forked from bartvdbraak/blender
e12c08e8d1
Apply clang format as proposed in T53211. For details on usage and instructions for migrating branches without conflicts, see: https://wiki.blender.org/wiki/Tools/ClangFormat
127 lines
3.0 KiB
C++
127 lines
3.0 KiB
C++
/*
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* Copyright 2018 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/* This is taken from alShaders/Cryptomatte/MurmurHash3.h:
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*
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* MurmurHash3 was written by Austin Appleby, and is placed in the public
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* domain. The author hereby disclaims copyright to this source code.
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*/
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#include <stdlib.h>
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#include <string.h>
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#include "util/util_algorithm.h"
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#include "util/util_murmurhash.h"
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#if defined(_MSC_VER)
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# define ROTL32(x, y) _rotl(x, y)
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# define ROTL64(x, y) _rotl64(x, y)
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# define BIG_CONSTANT(x) (x)
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#else
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ccl_device_inline uint32_t rotl32(uint32_t x, int8_t r)
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{
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return (x << r) | (x >> (32 - r));
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}
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# define ROTL32(x, y) rotl32(x, y)
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# define BIG_CONSTANT(x) (x##LLU)
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#endif
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CCL_NAMESPACE_BEGIN
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/* Block read - if your platform needs to do endian-swapping or can only
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* handle aligned reads, do the conversion here. */
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ccl_device_inline uint32_t mm_hash_getblock32(const uint32_t *p, int i)
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{
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return p[i];
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}
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/* Finalization mix - force all bits of a hash block to avalanche */
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ccl_device_inline uint32_t mm_hash_fmix32(uint32_t h)
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{
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h ^= h >> 16;
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h *= 0x85ebca6b;
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h ^= h >> 13;
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h *= 0xc2b2ae35;
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h ^= h >> 16;
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return h;
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}
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uint32_t util_murmur_hash3(const void *key, int len, uint32_t seed)
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{
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const uint8_t *data = (const uint8_t *)key;
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const int nblocks = len / 4;
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uint32_t h1 = seed;
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const uint32_t c1 = 0xcc9e2d51;
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const uint32_t c2 = 0x1b873593;
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const uint32_t *blocks = (const uint32_t *)(data + nblocks * 4);
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for (int i = -nblocks; i; i++) {
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uint32_t k1 = mm_hash_getblock32(blocks, i);
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k1 *= c1;
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k1 = ROTL32(k1, 15);
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k1 *= c2;
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h1 ^= k1;
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h1 = ROTL32(h1, 13);
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h1 = h1 * 5 + 0xe6546b64;
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}
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const uint8_t *tail = (const uint8_t *)(data + nblocks * 4);
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uint32_t k1 = 0;
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switch (len & 3) {
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case 3:
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k1 ^= tail[2] << 16;
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ATTR_FALLTHROUGH;
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case 2:
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k1 ^= tail[1] << 8;
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ATTR_FALLTHROUGH;
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case 1:
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k1 ^= tail[0];
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k1 *= c1;
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k1 = ROTL32(k1, 15);
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k1 *= c2;
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h1 ^= k1;
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}
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h1 ^= len;
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h1 = mm_hash_fmix32(h1);
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return h1;
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}
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/* This is taken from the cryptomatte specification 1.0 */
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float util_hash_to_float(uint32_t hash)
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{
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uint32_t mantissa = hash & ((1 << 23) - 1);
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uint32_t exponent = (hash >> 23) & ((1 << 8) - 1);
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exponent = max(exponent, (uint32_t)1);
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exponent = min(exponent, (uint32_t)254);
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exponent = exponent << 23;
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uint32_t sign = (hash >> 31);
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sign = sign << 31;
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uint32_t float_bits = sign | exponent | mantissa;
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float f;
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memcpy(&f, &float_bits, sizeof(uint32_t));
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return f;
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}
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CCL_NAMESPACE_END
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