diff --git a/web-world/examples/boid/boid.rkt b/web-world/examples/boid/boid.rkt
index 9905ed5..357fa4e 100644
--- a/web-world/examples/boid/boid.rkt
+++ b/web-world/examples/boid/boid.rkt
@@ -290,16 +290,20 @@
boids))
-;; draw: (listof boid) -> scene
-#;(define (draw boids)
- (for/fold ([scene (place-image (rectangle width height 'solid 'black)
- 320 240
- (empty-scene width height))])
- ([b boids])
- (place-image (circle 3 'solid (boid-color b))
- (vec-x (boid-position b))
- (vec-y (boid-position b))
- scene)))
+;; draw: (listof boid) view -> scene
+(define (draw boids dom)
+ (foldl (lambda (boid dom)
+ (define with-left (update-view-css (view-focus dom (boid-id boid))
+ "left"
+ (format "~apx"
+ (vec-x (boid-position boid)))))
+ (define with-left-and-top (update-view-css with-left
+ "top"
+ (format "~apx"
+ (vec-y (boid-position boid)))))
+ with-left-and-top)
+ dom
+ boids))
@@ -318,25 +322,26 @@
(define (new-population)
- (build-list 5 (lambda (i) (make-random-boid))))
+ (build-list 20 (lambda (i) (make-random-boid))))
;; visualize: -> void
;; Animates a scene of the boids flying around.
(define (visualize)
(define population (new-population))
+
+ (define view-with-boids (view-append-child
+ (view-focus (->view index.html) "playground")
+ (xexp->dom `(div ,@(map (lambda (b)
+ `(div (@ (id ,(boid-id b))
+ (class "boid"))
+ nbsp))
+ population)))))
+
(big-bang population
- (initial-view
- (view-append-child
- (view-focus (->view index.html) "playground")
- (xexp->dom `(div ,@(map (lambda (b)
- `(div (@ (id ,(boid-id b))
- (class "boid"))
- nbsp))
- population)))))
- (on-tick tick)
- #;(to-draw draw)
- ))
+ (initial-view view-with-boids)
+ (on-tick tick 1/20)
+ (to-draw draw)))
(visualize)
\ No newline at end of file
diff --git a/web-world/examples/boid/index.html b/web-world/examples/boid/index.html
index ee7c9b2..1b4b718 100644
--- a/web-world/examples/boid/index.html
+++ b/web-world/examples/boid/index.html
@@ -2,7 +2,7 @@
Boid