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Contents
#
# Graphing 2D Equations
# by Daniel Shiffman.
#
# Graphics the following equation:
# sin(n*cos(r) + 5*theta)
# where n is a function of horizontal mouse location.
#
def setup
size(640, 360)
end
def draw
load_pixels
n = (mouse_x * 10.0) / width
w = 16.0 # 2D space width
h = 16.0 # 2D space height
dx = w / width # Increment x this amount per pixel
dy = h / height # Increment y this amount per pixel
x = -w / 2 # Start x at -1 * width / 2
width.times do |i|
y = -h / 2 # Start y at -1 * height / 2
height.times do |j|
r = sqrt((x * x) + (y * y)) # Convert cartesian to polar
theta = atan2(y, x) # Convert cartesian to polar
# Compute 2D polar coordinate function
val = sin(n * cos(r) + 5 * theta) # Results in a value between -1 and 1
#val = cos(r) # Another simple function
#val = sin(theta) # Another simple function
# Map the resulting value to a grayscale value
pixels[i + j * width] = color((val + 1.0) * 255.0/2.0) # Scale to between 0 and 255
y += dy # Increment y
end
x += dx # Increment x
end
update_pixels
end
Version data entries
10 entries across 10 versions & 1 rubygems