/**
* Hj. Malthaner's routine included 2 different noise smoothing methods.
* We now use the "raw" int_noise one.
* However, it may be useful to move to the other routine in future.
* So it is included too.
*/
static double smoothed_noise(const int x, const int y, const int prime)
{
#if 0
/* A hilly world (four corner smooth) */
const double sides = int_noise(x - 1, y) + int_noise(x + 1, y) + int_noise(x, y - 1) + int_noise(x, y + 1);
const double center = int_noise(x, y);
return (sides + sides + center * 4) / 8.0;
#endif
/* This gives very hilly world */
return int_noise(x, y, prime);
}
/**
* This routine returns the smoothed interpolated noise for an x and y, using
* the values from the surrounding positions.
*/
static double interpolated_noise(const double x, const double y, const int prime)
{
const int integer_X = (int)x;
const int integer_Y = (int)y;
const double fractional_X = x - (double)integer_X;
const double fractional_Y = y - (double)integer_Y;
const double v1 = int_noise(integer_X, integer_Y, prime);
const double v2 = int_noise(integer_X + 1, integer_Y, prime);
const double v3 = int_noise(integer_X, integer_Y + 1, prime);
const double v4 = int_noise(integer_X + 1, integer_Y + 1, prime);
const double i1 = linear_interpolate(v1, v2, fractional_X);
const double i2 = linear_interpolate(v3, v4, fractional_X);
return linear_interpolate(i1, i2, fractional_Y);
}
