pythonrandomperlin-noiseheightmap
How to make a smoother Perlin noise generator?
Using a Perlin noise generator to make the tiles of a map the noise is too spiky. It has many elevations and no flat places. They don't look like mountains, islands or lakes; they are random with a lot of peaks.
1D:
def Noise(self, x): # I wrote this noise function but it seems too random
random.seed(x)
number = random.random()
if number < 0.5:
final = 0 - number * 2
elif number > 0.5:
final = number * 2
return final
def Noise(self, x): # I found this noise function on the internet
x = (x<<13) ^ x
return ( 1.0 - ( (x * (x * x * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0)
2D:
def Noise(self, x, y): # I wrote this noise function but it seems too random
n = x + y
random.seed(n)
number = random.random()
if number < 0.5:
final = 0 - number * 2
elif number > 0.5:
final = number * 2
return final
def Noise(self, x, y): # I found this noise function on the internet
n = x + y * 57
n = (n<<13) ^ n
return ( 1.0 - ( (x * (x * x * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0)
You don't need Matplotlib or NumPy; I'm using them for the graph to visualize the result:
import random
import matplotlib.pyplot as plt # To make graphs
from mpl_toolkits.mplot3d import Axes3D # To make 3D graphs
import numpy as np # To make graphs
class D(): # Base of classes D1 and D2
def Cubic_Interpolate(self, v0, v1, v2, v3, x):
P = (v3 - v2) - (v0 - v1)
Q = (v0 - v1) - P
R = v2 - v0
S = v1
return P * x**3 + Q * x**2 + R * x + S
class D1(D):
def __init__(self, lenght, octaves):
self.result = self.Perlin(lenght, octaves)
def Noise(self, x): # I wrote this noise function but it seems too random
random.seed(x)
number = random.random()
if number < 0.5:
final = 0 - number * 2
elif number > 0.5:
final = number * 2
return final
def Noise(self, x): # I found this noise function on the internet
x = (x<<13) ^ x
return ( 1.0 - ( (x * (x * x * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0)
def Perlin(self, lenght, octaves):
result = []
for x in range(lenght):
value = 0
for y in range(octaves):
frequency = 2 ** y
amplitude = 0.25 ** y
value += self.Interpolate_Noise(x * frequency) * amplitude
result.append(value)
print(f"{x} / {lenght} ({x/lenght*100:.2f}%): {round(x/lenght*10) * '#'} {(10-round(x/lenght*10)) * ' '}. Remaining {lenght-x}.") # I don't use `os.system('cls')` because it slow down the code.
return result
def Smooth_Noise(self, x):
return self.Noise(x) / 2 + self.Noise(x-1) / 4 + self.Noise(x+1) / 4
def Interpolate_Noise(self, x):
round_x = round(x)
frac_x = x - round_x
v0 = self.Smooth_Noise(round_x - 1)
v1 = self.Smooth_Noise(round_x)
v2 = self.Smooth_Noise(round_x + 1)
v3 = self.Smooth_Noise(round_x + 2)
return self.Cubic_Interpolate(v0, v1, v2, v3, frac_x)
def graph(self, *args):
plt.plot(np.array(self.result), '-', label = "Line")
for x in args:
plt.axhline(y=x, color='r', linestyle='-')
plt.xlabel('X')
plt.ylabel('Y')
plt.title("Simple Plot")
plt.legend()
plt.show()
class D2(D):
def __init__(self, lenght, octaves = 1):
self.lenght_axes = round(lenght ** 0.5)
self.lenght = self.lenght_axes ** 2
self.result = self.Perlin(self.lenght, octaves)
def Noise(self, x, y): # I wrote this noise function but it seems too random
n = x + y
random.seed(n)
number = random.random()
if number < 0.5:
final = 0 - number * 2
elif number > 0.5:
final = number * 2
return final
def Noise(self, x, y): # I found this noise function on the internet
n = x + y * 57
n = (n<<13) ^ n
return ( 1.0 - ( (x * (x * x * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0)
def Smooth_Noise(self, x, y):
corners = (self.Noise(x - 1, y - 1) + self.Noise(x + 1, y - 1) + self.Noise(x - 1, y + 1) + self.Noise(x + 1, y + 1) ) / 16
sides = (self.Noise(x - 1, y) + self.Noise(x + 1, y) + self.Noise(x, y - 1) + self.Noise(x, y + 1) ) / 8
center = self.Noise(x, y) / 4
return corners + sides + center
def Interpolate_Noise(self, x, y):
round_x = round(x)
frac_x = x - round_x
round_y = round(y)
frac_y = y - round_y
v11 = self.Smooth_Noise(round_x - 1, round_y - 1)
v12 = self.Smooth_Noise(round_x , round_y - 1)
v13 = self.Smooth_Noise(round_x + 1, round_y - 1)
v14 = self.Smooth_Noise(round_x + 2, round_y - 1)
i1 = self.Cubic_Interpolate(v11, v12, v13, v14, frac_x)
v21 = self.Smooth_Noise(round_x - 1, round_y)
v22 = self.Smooth_Noise(round_x , round_y)
v23 = self.Smooth_Noise(round_x + 1, round_y)
v24 = self.Smooth_Noise(round_x + 2, round_y)
i2 = self.Cubic_Interpolate(v21, v22, v23, v24, frac_x)
v31 = self.Smooth_Noise(round_x - 1, round_y + 1)
v32 = self.Smooth_Noise(round_x , round_y + 1)
v33 = self.Smooth_Noise(round_x + 1, round_y + 1)
v34 = self.Smooth_Noise(round_x + 2, round_y + 1)
i3 = self.Cubic_Interpolate(v31, v32, v33, v34, frac_x)
v41 = self.Smooth_Noise(round_x - 1, round_y + 2)
v42 = self.Smooth_Noise(round_x , round_y + 2)
v43 = self.Smooth_Noise(round_x + 1, round_y + 2)
v44 = self.Smooth_Noise(round_x + 2, round_y + 2)
i4 = self.Cubic_Interpolate(v41, v42, v43, v44, frac_x)
return self.Cubic_Interpolate(i1, i2, i3, i4, frac_y)
def Perlin(self, lenght, octaves):
result = []
for x in range(lenght):
value = 0
for y in range(octaves):
frequency = 2 ** y
amplitude = 0.25 ** y
value += self.Interpolate_Noise(x * frequency, x * frequency) * amplitude
result.append(value)
print(f"{x} / {lenght} ({x/lenght*100:.2f}%): {round(x/lenght*10) * '#'} {(10-round(x/lenght*10)) * ' '}. Remaining {lenght-x}.") # I don't use `os.system('cls')` because it slow down the code.
return result
def graph(self, color = 'viridis'):
# Other colors: https://matplotlib.org/examples/color/colormaps_reference.html
fig = plt.figure()
Z = np.array(self.result).reshape(self.lenght_axes, self.lenght_axes)
ax = fig.add_subplot(1, 2, 1, projection='3d')
X = np.arange(self.lenght_axes)
Y = np.arange(self.lenght_axes)
X, Y = np.meshgrid(X, Y)
d3 = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=color, linewidth=0, antialiased=False)
fig.colorbar(d3)
ax = fig.add_subplot(1, 2, 2)
d2 = ax.imshow(Z, cmap=color, interpolation='none')
fig.colorbar(d2)
plt.show()
The output isn't suitable for a map. Look at this output using:
test = D2(1000, 3)
test.graph()
Maybe it's difficult to notice in the 2D noise but in 1D it's easier:
test = D1(1000, 3)
test.graph()
The noise function from the internet has slightly smaller and less frequent peaks, but still too many. I am looking for something smoother, like this:
Or this:
I made this based on this pseudocode.
Pikalek:
Even with low values it has peaks and no curves or smooth/flat lines.
Solution
I've spotted these mistakes in your code:
- You need to multiply
Interpolate_Noiseparameter, to "zoom" into the map (for example, multiplyxwith0.01). If you do this in the 1D case, you'll see that the generated function is already much better - Increase the octave count from 3 to something larger (3 octaves don't generate too much detail)
- Use amplitude 0.5^octave, not 0.25^octave (but you can play with this parameter, so 0.25 is not inherently bad, but it doesn't give too much detail)
- For the 2D case, you need to have 2 outer loops (one for horizontal, and one for vertical. And of course, you still need to have the octave loop). So you need to "index" the noise properly with horizontal and vertical position, not just
xandx. - Remove smoothing altogether. Perlin noise doesn't need it.
- 2D noise function has a bug: it uses
xinstead ofnin the return expression - at cubic interpolation, you use
roundinstead ofmath.floor.
Here's an answer of mine, with a simple (C++) implementation of Perlin-like (it is not proper perlin) noise: https://stackoverflow.com/a/45121786/8157187