// OctavedNoise.h
// Implements the cOctavedNoise class template representing a noise generator that layers several octaves of another noise
#pragma once
template <typename N>
class cOctavedNoise
{
public:
cOctavedNoise(int a_Seed = 0):
m_Seed(a_Seed)
{
}
/** Sets a new seed for the generators. Relays the seed to all underlying octaves. */
void SetSeed(int a_Seed)
{
m_Seed = a_Seed;
for (auto oct: m_Octaves)
{
oct->SetSeed(a_Seed);
}
}
/** Adds a new octave to the list of octaves that compose this noise. */
void AddOctave(NOISE_DATATYPE a_Frequency, NOISE_DATATYPE a_Amplitude)
{
m_Octaves.emplace_back(m_Seed, a_Frequency, a_Amplitude);
}
/** Fills a 2D array with the values of the noise. */
void 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 = nullptr ///< Workspace that this function can use and trash.
) const
{
// Check that state is alright:
if (m_Octaves.empty())
{
ASSERT(!"cOctavedNoise: No octaves to generate!");
return;
}
// Allocate the workspace on the heap, if it wasn't given:
std::unique_ptr<NOISE_DATATYPE[]> workspaceHeap;
if (a_Workspace == nullptr)
{
workspaceHeap.reset(new NOISE_DATATYPE[a_SizeX * a_SizeY]);
a_Workspace = workspaceHeap.get();
}
// Generate the first octave directly into array:
int ArrayCount = a_SizeX * a_SizeY;
{
const cOctave & FirstOctave = m_Octaves.front();
FirstOctave.m_Noise.Generate2D(
a_Workspace, a_SizeX, a_SizeY,
a_StartX * FirstOctave.m_Frequency, a_EndX * FirstOctave.m_Frequency,
a_StartY * FirstOctave.m_Frequency, a_EndY * FirstOctave.m_Frequency
);
NOISE_DATATYPE Amplitude = FirstOctave.m_Amplitude;
for (int i = 0; i < ArrayCount; i++)
{
a_Array[i] = a_Workspace[i] * Amplitude;
}
}
// Add each octave:
for (auto itr = m_Octaves.cbegin() + 1, end = m_Octaves.cend(); itr != end; ++itr)
{
// Generate the 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 it into the output:
NOISE_DATATYPE Amplitude = itr->m_Amplitude;
for (int i = 0; i < ArrayCount; i++)
{
a_Array[i] += a_Workspace[i] * Amplitude;
}
} // for itr - m_Octaves[]
}
/** Fills a 3D array with the values of the noise. */
void Generate3D(
NOISE_DATATYPE * a_Array, ///< Array to generate into [x + a_SizeX * y + a_SizeX * a_SizeY * z]
int a_SizeX, int a_SizeY, int a_SizeZ, ///< 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_StartZ, NOISE_DATATYPE a_EndZ, ///< Noise-space coords of the array in the Z direction
NOISE_DATATYPE * a_Workspace = nullptr ///< Workspace that this function can use and trash, same size as a_Array
) const
{
// Check that state is alright:
if (m_Octaves.empty())
{
ASSERT(!"cOctavedNoise: No octaves to generate!");
return;
}
// Allocate the workspace on the heap, if it wasn't given:
std::unique_ptr<NOISE_DATATYPE[]> workspaceHeap;
if (a_Workspace == nullptr)
{
workspaceHeap.reset(new NOISE_DATATYPE[a_SizeX * a_SizeY * a_SizeZ]);
a_Workspace = workspaceHeap.get();
}
// Generate the first octave directly into array:
int ArrayCount = a_SizeX * a_SizeY * a_SizeZ;
{
const cOctave & FirstOctave = m_Octaves.front();
FirstOctave.m_Noise.Generate3D(
a_Workspace, a_SizeX, a_SizeY, a_SizeZ,
a_StartX * FirstOctave.m_Frequency, a_EndX * FirstOctave.m_Frequency,
a_StartY * FirstOctave.m_Frequency, a_EndY * FirstOctave.m_Frequency,
a_StartZ * FirstOctave.m_Frequency, a_EndZ * FirstOctave.m_Frequency
);
NOISE_DATATYPE Amplitude = FirstOctave.m_Amplitude;
for (int i = 0; i < ArrayCount; i++)
{
a_Array[i] = a_Workspace[i] * Amplitude;
}
}
// Add each octave:
for (auto itr = m_Octaves.cbegin() + 1, end = m_Octaves.cend(); itr != end; ++itr)
{
// Generate the noise for the octave:
itr->m_Noise.Generate3D(
a_Workspace, a_SizeX, a_SizeY, a_SizeZ,
a_StartX * itr->m_Frequency, a_EndX * itr->m_Frequency,
a_StartY * itr->m_Frequency, a_EndY * itr->m_Frequency,
a_StartZ * itr->m_Frequency, a_EndZ * itr->m_Frequency
);
// Add it into the output:
NOISE_DATATYPE Amplitude = itr->m_Amplitude;
for (int i = 0; i < ArrayCount; i++)
{
a_Array[i] += a_Workspace[i] * Amplitude;
}
} // for itr - m_Octaves[]
}
protected:
/** Stores information and state for one octave of the noise. */
class cOctave
{
public:
N m_Noise;
/** Coord multiplier. */
NOISE_DATATYPE m_Frequency;
/** Value multiplier. */
NOISE_DATATYPE m_Amplitude;
cOctave(int a_Seed, NOISE_DATATYPE a_Frequency, NOISE_DATATYPE a_Amplitude) :
m_Noise(a_Seed),
m_Frequency(a_Frequency),
m_Amplitude(a_Amplitude)
{
}
} ;
typedef std::vector<cOctave> cOctaves;
/** The seed used by the underlying generators. */
int m_Seed;
/** The octaves that compose this noise. */
cOctaves m_Octaves;
};
