// VoronoiMap.cpp
// Implements the cVoronoiMap class that implements a Voronoi algorithm over a noise to produce a map
#include "Globals.h"
#include "VoronoiMap.h"
cVoronoiMap::cVoronoiMap(int a_Seed, int a_CellSize) :
m_Noise(a_Seed * 13 + 7),
m_CellSize(a_CellSize)
{
}
void cVoronoiMap::SetCellSize(int a_CellSize)
{
m_CellSize = a_CellSize;
}
int cVoronoiMap::GetValueAt(int a_X, int a_Y)
{
int MinDist1, MinDist2;
return GetValueAt(a_X, a_Y, MinDist1, MinDist2);
}
int cVoronoiMap::GetValueAt(int a_X, int a_Y, int & a_MinDist)
{
int MinDist2;
return GetValueAt(a_X, a_Y, a_MinDist, MinDist2);
}
int cVoronoiMap::GetValueAt(int a_X, int a_Y, int & a_MinDist1, int & a_MinDist2)
{
// Note that due to historical reasons, the algorithm uses XZ coords, while the input uses XY coords.
// This is because the algorithm was first implemented directly in the biome generators which use MC coords.
int CellX = a_X / m_CellSize;
int CellZ = a_Y / m_CellSize;
// Get 5x5 neighboring cell seeds, compare distance to each. Return the value in the minumim-distance cell
int MinDist = m_CellSize * m_CellSize * 16; // There has to be a cell closer than this
int MinDist2 = MinDist;
int res = 0; // Will be overriden
for (int x = CellX - 2; x <= CellX + 2; x++)
{
int BaseX = x * m_CellSize;
for (int z = CellZ - 2; z < CellZ + 2; z++)
{
int OffsetX = (m_Noise.IntNoise3DInt(x, 16 * x + 32 * z, z) / 8) % m_CellSize;
int OffsetZ = (m_Noise.IntNoise3DInt(x, 32 * x - 16 * z, z) / 8) % m_CellSize;
int SeedX = BaseX + OffsetX;
int SeedZ = z * m_CellSize + OffsetZ;
int Dist = (SeedX - a_X) * (SeedX - a_X) + (SeedZ - a_Y) * (SeedZ - a_Y);
if (Dist < MinDist)
{
MinDist2 = MinDist;
MinDist = Dist;
res = m_Noise.IntNoise3DInt(x, x - z + 1000, z);
}
else if (Dist < MinDist2)
{
MinDist2 = Dist;
}
} // for z
} // for x
a_MinDist1 = MinDist;
a_MinDist2 = MinDist2;
return res;
}
