--- deliantra/server/include/util.h	2007/01/15 00:40:49	1.27
+++ deliantra/server/include/util.h	2007/01/15 01:25:41	1.28
@@ -8,6 +8,7 @@
 #endif
 
 #include <cstddef>
+#include <cmath>
 #include <new>
 #include <vector>
 
@@ -34,6 +35,36 @@
 #define IN_RANGE_EXC(val,beg,end) \
   ((unsigned int)(val) - (unsigned int)(beg) <  (unsigned int)(end) - (unsigned int)(beg))
 
+// this is much faster than crossfires original algorithm
+// on modern cpus
+inline int
+isqrt (int n)
+{
+  return (int)sqrtf ((float)n);
+}
+
+// this is only twice as fast as naive sqrtf (dx*dy+dy*dy)
+#if 0
+// and has a max. error of 6 in the range -100..+100.
+#else
+// and has a max. error of 9 in the range -100..+100.
+#endif
+inline int 
+idistance (int dx, int dy)
+{ 
+  unsigned int dx_ = abs (dx);
+  unsigned int dy_ = abs (dy);
+
+#if 0
+  return dx_ > dy_
+      ? (dx_ * 61685 + dy_ * 26870) >> 16
+      : (dy_ * 61685 + dx_ * 26870) >> 16;
+#else
+  return dx + dy - min (dx, dy) * 5 / 8;
+#endif
+}
+
+
 // makes dynamically allocated objects zero-initialised
 struct zero_initialised
 {