godot/thirdparty/libktx/lib/dfdutils/queries.c

/* -*- tab-width: 4; -*- */
/* vi: set sw=2 ts=4 expandtab: */

/* Copyright 2019-2020 The Khronos Group Inc.
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @file
 * @~English
 * @brief Utilities for querying info from a data format descriptor.
 * @author Mark Callow
 */

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <KHR/khr_df.h>
#include "dfd.h"

/**
 * @~English
 * @brief Get the number and size of the image components from a DFD.
 *
 * This simplified function is for use only with the DFDs for unpacked
 * formats which means all components have the same size.
 *
 * @param DFD Pointer to a Data Format Descriptor to interpret,
              described as 32-bit words in native endianness.
              Note that this is the whole descriptor, not just
              the basic descriptor block.
 * @param numComponents pointer to a 32-bit word in which the number of
                        components will be written.
 * @param componentByteLength pointer to a 32-bit word in which the size of
                              a component in bytes will be written.
 */
void
getDFDComponentInfoUnpacked(const uint32_t* DFD, uint32_t* numComponents,
                            uint32_t* componentByteLength)
{ … }

/**
 * @~English
 * @brief Return the number of "components" in the data.
 *
 * Calculates the number of uniques samples in the DFD by combining
 * multiple samples for the same channel. For uncompressed colorModels
 * this is the same as the number of components in the image data. For
 * block-compressed color models this is the number of samples in
 * the color model, typically 1 and in a few cases 2.
 *
 * @param DFD Pointer to a Data Format Descriptor for which,
 *            described as 32-bit words in native endianness.
 *            Note that this is the whole descriptor, not just
 *            the basic descriptor block.
 */
uint32_t getDFDNumComponents(const uint32_t* DFD)
{ … }


/**
 * @~English
 * @brief Reconstruct the value of bytesPlane0 from sample info.
 *
 * Reconstruct the value for data that has been variable-rate compressed so
 * has bytesPlane0 = 0.  For DFDs that are valid for KTX files. Little-endian
 * data only and no multi-plane formats.
 *
 * @param DFD Pointer to a Data Format Descriptor for which,
 *            described as 32-bit words in native endianness.
 *            Note that this is the whole descriptor, not just
 *            the basic descriptor block.
 */
uint32_t
reconstructDFDBytesPlane0FromSamples(const uint32_t* DFD)
{ … }

/**
 * @~English
 * @brief Reconstruct the value of bytesPlane0 from sample info.
 *
 * @see reconstructDFDBytesPlane0FromSamples for details.
 * @deprecated For backward comparibility only. Use
 *             reconstructDFDBytesPlane0FromSamples.
 *
 * @param DFD Pointer to a Data Format Descriptor for which,
 *            described as 32-bit words in native endianness.
 *            Note that this is the whole descriptor, not just
 *            the basic descriptor block.
 * @param bytesPlane0  pointer to a 32-bit word in which the recreated
 *                    value of bytesPlane0 will be written.
 */
void
recreateBytesPlane0FromSampleInfo(const uint32_t* DFD, uint32_t* bytesPlane0)
{ … }