diff options
Diffstat (limited to 'indra/llmath/llmath.h')
| -rw-r--r-- | indra/llmath/llmath.h | 34 |
1 files changed, 32 insertions, 2 deletions
diff --git a/indra/llmath/llmath.h b/indra/llmath/llmath.h index fde210ef50..0372bae106 100644 --- a/indra/llmath/llmath.h +++ b/indra/llmath/llmath.h @@ -477,8 +477,8 @@ inline F32 llsimple_angle(F32 angle) return angle; } -//calculate the nearesr power of two number for val, bounded by max_power_two -inline U32 get_nearest_power_two(U32 val, U32 max_power_two) +//SDK - Renamed this to get_lower_power_two, since this is what this actually does. +inline U32 get_lower_power_two(U32 val, U32 max_power_two) { if(!max_power_two) { @@ -493,4 +493,34 @@ inline U32 get_nearest_power_two(U32 val, U32 max_power_two) return max_power_two ; } + +// calculate next highest power of two, limited by max_power_two +// This is taken from a brilliant little code snipped on http://acius2.blogspot.com/2007/11/calculating-next-power-of-2.html +// Basically we convert the binary to a solid string of 1's with the same +// number of digits, then add one. We subtract 1 initially to handle +// the case where the number passed in is actually a power of two. +// WARNING: this only works with 32 bit ints. +inline U32 get_next_power_two(U32 val, U32 max_power_two) +{ + if(!max_power_two) + { + max_power_two = 1 << 31 ; + } + + if(val >= max_power_two) + { + return max_power_two; + } + + val--; + val = (val >> 1) | val; + val = (val >> 2) | val; + val = (val >> 4) | val; + val = (val >> 8) | val; + val = (val >> 16) | val; + val++; + + return val; +} + #endif |