first program in raytracing in a weekend in racket

raytracing.rkt

#lang racket


(define nx 200)
(define ny 100)
(display (string-append "P3\n"
                        (number->string nx) " "
                        (number->string ny) "\n255\n"))
(for ([j (in-range (- ny 1) 0 -1)])

  (for ([i (in-range 0 (- nx 1))])
    
    (let ([r (/ i nx)]
             [g (/ j ny)]
             [b 0.2])

      (let ([ir (exact-round (* 255.99 r))]
            [ig (exact-round (* 255.99 g))]
            [ib (exact-round (* 255.99 b))])


        (display (string-append (number->string ir)
                                " " (number->string ig)
                                " " (number->string ib) "\n"))

        ) ;; end of inner let

   
      ) ;; end of let first let
    
    ) ;; end of inner for


  )