mathutils.cpp

#include "mathutils.h"
#include <cmath>
#include <iostream>
#include <math.h>

MathUtils::MathUtils()
{
}

double MathUtils::fonctionQuadratique(double min, double max, double x) {

    return x<min?0.0:x>=max?1.0:1.0-pow((1.0-pow((x-min)/(max-min),2)),2);
}

double MathUtils::fonctionQuadratiqueInv(double min, double max, double x) {
    return 1.0-fonctionQuadratique(min,max,x);
}

double MathUtils::interpolate(double before_p0, double p0, double p1, double after_p1, double t)
{
    //Calcul des coefficients de notre polynôme
    double a3 = -0.5*before_p0 + 1.5*p0 - 1.5*p1 + 0.5*after_p1;
    double a2 = before_p0 - 2.5*p0 + 2*p1 - 0.5*after_p1;
    double a1 = -0.5*before_p0 + 0.5*p1;
    double a0 = p0;

    //Calcul de la valeur de ce polynôme en t
    return (a3 * t*t*t) + (a2 * t*t) + (a1 * t) + a0;
}

double MathUtils::ridge(double n, double s) {
    return n>s?2*s-n:n;
}

double MathUtils::mod(double a, double b) {
    while(a>b) {a-=b;}
    return a;
}

double MathUtils::dabs(double d) {
    return d>=0?d:-d;
}

double MathUtils::aireTriangle(const Vector2D & a, const Vector2D & b, const Vector2D & c)
{
    double ab = a.distanceToPoint2D(b);
    double ac = a.distanceToPoint2D(c);
    double cb = c.distanceToPoint2D(b);
    double s = (ab+ac+cb)/2;

    return sqrt(s*(s-ab)*(s-ac)*(s-cb));
}

double MathUtils::random(double min, double max)
{
    double f = (double)rand() / RAND_MAX;
    return min + f * (max - min);
}