diff options
| author | Thilo Schulz <arny@ats.s.bawue.de> | 2011-05-15 14:55:47 +0000 |
|---|---|---|
| committer | Tim Angus <tim@ngus.net> | 2013-01-09 22:29:01 +0000 |
| commit | 2958797d9f6ab773138f142412b2bd1aa5896a0f (patch) | |
| tree | beb18626e1eeed209c163916cc7144f78c88734a /src | |
| parent | b135216385b8821dee57d20cca4464332b00ecc0 (diff) | |
Optimise VectorNormalize functions, patch by Matt Turner
Diffstat (limited to 'src')
| -rw-r--r-- | src/qcommon/q_math.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/src/qcommon/q_math.c b/src/qcommon/q_math.c index e435590f..7a480510 100644 --- a/src/qcommon/q_math.c +++ b/src/qcommon/q_math.c @@ -835,10 +835,12 @@ vec_t VectorNormalize( vec3_t v ) { float length, ilength; length = v[0]*v[0] + v[1]*v[1] + v[2]*v[2]; - length = sqrt (length); if ( length ) { - ilength = 1/length; + /* writing it this way allows gcc to recognize that rsqrt can be used */ + ilength = 1/(float)sqrt (length); + /* sqrt(length) = length * (1 / sqrt(length)) */ + length *= ilength; v[0] *= ilength; v[1] *= ilength; v[2] *= ilength; @@ -851,11 +853,13 @@ vec_t VectorNormalize2( const vec3_t v, vec3_t out) { float length, ilength; length = v[0]*v[0] + v[1]*v[1] + v[2]*v[2]; - length = sqrt (length); if (length) { - ilength = 1/length; + /* writing it this way allows gcc to recognize that rsqrt can be used */ + ilength = 1/(float)sqrt (length); + /* sqrt(length) = length * (1 / sqrt(length)) */ + length *= ilength; out[0] = v[0]*ilength; out[1] = v[1]*ilength; out[2] = v[2]*ilength; |