a00cf02241
Add support glTF KHR_texture_basisu extension
85 lines
2.4 KiB
C++
85 lines
2.4 KiB
C++
/* -*- tab-width: 4; -*- */
|
|
/* vi: set sw=2 ts=4 expandtab textwidth=70: */
|
|
|
|
/*
|
|
* Copyright 2019-2020 The Khronos Group Inc.
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*/
|
|
|
|
/**
|
|
* @internal
|
|
* @file basisu_sgd.h
|
|
* @~English
|
|
*
|
|
* @brief Declare global data for Basis LZ supercompression with ETC1S.
|
|
*
|
|
* These functions are private and should not be used outside the library.
|
|
*/
|
|
|
|
#ifndef _BASIS_SGD_H_
|
|
#define _BASIS_SGD_H_
|
|
|
|
#include <stdint.h>
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
// This must be the same value as cSliceDescFlagsFrameIsIFrame so we can just
|
|
// invert the bit when passing back & forth. As FrameIsIFrame is within
|
|
// a C namespace it can't easily be accessed from a c header.
|
|
enum bu_image_flags__bits_e { eBUImageIsPframe = 0x02 };
|
|
|
|
typedef uint32_t buFlags;
|
|
|
|
typedef struct ktxBasisLzGlobalHeader {
|
|
uint16_t endpointCount;
|
|
uint16_t selectorCount;
|
|
uint32_t endpointsByteLength;
|
|
uint32_t selectorsByteLength;
|
|
uint32_t tablesByteLength;
|
|
uint32_t extendedByteLength;
|
|
} ktxBasisLzGlobalHeader;
|
|
|
|
// This header is followed by imageCount "slice" descriptions.
|
|
|
|
// 1, or 2 slices per image (i.e. layer, face & slice).
|
|
// These offsets are relative to start of a mip level as given by the
|
|
// main levelIndex.
|
|
typedef struct ktxBasisLzEtc1sImageDesc {
|
|
buFlags imageFlags;
|
|
uint32_t rgbSliceByteOffset;
|
|
uint32_t rgbSliceByteLength;
|
|
uint32_t alphaSliceByteOffset;
|
|
uint32_t alphaSliceByteLength;
|
|
} ktxBasisLzEtc1sImageDesc;
|
|
|
|
#define BGD_ETC1S_IMAGE_DESCS(bgd) \
|
|
reinterpret_cast<ktxBasisLzEtc1sImageDesc*>(bgd + sizeof(ktxBasisLzGlobalHeader))
|
|
|
|
// The are followed in the global data by these ...
|
|
// uint8_t[endpointsByteLength] endpointsData;
|
|
// uint8_t[selectorsByteLength] selectorsData;
|
|
// uint8_t[tablesByteLength] tablesData;
|
|
|
|
#define BGD_ENDPOINTS_ADDR(bgd, imageCount) \
|
|
(bgd + sizeof(ktxBasisLzGlobalHeader) + sizeof(ktxBasisLzEtc1sImageDesc) * imageCount)
|
|
|
|
#define BGD_SELECTORS_ADDR(bgd, bgdh, imageCount) (BGD_ENDPOINTS_ADDR(bgd, imageCount) + bgdh.endpointsByteLength)
|
|
|
|
#define BGD_TABLES_ADDR(bgd, bgdh, imageCount) (BGD_SELECTORS_ADDR(bgd, bgdh, imageCount) + bgdh.selectorsByteLength)
|
|
|
|
#define BGD_EXTENDED_ADDR(bgd, bgdh, imageCount) (BGD_TABLES_ADDR(bgd, bgdh, imageCount) + bgdh.tablesByteLength)
|
|
|
|
// Just because this is a convenient place to put it for basis_{en,trans}code.
|
|
enum alpha_content_e {
|
|
eNone,
|
|
eAlpha,
|
|
eGreen
|
|
};
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif /* _BASIS_SGD_H_ */
|