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// 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_Noise1(a_Seed + 1),
m_Noise2(a_Seed + 2),
m_Noise3(a_Seed + 3),
m_CellSize(a_CellSize),
m_CurrentCellX(9999999), // Cell coords that are definitely out of the range for normal generator, so that the first query will overwrite them
m_CurrentCellZ(9999999)
{
}
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;
UpdateCell(CellX, CellZ);
// 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 = 0; x < 5; x++)
{
for (int z = 0; z < 5; z++)
{
int SeedX = m_SeedX[x][z];
int SeedZ = m_SeedZ[x][z];
int Dist = (SeedX - a_X) * (SeedX - a_X) + (SeedZ - a_Y) * (SeedZ - a_Y);
if (Dist < MinDist)
{
MinDist2 = MinDist;
MinDist = Dist;
res = m_Noise3.IntNoise2DInt(x + CellX - 2, z + CellZ - 2);
}
else if (Dist < MinDist2)
{
MinDist2 = Dist;
}
} // for z
} // for x
a_MinDist1 = MinDist;
a_MinDist2 = MinDist2;
return res;
}
void cVoronoiMap::UpdateCell(int a_CellX, int a_CellZ)
{
// If the specified cell is currently cached, bail out:
if ((a_CellX == m_CurrentCellX) && (a_CellZ == m_CurrentCellZ))
{
return;
}
// Update the cell cache for the new cell position:
int NoiseBaseX = a_CellX - 2;
int NoiseBaseZ = a_CellZ - 2;
for (int x = 0; x < 5; x++)
{
int BaseX = (NoiseBaseX + x) * m_CellSize;
for (int z = 0; z < 5; z++)
{
int OffsetX = (m_Noise1.IntNoise2DInt(NoiseBaseX + x, NoiseBaseZ + z) / 8) % m_CellSize;
int OffsetZ = (m_Noise2.IntNoise2DInt(NoiseBaseX + x, NoiseBaseZ + z) / 8) % m_CellSize;
m_SeedX[x][z] = BaseX + OffsetX;
m_SeedZ[x][z] = (NoiseBaseZ + z) * m_CellSize + OffsetZ;
} // for z
} // for x
m_CurrentCellX = a_CellX;
m_CurrentCellZ = a_CellZ;
}
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