frpong/src/cljs/frpong/core.cljs

197 lines
8.6 KiB
Clojure

(ns frpong.core
(:require [frpong.helpers :as h]
[cljs.core.async :refer [<! >! chan put!]]
[domina :as dom :refer [log]])
(:require-macros [cljs.core.async.macros :as m :refer [go]]
[frpong.core :refer (go-loop)]))
;;
;; Signal Diagram
;;
;; +---------------------+
;; | +-------------+ |
;; | | | |
;; v v | |
;; +----------+ vel-chan | |
;; +-->|c-detector+----------+ |
;; | +----------+ | |
;; | +-----------------+ |
;; | | +-----------------+
;; | | | |
;; | v v |
;; +---------+ frame-chan +------+ tick-chan | +----------+ pos-chan |
;; |frame-gen+------------>|ticker+-----------+-->|positioner+--------------+
;; +---------+ +------+ +----------+ |
;; +---------------------+
;; |
;; v
;; +----------+
;; | renderer |
;; +----------+
(defn abs [x] (.abs js/Math x))
(defn tick-chan [frames]
(let [c (chan)]
(go
(loop [prev (<! frames)]
(let [t (<! frames)]
(when (< t (* 10 prev))
(>! c t))
(recur t))))
c))
(defn ticker [[frames stop-frames] ticks game-state]
(let [ticks-in (tick-chan (h/diff-chan frames))]
(go-loop
(if-not (= :gameover (<! game-state))
(>! ticks (<! ticks-in))
(stop-frames)))))
(defn ball-positioner [ticks vel pos-in pos-out]
(go-loop
(let [tick (<! ticks)
[vel-x vel-y] (<! vel)
[x y] (<! pos-in)
pos-next [(+ x (* vel-x tick)) (+ y (* vel-y tick))]]
(>! pos-out pos-next))))
(defn paddle-positioner [keycodes max-y movement pos-in pos-out]
(let [keys (h/key-chan keycodes)]
(go-loop
(let [pos (<! pos-in)]
(>! pos-out
(condp = (<! keys)
:up (max (- pos movement) 0)
:down (min (+ pos movement) max-y)))))))
(defn collision-detector
[{:keys [width height padding paddle-size paddle-width]}
ticks game-state pos vel-in vel-out pl-pos pr-pos]
(let [ef-paddle-width (+ paddle-width padding)
adjust-v (fn [state v] [(condp = state
:collision-left (abs v)
:collision-right (- (abs v))
:moving v
:gameover 0)
state])
in-y-range? (fn [y p-pos] (and (> y (+ p-pos padding))
(< y (- (+ p-pos paddle-size) padding))))
detect-x-collision (fn [x y pl-pos pr-pos]
(cond
(< x ef-paddle-width)
(if (in-y-range? y pl-pos) :collision-left :gameover)
(> x (- width ef-paddle-width))
(if (in-y-range? y pr-pos) :collision-right :gameover)
:else :moving))
detect-y-collision (fn [y] (cond
(< y padding) :collision-left
(> y (- height padding)) :collision-right
:else :moving))]
(go-loop
(let [tick (<! ticks)
[vel-x vel-y] (<! vel-in)
[x y] (<! pos)
pl-pos (<! pl-pos)
pr-pos (<! pr-pos)
[xn yn] [(+ x (* vel-x tick)) (+ y (* vel-y tick))]
[vel-xn bs-x] (adjust-v (detect-x-collision xn yn pl-pos pr-pos) vel-x)
[vel-yn bs-y] (adjust-v (detect-y-collision yn) vel-y)]
(>! vel-out [vel-xn vel-yn])
(>! game-state
(cond
(= bs-x :gameover) :gameover
(or (= bs-x :collision-left) (= bs-x :collision-right)
(= bs-y :collision-left) (= bs-y :collision-right)) :collision
:else :moving))))))
(defn renderer [game-state pos pl-pos pr-pos]
(let [ball-el (dom/by-id "ball")
state-el (dom/by-id "state")
lpaddle-el (dom/by-id "lpaddle")
rpaddle-el (dom/by-id "rpaddle")]
(go-loop
(let [[x y] (<! pos)
gs (<! game-state)]
(dom/set-text! state-el (name gs))
(doto ball-el
(dom/set-attr! "cx" x)
(dom/set-attr! "cy" y))))
(go-loop
(dom/set-attr! lpaddle-el "y" (<! pl-pos)))
(go-loop
(dom/set-attr! rpaddle-el "y" (<! pr-pos)))))
(defn game-setup [{:keys [width height padding paddle-size] :as layout} paddle-movement
frames game-state pos vel pl-pos pr-pos]
(let [max-y (- height paddle-size)
ticks (chan)
[tick-pos tick-collsion tick-pl tick-pr] (h/multiplex ticks 4)
[pos-in pos-collision pos-render] (h/multiplex pos 3)
[vel-pos vel-collision] (h/multiplex vel 2)
[pl-pos-in pl-pos-collision pl-pos-render] (h/multiplex pl-pos 3)
[pr-pos-in pr-pos-collision pr-pos-render] (h/multiplex pr-pos 3)
[game-state-ticker game-state-render] (h/multiplex game-state 2)]
(ticker frames ticks game-state-ticker)
(ball-positioner tick-pos vel-pos pos-in pos)
(collision-detector layout tick-collsion game-state pos-collision vel-collision vel
(h/sustain pl-pos-collision tick-pl)
(h/sustain pr-pos-collision tick-pr))
(paddle-positioner {83 :down 87 :up} max-y paddle-movement pl-pos-in pl-pos)
(paddle-positioner {38 :up 40 :down} max-y paddle-movement pr-pos-in pr-pos)
[game-state-render pos-render pl-pos-render pr-pos-render]))
(defn game-init [{:keys [height paddle-size] :as layout}
{:keys [init-pos init-vel paddle-movement]} frames]
(let [init-paddle-pos (/ (- height paddle-size) 2)
pos (chan 1)
vel (chan 1)
pl-pos (chan 1)
pr-pos (chan 1)
game-state (chan 1)]
(put! pos init-pos)
(put! vel init-vel)
(put! pl-pos init-paddle-pos)
(put! pr-pos init-paddle-pos)
(put! game-state :moving)
(apply renderer
(game-setup layout paddle-movement frames game-state pos vel pl-pos pr-pos))))
(defn ^:export init []
(let [layout {:width 800
:height 400
:padding 5
:paddle-size 100
:paddle-width 10
:ball-radius 5}
init-vals {:init-pos [50 100]
:init-vel [0.3 0.33]
:paddle-movement 20}
[frames stop-frames] (h/frame-chan)
[frames-fps frames-count frames-game] (h/multiplex frames 3)
fps (h/map-chan #(/ 1000 %) (h/diff-chan frames-fps))
frames-count (h/counting-chan frames-count)
fps-el (dom/by-id "fps")
frame-el (dom/by-id "frame")]
(doto (dom/by-id "canvas")
(dom/set-style! "width" (str (:width layout) "px"))
(dom/set-style! "height" (str (:height layout) "px")))
(doto (dom/by-id "ball")
(dom/set-attr! "r" (:ball-radius layout))
(dom/set-attr! "cx" (first (:init-pos init-vals)))
(dom/set-attr! "cy" (second (:init-pos init-vals))))
(doseq [id ["lpaddle" "rpaddle"]]
(doto (dom/by-id id)
(dom/set-attr! "width" (:paddle-width layout))
(dom/set-attr! "height" (:paddle-size layout))
(dom/set-attr! "y" (/ (- (:height layout) (:paddle-size layout)) 2))))
(dom/set-attr! (dom/by-id "lpaddle") "x" 0)
(dom/set-attr! (dom/by-id "rpaddle") "x" (- (:width layout) (:paddle-width layout)))
(go-loop
(dom/set-text! fps-el (<! fps))
(dom/set-text! frame-el (<! frames-count)))
(game-init layout init-vals [frames-game stop-frames])))