(fn make-simplex-noise [radius? harmonics? width? height?]
"Generate 2d tiling simplex noise tile.
The generated tile will be saved in the user save directory.
radius? The radius of the x and y orthogonal circles in 4 d space. Larger radius ~= higher frequency
harmonics? How many harmonics do you want to include? Default 3
width? The width of the tile generated
height? The height the tile generated
example: (make-simplex-noise 10)"
(let [r (or radius? 10)
n (or harmonics? 3)
w (or width? 256)
h (or height? width? 256)
amplitude-decay 0.5
radius-increase 2
off-x (/ (math.random 1 100000) 100000)
off-y (/ (math.random 1 100000) 100000)
lg love.graphics
canvas (lg.newCanvas w h)
data (canvas:newImageData)]
(fn cliffords-torus-mapping [r j i w h off-x? off-y?]
(let [x1 (+ off-x (- r))
off-x (or off-x? 0)
off-y (or off-y? 0)
x2 (+ off-x (+ r))
y1 (+ off-y (- r))
y2 (+ off-y (+ r))
s (/ j w)
t (/ i h)
dx (- x2 x1)
dy (- y2 y1)
nx (+ x1 (* (/ dx (* 2 math.pi)) (math.cos (* s 2 math.pi) )))
ny (+ y1 (* (/ dy (* 2 math.pi)) (math.cos (* t 2 math.pi) )))
nz (+ x1 (* (/ dx (* 2 math.pi)) (math.sin (* s 2 math.pi) )))
nw (+ y1 (* (/ dy (* 2 math.pi)) (math.sin (* t 2 math.pi) )))
r (love.math.noise nx ny nz nw)]
r))
(for [i 1 h]
(for [j 1 w]
(var value 0)
(var amplitude 1)
(var radius r)
(for [harmonic 1 n]
(local rand (cliffords-torus-mapping radius j i w h off-x off-y))
(set value (+ value (* amplitude rand)))
(set radius (* radius radius-increase))
(set amplitude (* amplitude amplitude-decay)))
(set value (* 1.75 (/ value n)))
(data:setPixel (- i 1) (- j 1) value value value 1)))
(data:encode "png" (.. "simplex-noise-r=" r "h=" n ".png"))))