From dfd6bc3c91c7bd508b5bde820366784bd980a677 Mon Sep 17 00:00:00 2001 From: Jared Adams Date: Tue, 14 Apr 2009 16:44:03 -0600 Subject: Start a MathUtils file It has fast(inv)sqrt and weightedAverage. Also cleanup the last ocmmit a bit. --- src/utils/fastsqrt.h | 24 ------------------------ 1 file changed, 24 deletions(-) delete mode 100644 src/utils/fastsqrt.h (limited to 'src/utils') diff --git a/src/utils/fastsqrt.h b/src/utils/fastsqrt.h deleted file mode 100644 index 78768149..00000000 --- a/src/utils/fastsqrt.h +++ /dev/null @@ -1,24 +0,0 @@ -/* A very fast function to calculate the approximate inverse square root of a - * floating point value and a helper function that uses it for getting the - * normal squareroot. For an explanation of the inverse squareroot function - * read: - * http://www.math.purdue.edu/~clomont/Math/Papers/2003/InvSqrt.pdf - * - * Unfortunately the original creator of this function seems to be unknown. - */ - -float fastInvSqrt(float x) -{ - union { int i; float x; } tmp; - float xhalf = 0.5f * x; - tmp.x = x; - tmp.i = 0x5f375a86 - (tmp.i >> 1); - x = tmp.x; - x = x * (1.5f - xhalf * x * x); - return x; -} - -float fastSqrt(float x) -{ - return 1.0f / fastInvSqrt(x); -} -- cgit v1.2.3-60-g2f50