93 lines
2.2 KiB
Factor
93 lines
2.2 KiB
Factor
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! Run this file to write a Mandelbrot fractal to "mandel.ppm".
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IN: mandel
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USING: arrays compiler io kernel math namespaces sequences
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strings test ;
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: max-color 360 ; inline
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: zoom-fact 0.8 ; inline
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: width 640 ; inline
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: height 480 ; inline
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: nb-iter 40 ; inline
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: center -0.65 ; inline
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: f_ >r swap rot >r 2dup r> 6 * r> - ;
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: p ( v s x -- v p x ) >r dupd neg 1 + * r> ;
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: q ( v s f -- q ) * neg 1 + * ;
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: t_ ( v s f -- t_ ) neg 1 + * neg 1 + * ;
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: mod-cond ( p vector -- )
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#! Call p mod q'th entry of the vector of quotations, where
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#! q is the length of the vector. The value q remains on the
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#! stack.
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[ dupd length mod ] keep nth call ;
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: hsv>rgb ( h s v -- r g b )
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pick 6 * >fixnum {
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[ f_ t_ p swap ] ! v p t
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[ f_ q p -rot ] ! q v p
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[ f_ t_ p swapd ] ! p v t
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[ f_ q p rot ] ! p q v
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[ f_ t_ p swap rot ] ! t p v
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[ f_ q p ] ! v p q
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} mod-cond ;
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: scale 255 * >fixnum ; inline
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: scale-rgb ( r g b -- n )
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rot scale rot scale rot scale 3array ;
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: sat 0.85 ; inline
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: val 0.85 ; inline
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: <color-map> ( nb-cols -- map )
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dup [
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360 * swap 1+ / 360 / sat val
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hsv>rgb scale-rgb
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] map-with ;
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: iter ( c z nb-iter -- x )
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over absq 4.0 >= over zero? or
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[ 2nip ] [ 1- >r sq dupd + r> iter ] if ; inline
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SYMBOL: cols
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: x-inc width 200000 zoom-fact * / ; inline
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: y-inc height 150000 zoom-fact * / ; inline
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: c ( i j -- c )
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>r
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x-inc * center real x-inc width 2 / * - + >float
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r>
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y-inc * center imaginary y-inc height 2 / * - + >float
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rect> ; inline
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: render ( -- )
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height [
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width [
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2dup swap c 0 nb-iter iter dup zero? [
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drop "\0\0\0"
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] [
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cols get [ length mod ] keep nth
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] if %
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] repeat
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] repeat ;
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: ppm-header ( w h -- )
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"P6\n" % swap # " " % # "\n255\n" % ;
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: sbuf-size width height * 3 * 100 + ;
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: run ( -- string )
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[
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sbuf-size <sbuf> building set
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width height ppm-header
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nb-iter max-color min <color-map> cols set
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render
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building get >string
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] with-scope ;
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: run>file ( file -- )
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"Generating " write dup write "..." print
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<file-writer> [ run write ] with-stream ;
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