Optimized Morton

This commit is contained in:
Huw Pascoe 2017-09-24 22:24:45 +01:00
parent 93930a966f
commit 876aa82c29

View file

@ -8,17 +8,11 @@
namespace VideoCore { namespace VideoCore {
/** // 8x8 Z-Order coordinate from 2D coordinates
* Interleave the lower 3 bits of each coordinate to get the intra-block offsets, which are
* arranged in a Z-order curve. More details on the bit manipulation at:
* https://fgiesen.wordpress.com/2009/12/13/decoding-morton-codes/
*/
static inline u32 MortonInterleave(u32 x, u32 y) { static inline u32 MortonInterleave(u32 x, u32 y) {
u32 i = (x & 7) | ((y & 7) << 8); // ---- -210 static const u32 xlut[] = {0x00, 0x01, 0x04, 0x05, 0x10, 0x11, 0x14, 0x15};
i = (i ^ (i << 2)) & 0x1313; // ---2 --10 static const u32 ylut[] = {0x00, 0x02, 0x08, 0x0a, 0x20, 0x22, 0x28, 0x2a};
i = (i ^ (i << 1)) & 0x1515; // ---2 -1-0 return xlut[x % 8] + ylut[y % 8];
i = (i | (i >> 7)) & 0x3F;
return i;
} }
/** /**