double Perlin2D::getPerlin(int x, int y){
double somme = 0;
double p = 1;
int f = 1;
int i;
for(i = 0 ; i < m_nbOctave ; ++i) {
somme += p * fonction_bruit2D(x * f, y * f);
p *= m_persistance;
f *= 2;
}
return somme * (1 - m_persistance) / (1 - p);
}
double bruit_coherent2D(double x, double y, t_n2D *N2D)
{
double somme;
double p;
int f;
int i;
somme = 0;
p = 1;
f = 1;
i = 0;
while (i < OCTAVES)
{
somme += p * fonction_bruit2D(x * f, y * f, N2D);
p *= PERSISTANCE;
f *= 2;
i++;
}
return (somme * (1 - PERSISTANCE) / (1 - p));
}