GetRandomBell

Adds a console function called GetRandomBell() that returns a random
number that is normally distributed.  Mean and standard deviation can
optionally be included.  This required adding one new file to the
project.  This one done in VS2013 and VS2015.  Additional compilers will
need to add the file as well.

engine/compilers/VisualStudio 2013/Torque 2D.vcxproj

@@ -961,6 +961,7 @@
     <ClInclude Include="..\..\source\io\zip\zipTempStream.h" />
     <ClInclude Include="..\..\source\math\box_ScriptBinding.h" />
     <ClInclude Include="..\..\source\math\matrix_ScriptBinding.h" />
+    <ClInclude Include="..\..\source\math\mNormalDistribution.h" />
     <ClInclude Include="..\..\source\math\random_ScriptBinding.h" />
     <ClInclude Include="..\..\source\math\rectClipper.h" />
     <ClInclude Include="..\..\source\math\vector_ScriptBinding.h" />

engine/compilers/VisualStudio 2013/Torque 2D.vcxproj.filters

@@ -3198,6 +3198,9 @@
     <ClInclude Include="..\..\source\audio\audioDescriptions.h">
       <Filter>audio</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\source\math\mNormalDistribution.h">
+      <Filter>math</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <CustomBuild Include="..\..\source\math\mMath_ASM.asm">

engine/compilers/VisualStudio 2015/Torque 2D.vcxproj

@@ -961,6 +961,7 @@
     <ClInclude Include="..\..\source\io\zip\zipTempStream.h" />
     <ClInclude Include="..\..\source\math\box_ScriptBinding.h" />
     <ClInclude Include="..\..\source\math\matrix_ScriptBinding.h" />
+    <ClInclude Include="..\..\source\math\mNormalDistribution.h" />
     <ClInclude Include="..\..\source\math\random_ScriptBinding.h" />
     <ClInclude Include="..\..\source\math\rectClipper.h" />
     <ClInclude Include="..\..\source\math\vector_ScriptBinding.h" />

engine/compilers/VisualStudio 2015/Torque 2D.vcxproj.filters

@@ -3198,6 +3198,9 @@
     <ClInclude Include="..\..\source\audio\audioDescriptions.h">
       <Filter>audio</Filter>
     </ClInclude>
+    <ClCompile Include="..\..\source\math\mNormalDistribution.h">
+      <Filter>math</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <CustomBuild Include="..\..\source\math\mMath_ASM.asm">

engine/source/math/mNormalDistribution.h

@@ -0,0 +1,66 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) 2013 GarageGames, LLC
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//-----------------------------------------------------------------------------
+
+#ifndef _MNORMALDISTRIBUTION_H_
+#define _MNORMALDISTRIBUTION_H_
+
+#include <random>
+
+//-----------------------------------------------------------------------------
+// Modified from this Stack Overflow answer: http://stackoverflow.com/a/28619226/289956
+//-----------------------------------------------------------------------------
+
+class NormalDistributionGenerator
+{
+   std::mt19937 generator;
+   std::normal_distribution<F64> distribution;
+   S32 min;
+   S32 max;
+public:
+   NormalDistributionGenerator(S32 min, S32 max) :
+      distribution(std::round((min + max) / 2), std::round((max - min) / 6)), min(min), max(max)
+   {
+      generator.seed(Platform::getRealMilliseconds());
+   }
+
+   NormalDistributionGenerator(S32 min, S32 max, S32 mean) :
+      distribution(mean, std::round((max - min) / 6)), min(min), max(max)
+   {
+      generator.seed(Platform::getRealMilliseconds());
+   }
+
+   NormalDistributionGenerator(S32 min, S32 max, S32 mean, S32 stddev) :
+      distribution(mean, stddev), min(min), max(max)
+   {
+      generator.seed(Platform::getRealMilliseconds());
+   }
+
+   S32 operator ()() {
+      while (true) {
+         S32 number = (S32)std::round(this->distribution(generator));
+         if (number >= this->min && number <= this->max)
+            return number;
+      }
+   }
+};
+
+#endif //_MNORMALDISTRIBUTION_H_

engine/source/math/random_ScriptBinding.h

@@ -20,6 +20,8 @@
 // IN THE SOFTWARE.
 //-----------------------------------------------------------------------------
 
+#include "math/mNormalDistribution.h"
+
 ConsoleFunctionGroupBegin(RandomNumbers, "Functions relating to the generation of random numbers.");
 
 
@@ -111,6 +113,61 @@ ConsoleFunctionWithDocs(getRandomF, ConsoleFloat, 3, 3, (min, max))
     
 }
 
+/*! Gets a random integer number with normal distribution (a bell curve) from min to max with optional mean and standard deviation.
+@param min The minimum range of the random integer number.
+@param max The maximum range of the random integer number.
+@param mean The Most commonly occuring value or the center of the "bell". Must be between the min and max. Defaults to the center value between min and max.
+@param stdDev The standard deviation affects how far values tend to be from the mean. Defaults to 1/6th of the difference between min and max.
+@return A random floating-point number from min to max.
+*/
+ConsoleFunctionWithDocs(getRandomBell, ConsoleInt, 3, 5, (min, max, [ mean ]?, [ stdDev ]?))
+{
+   S32 min = dAtoi(argv[1]);
+   S32 max = dAtoi(argv[2]);
+
+   if (min > max)
+   {
+      const S32 temp = min;
+      min = max;
+      max = temp;
+   }
+
+   if (argc == 3)
+   {
+      NormalDistributionGenerator g(min, max);
+      return g();
+   }
+   else if (argc > 3 && argc <= 5)
+   {
+      S32 mean = dAtoi(argv[3]);
+      if (mean > max)
+      {
+         mean = max;
+      }
+
+      if (mean < min)
+      {
+         mean = min;
+      }
+
+      if (argc == 4)
+      {
+         NormalDistributionGenerator g(min, max, mean);
+         return g();
+      }
+      else
+      {
+         NormalDistributionGenerator g(min, max, mean, dAtoi(argv[4]));
+         return g();
+      }
+   }
+   else
+   {
+      Con::warnf("getRandomBell() - Invalid number of parameters!");
+      return 0;
+   }
+}
+
 //------------------------------------------------------------------------------
 
 ConsoleFunctionGroupEnd(RandomNumbers)