From 40a38066c8a4b53017bb5f422e126dd2c6b20fd5 Mon Sep 17 00:00:00 2001 From: Joshua Grams Date: Thu, 23 Mar 2006 16:56:23 +0000 Subject: [PATCH] rewording bounce calculations. --- sprite.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/sprite.c b/sprite.c index ec9fb01..0a6ab87 100644 --- a/sprite.c +++ b/sprite.c @@ -299,7 +299,7 @@ void bounce(Sprite *a, Sprite *b) { float x, y, n; - float da, db; + float va, vb; float ma, mb, mr; // (x, y) is unit vector pointing from A's center to B's center. @@ -308,13 +308,13 @@ 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. - da = max(x*a->dx + y*a->dy, 0); - db = min(x*b->dx + y*b->dy, 0); + va = max(x*a->dx + y*a->dy, 0); + vb = min(x*b->dx + y*b->dy, 0); // mass ratio ma = sprite_mass(a); mb = sprite_mass(b); if(ma && mb) mr = mb/ma; else mr = 1; - a->dx += x*(db*mr - da); a->dy += y*(db*mr - da); - b->dx += x*(da/mr - db); b->dy += y*(da/mr - db); + a->dx += x*(mb*vb - ma*va)/ma; a->dy += y*(mb*vb - ma*va)/ma; + b->dx += x*(ma*va - mb*vb)/mb; b->dy += y*(ma*va - mb*vb)/mb; } -- 1.7.10.4