Authors: Updated Authors.itexi

[lilypond.git] / lily / skyline.cc

diff --git a/lily/skyline.cc b/lily/skyline.cc
index 8654f0d973d26af771c106c44d441908dcb9fb27..6d6b58ca109d6d34cccc347d7d616cccddd743df 100644 (file)
--- a/lily/skyline.cc
+++ b/lily/skyline.cc
@@ -1,7 +1,7 @@
 /*
   This file is part of LilyPond, the GNU music typesetter.
 
-  Copyright (C) 2006--2012 Joe Neeman <joeneeman@gmail.com>
+  Copyright (C) 2006--2014 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
@@ -22,7 +22,6 @@
 #include <deque>
 #include <cstdio>
 
-#include "ly-smobs.icc"
 
 /* A skyline is a sequence of non-overlapping buildings: something like
    this:
@@ -125,6 +124,12 @@ Building::precompute (Real start, Real start_height, Real end_height, Real end)
       assert (start_height == end_height);
       y_intercept_ = start_height;
     }
+  else if (fabs(slope_) > 1e6)
+    // too steep to be stored in slope-intercept form, given round-off error
+    {
+      slope_ = 0.0;
+      y_intercept_ = max(start_height, end_height);
+    }
   else
     y_intercept_ = start_height - slope_ * start;
 }
@@ -169,7 +174,9 @@ Building::shift_to_intersect (Real x, Real y) const
 }
 
 static Real
-first_intersection (Building const &b, list<Building> *const s, Real start_x)
+first_intersection (Building const &b, list<Building> *s, Real start_x)
+/* Return the first x >= start_x where skyline s above Building b.
+ * Removes buildings from s that are concealed by b. */
 {
   while (!s->empty () && start_x < b.end_)
     {
@@ -299,7 +306,7 @@ Skyline::internal_merge_skyline (list<Building> *s1, list<Building> *s2,
           last_end = x;
           continue;
         }
-
+      // first_intersection() removes buildings from s2 if b hides them
       Real end = first_intersection (b, s2, x);
       if (s2->empty ())
         {
@@ -308,6 +315,8 @@ Skyline::internal_merge_skyline (list<Building> *s1, list<Building> *s2,
           break;
         }
 
+      // Should be (end > x), during ver2.19.  end == x happens fairly often,
+      // and we do not need to keep vertical segments within a skyline.
       if (end >= x)
         {
           b.leading_part (end);
@@ -318,6 +327,9 @@ Skyline::internal_merge_skyline (list<Building> *s1, list<Building> *s2,
 
       if (end >= s1->front ().end_)
         s1->pop_front ();
+      // Should add during ver2.19 (to avoid an endless loop
+      // when  merging identical skylines with a vertical segment)
+      // if (end >= s2->front().end_) s2->pop_front();
 
       x = end;
     }
@@ -849,9 +861,7 @@ Skyline::clear ()
 
 /****************************************************************/
 
-IMPLEMENT_SIMPLE_SMOBS (Skyline);
-IMPLEMENT_TYPE_P (Skyline, "ly:skyline?");
-IMPLEMENT_DEFAULT_EQUAL_P (Skyline);
+const char Skyline::type_p_name_[] = "ly:skyline?";
 
 SCM
 Skyline::mark_smob (SCM s)