documentation of the power-user settings.
*
* Note for any settings which are associated with a specific color component, the value in the
* config applies to the component that exists after any compression data swizzle is applied.
*/
struct astcenc_config
{
/** @brief The color profile. */
astcenc_profile profile;
/** @brief The set of set flags. */
unsigned int flags;
/** @brief The ASTC block size X dimension. */
unsigned int block_x;
/** @brief The ASTC block size Y dimension. */
unsigned int block_y;
/** @brief The ASTC block size Z dimension. */
unsigned int block_z;
/** @brief The red component weight scale for error weighting (-cw). */
float cw_r_weight;
/** @brief The green component weight scale for error weighting (-cw). */
float cw_g_weight;
/** @brief The blue component weight scale for error weighting (-cw). */
float cw_b_weight;
/** @brief The alpha component weight scale for error weighting (-cw). */
float cw_a_weight;
/**
* @brief The radius for any alpha-weight scaling (-a).
*
* It is recommended that this is set to 1 when using FLG_USE_ALPHA_WEIGHT on a texture that
* will be sampled using linear texture filtering to minimize color bleed out of transparent
* texels that are adjacent to non-transparent texels.
*/
unsigned int a_scale_radius;
/** @brief The RGBM scale factor for the shared multiplier (-rgbm). */
float rgbm_m_scale;
/**
* @brief The maximum number of partitions searched (-partitioncountlimit).
*
* Valid values are between 1 and 4.
*/
unsigned int tune_partition_count_limit;
/**
* @brief The maximum number of partitions searched (-2partitionindexlimit).
*
* Valid values are between 1 and 1024.
*/
unsigned int tune_2partition_index_limit;
/**
* @brief The maximum number of partitions searched (-3partitionindexlimit).
*
* Valid values are between 1 and 1024.
*/
unsigned int tune_3partition_index_limit;
/**
* @brief The maximum number of partitions searched (-4partitionindexlimit).
*
* Valid values are between 1 and 1024.
*/
unsigned int tune_4partition_index_limit;
/**
* @brief The maximum centile for block modes searched (-blockmodelimit).
*
* Valid values are between 1 and 100.
*/
unsigned int tune_block_mode_limit;
/**
* @brief The maximum iterative refinements applied (-refinementlimit).
*
* Valid values are between 1 and N; there is no technical upper limit
* but little benefit is expected after N=4.
*/
unsigned int tune_refinement_limit;
/**
* @brief The number of trial candidates per mode search (-candidatelimit).
*
* Valid values are between 1 and TUNE_MAX_TRIAL_CANDIDATES.
*/
unsigned int tune_candidate_limit;
/**
* @brief The number of trial partitionings per search (-2partitioncandidatelimit).
*
* Valid values are between 1 and TUNE_MAX_PARTITIONING_CANDIDATES.
*/
unsigned int tune_2partitioning_candidate_limit;
/**
* @brief The number of trial partitionings per search (-3partitioncandidatelimit).
*
* Valid values are between 1 and TUNE_MAX_PARTITIONING_CANDIDATES.
*/
unsigned int tune_3partitioning_candidate_limit;
/**
* @brief The number of trial partitionings per search (-4partitioncandidatelimit).
*
* Valid values are between 1 and TUNE_MAX_PARTITIONING_CANDIDATES.
*/
unsigned int tune_4partitioning_candidate_limit;
/**
* @brief The dB threshold for stopping block search (-dblimit).
*
* This option is ineffective for HDR textures.
*/
float tune_db_limit;
/**
* @brief The amount of MSE overshoot needed to early-out trials.
*
* The first early-out is for 1 partition, 1 plane trials, where we try a minimal encode using
* the high probability block modes. This can short-cut compression for simple blocks.
*
* The second early-out is for refinement trials, where we can exit refinement once quality is
* reached.
*/
float tune_mse_overshoot;
/**
* @brief The threshold for skipping 3.1/4.1 trials (-2partitionlimitfactor).
*
* This option is further scaled for normal maps, so it skips less often.
*/
float tune_2partition_early_out_limit_factor;
/**
* @brief The threshold for skipping 4.1 trials (-3partitionlimitfactor).
*
* This option is further scaled for normal maps, so it skips less often.
*/
float tune_3partition_early_out_limit_factor;
/**
* @brief The threshold for skipping two weight planes (-2planelimitcorrelation).
*
* This option is ineffective for normal maps.
*/
float tune_2plane_early_out_limit_correlation;
/**
* @brief The config enable for the mode0 fast-path search.
*
* If this is set to TUNE_MIN_TEXELS_MODE0 or higher then the early-out fast mode0
* search is enabled. This option is ineffective for 3D block sizes.
*/
float tune_search_mode0_enable;
/**
* @brief The progress callback, can be @c nullptr.
*
* If this is specified the codec will peridocially report progress for
* compression as a percentage between 0 and 100. The callback is called from one
* of the compressor threads, so doing significant work in the callback will
* reduce compression performance.
*/
astcenc_progress_callback progress_callback;
#if defined(ASTCENC_DIAGNOSTICS)
/**
* @brief The path to save the diagnostic trace data to.
*
* This option is not part of the public API, and requires special builds
* of the library.
*/
const char* trace_file_path;
#endif
};
/**
* @brief An uncompressed 2D or 3D image.
*
* 3D image are passed in as an array of 2D slices. Each slice has identical
* size and color format.
*/
struct astcenc_image
{
/** @brief The X dimension of the image, in texels. */
unsigned int dim_x;
/** @brief The Y dimension of the image, in texels. */
unsigned int dim_y;
/** @brief The Z dimension of the image, in texels. */
unsigned int dim_z;
/** @brief The data type per component. */
astcenc_type data_type;
/** @brief The array of 2D slices, of length @c dim_z. */
void** data;
};
/**
* @brief A block encoding metadata query result.
*
* If the block is an error block or a constant color block or an error block all fields other than
* the profile, block dimensions, and error/constant indicator will be zero.
*/
struct astcenc_block_info
{
/** @brief The block encoding color profile. */
astcenc_profile profile;
/** @brief The number of texels in the X dimension. */
unsigned int block_x;
/** @brief The number of texels in the Y dimension. */
unsigned int block_y;
/** @brief The number of texel in the Z dimension. */
unsigned int block_z;
/** @brief The number of texels in the block. */
unsigned int texel_count;
/** @brief True if this block is an error block. */
bool is_error_block;
/** @brief True if this block is a constant color block. */
bool is_constant_block;
/** @brief True if this block is an HDR block. */
bool is_hdr_block;
/** @brief True if this block uses two weight planes. */
bool is_dual_plane_block;
/** @brief The number of partitions if not constant color. */
unsigned int partition_count;
/** @brief The partition index if 2 - 4 partitions used. */
unsigned int partition_index;
/** @brief The component index of the second plane if dual plane. */
unsigned int dual_plane_component;
/** @brief The color endpoint encoding mode for each partition. */
unsigned int color_endpoint_modes[4];
/** @brief The number of color endpoint quantization levels. */
unsigned int color_level_count;
/** @brief The number of weight quantization levels. */
unsigned int weight_level_count;
/** @brief The number of weights in the X dimension. */
unsigned int weight_x;
/** @brief The number of weights in the Y dimension. */
unsigned int weight_y;
/** @brief The number of weights in the Z dimension. */
unsigned int weight_z;
/** @brief The unpacked color endpoints for each partition. */
float color_endpoints[4][2][4];
/** @brief The per-texel interpolation weights for the block. */
float weight_values_plane1[216];
/** @brief The per-texel interpolation weights for the block. */
float weight_values_plane2[216];
/** @brief The per-texel partition assignments for the block. */
uint8_t partition_assignment[216];
};
/**
* Populate a codec config based on default settings.
*
* Power users can edit the returned config struct to fine tune before allocating the context.
*
* @param profile Color profile.
* @param block_x ASTC block size X dimension.
* @param block_y ASTC block size Y dimension.
* @param block_z ASTC block size Z dimension.
* @param quality Search quality preset / effort level. Either an
* @c ASTCENC_PRE_* value, or a effort level between 0
* and 100. Performance is not linear between 0 and 100.
* @param flags A valid set of @c ASTCENC_FLG_* flag bits.
* @param[out] config Output config struct to populate.
*
* @return @c ASTCENC_SUCCESS on success, or an error if the inputs are invalid
* either individually, or in combination.
*/
ASTCENC_PUBLIC astcenc_error astcenc_config_init(
astcenc_profile profile,
unsigned int block_x,
unsigned int block_y,
unsigned int block_z,
float quality,
unsigned int flags,
astcenc_config* config);
/**
* @brief Allocate a new codec context based on a config.
*
* This function allocates all of the memory resources and threads needed by the codec. This can be
* slow, so it is recommended that contexts are reused to serially compress or decompress multiple
* images to amortize setup cost.
*
* Contexts can be allocated to support only decompression using the @c ASTCENC_FLG_DECOMPRESS_ONLY
* flag when creating the configuration. The compression functions will fail if invoked. For a
* decompress-only library build the @c ASTCENC_FLG_DECOMPRESS_ONLY flag must be set when creating
* any context.
*
* @param[in] config Codec config.
* @param thread_count Thread count to configure for.
* @param[out] context Location to store an opaque context pointer.
*
* @return @c ASTCENC_SUCCESS on success, or an error if context creation failed.
*/
ASTCENC_PUBLIC astcenc_error astcenc_context_alloc(
const astcenc_config* config,
unsigned int thread_count,
astcenc_context** context);
/**
* @brief Compress an image.
*
* A single context can only compress or decompress a single image at a time.
*
* For a context configured for multi-threading, any set of the N threads can call this function.
* Work will be dynamically scheduled across the threads available. Each thread must have a unique
* @c thread_index.
*
* @param context Codec context.
* @param[in,out] image An input image, in 2D slices.
* @param swizzle Compression data swizzle, applied before compression.
* @param[out] data_out Pointer to output data array.
* @param data_len Length of the output data array.
* @param thread_index Thread index [0..N-1] of calling thread.
*
* @return @c ASTCENC_SUCCESS on success, or an error if compression failed.
*/
ASTCENC_PUBLIC astcenc_error astcenc_compress_image(
astcenc_context* context,
astcenc_image* image,
const astcenc_swizzle* swizzle,
uint8_t* data_out,
size_t data_len,
unsigned int thread_index);
/**
* @brief Reset the codec state for a new compression.
*
* The caller is responsible for synchronizing threads in the worker thread pool. This function must
* only be called when all threads have exited the @c astcenc_compress_image() function for image N,
* but before any thread enters it for image N + 1.
*
* Calling this is not required (but won't hurt), if the context is created for single threaded use.
*
* @param context Codec context.
*
* @return @c ASTCENC_SUCCESS on success, or an error if reset failed.
*/
ASTCENC_PUBLIC astcenc_error astcenc_compress_reset(
astcenc_context* context);
/**
* @brief Decompress an image.
*
* @param context Codec context.
* @param[in] data Pointer to compressed data.
* @param data_len Length of the compressed data, in bytes.
* @param[in,out] image_out Output image.
* @param swizzle Decompression data swizzle, applied after decompression.
* @param thread_index Thread index [0..N-1] of calling thread.
*
* @return @c ASTCENC_SUCCESS on success, or an error if decompression failed.
*/
ASTCENC_PUBLIC astcenc_error astcenc_decompress_image(
astcenc_context* context,
const uint8_t* data,
size_t data_len,
astcenc_image* image_out,
const astcenc_swizzle* swizzle,
unsigned int thread_index);
/**
* @brief Reset the codec state for a new decompression.
*
* The caller is responsible for synchronizing threads in the worker thread pool. This function must
* only be called when all threads have exited the @c astcenc_decompress_image() function for image
* N, but before any thread enters it for image N + 1.
*
* Calling this is not required (but won't hurt), if the context is created for single threaded use.
*
* @param context Codec context.
*
* @return @c ASTCENC_SUCCESS on success, or an error if reset failed.
*/
ASTCENC_PUBLIC astcenc_error astcenc_decompress_reset(
astcenc_context* context);
/**
* Free the compressor context.
*
* @param context The codec context.
*/
ASTCENC_PUBLIC void astcenc_context_free(
astcenc_context* context);
/**
* @brief Provide a high level summary of a block's encoding.
*
* This feature is primarily useful for codec developers but may be useful for developers building
* advanced content packaging pipelines.
*
* @param context Codec context.
* @param data One block of compressed ASTC data.
* @param info The output info structure to populate.
*
* @return @c ASTCENC_SUCCESS if the block was decoded, or an error otherwise. Note that this
* function will return success even if the block itself was an error block encoding, as the
* decode was correctly handled.
*/
ASTCENC_PUBLIC astcenc_error astcenc_get_block_info(
astcenc_context* context,
const uint8_t data[16],
astcenc_block_info* info);
/**
* @brief Get a printable string for specific status code.
*
* @param status The status value.
*
* @return A human readable nul-terminated string.
*/
ASTCENC_PUBLIC const char* astcenc_get_error_string(
astcenc_error status);
#endif