veclavtlica
37 lines
1.1 KiB
C
37 lines
1.1 KiB
C
#ifndef COM_ZORD_H
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#define COM_ZORD_H
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#include <stdint.h>
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// #include <immintrin.h>
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extern const uint16_t com_zord_morton_table[];
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/* Z-filling curve to help with cache and data locality. */
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static inline uint32_t com_zord_order(uint16_t x, uint16_t y) {
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return (com_zord_morton_table[y >> 8] << 17) |
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(com_zord_morton_table[x >> 8] << 16) |
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(com_zord_morton_table[y & 0xFF] << 1) |
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(com_zord_morton_table[x & 0xFF]);
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// return _pdep_u32(x, 0x55555555) | _pdep_u32(y, 0xAAAAAAAA);
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}
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/* https://en.wikipedia.org/wiki/Z-order_curve#Coordinate_values*/
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static inline uint32_t com_zord_inc_x(uint32_t z) {
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return (((z | 0b10101010) + 1) & 0b01010101) | (z & 0b10101010);
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}
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static inline uint32_t com_zord_dec_x(uint32_t z) {
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return (((z & 0b01010101) - 1) & 0b01010101) | (z & 0b10101010);
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}
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static inline uint32_t com_zord_inc_y(uint32_t z) {
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return (((z | 0b01010101) + 1) & 0b10101010) | (z & 0b01010101);
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}
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static inline uint32_t com_zord_dec_y(uint32_t z) {
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return (((z & 0b10101010) - 1) & 0b10101010) | (z & 0b01010101);
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}
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#endif
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