lpi (Lode's Programming Interface) Code

/*
Copyright (c) 2005-2008 Lode Vandevenne
All rights reserved.

This file is part of Lode's Programming Interface.

Lode's Programming Interface is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Lode's Programming Interface is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Lode's Programming Interface.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef LPI_MATH_H_INCLUDED
#define LPI_MATH_H_INCLUDED

#include <vector>
#include <cmath>
#include <algorithm> //std::min and std::max

namespace lpi
{

void sort(std::vector<int> &order, std::vector<double> &dist);

double getRandom();
int getRandom(int first, int last); //get random number in the range of integers first-last (including last)
double getRandom(double first, double last); //get random number in the range of doubles first-last

int wrap(int i, int n); //wraps i between 0 and n, using the modulo operator
int clamp(int a, int low, int high);
double clamp(double a, double low, double high);

bool isPowerOfTwo(int n);
int floatMod(double f, int m); //TODO: remove, this is just fmod from the C library
int gcd(int a, int b);

static const double pi = 3.14159265358979323846264338327950288419716939937510; //why isn't this in standard C++ anyway
static const double twopi = 6.283185307179586477;

inline int intdown(double f) //intdown(0.5) becomes 0, intdown(-0.5) becomes -1, intdown(0.0) becomes something unknown, it's a border
{
  if(f > 0) return int(f);
  else return int(f) - 1;
}

inline int intdivdown(int a, int b) //divide so that 2/2 = 1, 1/2 = 0, -1/2 = -1, -2/2 = -1, ... (more logical on 2D tile maps than the standard integer dividion)
{
  if(a < 0) return -((-a - 1) / b + 1);
  else return a / b;
}

/*
For the solve functions below:
*) return value is number of real solutions
*) if the number of solutions is smaller than the number of "x" parameters, then
   the valid values are filled in the first x'es.
*) the last x'es will then contain meaningless values that may be either
   the real part of a complex solutions, an uninitialized value, or the value
   they already had before being given as parameter to the function, but there's
   no way provided to find whether or not that's the case, so only use the
   first x'es that are said to be valid according to the return value
*) in some functions it's specified that the x'es will have the real part of the
   complex solution, e.g. for quadsol
*/
int linsol(double& x1, double a, double b); //linear equation solution (ax+b=0). if a == 0.0, then it'll return that there were 0 solutions
int quadsol(double& x1, double& x2, double a, double b, double c); //quadratic equation solution (axx+bx+c=0)
int cubicsol(double& x1, double& x2, double& x3, double a, double b, double c, double d); //cubic equation solution (axxx+bxx+cx+d=0). number of real solutions is always at least 1 if a isn't 0.0, else quadsol will be called.
int quartsol(double& x1, double& x2, double& x3, double& x4, double a, double b, double c, double d, double e); //quadratic equation solution (axxxx+bxxx+cxx+dx+e=0)


}

#endif