Add .py files to SOURCE_FILES instead of EXTRA_DIST_FILES. Fixes dist.

[lilypond.git] / lily / spring.cc

diff --git a/lily/spring.cc b/lily/spring.cc
index 264c8abfa159910cc251ef26028571e8f86574c9..60bc0aec77ca736084ed1afd18430b6a4bc0d9ea 100644 (file)
--- a/lily/spring.cc
+++ b/lily/spring.cc
@@ -1,9 +1,20 @@
 /*
-  spring.cc -- declare Spring
+  This file is part of LilyPond, the GNU music typesetter.
 
-  source file of the GNU LilyPond music typesetter
+  Copyright (C) 2007--2011 Joe Neeman <joeneeman@gmail.com>
 
-  (c) 2007--2009 Joe Neeman <joeneeman@gmail.com>
+  LilyPond is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  LilyPond is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include "spring.hh"
@@ -40,9 +51,11 @@ Spring::update_blocking_force ()
     blocking_force_ = (min_distance_ - distance_) / inverse_compress_strength_;
 
   // If the spring is fixed, it's not clear what the natural value
-  // of blocking_force_ would be. -infinity_f works fine for now.
+  // of blocking_force_ would be (because it always blocks).
+  // -infinity_f works fine for now.
+  // If inverse_stretch_strength > 0, the spring is not fixed (because it can stretch).
   if (isnan (blocking_force_) || blocking_force_ == infinity_f)
-    blocking_force_ = -infinity_f;
+    blocking_force_ = (inverse_stretch_strength_ > 0) ? 0.0 : -infinity_f;
 
   if (blocking_force_ >= 0)
     inverse_compress_strength_ = 0;
@@ -163,12 +176,24 @@ Spring::set_blocking_force (Real f)
 
 void
 Spring::set_default_strength ()
+{
+  set_default_stretch_strength ();
+  set_default_compress_strength ();
+}
+
+void
+Spring::set_default_compress_strength ()
 {
   inverse_compress_strength_ = (distance_ >= min_distance_) ? distance_ - min_distance_ : 0;
-  inverse_stretch_strength_ = distance_;
   update_blocking_force ();
 }
 
+void
+Spring::set_default_stretch_strength ()
+{
+  inverse_stretch_strength_ = distance_;
+}
+
 Real
 Spring::length (Real f) const
 {