From 34b5b5ffb1d66ecc66d6940364c457b29de4aa2a Mon Sep 17 00:00:00 2001
From: Abhinav Sarkar <abhinav.sarkar@gmail.com>
Date: Thu, 26 Sep 2013 02:45:13 +0530
Subject: [PATCH] Added paddle positioner

---
 resources/public/index.html  |  4 +-
 src/cljs/frpong/core.cljs    | 76 ++++++++++++++++++++++++++----------
 src/cljs/frpong/helpers.cljs | 29 ++++++--------
 3 files changed, 70 insertions(+), 39 deletions(-)

diff --git a/resources/public/index.html b/resources/public/index.html
index 50ec202..9e2badb 100644
--- a/resources/public/index.html
+++ b/resources/public/index.html
@@ -13,7 +13,9 @@
     <div>Position: <span id="pos"></span></div>
     <div>Velocity: <span id="vel"></span></div>
     <svg style="width: 600px; height: 400px; border: 1px black solid" id="canvas">
-        <circle id="ball" r="5" cx="5" cy="100"/>
+        <circle id="ball" r="5" cx="5" cy="100" />
+        <rect id="lpaddle" x="0" y="160" width="10" height="80" />
+        <rect id="rpaddle" x="590" y="160" width="10" height="80" />
     </svg>
     
     <!-- pointing to cljsbuild generated js file -->
diff --git a/src/cljs/frpong/core.cljs b/src/cljs/frpong/core.cljs
index 4849ba5..673af84 100644
--- a/src/cljs/frpong/core.cljs
+++ b/src/cljs/frpong/core.cljs
@@ -1,5 +1,5 @@
 (ns frpong.core
-  (:require [frpong.helpers :as h :refer [log]]
+  (:require [frpong.helpers :as h]
             [cljs.core.async :as async
              :refer [<! >! chan put! close! sliding-buffer dropping-buffer timeout]]
             [domina :as dom :refer [log]]
@@ -42,7 +42,7 @@
             (recur t))))
     c))
 
-(defn positioner [tick-chan vel-chan pos-chan-in pos-chan-out]
+(defn ball-positioner [tick-chan vel-chan pos-chan-in pos-chan-out]
   (go-loop
     (let [tick (<! tick-chan)
           [vel-x vel-y] (<! vel-chan)
@@ -52,7 +52,7 @@
 
 (defn collision-detector [width height padding tick-chan pos-chan vel-chan-in vel-chan-out]
   (go-loop
-    (let [adjust-v (fn [p v size] 
+    (let [adjust-v (fn [p v size]
                       (cond
                         (< p padding) (abs v)
                         (> p (- size padding)) (- (abs v))
@@ -65,33 +65,65 @@
           vel-yn (adjust-v yn vel-y height)]
       (>! vel-chan-out [vel-xn vel-yn]))))
 
-(defn render-loop [pos-chan vel-chan]
+(defn key-chan [keycodes]
+  (let [source (h/event-chan :keydown)
+        c (chan)]
+    (go-loop
+      (let [kc (:keyCode (<! source))]
+        (when (contains? keycodes kc)
+          (>! c (keycodes kc)))))
+    c))
+
+(defn paddle-positioner [keycodes max-y movement pos-chan-in pos-chan-out]
+  (let [key-chan (key-chan keycodes)]
+    (go-loop
+      (let [dir (<! key-chan)
+            pos (<! pos-chan-in)]
+        (condp = dir
+          :up (>! pos-chan-out (max (- pos movement) 0))
+          :down (>! pos-chan-out (min (+ pos movement) max-y)))))))
+
+(defn render-loop [[pos-chan vel-chan pl-pos-chan pr-pos-chan]]
   (go-loop
     (let [[x y] (map int (<! pos-chan))
           vel (<! vel-chan)]
       (dom/set-text! (dom/by-id "pos") [x y])
       (dom/set-text! (dom/by-id "vel") vel)
       (dom/set-attr! (dom/by-id "ball") "cx" x)
-      (dom/set-attr! (dom/by-id "ball") "cy" y))))
+      (dom/set-attr! (dom/by-id "ball") "cy" y)))
+  (go-loop
+    (dom/set-attr! (dom/by-id "lpaddle") "y" (<! pl-pos-chan)))
+  (go-loop
+    (dom/set-attr! (dom/by-id "rpaddle") "y" (<! pr-pos-chan))))
 
-(defn game-setup [width height padding frame-chan pos-chan vel-chan]
-  (let [[tick-chan-pos tick-chan-collsion] (h/dup-chan (tick-chan (h/diff-chan frame-chan)))
-        [pos-chan-pos pos-chan-render pos-chan-collision] (h/multiplex pos-chan 3)
-        [vel-chan-pos vel-chan-collision vel-chan-render] (h/multiplex vel-chan 3)]
-    (positioner tick-chan-pos vel-chan-pos pos-chan-pos pos-chan)
+(defn game-setup [{:keys [width height padding paddle-size]} paddle-movement
+                  frame-chan pos-chan vel-chan pl-pos-chan pr-pos-chan]
+  (let [max-y (- height paddle-size)
+        [tick-chan-pos tick-chan-collsion] (h/dup-chan (tick-chan (h/diff-chan frame-chan)))
+        [pos-chan-pos pos-chan-collision pos-chan-render] (h/multiplex pos-chan 3)
+        [vel-chan-pos vel-chan-collision vel-chan-render] (h/multiplex vel-chan 3)
+        [pl-pos-chan-pos pl-pos-chan-render] (h/multiplex pl-pos-chan 2)
+        [pr-pos-chan-pos pr-pos-chan-render] (h/multiplex pr-pos-chan 2)]
+    (ball-positioner tick-chan-pos vel-chan-pos pos-chan-pos pos-chan)
     (collision-detector width height padding
       tick-chan-collsion pos-chan-collision vel-chan-collision vel-chan)
-    [pos-chan-render vel-chan-render]))
+    (paddle-positioner {83 :down 87 :up} max-y paddle-movement pl-pos-chan-pos pl-pos-chan)
+    (paddle-positioner {38 :up 40 :down} max-y paddle-movement pr-pos-chan-pos pr-pos-chan)
+    [pos-chan-render vel-chan-render pl-pos-chan-render pr-pos-chan-render]))
 
-(defn game-init [width height padding init-pos init-vel frame-chan]
+(defn game-init [layout {:keys [init-pos init-vel paddle-movement]} frame-chan]
   (let [pos-chan (chan 1)
         vel-chan (chan 1)
-        [pos-chan-render vel-chan-render] 
-          (game-setup width height padding frame-chan pos-chan vel-chan)]
+        pl-pos-chan (chan 1)
+        pr-pos-chan (chan 1)]
     (put! pos-chan init-pos)
     (put! vel-chan init-vel)
+    (put! pl-pos-chan 160)
+    (put! pr-pos-chan 160)
 
-    (render-loop pos-chan-render vel-chan-render)))
+    (render-loop
+      (game-setup layout paddle-movement
+                  frame-chan pos-chan vel-chan pl-pos-chan pr-pos-chan))))
 
 (defn ^:export init []
   (let [frame-chan (h/frame-chan)
@@ -100,12 +132,14 @@
         fps-chan (h/map-chan #(/ 1000 %) (h/diff-chan frame-chan-fps))
         frame-count-chan (h/counting-chan frame-chan-count)
 
-        width 600
-        height 400
-        padding 5
-        init-pos [5 100]
-        init-vel [0.2 0.22]]
+        layout {:width 600
+                :height 400
+                :padding 5
+                :paddle-size 80}
+        init-vals {:init-pos [5 100]
+                   :init-vel [0.2 0.22]
+                   :paddle-movement 10}]
     (go-loop
       (dom/set-text! (dom/by-id "fps") (<! fps-chan))
       (dom/set-text! (dom/by-id "frame") (<! frame-count-chan)))
-    (game-init width height padding init-pos init-vel frame-chan-game)))
+    (game-init layout init-vals frame-chan-game)))
diff --git a/src/cljs/frpong/helpers.cljs b/src/cljs/frpong/helpers.cljs
index 566bf37..2f326cd 100644
--- a/src/cljs/frpong/helpers.cljs
+++ b/src/cljs/frpong/helpers.cljs
@@ -9,8 +9,6 @@
 (defn now []
   (.valueOf (js/Date.)))
 
-(defn log [s] (.log js/console s))
-
 (defn put-all! [cs x]
   (doseq [c cs]
     (put! c x)))
@@ -81,20 +79,17 @@
     (throttle (chan) source control))
   ([c source control]
     (go
-      (loop [state ::init last nil cs [source]]
-        (let [[_ sync] cs]
-          (let [[v sc] (alts! cs)]
-            (condp = sc
-              source (condp = state
-                       ::init (do (>! c v)
-                                (recur ::throttling last
-                                  (conj cs control)))
-                       ::throttling (recur state v cs))
-              sync (if last 
-                     (do (>! c last)
-                       (recur state nil
-                         (conj (pop cs) control)))
-                     (recur ::init last (pop cs))))))))
+      (loop [state ::init last nil]
+        (let [[v sc] (alts! [source control])]
+          (condp = sc
+            source (condp = state
+                     ::init (do (>! c v)
+                              (recur ::throttling last))
+                     ::throttling (recur state v))
+            control (if last 
+                      (do (>! c last)
+                       (recur state nil))
+                     (recur ::init last))))))
     c))
 
 (defn debounce
@@ -153,7 +148,7 @@
 
 (defn event-chan [event-type]
   (let [c (chan)]
-    (ev/listen! js/document event-type #(put! c %))
+    (ev/listen! event-type #(put! c %))
     c))
 
 (defn frame-chan []