| /* -*- 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 | |
| */ | |
| /** | |
| * @~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) | |
| { | |
| const uint32_t *BDFDB = DFD+1; | |
| uint32_t numSamples = KHR_DFDSAMPLECOUNT(BDFDB); | |
| uint32_t sampleNumber; | |
| uint32_t currentChannel = ~0U; /* Don't start matched. */ | |
| /* This is specifically for unpacked formats which means the size of */ | |
| /* each component is the same. */ | |
| *numComponents = 0; | |
| for (sampleNumber = 0; sampleNumber < numSamples; ++sampleNumber) { | |
| uint32_t sampleByteLength = (KHR_DFDSVAL(BDFDB, sampleNumber, BITLENGTH) + 1) >> 3U; | |
| uint32_t sampleChannel = KHR_DFDSVAL(BDFDB, sampleNumber, CHANNELID); | |
| if (sampleChannel == currentChannel) { | |
| /* Continuation of the same channel. */ | |
| /* Accumulate the byte length. */ | |
| *componentByteLength += sampleByteLength; | |
| } else { | |
| /* Everything is new. Hopefully. */ | |
| currentChannel = sampleChannel; | |
| (*numComponents)++; | |
| *componentByteLength = sampleByteLength; | |
| } | |
| } | |
| } | |
| /** | |
| * @~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) | |
| { | |
| const uint32_t *BDFDB = DFD+1; | |
| uint32_t currentChannel = ~0U; /* Don't start matched. */ | |
| uint32_t numComponents = 0; | |
| uint32_t numSamples = KHR_DFDSAMPLECOUNT(BDFDB); | |
| uint32_t sampleNumber; | |
| for (sampleNumber = 0; sampleNumber < numSamples; ++sampleNumber) { | |
| uint32_t sampleChannel = KHR_DFDSVAL(BDFDB, sampleNumber, CHANNELID); | |
| if (sampleChannel != currentChannel) { | |
| numComponents++; | |
| currentChannel = sampleChannel; | |
| } | |
| } | |
| return numComponents; | |
| } | |
| /** | |
| * @~English | |
| * @brief Reconstruct the value of bytesPlane0 from sample info. | |
| * | |
| * @deprecated Use reconstructDFDBytesPlanesFromSamples. This does not handle | |
| * the possible second plane of the ETC1S model. | |
| * | |
| * Reconstruct the value for data that has been variable-rate compressed | |
| * and and whose bytesPlane0 value has been set to 0. For DFDs that | |
| * are valid for KTX files. Little-endian data only and no multi-plane models | |
| * except ETC1S. | |
| * | |
| * @param DFD Pointer to the Data Format Descriptor for which to provide | |
| * the value described as 32-bit words in native endianness. | |
| * Note that this is the whole descriptor, not just | |
| * the basic descriptor block. | |
| * @return The number of bytes a pixel occupies in bytesPlane0. | |
| */ | |
| uint32_t | |
| reconstructDFDBytesPlane0FromSamples(const uint32_t* DFD) | |
| { | |
| const uint32_t *BDFDB = DFD+1; | |
| uint32_t numSamples = KHR_DFDSAMPLECOUNT(BDFDB); | |
| uint32_t sampleNumber; | |
| uint32_t bitsPlane0 = 0; | |
| int32_t largestOffset = 0; | |
| uint32_t sampleNumberWithLargestOffset = 0; | |
| // Special case these depth{,-stencil} formats. The unused bits are | |
| // in the MSBs so have no visibility in the DFD therefore the max offset | |
| // algorithm below returns a value that is too small. | |
| if (KHR_DFDSVAL(BDFDB, 0, CHANNELID) == KHR_DF_CHANNEL_COMMON_DEPTH) { | |
| if (numSamples == 1) { | |
| if (KHR_DFDSVAL(BDFDB, 0, BITLENGTH) + 1 == 24) { | |
| // X8_D24_UNORM_PACK32, | |
| return 4; | |
| } | |
| } else if (numSamples == 2) { | |
| if (KHR_DFDSVAL(BDFDB, 0, BITLENGTH) + 1 == 16) { | |
| // D16_UNORM_S8_UINT | |
| return 4; | |
| } | |
| if (KHR_DFDSVAL(BDFDB, 0, BITLENGTH) + 1 == 32 | |
| && KHR_DFDSVAL(BDFDB, 1, CHANNELID) == KHR_DF_CHANNEL_COMMON_STENCIL) { | |
| // D32_SFLOAT_S8_UINT | |
| return 8; | |
| } | |
| } | |
| } | |
| if (KHR_DFDVAL(BDFDB, MODEL) == KHR_DF_MODEL_ETC1S) { | |
| // Size of the first plane. | |
| return 8; | |
| } | |
| for (sampleNumber = 0; sampleNumber < numSamples; ++sampleNumber) { | |
| int32_t sampleBitOffset = KHR_DFDSVAL(BDFDB, sampleNumber, BITOFFSET); | |
| if (sampleBitOffset > largestOffset) { | |
| largestOffset = sampleBitOffset; | |
| sampleNumberWithLargestOffset = sampleNumber; | |
| } | |
| } | |
| /* The sample bitLength field stores the bit length - 1. */ | |
| uint32_t sampleBitLength = KHR_DFDSVAL(BDFDB, sampleNumberWithLargestOffset, BITLENGTH) + 1; | |
| bitsPlane0 = largestOffset + sampleBitLength; | |
| return bitsPlane0 >> 3U; | |
| } | |
| /** | |
| * @~English | |
| * @brief Reconstruct the values of bytesPlane[01] from sample info. | |
| * | |
| * Reconstruct the values for data that has been variable-rate compressed | |
| * and whose bytesPlane[01] values have been set to 0 and update the | |
| * fields of the target DFD. For DFDs that are valid for KTX files. | |
| * Little-endian data only and no multi-plane models except ETC1S hence | |
| * only looking at bytesPlane0 abd bytesPlane1. | |
| * | |
| * @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. | |
| */ | |
| void | |
| reconstructDFDBytesPlanesFromSamples(uint32_t* DFD) | |
| { | |
| uint32_t *BDFDB = DFD+1; | |
| KHR_DFDSETVAL(BDFDB, BYTESPLANE0, reconstructDFDBytesPlane0FromSamples(DFD)); | |
| if (KHR_DFDVAL(BDFDB, MODEL) == KHR_DF_MODEL_ETC1S) { | |
| if (KHR_DFDSAMPLECOUNT(BDFDB) == 2) | |
| KHR_DFDSETVAL(BDFDB, BYTESPLANE1, 8); | |
| } | |
| } | |
| /** | |
| * @~English | |
| * @brief Reconstruct the value of bytesPlane0 from sample info. | |
| * | |
| * @see reconstructDFDBytesPlane0FromSamples for details. | |
| * @deprecated For backward comparibility only. Use | |
| * reconstructDFDBytesPlanesFromSamples. | |
| * | |
| * @param DFD Pointer to the Data Format Descriptor for which to provide | |
| * the value 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) | |
| { | |
| *bytesPlane0 = reconstructDFDBytesPlane0FromSamples(DFD); | |
| } | |