From: ehofman <ehofman>
Date: Sat, 28 Jun 2003 12:58:59 +0000 (+0000)
Subject: Fix some problems
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=dcdf8a4d5c6b526dc58445b647d37c1fb53f2748;p=simgear.git

Fix some problems
---

diff --git a/simgear/math/fastmath.cxx b/simgear/math/fastmath.cxx
index ce8e253b..c95ccbcc 100644
--- a/simgear/math/fastmath.cxx
+++ b/simgear/math/fastmath.cxx
@@ -47,46 +47,17 @@ double fast_exp(double val) {
 }
 
 
-double fast_log2 (double val)
-{
-   int * const    exp_ptr = reinterpret_cast <int *> (&val);
-   int            x = *exp_ptr;
-   const int      log_2 = ((x >> 23) & 255) - 128;
-   x &= ~(255 << 23);
-   x += 127 << 23;
-   *exp_ptr = x;
-
-   val = ((-1.0f/3) * val + 2) * val - 2.0f/3;   // (1)
-
-   return (val + log_2);
-}
-
-/**
- * This function is about 3 times faster than the system log() function
- * and has an error of about 0.01%
- */
-double fast_log (double val)
-{
-   return (fast_log2 (val) * 0.69314718f);
-}
-
-double fast_log10 (double val)
-{
-   return (fast_log (val) / fast_log (10));
-}
-
-
 /**
  * While we're on the subject, someone might have use for these as well?
  * Float Shift Left and Float Shift Right. Do what you want with this.
  */
-void fast_BSL(double &x, register unsigned long shiftAmount) {
+void fast_BSL(float &x, register unsigned long shiftAmount) {
 
 	*(unsigned long*)&x+=shiftAmount<<23;
 
 }
 
-void fast_BSR(double &x, register unsigned long shiftAmount) {
+void fast_BSR(float &x, register unsigned long shiftAmount) {
 
 	*(unsigned long*)&x-=shiftAmount<<23;
 
diff --git a/simgear/math/fastmath.hxx b/simgear/math/fastmath.hxx
index b2b5595a..7ce8f461 100644
--- a/simgear/math/fastmath.hxx
+++ b/simgear/math/fastmath.hxx
@@ -28,12 +28,40 @@
 
 #include <math.h>
 
-double fast_exp(double y);
-double fast_log(double val);
-double fast_log2 (double val);
-double fast_log10(double val);
-void fast_BSL(double &x, register unsigned long shiftAmount);
-void fast_BSR(double &x, register unsigned long shiftAmount);
+
+double fast_exp(double val);
+
+void fast_BSL(float &x, register unsigned long shiftAmount);
+void fast_BSR(float &x, register unsigned long shiftAmount);
+
+inline float fast_log2 (float val)
+{
+   int * const    exp_ptr = reinterpret_cast <int *> (&val);
+   int            x = *exp_ptr;
+   const int      log_2 = ((x >> 23) & 255) - 128;
+   x &= ~(255 << 23);
+   x += 127 << 23;
+   *exp_ptr = x;
+
+   val = ((-1.0f/3) * val + 2) * val - 2.0f/3;   // (1)
+
+   return (val + log_2);
+}
+
+/**
+ * This function is about 3 times faster than the system log() function
+ * and has an error of about 0.01%
+ */
+inline float fast_log (const float &val)
+{
+   return (fast_log2 (val) * 0.69314718f);
+}
+
+inline float fast_log10 (const float &val)
+{
+   return (fast_log2(val) / 3.321928095f);
+}
+
 
 #endif // !_SG_FMATH_HXX
 
diff --git a/simgear/sound/sound.cxx b/simgear/sound/sound.cxx
index 8ceaf182..280f72e0 100644
--- a/simgear/sound/sound.cxx
+++ b/simgear/sound/sound.cxx
@@ -32,7 +32,6 @@
 
 #include <simgear/debug/logstream.hxx>
 #include <simgear/props/condition.hxx>
-#include <simgear/math/fastmath.hxx>
 
 
 #include "sound.hxx"
@@ -42,8 +41,8 @@
 static double _snd_inv(double v)   { return (v == 0) ? 1e99 : 1/v; }
 static double _snd_abs(double v)   { return (v >= 0) ? v : -v; }
 static double _snd_sqrt(double v)  { return (v < 0) ? sqrt(-v) : sqrt(v); }
-static double _snd_log10(double v) { return (v < 1) ? 0 : fast_log10(v); }
-static double _snd_log(double v)   { return (v < 1) ? 0 : fast_log(v); }
+static double _snd_log10(double v) { return (v < 1) ? 0 : log10(v); }
+static double _snd_log(double v)   { return (v < 1) ? 0 : log(v); }
 // static double _snd_sqr(double v)   { return v*v; }
 // static double _snd_pow3(double v)  { return v*v*v; }