Cool Art

.gitignore

@@ -1 +1,3 @@
 .direnv/
+__pycache__/
+.DS_Store

perlin_noise.py

@@ -0,0 +1,49 @@
+import math
+import random
+from math import pi
+
+
+# returns the unit vector of angle
+def unitVector(angle):
+    return (math.cos(angle), math.sin(angle))
+
+
+# needs to be extended for any size vector
+def dotProduct(point1, point2):
+    return point1[0] * point2[0] + point1[1] * point2[1]
+
+
+# interp uses a cubic function to perform a weighted average of a0 and a1
+def interp(a0,  a1,  w):
+    weight = 3*math.pow(w, 2) - 2*math.pow(w, 3)
+    return a0*(1-weight) + a1*weight
+
+
+# angles provides the four gradient angles for the grid in a tuple
+# starting from top left then going clockwise
+# coords provides the (x, y) coordinates on the grid,  assuming top left is (0, 0)
+def perlinNoise(coords, gridSize, angles):
+    topLeftGradient = unitVector(angles[0])
+    topRightGradient = unitVector(angles[1])
+    bottomRightGradient = unitVector(angles[2])
+    bottomLeftGradient = unitVector(angles[3])
+    coords = (((coords[0] + 1) * 1000) % gridSize,
+              ((coords[1] + 1) * 1000) % gridSize)
+    topLeftVector = coords
+    topRightVector = (gridSize - coords[0], coords[1])
+    bottomRightVector = (gridSize - coords[0],  gridSize - coords[1])
+    bottomLeftVector = (coords[0], gridSize - coords[1])
+    topLeft = dotProduct(topLeftGradient, topLeftVector)
+    topRight = dotProduct(topRightGradient, topRightVector)
+    bottomRight = dotProduct(bottomRightGradient, bottomRightVector)
+    bottomLeft = dotProduct(bottomLeftGradient, bottomLeftVector)
+    topAverage = interp(topLeft, topRight, coords[0]/gridSize)
+    bottomAverage = interp(bottomLeft, bottomRight, coords[0]/gridSize)
+    average = interp(topAverage, bottomAverage, coords[1]/gridSize)
+    return average/gridSize
+
+
+if __name__ == "__main__":
+    print(perlinNoise((.002, .235), 350, (random.uniform(0, 2*pi),
+          random.uniform(0, 2*pi), random.uniform(0, 2*pi),
+          random.uniform(0, 2*pi))))

random_art.py

@@ -1,5 +1,6 @@
 import random
-
+from math import pi, sin, cos, tan, atan, acos, asin
+import perlin_noise as pn
 # Your job is to create better version of create_expression and
 # run_expression to create random art.
 # Your expression should have a __str__() function defined for it.
@@ -8,7 +9,34 @@
 def create_expression():
     """This function takes no arguments and returns an expression that
     generates a number between -1.0 and 1.0, given x and y coordinates."""
-    expr = lambda x, y: (random.random() * 2) - 1
+    angles1 = generate_angles()
+    angles2 = generate_angles()
+    angles3 = generate_angles()
+    grid_size1 = generate_grid_size()
+    grid_size2 = generate_grid_size()
+    grid_size3 = generate_grid_size()
+    offset_1x = random.random()
+    offset_1y = random.random()
+    offset_2x = random.random()
+    offset_2y = random.random()
+    trig1 = trig_func()
+    trig2 = trig_func()
+    trig3 = trig_func()
+    func1 = f()
+    func2 = f()
+    func3 = f()
+    func4 = f()
+    func5 = f()
+
+    def expr(x, y):
+        value1 = trig2(pi * func5(trig1(func1(pn.perlinNoise((x + offset_1x,
+                       y + offset_1y), grid_size1, angles1)) * pi)))
+        value2 = trig2(func3(pn.perlinNoise((x + offset_2x, y + offset_2y),
+                       grid_size2, angles2) * pi))
+        value3 = trig1(func2(pn.perlinNoise((x + offset_2y, y + offset_1x),
+                       grid_size3, angles3)) * pi)
+        return trig2(pi * func4(trig3(pi * func2(value1 *
+                     value2 - (value3 + x * y)))))
     return expr
 
 
@@ -17,3 +45,20 @@ def run_expression(expr, x, y):
     an x and y value. It runs the expression, passing the x and y values
     to it and returns a value between -1.0 and 1.0."""
     return expr(x, y)
+
+
+def generate_angles():
+    return (random.uniform(0, 2*pi), random.uniform(0, 2*pi),
+            random.uniform(0, 2*pi), random.uniform(0, 2*pi))
+
+
+def generate_grid_size():
+    return random.randint(2500, 4500)
+
+
+def trig_func():
+        return random.choice([sin, cos])
+
+
+def f():
+        return random.choice([sin, tan, cos, atan])