// (x, y) is unit vector pointing from A's center to B's center.
x = (b->x + b->w / 2) - (a->x + a->w / 2);
// (x, y) is unit vector pointing from A's center to B's center.
x = (b->x + b->w / 2) - (a->x + a->w / 2);
n = sqrt(x*x + y*y); x /= n; y /= n;
// velocities along (x, y), or 0 if already moving away.
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;
- 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;
+ a->dx += 2*x*(vc-va); a->dy += 2*y*(vc-va);
+ b->dx += 2*x*(vc-vb); b->dy += 2*y*(vc-vb);