85 lines
2.4 KiB
C++
85 lines
2.4 KiB
C++
/* -*- tab-width: 4; -*- */
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/* vi: set sw=2 ts=4 expandtab textwidth=70: */
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/*
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* Copyright 2019-2020 The Khronos Group Inc.
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @internal
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* @file basisu_sgd.h
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* @~English
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*
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* @brief Declare global data for Basis LZ supercompression with ETC1S.
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*
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* These functions are private and should not be used outside the library.
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*/
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#ifndef _BASIS_SGD_H_
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#define _BASIS_SGD_H_
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#include <stdint.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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// This must be the same value as cSliceDescFlagsFrameIsIFrame so we can just
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// invert the bit when passing back & forth. As FrameIsIFrame is within
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// a C namespace it can't easily be accessed from a c header.
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enum bu_image_flags__bits_e { ETC1S_P_FRAME = 0x02 };
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typedef uint32_t buFlags;
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typedef struct ktxBasisLzGlobalHeader {
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uint16_t endpointCount;
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uint16_t selectorCount;
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uint32_t endpointsByteLength;
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uint32_t selectorsByteLength;
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uint32_t tablesByteLength;
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uint32_t extendedByteLength;
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} ktxBasisLzGlobalHeader;
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// This header is followed by imageCount "slice" descriptions.
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// 1, or 2 slices per image (i.e. layer, face & slice).
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// These offsets are relative to start of a mip level as given by the
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// main levelIndex.
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typedef struct ktxBasisLzEtc1sImageDesc {
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buFlags imageFlags;
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uint32_t rgbSliceByteOffset;
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uint32_t rgbSliceByteLength;
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uint32_t alphaSliceByteOffset;
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uint32_t alphaSliceByteLength;
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} ktxBasisLzEtc1sImageDesc;
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#define BGD_ETC1S_IMAGE_DESCS(bgd) \
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reinterpret_cast<ktxBasisLzEtc1sImageDesc*>(bgd + sizeof(ktxBasisLzGlobalHeader))
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// The are followed in the global data by these ...
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// uint8_t[endpointsByteLength] endpointsData;
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// uint8_t[selectorsByteLength] selectorsData;
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// uint8_t[tablesByteLength] tablesData;
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#define BGD_ENDPOINTS_ADDR(bgd, imageCount) \
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(bgd + sizeof(ktxBasisLzGlobalHeader) + sizeof(ktxBasisLzEtc1sImageDesc) * imageCount)
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#define BGD_SELECTORS_ADDR(bgd, bgdh, imageCount) (BGD_ENDPOINTS_ADDR(bgd, imageCount) + bgdh.endpointsByteLength)
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#define BGD_TABLES_ADDR(bgd, bgdh, imageCount) (BGD_SELECTORS_ADDR(bgd, bgdh, imageCount) + bgdh.selectorsByteLength)
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#define BGD_EXTENDED_ADDR(bgd, bgdh, imageCount) (BGD_TABLES_ADDR(bgd, bgdh, imageCount) + bgdh.tablesByteLength)
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// Just because this is a convenient place to put it for basis_{en,trans}code.
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enum alpha_content_e {
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eNone,
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eAlpha,
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eGreen
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};
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#ifdef __cplusplus
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}
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#endif
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#endif /* _BASIS_SGD_H_ */
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