def grassTexture(imgSize=(256,256)):
"""Return a green, 'grassy' texture (PNMImage) of the given image size,
produced using 2D Perlin noise."""
# Initialuse the PNMImage object
img = PNMImage(*imgSize)
# Initalise 4 PerlinNoise2 objects to produce noise at different scales
noise1 = PerlinNoise2()
noise1.setScale(2.0)
noise2 = PerlinNoise2()
noise2.setScale(5.0)
noise3 = PerlinNoise2()
noise3.setScale(0.25)
noise4 = PerlinNoise2()
noise4.setScale(0.125)
# For each pixel in the image, set the red and blue values of the pixel to
# constant values, and set the green value of the pixel using all 4
# PerlinNoise2 objects.
red = 0.125 # Colour values in PNMImage are doubles in the range [0.0,1.0]
blue = 0.0625
for x in xrange(imgSize[0]):
for y in xrange(imgSize[1]):
img.setRed(x,y,red)
img.setBlue(x,y,blue)
pos = Vec2(1.0/32*x, 1.0/32*y)
img.setGreen(x,y,(0.5 + noise1(pos)*0.0625 + noise2(pos)*0.0625 +
noise3(pos)*0.125 + noise4(pos)*0.0625))
return img
def greenNoise(imgSize=(32,32),scale=0.25):
"""Return a PNMImage of the given size containing Perlin noise at the given
scale in the green colour values of the image pixels."""
# Initialuse the PNMImage object
img = PNMImage(*imgSize)
# Initalise PerlinNoise2 object
noise = PerlinNoise2()
noise.setScale(scale)
# Fill in the pixels of img, setting the red and blue values of each pixel
# to 0 and the green value to Perlin noise.
for x in xrange(imgSize[0]):
for y in xrange(imgSize[1]):
img.setRed(x,y,0)
img.setBlue(x,y,0)
pos = Vec2(1.0/32*x, 1.0/32*y)
img.setGreen(x,y,(noise(pos)+1.0)/2.0)
return img
