From: Joshua Grams <josh@qualdan.com>
Date: Sat, 25 Mar 2006 21:16:48 +0000 (+0000)
Subject: proper moving-away detection in bounce()?
X-Git-Tag: 0.4~11
X-Git-Url: https://jasonwoof.com/gitweb/?p=vor.git;a=commitdiff_plain;h=37b3a2e06abc694205e843a573c4bb2eaaabb730

proper moving-away detection in bounce()?
---

diff --git a/sprite.c b/sprite.c
index e63fd68..1a35a6a 100644
--- a/sprite.c
+++ b/sprite.c
@@ -349,8 +349,9 @@ bounce(Sprite *a, Sprite *b)
 	n = sqrt(x*x + y*y); x /= n; y /= n;
 
 	// velocities along (x, y), or 0 if already moving away.
-	va = max(x*a->dx + y*a->dy, 0);
-	vb = min(x*b->dx + y*b->dy, 0);
+	va = x*a->dx + y*a->dy;
+	vb = x*b->dx + y*b->dy;
+	if(vb-va > 0) return;
 
 	ma = sprite_mass(a); mb = sprite_mass(b);
 	vc = (va*ma + vb*mb) / (ma+mb);