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faster pathfinding. From here, neighbors is slow.

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2014-09-11 18:34:23 -07:00
parent 9528a04a58
commit 124e89594b
1 changed files with 61 additions and 49 deletions
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110
desktop/src-common/advent/pathfind.clj
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@@ -7,6 +7,7 @@
[clojure.data.priority-map :refer [priority-map]])
(:import [com.badlogic.gdx.files FileHandle]
[com.badlogic.gdx Files]
[java.lang Math]
[com.badlogic.gdx.graphics Camera Color GL20 OrthographicCamera
PerspectiveCamera Pixmap Pixmap$Format PixmapIO Texture
VertexAttributes$Usage]))
@@ -16,63 +17,71 @@
(doseq [row (take-nth skip my-map)]
(println (take-nth skip (map {1 \space 0 "W" "X" "X" "." "."} row))))))
(defn random-map [] (-> (vec (take (/ 240 4) (repeatedly (fn [] (vec (take (/ 320 4) (repeatedly (fn [] (rand-nth [1 1 1 1 1 5 0])))))))))
(defn random-map [] (-> (vec (take (/ 240 4) (repeatedly (fn [] (vec (take (/ 320 4) (repeatedly (fn [] (rand-nth [1 1 1 5 5 0])))))))))
(update-in [1 1] (constantly 1))
(update-in [50 50] (constantly 1))))
(defn neighbors [[x y] my-map]
(let [candidates [[(dec x) (dec y)] [x (dec y)] [(inc x) (dec y)]
[(dec x) y] [(inc x) y]
[(dec x) (inc y)] [x (inc y)] [(inc x) (inc y)]]]
(remove #(= 0 (get-in my-map (reverse %)))
(filter (fn [[x y]] (and (< -1 x (count (first my-map)))
(< -1 y (count my-map)))) candidates))))
(defn neighbors [[^long x ^long y] my-map]
(let [candidates [[^long (dec x) ^long (dec y)] [x ^long (dec y)] [^long (inc x) ^long (dec y)]
[^long (dec x) y] [^long (inc x) y]
[^long (dec x) ^long (inc y)] [x ^long (inc y)] [^long (inc x) ^long (inc y)]]
width (count (first my-map))
height (count my-map)]
(vec (remove #(= 0 (get-in my-map (reverse %)))
(filter (fn [[x y]] (and (< -1 x width)
(< -1 y height))) candidates)))))
(defn resolve-path [came-from play-loc target-loc]
(if (nil? (came-from target-loc))
nil
(loop [path []
current-node target-loc]
(if (or (= current-node play-loc)
(nil? current-node))
(reverse (map (fn [[x y]] [x y]) (conj path current-node)))
(recur
(conj path current-node)
(came-from current-node))))))
(let [came-from (into {} came-from)]
(defn heuristic [[goal-x goal-y] [current-x current-y]]
(let [dist-x (Math/abs (- goal-x current-x ))
dist-y (Math/abs (- goal-y current-y))
d2 (Math/sqrt 2)]
(+ dist-x dist-y (* (- d2 1)
(min dist-x dist-y)))))
(if (nil? (came-from target-loc))
nil
(loop [path []
current-node (vec target-loc)]
(if (or (= current-node play-loc)
(nil? current-node))
(reverse (map (fn [[x y]] [x y]) (conj path current-node)))
(recur
(conj path current-node)
(came-from (vec current-node))))))))
(def d2 ^double (- (Math/sqrt 2) 1))
(defn heuristic [^long goal-x ^long goal-y ^long current-x ^long current-y]
(let [dist-x ^long (if (< goal-x current-x)
^long (- current-x goal-x)
^long (- goal-x current-x ))
dist-y ^long (if (< goal-y current-y)
^long (- current-y goal-y)
^long (- goal-y current-y))]
^long (+ dist-x dist-y (* ^double d2
^long (min dist-x dist-y)))))
(defn visit-all [my-map play-loc target-loc]
(if (= 0 (get-in my-map (reverse target-loc)))
nil
(loop [cost-so-far {play-loc 0}
came-from {}
fronteir (priority-map play-loc 0)]
(let [current-loc (first (keys fronteir))]
(if (or (empty? fronteir)
(= current-loc target-loc))
(resolve-path came-from play-loc target-loc)
(let [neighbors (neighbors current-loc my-map)
[cost-so-far came-from fronteir] (reduce (fn [[cost-so-far came-from fronteir] neighbor]
(let [new-cost (+ (cost-so-far current-loc) (get-in my-map (reverse neighbor)))]
(if (or (nil? (cost-so-far neighbor))
(< new-cost (cost-so-far neighbor)))
[(assoc cost-so-far neighbor new-cost)
(assoc came-from neighbor current-loc)
(assoc fronteir neighbor (+ new-cost (heuristic target-loc neighbor)))]
[cost-so-far came-from fronteir]
)))
[cost-so-far came-from fronteir]
neighbors)]
(recur cost-so-far came-from (dissoc fronteir current-loc))))))))
(let [play-loc (vec play-loc)
target-log (vec target-loc)]
(if (= 0 (get-in my-map (reverse target-loc)))
nil
(let [cost-so-far ^java.util.HashMap (java.util.HashMap. {play-loc 0})
came-from ^java.util.HashMap (java.util.HashMap.)
fronteir ^java.util.PriorityQueue (java.util.PriorityQueue. 100 (comparator (fn [a b] (< (:cost a) (:cost b)))))]
(.offer fronteir {:cost 0 :loc play-loc})
(loop [current-loc (.poll fronteir)]
(if (or (nil? current-loc)
(= (:loc current-loc) target-loc))
(resolve-path came-from play-loc target-loc)
(do (doseq [neighbor (neighbors (:loc current-loc) my-map)]
(let [cost-for-neighbor (.get cost-so-far neighbor)
new-cost (+ (.get cost-so-far (:loc current-loc)) (get-in my-map (reverse neighbor)))]
(when (or (nil? cost-for-neighbor)
(< new-cost cost-for-neighbor))
(.put came-from (vec neighbor) (vec (:loc current-loc)))
(.put cost-so-far (vec neighbor) new-cost)
(.offer fronteir {:cost (+ new-cost (heuristic (first target-loc) (second target-loc) (first neighbor) (second neighbor)))
:loc neighbor}))))
(recur (.poll fronteir)))))))))
(defn print-resolved [path my-map]
@@ -87,8 +96,11 @@
nil)
(defn test-pathfind []
(let [my-map (random-map)]
(print-resolved (visit-all my-map [1 1] [50 50]) my-map)))
(let [my-map (random-map)
path (visit-all my-map [1 1] [50 50])]
(println "Test")
(print-resolved path my-map)
(println path)))
(defn map-from-resource [filename]
(let [pm (pixmap filename)