From: Javier Sancho <jsf@jsancho.org>
Date: Sun, 26 Jun 2016 08:32:14 +0000 (+0200)
Subject: Function for update one particle
X-Git-Url: https://git.jsancho.org/?a=commitdiff_plain;h=refs%2Fheads%2Fengine-draft;p=gacela.git

Function for update one particle
---

diff --git a/examples/particle-system.scm b/examples/particle-system.scm
index 2b2c1b5..a0d659a 100644
--- a/examples/particle-system.scm
+++ b/examples/particle-system.scm
@@ -39,26 +39,26 @@
 	  (draw-quad (list x y z) #:color (list r g b))))))
    particles))
 
+(define (update-particle particle)
+  (match particle
+    ((x y z vx vy vz)
+     (let* ((distance-squared (+ (* x x) (* y y) (* z z)))
+	    (distance (sqrt distance-squared))
+	    (F (/ -200 distance-squared))
+	    (ax (* F (/ x distance)))
+	    (ay (* F (/ y distance)))
+	    (az (* F (/ z distance))))
+       (list (+ x (* vx dt) (* ax half-dt-squared))
+	     (+ y (* vy dt) (* ay half-dt-squared))
+	     (+ z (* vz dt) (* az half-dt-squared))
+	     (+ vx (* ax dt))
+	     (+ vy (* ay dt))
+	     (+ vz (* az dt)))))))
+
 (define (update-particles dt)
   (let ((half-dt-squared (* 0.5 dt dt)))
     (set! *particles*
-      (map
-       (lambda (particle)
-	 (match particle
-	   ((x y z vx vy vz)
-	    (let* ((distance-squared (+ (* x x) (* y y) (* z z)))
-		   (distance (sqrt distance-squared))
-		   (F (/ -200 distance-squared))
-		   (ax (* F (/ x distance)))
-		   (ay (* F (/ y distance)))
-		   (az (* F (/ z distance))))
-	      (list (+ x (* vx dt) (* ax half-dt-squared))
-		    (+ y (* vy dt) (* ay half-dt-squared))
-		    (+ z (* vz dt) (* az half-dt-squared))
-		    (+ vx (* ax dt))
-		    (+ vy (* ay dt))
-		    (+ vz (* az dt)))))))
-       *particles*))))
+      (map update-particle *particles*))))
 
 (define (prepare-particles n)
   (cond ((= n 0)