1638 Night

(meta linear-colour-space: 1)

(define
  ;; fade out any lines which are far away from the focal points
  interest (interp/build from: [0.2 1.5] to: [0 1] clamping: true))

;; call 'fun' for every point on a nXn grid on the canvas
(fn (grid n: 10 fun: 1)
    (define
      remap-x (interp/build from: [0 (- n 1)] to: [0 canvas/width])
      remap-y (interp/build from: [0 (- n 1)] to: [0 canvas/height]))
    (loop (y from: 0 to: n)
          (loop (x from: 0 to: n)
                (fn-call (fun position: [(interp/value from: remap-x t: x)
                                         (interp/value from: remap-y t: y)])))))


;; render the background grid
(define
  focal-bg-a (focal/build-point position: [{525 (gen/stray-int from: 525 by: 100)}
                                           {348 (gen/stray-int from: 348 by: 100)}]
                                distance: {750 (gen/stray-int from: 750 by: 40)}
                                falloff: linear)
  focal-bg-b (focal/build-point position: [{542 (gen/stray-int from: 542 by: 100)}
                                           {765 (gen/stray-int from: 765 by: 10)}]
                                distance: {891 (gen/stray-int from: 891 by: 50)}
                                falloff: linear)
  col-fn-bg (col/build-bezier a: {(col/rgb r: 0.093 g: 0.208 b: 0.298 alpha: 0.247) (gen/col)}
                              b: {(col/rgb r: 0.422 g: 0.034 b: 0.083 alpha: 0.373) (gen/col)}
                              c: {(col/rgb r: 0.279 g: 0.904 b: 0.485 alpha: 0.503) (gen/col)}
                              d: {(col/rgb r: 0.299 g: 0.192 b: 0.862 alpha: 0.987) (gen/col)}))



(fn (draw-element-bg position: [0 0])
    (define
      interest-a (focal/value from: focal-bg-a position: position)
      interest-b (focal/value from: focal-bg-b position: position)
      combined-interest (+ interest-a interest-b)
      alpha (interp/value from: interest t: combined-interest))
    (on-matrix-stack
      (translate vector: position)
      (rotate angle: (* combined-interest {334 (gen/stray-int from: 334 by: 30)}))
      (circle position: [0 0]
              colour: (col/set-alpha from: (col/value from: col-fn-bg t: interest-a) value: alpha)
              width: {41 (gen/stray-int from: 41 by: 20)}
              height: {461 (gen/stray-int from: 461 by: 50)}
              tessellation: 20)))

(grid n: {35 (gen/stray-int from: 35 by: 5)}
      fun: (address-of draw-element-bg))

;; render the foreground
(define
  focal-fg-a (focal/build-point position: {[311 396] (gen/int min: 0 max: 1000)}
                                distance: {453 (gen/int min: 0 max: 500)}
                                falloff: linear)
  focal-fg-b (focal/build-point position: {[157 178] (gen/int min: 0 max: 1000)}
                                distance: {386 (gen/int min: 0 max: 600)}
                                falloff: linear)
  col-fn-fg (col/build-bezier a: {(col/rgb r: 0.762 g: 0.048 b: 0.407 alpha: 0.093) (gen/col)}
                              b: {(col/rgb r: 0.474 g: 0.751 b: 0.507 alpha: 0.657) (gen/col)}
                              c: {(col/rgb r: 0.179 g: 0.398 b: 0.683 alpha: 0.380) (gen/col)}
                              d: {(col/rgb r: 0.425 g: 0.207 b: 0.393 alpha: 0.825) (gen/col)}))

(fn (draw-element-fg position: [0 0])
    (define
      interest-a (focal/value from: focal-fg-a position: position)
      interest-b (focal/value from: focal-fg-b position: position)
      combined-interest (+ interest-a interest-b)
      alpha (interp/value from: interest t: combined-interest))
    (on-matrix-stack
      (translate vector: position)
      (rotate angle: (* combined-interest {151 (gen/stray-int from: 151 by: 30)}))
      (circle position: [0 0]
              colour: (col/set-alpha from: (col/value from: col-fn-fg t: interest-a) value: alpha)
              width: {13 (gen/stray-int from: 13 by: 7)}
              height: {263 (gen/stray-int from: 263 by: 50)}
              tessellation: 20)))

(grid n: {36 (gen/int min: 30 max: 40)}
      fun: (address-of draw-element-fg))