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cuberite-2a/source/Noise.cpp

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#include "Globals.h" // NOTE: MSVC stupidness requires this to be the same across all modules
#include "Noise.h"
#if NOISE_USE_SSE
#include <smmintrin.h> //_mm_mul_epi32
#endif
#define FAST_FLOOR(x) (((x) < 0) ? (((int)x) - 1) : ((int)x))
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Globals:
void IntArrayLinearInterpolate2D(
int * a_Array,
int a_SizeX, int a_SizeY, // Dimensions of the array
int a_AnchorStepX, int a_AnchorStepY // Distances between the anchor points in each direction
)
{
// First interpolate columns where the anchor points are:
int LastYCell = a_SizeY - a_AnchorStepY;
for (int y = 0; y < LastYCell; y += a_AnchorStepY)
{
int Idx = a_SizeX * y;
for (int x = 0; x < a_SizeX; x += a_AnchorStepX)
{
int StartValue = a_Array[Idx];
int EndValue = a_Array[Idx + a_SizeX * a_AnchorStepY];
int Diff = EndValue - StartValue;
for (int CellY = 1; CellY < a_AnchorStepY; CellY++)
{
a_Array[Idx + a_SizeX * CellY] = StartValue + CellY * Diff / a_AnchorStepY;
} // for CellY
Idx += a_AnchorStepX;
} // for x
} // for y
// Now interpolate in rows, each row has values in the anchor columns
int LastXCell = a_SizeX - a_AnchorStepX;
for (int y = 0; y < a_SizeY; y++)
{
int Idx = a_SizeX * y;
for (int x = 0; x < LastXCell; x += a_AnchorStepX)
{
int StartValue = a_Array[Idx];
int EndValue = a_Array[Idx + a_AnchorStepX];
int Diff = EndValue - StartValue;
for (int CellX = 1; CellX < a_AnchorStepX; CellX++)
{
a_Array[Idx + CellX] = StartValue + CellX * Diff / a_AnchorStepX;
} // for CellY
Idx += a_AnchorStepX;
}
}
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// cCubicCell2D:
class cCubicCell2D
{
public:
cCubicCell2D(
const cNoise & a_Noise, ///< Noise to use for generating the random values
NOISE_DATATYPE * a_Array, ///< Array to generate into [x + a_SizeX * y]
int a_SizeX, int a_SizeY, ///< Count of the array, in each direction
const NOISE_DATATYPE * a_FracX, ///< Pointer to the array that stores the X fractional values
const NOISE_DATATYPE * a_FracY ///< Pointer to the attay that stores the Y fractional values
);
/// Uses current m_WorkRnds[] to generate part of the array
void Generate(
int a_FromX, int a_ToX,
int a_FromY, int a_ToY
);
/// Initializes m_WorkRnds[] with the specified Floor values
void InitWorkRnds(int a_FloorX, int a_FloorY);
/// Updates m_WorkRnds[] for the new Floor values.
void Move(int a_NewFloorX, int a_NewFloorY);
protected:
typedef NOISE_DATATYPE Workspace[4][4];
const cNoise & m_Noise;
Workspace * m_WorkRnds; ///< The current random values; points to either m_Workspace1 or m_Workspace2 (doublebuffering)
Workspace m_Workspace1; ///< Buffer 1 for workspace doublebuffering, used in Move()
Workspace m_Workspace2; ///< Buffer 2 for workspace doublebuffering, used in Move()
int m_CurFloorX;
int m_CurFloorY;
NOISE_DATATYPE * m_Array;
int m_SizeX, m_SizeY;
const NOISE_DATATYPE * m_FracX;
const NOISE_DATATYPE * m_FracY;
} ;
cCubicCell2D::cCubicCell2D(
const cNoise & a_Noise, ///< Noise to use for generating the random values
NOISE_DATATYPE * a_Array, ///< Array to generate into [x + a_SizeX * y]
int a_SizeX, int a_SizeY, ///< Count of the array, in each direction
const NOISE_DATATYPE * a_FracX, ///< Pointer to the array that stores the X fractional values
const NOISE_DATATYPE * a_FracY ///< Pointer to the attay that stores the Y fractional values
) :
m_Noise(a_Noise),
m_WorkRnds(&m_Workspace1),
m_Array(a_Array),
m_SizeX(a_SizeX),
m_SizeY(a_SizeY),
m_FracX(a_FracX),
m_FracY(a_FracY)
{
}
void cCubicCell2D::Generate(
int a_FromX, int a_ToX,
int a_FromY, int a_ToY
)
{
for (int y = a_FromY; y < a_ToY; y++)
{
NOISE_DATATYPE Interp[4];
NOISE_DATATYPE FracY = m_FracY[y];
Interp[0] = cNoise::CubicInterpolate((*m_WorkRnds)[0][0], (*m_WorkRnds)[0][1], (*m_WorkRnds)[0][2], (*m_WorkRnds)[0][3], FracY);
Interp[1] = cNoise::CubicInterpolate((*m_WorkRnds)[1][0], (*m_WorkRnds)[1][1], (*m_WorkRnds)[1][2], (*m_WorkRnds)[1][3], FracY);
Interp[2] = cNoise::CubicInterpolate((*m_WorkRnds)[2][0], (*m_WorkRnds)[2][1], (*m_WorkRnds)[2][2], (*m_WorkRnds)[2][3], FracY);
Interp[3] = cNoise::CubicInterpolate((*m_WorkRnds)[3][0], (*m_WorkRnds)[3][1], (*m_WorkRnds)[3][2], (*m_WorkRnds)[3][3], FracY);
int idx = y * m_SizeX + a_FromX;
for (int x = a_FromX; x < a_ToX; x++)
{
m_Array[idx++] = cNoise::CubicInterpolate(Interp[0], Interp[1], Interp[2], Interp[3], m_FracX[x]);
} // for x
} // for y
}
void cCubicCell2D::InitWorkRnds(int a_FloorX, int a_FloorY)
{
m_CurFloorX = a_FloorX;
m_CurFloorY = a_FloorY;
for (int x = 0; x < 4; x++)
{
int cx = a_FloorX + x - 1;
for (int y = 0; y < 4; y++)
{
int cy = a_FloorY + y - 1;
(*m_WorkRnds)[x][y] = (NOISE_DATATYPE)m_Noise.IntNoise2D(cx, cy);
}
}
}
void cCubicCell2D::Move(int a_NewFloorX, int a_NewFloorY)
{
// Swap the doublebuffer:
int OldFloorX = m_CurFloorX;
int OldFloorY = m_CurFloorY;
Workspace * OldWorkRnds = m_WorkRnds;
m_WorkRnds = (m_WorkRnds == &m_Workspace1) ? &m_Workspace2 : &m_Workspace1;
// Reuse as much of the old workspace as possible:
int DiffX = OldFloorX - a_NewFloorX;
int DiffY = OldFloorY - a_NewFloorY;
for (int x = 0; x < 4; x++)
{
int cx = a_NewFloorX + x - 1;
int OldX = x - DiffX; // Where would this X be in the old grid?
for (int y = 0; y < 4; y++)
{
int cy = a_NewFloorY + y - 1;
int OldY = y - DiffY; // Where would this Y be in the old grid?
if ((OldX >= 0) && (OldX < 4) && (OldY >= 0) && (OldY < 4))
{
(*m_WorkRnds)[x][y] = (*OldWorkRnds)[OldX][OldY];
}
else
{
(*m_WorkRnds)[x][y] = (NOISE_DATATYPE)m_Noise.IntNoise2D(cx, cy);
}
}
}
m_CurFloorX = a_NewFloorX;
m_CurFloorY = a_NewFloorY;
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// cNoise:
cNoise::cNoise(unsigned int a_Seed) :
m_Seed(a_Seed)
{
}
cNoise::cNoise(const cNoise & a_Noise) :
m_Seed(a_Noise.m_Seed)
{
}
NOISE_DATATYPE cNoise::LinearNoise1D(NOISE_DATATYPE a_X) const
{
int BaseX = FAST_FLOOR(a_X);
NOISE_DATATYPE FracX = a_X - BaseX;
return LinearInterpolate(IntNoise1D(BaseX), IntNoise1D(BaseX + 1), FracX);
}
NOISE_DATATYPE cNoise::CosineNoise1D(NOISE_DATATYPE a_X) const
{
int BaseX = FAST_FLOOR(a_X);
NOISE_DATATYPE FracX = a_X - BaseX;
return CosineInterpolate(IntNoise1D(BaseX), IntNoise1D(BaseX + 1), FracX);
}
NOISE_DATATYPE cNoise::CubicNoise1D(NOISE_DATATYPE a_X) const
{
int BaseX = FAST_FLOOR(a_X);
NOISE_DATATYPE FracX = a_X - BaseX;
return CubicInterpolate(IntNoise1D(BaseX - 1), IntNoise1D(BaseX), IntNoise1D(BaseX + 1), IntNoise1D(BaseX + 2), FracX);
}
NOISE_DATATYPE cNoise::SmoothNoise1D(int a_X) const
{
return IntNoise1D(a_X) / 2 + IntNoise1D(a_X - 1) / 4 + IntNoise1D(a_X + 1) / 4;
}
NOISE_DATATYPE cNoise::CubicNoise2D(NOISE_DATATYPE a_X, NOISE_DATATYPE a_Y) const
{
const int BaseX = FAST_FLOOR(a_X);
const int BaseY = FAST_FLOOR(a_Y);
const NOISE_DATATYPE points[4][4] =
{
IntNoise2D(BaseX - 1, BaseY - 1), IntNoise2D(BaseX, BaseY - 1), IntNoise2D(BaseX + 1, BaseY - 1), IntNoise2D(BaseX + 2, BaseY - 1),
IntNoise2D(BaseX - 1, BaseY), IntNoise2D(BaseX, BaseY), IntNoise2D(BaseX + 1, BaseY), IntNoise2D(BaseX + 2, BaseY),
IntNoise2D(BaseX - 1, BaseY + 1), IntNoise2D(BaseX, BaseY + 1), IntNoise2D(BaseX + 1, BaseY + 1), IntNoise2D(BaseX + 2, BaseY + 1),
IntNoise2D(BaseX - 1, BaseY + 2), IntNoise2D(BaseX, BaseY + 2), IntNoise2D(BaseX + 1, BaseY + 2), IntNoise2D(BaseX + 2, BaseY + 2),
};
const NOISE_DATATYPE FracX = a_X - BaseX;
const NOISE_DATATYPE interp1 = CubicInterpolate(points[0][0], points[0][1], points[0][2], points[0][3], FracX);
const NOISE_DATATYPE interp2 = CubicInterpolate(points[1][0], points[1][1], points[1][2], points[1][3], FracX);
const NOISE_DATATYPE interp3 = CubicInterpolate(points[2][0], points[2][1], points[2][2], points[2][3], FracX);
const NOISE_DATATYPE interp4 = CubicInterpolate(points[3][0], points[3][1], points[3][2], points[3][3], FracX);
const NOISE_DATATYPE FracY = a_Y - BaseY;
return CubicInterpolate(interp1, interp2, interp3, interp4, FracY);
}
NOISE_DATATYPE cNoise::CubicNoise3D(NOISE_DATATYPE a_X, NOISE_DATATYPE a_Y, NOISE_DATATYPE a_Z) const
{
const int BaseX = FAST_FLOOR(a_X);
const int BaseY = FAST_FLOOR(a_Y);
const int BaseZ = FAST_FLOOR(a_Z);
const NOISE_DATATYPE points1[4][4] = {
IntNoise3D(BaseX - 1, BaseY - 1, BaseZ - 1), IntNoise3D(BaseX, BaseY - 1, BaseZ - 1), IntNoise3D(BaseX + 1, BaseY - 1, BaseZ - 1), IntNoise3D(BaseX + 2, BaseY - 1, BaseZ - 1),
IntNoise3D(BaseX - 1, BaseY, BaseZ - 1), IntNoise3D(BaseX, BaseY, BaseZ - 1), IntNoise3D(BaseX + 1, BaseY, BaseZ - 1), IntNoise3D(BaseX + 2, BaseY, BaseZ - 1),
IntNoise3D(BaseX - 1, BaseY + 1, BaseZ - 1), IntNoise3D(BaseX, BaseY + 1, BaseZ - 1), IntNoise3D(BaseX + 1, BaseY + 1, BaseZ - 1), IntNoise3D(BaseX + 2, BaseY + 1, BaseZ - 1),
IntNoise3D(BaseX - 1, BaseY + 2, BaseZ - 1), IntNoise3D(BaseX, BaseY + 2, BaseZ - 1), IntNoise3D(BaseX + 1, BaseY + 2, BaseZ - 1), IntNoise3D(BaseX + 2, BaseY + 2, BaseZ - 1),
};
const NOISE_DATATYPE FracX = (a_X) - BaseX;
const NOISE_DATATYPE x1interp1 = CubicInterpolate( points1[0][0], points1[0][1], points1[0][2], points1[0][3], FracX );
const NOISE_DATATYPE x1interp2 = CubicInterpolate( points1[1][0], points1[1][1], points1[1][2], points1[1][3], FracX );
const NOISE_DATATYPE x1interp3 = CubicInterpolate( points1[2][0], points1[2][1], points1[2][2], points1[2][3], FracX );
const NOISE_DATATYPE x1interp4 = CubicInterpolate( points1[3][0], points1[3][1], points1[3][2], points1[3][3], FracX );
const NOISE_DATATYPE points2[4][4] = {
IntNoise3D( BaseX-1, BaseY-1, BaseZ ), IntNoise3D( BaseX, BaseY-1, BaseZ ), IntNoise3D( BaseX+1, BaseY-1, BaseZ ), IntNoise3D( BaseX+2, BaseY-1, BaseZ ),
IntNoise3D( BaseX-1, BaseY, BaseZ ), IntNoise3D( BaseX, BaseY, BaseZ ), IntNoise3D( BaseX+1, BaseY, BaseZ ), IntNoise3D( BaseX+2, BaseY, BaseZ ),
IntNoise3D( BaseX-1, BaseY+1, BaseZ ), IntNoise3D( BaseX, BaseY+1, BaseZ ), IntNoise3D( BaseX+1, BaseY+1, BaseZ ), IntNoise3D( BaseX+2, BaseY+1, BaseZ ),
IntNoise3D( BaseX-1, BaseY+2, BaseZ ), IntNoise3D( BaseX, BaseY+2, BaseZ ), IntNoise3D( BaseX+1, BaseY+2, BaseZ ), IntNoise3D( BaseX+2, BaseY+2, BaseZ ),
};
const NOISE_DATATYPE x2interp1 = CubicInterpolate( points2[0][0], points2[0][1], points2[0][2], points2[0][3], FracX );
const NOISE_DATATYPE x2interp2 = CubicInterpolate( points2[1][0], points2[1][1], points2[1][2], points2[1][3], FracX );
const NOISE_DATATYPE x2interp3 = CubicInterpolate( points2[2][0], points2[2][1], points2[2][2], points2[2][3], FracX );
const NOISE_DATATYPE x2interp4 = CubicInterpolate( points2[3][0], points2[3][1], points2[3][2], points2[3][3], FracX );
const NOISE_DATATYPE points3[4][4] = {
IntNoise3D( BaseX-1, BaseY-1, BaseZ+1 ), IntNoise3D( BaseX, BaseY-1, BaseZ+1 ), IntNoise3D( BaseX+1, BaseY-1, BaseZ+1 ), IntNoise3D( BaseX+2, BaseY-1, BaseZ+1 ),
IntNoise3D( BaseX-1, BaseY, BaseZ+1 ), IntNoise3D( BaseX, BaseY, BaseZ+1 ), IntNoise3D( BaseX+1, BaseY, BaseZ+1 ), IntNoise3D( BaseX+2, BaseY, BaseZ+1 ),
IntNoise3D( BaseX-1, BaseY+1, BaseZ+1 ), IntNoise3D( BaseX, BaseY+1, BaseZ+1 ), IntNoise3D( BaseX+1, BaseY+1, BaseZ+1 ), IntNoise3D( BaseX+2, BaseY+1, BaseZ+1 ),
IntNoise3D( BaseX-1, BaseY+2, BaseZ+1 ), IntNoise3D( BaseX, BaseY+2, BaseZ+1 ), IntNoise3D( BaseX+1, BaseY+2, BaseZ+1 ), IntNoise3D( BaseX+2, BaseY+2, BaseZ+1 ),
};
const NOISE_DATATYPE x3interp1 = CubicInterpolate( points3[0][0], points3[0][1], points3[0][2], points3[0][3], FracX );
const NOISE_DATATYPE x3interp2 = CubicInterpolate( points3[1][0], points3[1][1], points3[1][2], points3[1][3], FracX );
const NOISE_DATATYPE x3interp3 = CubicInterpolate( points3[2][0], points3[2][1], points3[2][2], points3[2][3], FracX );
const NOISE_DATATYPE x3interp4 = CubicInterpolate( points3[3][0], points3[3][1], points3[3][2], points3[3][3], FracX );
const NOISE_DATATYPE points4[4][4] = {
IntNoise3D( BaseX-1, BaseY-1, BaseZ+2 ), IntNoise3D( BaseX, BaseY-1, BaseZ+2 ), IntNoise3D( BaseX+1, BaseY-1, BaseZ+2 ), IntNoise3D( BaseX+2, BaseY-1, BaseZ+2 ),
IntNoise3D( BaseX-1, BaseY, BaseZ+2 ), IntNoise3D( BaseX, BaseY, BaseZ+2 ), IntNoise3D( BaseX+1, BaseY, BaseZ+2 ), IntNoise3D( BaseX+2, BaseY, BaseZ+2 ),
IntNoise3D( BaseX-1, BaseY+1, BaseZ+2 ), IntNoise3D( BaseX, BaseY+1, BaseZ+2 ), IntNoise3D( BaseX+1, BaseY+1, BaseZ+2 ), IntNoise3D( BaseX+2, BaseY+1, BaseZ+2 ),
IntNoise3D( BaseX-1, BaseY+2, BaseZ+2 ), IntNoise3D( BaseX, BaseY+2, BaseZ+2 ), IntNoise3D( BaseX+1, BaseY+2, BaseZ+2 ), IntNoise3D( BaseX+2, BaseY+2, BaseZ+2 ),
};
const NOISE_DATATYPE x4interp1 = CubicInterpolate( points4[0][0], points4[0][1], points4[0][2], points4[0][3], FracX );
const NOISE_DATATYPE x4interp2 = CubicInterpolate( points4[1][0], points4[1][1], points4[1][2], points4[1][3], FracX );
const NOISE_DATATYPE x4interp3 = CubicInterpolate( points4[2][0], points4[2][1], points4[2][2], points4[2][3], FracX );
const NOISE_DATATYPE x4interp4 = CubicInterpolate( points4[3][0], points4[3][1], points4[3][2], points4[3][3], FracX );
const NOISE_DATATYPE FracY = (a_Y) - BaseY;
const NOISE_DATATYPE yinterp1 = CubicInterpolate( x1interp1, x1interp2, x1interp3, x1interp4, FracY );
const NOISE_DATATYPE yinterp2 = CubicInterpolate( x2interp1, x2interp2, x2interp3, x2interp4, FracY );
const NOISE_DATATYPE yinterp3 = CubicInterpolate( x3interp1, x3interp2, x3interp3, x3interp4, FracY );
const NOISE_DATATYPE yinterp4 = CubicInterpolate( x4interp1, x4interp2, x4interp3, x4interp4, FracY );
const NOISE_DATATYPE FracZ = (a_Z) - BaseZ;
return CubicInterpolate( yinterp1, yinterp2, yinterp3, yinterp4, FracZ );
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// cCubicNoise:
#ifdef _DEBUG
int cCubicNoise::m_NumSingleX = 0;
int cCubicNoise::m_NumSingleXY = 0;
int cCubicNoise::m_NumSingleY = 0;
int cCubicNoise::m_NumCalls = 0;
#endif // _DEBUG
cCubicNoise::cCubicNoise(int a_Seed) :
m_Noise(a_Seed)
{
}
void cCubicNoise::Generate2D(
NOISE_DATATYPE * a_Array, ///< Array to generate into [x + a_SizeX * y]
int a_SizeX, int a_SizeY, ///< Size of the array (num doubles), in each direction
NOISE_DATATYPE a_StartX, NOISE_DATATYPE a_EndX, ///< Noise-space coords of the array in the X direction
NOISE_DATATYPE a_StartY, NOISE_DATATYPE a_EndY ///< Noise-space coords of the array in the Y direction
) const
{
ASSERT(a_SizeX < MAX_SIZE);
ASSERT(a_SizeY < MAX_SIZE);
ASSERT(a_StartX < a_EndX);
ASSERT(a_StartY < a_EndY);
// Calculate the integral and fractional parts of each coord:
int FloorX[MAX_SIZE];
int FloorY[MAX_SIZE];
NOISE_DATATYPE FracX[MAX_SIZE];
NOISE_DATATYPE FracY[MAX_SIZE];
int SameX[MAX_SIZE];
int SameY[MAX_SIZE];
int NumSameX, NumSameY;
CalcFloorFrac(a_SizeX, a_StartX, a_EndX, FloorX, FracX, SameX, NumSameX);
CalcFloorFrac(a_SizeY, a_StartY, a_EndY, FloorY, FracY, SameY, NumSameY);
cCubicCell2D Cell(m_Noise, a_Array, a_SizeX, a_SizeY, FracX, FracY);
Cell.InitWorkRnds(FloorX[0], FloorY[0]);
#ifdef _DEBUG
// Statistics on the noise-space coords:
if (NumSameX == 1)
{
m_NumSingleX++;
if (NumSameY == 1)
{
m_NumSingleXY++;
}
}
if (NumSameY == 1)
{
m_NumSingleY++;
}
m_NumCalls++;
#endif _DEBUG
// Calculate query values using Cell:
int FromY = 0;
for (int y = 0; y < NumSameY; y++)
{
int ToY = FromY + SameY[y];
int FromX = 0;
int CurFloorY = FloorY[FromY];
for (int x = 0; x < NumSameX; x++)
{
int ToX = FromX + SameX[x];
Cell.Generate(FromX, ToX, FromY, ToY);
Cell.Move(FloorX[ToX], CurFloorY);
FromX = ToX;
}
Cell.Move(FloorX[0], FloorY[ToY]);
FromY = ToY;
}
}
void cCubicNoise::CalcFloorFrac(
int a_Size,
NOISE_DATATYPE a_Start, NOISE_DATATYPE a_End,
int * a_Floor, NOISE_DATATYPE * a_Frac,
int * a_Same, int & a_NumSame
) const
{
NOISE_DATATYPE val = a_Start;
NOISE_DATATYPE dif = (a_End - a_Start) / a_Size;
for (int i = 0; i < a_Size; i++)
{
a_Floor[i] = FAST_FLOOR(val);
a_Frac[i] = val - a_Floor[i];
val += dif;
}
// Mark up the same floor values into a_Same / a_NumSame:
int CurFloor = a_Floor[0];
int LastSame = 0;
a_NumSame = 0;
for (int i = 1; i < a_Size; i++)
{
if (a_Floor[i] != CurFloor)
{
a_Same[a_NumSame] = i - LastSame;
LastSame = i;
a_NumSame += 1;
CurFloor = a_Floor[i];
}
} // for i - a_Floor[]
if (LastSame < a_Size)
{
a_Same[a_NumSame] = a_Size - LastSame;
a_NumSame += 1;
}
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// cPerlinNoise:
cPerlinNoise::cPerlinNoise(void) :
m_Seed(0)
{
}
cPerlinNoise::cPerlinNoise(int a_Seed) :
m_Seed(a_Seed)
{
}
void cPerlinNoise::SetSeed(int a_Seed)
{
m_Seed = a_Seed;
}
void cPerlinNoise::AddOctave(float a_Frequency, float a_Amplitude)
{
m_Octaves.push_back(cOctave(m_Seed * (m_Octaves.size() + 4) * 4 + 1024, a_Frequency, a_Amplitude));
}
void cPerlinNoise::Generate2D(
NOISE_DATATYPE * a_Array, ///< Array to generate into [x + a_SizeX * y]
int a_SizeX, int a_SizeY, ///< Count of the array, in each direction
NOISE_DATATYPE a_StartX, NOISE_DATATYPE a_EndX, ///< Noise-space coords of the array in the X direction
NOISE_DATATYPE a_StartY, NOISE_DATATYPE a_EndY, ///< Noise-space coords of the array in the Y direction
NOISE_DATATYPE * a_Workspace ///< Workspace that this function can use and trash
) const
{
if (m_Octaves.empty())
{
// No work to be done
return;
}
bool ShouldFreeWorkspace = (a_Workspace == NULL);
int ArrayCount = a_SizeX * a_SizeY;
if (ShouldFreeWorkspace)
{
a_Workspace = new NOISE_DATATYPE[ArrayCount];
}
// Generate the first octave directly into array:
m_Octaves.front().m_Noise.Generate2D(
a_Workspace, a_SizeX, a_SizeY,
a_StartX * m_Octaves.front().m_Frequency, a_EndX * m_Octaves.front().m_Frequency,
a_StartY * m_Octaves.front().m_Frequency, a_EndY * m_Octaves.front().m_Frequency
);
NOISE_DATATYPE Amplitude = m_Octaves.front().m_Amplitude;
for (int i = 0; i < ArrayCount; i++)
{
a_Array[i] *= Amplitude;
}
// Add each octave:
for (cOctaves::const_iterator itr = m_Octaves.begin() + 1, end = m_Octaves.end(); itr != end; ++itr)
{
// Generate cubic noise for the octave:
itr->m_Noise.Generate2D(
a_Workspace, a_SizeX, a_SizeY,
a_StartX * itr->m_Frequency, a_EndX * itr->m_Frequency,
a_StartY * itr->m_Frequency, a_EndY * itr->m_Frequency
);
// Add the cubic noise into the output:
NOISE_DATATYPE Amplitude = itr->m_Amplitude;
for (int i = 0; i < ArrayCount; i++)
{
a_Array[i] += a_Workspace[i] * Amplitude;
}
}
if (ShouldFreeWorkspace)
{
delete[] a_Workspace;
}
}