source file of the GNU LilyPond music typesetter
- (c) 1999--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
+ (c) 1999--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
TODO:
- add support for different stretch/shrink constants?
Simple_spacer::rod_force (int l, int r, Real dist)
{
Real d = range_ideal_len (l, r);
- Real c = range_stiffness (l, r, d > dist);
+ Real c = range_stiffness (l, r, dist > d);
Real block_stretch = dist - d;
+
+ if (isinf (c) && block_stretch == 0) /* take care of the 0*infinity_f case */
+ return 0;
return c * block_stretch;
}
Real spring_dist = range_ideal_len (l, r);
if (spring_dist < dist)
for (int i = l; i < r; i++)
- springs_[i].set_distance (springs_[i].distance () * dist / spring_dist);
+ {
+ if (spring_dist)
+ springs_[i].set_distance (springs_[i].distance () * dist / spring_dist);
+ else
+ springs_[i].set_distance (dist / (r - l));
+ }
return;
}
for (vsize i=0; i < springs_.size (); i++)
inv_hooke += springs_[i].inverse_stretch_strength ();
+ if (inv_hooke == 0.0) /* avoid division by zero. If springs are infinitely stiff */
+ return 0.0; /* anyway, then it makes no difference what the force is */
+
assert (cur_len <= line_len_);
return (line_len_ - cur_len) / inv_hooke + force_;
}
vector<Spring> sorted_springs = springs_;
sort (sorted_springs.begin (), sorted_springs.end (), greater<Spring> ());
+
for (vsize i = 0; i < sorted_springs.size (); i++)
{
Spring sp = sorted_springs[i];
/* Use a convex compression penalty. */
Real f = force_;
- return f - (f < 0 ? f*f*f*f*4 : 0);
+ return f - (f < 0 ? f*f*f*f*2 : 0);
}
/****************************************************************/
-/*
- TODO: should a add penalty for widely varying spring forces (caused
- by constraints, eg.
-
-
- . =====
- . | |
- .o|o|x ##x
- .
-
- The ## forces the notes apart; we shouldn't allow the O's to touch
- this closely.
-*/
-
struct Rod_description
{
vsize r_;