//This is the recursive function that implements the random midpoint
//displacement algorithm. It will call itself until the grid pieces
//become smaller than one pixel.
private static void DivideGrid(Matrix matrix, RandomGeneratorXorShift rnd, int x, int y, int size, int c1, int c2, int c3, int c4, int roughness)
{
int Edge1, Edge2, Edge3, Edge4, Middle;
if (size > 1)
{
int newSize = size / 2;
Middle = (c1 + c2 + c3 + c4) / 4 + Displace(rnd, newSize, roughness); //Randomly displace the midpoint!
Edge1 = (c1 + c2) / 2;
Edge2 = (c2 + c3) / 2;
Edge3 = (c3 + c4) / 2;
Edge4 = (c4 + c1) / 2;
//Make sure that the midpoint doesn't accidentally "randomly displaced" past the boundaries!
if (Middle < 0)
Middle = 0;
else if (Middle > 255)
Middle = 255;
//Do the operation over again for each of the four new grids.
DivideGrid(matrix, rnd, x, y, newSize, c1, Edge1, Middle, Edge4, roughness);
DivideGrid(matrix, rnd, x + newSize, y, newSize, Edge1, c2, Edge2, Middle, roughness);
DivideGrid(matrix, rnd, x + newSize, y + newSize, newSize, Middle, Edge2, c3, Edge3, roughness);
DivideGrid(matrix, rnd, x, y + newSize, newSize, Edge4, Middle, Edge3, c4, roughness);
}
else //This is the "base case," where each grid piece is less than the size of a pixel.
{
//The four corners of the grid piece will be averaged and drawn as a single pixel.
int c = (c1 + c2 + c3 + c4) / 4;
matrix.SetValue(x, y, (byte) c);
}
}
//This is something of a "helper function" to create an initial grid
//before the recursive function is called.
public static void DrawPlasma(Matrix matrix, int seed, int roughness)
{
if (roughness < 1)
roughness = 1;
int c1, c2, c3, c4;
RandomGeneratorXorShift rnd = new RandomGeneratorXorShift(seed);
//Assign the four corners of the intial grid random color values
//These will end up being the colors of the four corners of the applet.
c1 = rnd.Range(0, 256);
c2 = rnd.Range(0, 256);
c3 = rnd.Range(0, 256);
c4 = rnd.Range(0, 256);
DivideGrid(matrix, rnd, 0, 0, matrix.size, c1, c2, c3, c4, roughness);
}
//This is something of a "helper function" to create an initial grid
//before the recursive function is called.
static public void DrawPlasma(Matrix matrix, int seed, int roughness)
{
if (roughness < 1)
{
roughness = 1;
}
int c1, c2, c3, c4;
RandomGeneratorXorShift rnd = new RandomGeneratorXorShift(seed);
//Assign the four corners of the intial grid random color values
//These will end up being the colors of the four corners of the applet.
c1 = rnd.Range(0, 256);
c2 = rnd.Range(0, 256);
c3 = rnd.Range(0, 256);
c4 = rnd.Range(0, 256);
DivideGrid(matrix, rnd, 0, 0, matrix.size, c1, c2, c3, c4, roughness);
}
public PerlinNoiseFixed(int seed)
{
RandomGeneratorXorShift rnd = new RandomGeneratorXorShift(seed);
int i, j, k;
for (i = 0; i < B; i++)
{
m_perm[i] = i;
}
while (--i != 0)
{
k = m_perm[i];
j = rnd.Range(0, B);
m_perm[i] = m_perm[j];
m_perm[j] = k;
}
for (i = 0; i < B; i++)
{
m_perm[B + i] = m_perm[i];
}
}
//This is the recursive function that implements the random midpoint
//displacement algorithm. It will call itself until the grid pieces
//become smaller than one pixel.
static private void DivideGrid(Matrix matrix, RandomGeneratorXorShift rnd, int x, int y, int size, int c1, int c2, int c3, int c4, int roughness)
{
int Edge1, Edge2, Edge3, Edge4, Middle;
if (size > 1)
{
int newSize = size / 2;
Middle = (c1 + c2 + c3 + c4) / 4 + Displace(rnd, newSize, roughness); //Randomly displace the midpoint!
Edge1 = (c1 + c2) / 2;
Edge2 = (c2 + c3) / 2;
Edge3 = (c3 + c4) / 2;
Edge4 = (c4 + c1) / 2;
//Make sure that the midpoint doesn't accidentally "randomly displaced" past the boundaries!
if (Middle < 0)
{
Middle = 0;
}
else if (Middle > 255)
{
Middle = 255;
}
//Do the operation over again for each of the four new grids.
DivideGrid(matrix, rnd, x, y, newSize, c1, Edge1, Middle, Edge4, roughness);
DivideGrid(matrix, rnd, x + newSize, y, newSize, Edge1, c2, Edge2, Middle, roughness);
DivideGrid(matrix, rnd, x + newSize, y + newSize, newSize, Middle, Edge2, c3, Edge3, roughness);
DivideGrid(matrix, rnd, x, y + newSize, newSize, Edge4, Middle, Edge3, c4, roughness);
}
else //This is the "base case," where each grid piece is less than the size of a pixel.
{
//The four corners of the grid piece will be averaged and drawn as a single pixel.
int c = (c1 + c2 + c3 + c4) / 4;
matrix.SetValue(x, y, (byte)c);
}
}
public PerlinNoise(int seed)
{
RandomGeneratorXorShift rnd = new RandomGeneratorXorShift(seed);
int i, j, k;
for (i = 0; i < B; i++)
{
m_perm[i] = i;
}
while (--i != 0)
{
k = m_perm[i];
j = rnd.Range(0, B);
m_perm[i] = m_perm[j];
m_perm[j] = k;
}
for (i = 0; i < B; i++)
{
m_perm[B + i] = m_perm[i];
}
}
//Randomly displaces color value for midpoint depending on size
//of grid piece.
static int Displace(RandomGeneratorXorShift rnd, int num, int roughness)
{
return rnd.Range((-num * roughness) / 2 , (num * roughness) / 2 + 1);
}
//Randomly displaces color value for midpoint depending on size
//of grid piece.
static int Displace(RandomGeneratorXorShift rnd, int num, int roughness)
{
return(rnd.Range((-num * roughness) / 2, (num * roughness) / 2 + 1));
}
