Allow geocentric distance computations to return radians.

[simgear.git] / simgear / math / sg_random.h

diff --git a/simgear/math/sg_random.h b/simgear/math/sg_random.h
index 8b263b33a2f0f2b033ad23c1466dae1568bb18ca..1fed733d3aa5c683d8903177350ab70a0643c126 100644 (file)
--- a/simgear/math/sg_random.h
+++ b/simgear/math/sg_random.h
@@ -5,7 +5,7 @@
 
 // Written by Curtis Olson, started July 1997.
 //
-// Copyright (C) 1997  Curtis L. Olson  - curt@infoplane.com
+// Copyright (C) 1997  Curtis L. Olson  - http://www.flightgear.org/~curt
 //
 // This library is free software; you can redistribute it and/or
 // modify it under the terms of the GNU Library General Public
@@ -17,10 +17,9 @@
 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 // Library General Public License for more details.
 //
-// You should have received a copy of the GNU Library General Public
-// License along with this library; if not, write to the
-// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-// Boston, MA  02111-1307, USA.
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 //
 // $Id$
 
@@ -34,18 +33,50 @@ extern "C" {
 #endif                                   
 
 
+#define MT_N 624
+#define MT_M 397
+
+/**
+ * Structure to hold MT algorithm state to easily allow independant
+ * sets of random numbers with different seeds.
+ */
+struct {unsigned int array[MT_N]; int index; } typedef mt;
+
+/**
+ * Initialize a new MT state with a given seed.
+ */
+void mt_init(mt *mt, unsigned int seed);
+
+/**
+ * Generate a new 32-bit random number based on the given MT state.
+ */
+unsigned int mt_rand32( mt *mt);
+
+/**
+ * Generate a new random number between [0.0, 1.0) based 
+ * on the given MT state.
+ */
+double mt_rand(mt *mt);
+ 
 /**
  * Seed the random number generater with time() so we don't see the
  * same sequence every time.
  */
 void sg_srandom_time();
 
+/**
+ * Seed the random number generater with time() in 10 minute intervals
+ * so we get the same sequence within 10 minutes interval.
+ * This is useful for synchronizing two display systems.
+ */
+void sg_srandom_time_10();
+
 /**
  * Seed the random number generater with your own seed so can set up
  * repeatable randomization.
  * @param seed random number generator seed
  */
-void sg_srandom( unsigned int seed );
+void sg_srandom(unsigned int seed );
 
 /**
  * Return a random number between [0.0, 1.0)