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Granite/bitextract.h at master · Themaister/Granite · GitHub

 3 years ago
source link: https://github.com/Themaister/Granite/blob/master/assets/shaders/decode/bitextract.h
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Granite/bitextract.h at master · Themaister/Granite · GitHub

83 lines (75 sloc) 2.89 KB

/* Copyright (c) 2020 Hans-Kristian Arntzen * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */

#ifndef BITEXTRACT_H_ #define BITEXTRACT_H_

int extract_bits(uvec4 payload, int offset, int bits) { int last_offset = offset + bits - 1; int result;

if (bits <= 0) result = 0; else if ((last_offset >> 5) == (offset >> 5)) result = int(bitfieldExtract(payload[offset >> 5], offset & 31, bits)); else { int first_bits = 32 - (offset & 31); int result_first = int(bitfieldExtract(payload[offset >> 5], offset & 31, first_bits)); int result_second = int(bitfieldExtract(payload[(offset >> 5) + 1], 0, bits - first_bits)); result = result_first | (result_second << first_bits); } return result; }

int extract_bits_sign(uvec4 payload, int offset, int bits) { int last_offset = offset + bits - 1; int result;

if (bits <= 0) result = 0; else if ((last_offset >> 5) == (offset >> 5)) result = bitfieldExtract(int(payload[offset >> 5]), offset & 31, bits); else { int first_bits = 32 - (offset & 31); int result_first = int(bitfieldExtract(payload[offset >> 5], offset & 31, first_bits)); int result_second = bitfieldExtract(int(payload[(offset >> 5) + 1]), 0, bits - first_bits); result = result_first | (result_second << first_bits); } return result; }

int extract_bits_reverse(uvec4 payload, int offset, int bits) { int last_offset = offset + bits - 1; int result;

if (bits <= 0) result = 0; else if ((last_offset >> 5) == (offset >> 5)) result = int(bitfieldReverse(bitfieldExtract(payload[offset >> 5], offset & 31, bits)) >> (32 - bits)); else { int first_bits = 32 - (offset & 31); uint result_first = bitfieldExtract(payload[offset >> 5], offset & 31, first_bits); uint result_second = bitfieldExtract(payload[(offset >> 5) + 1], 0, bits - first_bits); result = int(bitfieldReverse(result_first | (result_second << first_bits)) >> (32 - bits)); } return result; }

#endif


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