X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fskyline.cc;h=6e64a2c96b6983ba4fac58ebb05026536c058c1e;hb=5b4b0d6e9a197e8f9eb085b7c2ad78b8be3e5cfc;hp=c009608fc96d5b3d12d0c23671c9de112d0f583e;hpb=9c5c0885f84ce3d3ec852c13af2d66f18d8b07c9;p=lilypond.git diff --git a/lily/skyline.cc b/lily/skyline.cc index c009608fc9..6e64a2c96b 100644 --- a/lily/skyline.cc +++ b/lily/skyline.cc @@ -2,7 +2,7 @@ source file of the GNU LilyPond music typesetter - (c) 2006 Joe Neeman + (c) 2006--2008 Joe Neeman */ #include "skyline.hh" @@ -42,169 +42,104 @@ but the distance routine does. */ -/* - FIXME: - - * Consider to use - - typedef list Skyline; - struct Skyline_point - { - Real x; - Drul_array ys; - }; - - this is a cleaner representation, as it doesn't duplicate the X, and - doesn't need bogus buildings at infinity --hwn. - - - * All the messing around with EPS is very fishy. There are no - complicated numerical algorithms involved, so EPS should not be - necessary. - - --hwn - - - */ - -#define EPS 1e-10 - -static inline bool -approx_equal (Real x, Real y) -{ - return abs (x - y) < EPS || (isinf (x) && isinf (y) && ((x > 0) == (y > 0))); -} +/* If we start including very thin buildings, numerical accuracy errors can + arise. Therefore, we ignore all buildings that are less than epsilon wide. */ +#define EPS 1e-5 -static inline bool -approx_greater_than (Real x, Real y) -{ - return x > y + EPS; -} - -static inline bool -approx_less_than (Real x, Real y) -{ - return x < y - EPS; -} - -static inline bool -approx_less_equal (Real x, Real y) -{ - return x <= y + EPS; -} - -static inline bool -approx_greater_equal (Real x, Real y) +static void +print_buildings (list const &b) { - return x >= y - EPS; + for (list::const_iterator i = b.begin (); i != b.end (); i++) + i->print (); } void Skyline::print () const { - for (list::const_iterator i = buildings_.begin (); - i != buildings_.end (); i++) - { - (*i).print (); - } + print_buildings (buildings_); } -static bool -is_legal_skyline (list const &buildings) +void +Skyline::print_points () const { - list::const_iterator i; - Real last_x = -infinity_f; - for (i = buildings.begin (); i != buildings.end (); i++) - { - if (i->iv_[LEFT] != last_x) - return false; - last_x = i->iv_[RIGHT]; - if (isinf (i->iv_.length ()) && i->height_[LEFT] != i->height_[RIGHT]) - return false; - } - return last_x == infinity_f; + vector ps (to_points (X_AXIS)); + + for (vsize i = 0; i < ps.size (); i++) + printf ("(%f,%f)%s" , ps[i][X_AXIS], ps[i][Y_AXIS], + (i%2)==1 ? "\n" : " "); } Building::Building (Real start, Real start_height, Real end_height, Real end) - : iv_ (start, end) { - height_[LEFT] = start_height; - height_[RIGHT] = end_height; - if (isinf (start) || isinf (end)) assert (start_height == end_height); - precompute (); + end_ = end; + precompute (start, start_height, end_height, end); } Building::Building (Box const &b, Real horizon_padding, Axis horizon_axis, Direction sky) { + Real start = b[horizon_axis][LEFT] - horizon_padding; + Real end = b[horizon_axis][RIGHT] + horizon_padding; Real height = sky * b[other_axis (horizon_axis)][sky]; - iv_ = b[horizon_axis]; - iv_.widen (horizon_padding + EPS); - height_[LEFT] = height; - height_[RIGHT] = height; - - if (sane ()) - precompute (); + end_ = end; + precompute (start, height, height, end); } void -Building::precompute () +Building::precompute (Real start, Real start_height, Real end_height, Real end) { - slope_ = (height_[RIGHT] - height_[LEFT]) / (iv_.length()); - if (height_[LEFT] == height_[RIGHT]) /* in case they're both infinity */ + slope_ = (end_height - start_height) / (end - start); + if (start_height == end_height) /* if they were both infinite, we would get nan, not 0, from the prev line */ slope_ = 0; assert (!isinf (slope_) && !isnan (slope_)); - if (isinf (iv_[START])) + if (isinf (start)) { - assert (slope_ == 0); - y_intercept_ = height_[LEFT]; + assert (start_height == end_height); + y_intercept_ = start_height; } else - y_intercept_ = height_[LEFT] - slope_ * iv_[START]; + y_intercept_ = start_height - slope_ * start; } Real Building::height (Real x) const { - if (isinf (x)) - return (x > 0) ? height_[RIGHT] : height_[LEFT]; - return slope_*x + y_intercept_; + return isinf (x) ? y_intercept_ : slope_*x + y_intercept_; } void Building::print () const { - printf ("X[%f,%f] -> Y[%f,%f]\n", - iv_[LEFT], iv_[RIGHT], - height_[LEFT], height_[RIGHT]); + printf ("%f x + %f ends at %f\n", slope_, y_intercept_, end_); } Real Building::intersection_x (Building const &other) const { - return (y_intercept_ - other.y_intercept_) / (other.slope_ - slope_); + Real ret = (y_intercept_ - other.y_intercept_) / (other.slope_ - slope_); + return isnan (ret) ? -infinity_f : ret; } void Building::leading_part (Real chop) { - assert (chop > iv_[LEFT] && chop <= iv_[RIGHT] && !approx_equal (chop, iv_[LEFT])); - iv_[RIGHT] = chop; - height_[RIGHT] = height (chop); + assert (chop <= end_); + end_ = chop; } Building -Building::sloped_neighbour (Real horizon_padding, Direction d) const +Building::sloped_neighbour (Real start, Real horizon_padding, Direction d) const { - Real left = iv_[d]; - Real right = iv_[d] + d * horizon_padding; - Real left_height = height_[d]; - Real right_height = height_[d] - horizon_padding; + Real x = (d == LEFT) ? start : end_; + Real left = x; + Real right = x + d * horizon_padding; + Real left_height = height (x); + Real right_height = left_height - horizon_padding; if (d == LEFT) { swap (left, right); @@ -213,88 +148,74 @@ Building::sloped_neighbour (Real horizon_padding, Direction d) const return Building (left, left_height, right_height, right); } -bool -Building::sane () const +static Real +first_intersection (Building const &b, list *const s, Real start_x) { - return approx_less_than (iv_[LEFT], iv_[RIGHT]) - && !isinf (height_[RIGHT]) - && !isinf (height_[LEFT]); -} + while (!s->empty () && start_x < b.end_) + { + Building c = s->front (); + if (c.conceals (b, start_x)) + return start_x; -static void -skyline_trailing_part (list *sky, Real x) -{ - if (approx_equal (x, sky->front ().iv_[RIGHT])) - sky->pop_front (); - else - assert (x < sky->front ().iv_[RIGHT]); + Real i = b.intersection_x (c); + if (i > start_x && i <= b.end_ && i <= c.end_) + return i; - if (!sky->empty ()) - { - sky->front ().iv_[LEFT] = x; - sky->front ().height_[LEFT] = sky->front ().height (x); + start_x = c.end_; + if (b.end_ > c.end_) + s->pop_front (); } + return b.end_; } bool -Building::conceals_beginning (Building const &other) const +Building::conceals (Building const &other, Real x) const { - bool w = false; - Real h = other.height (iv_[LEFT]); - if (approx_equal (height_[LEFT], h)) - w = slope_ > other.slope_; - else if (height_[LEFT] > h) - w = true; - else - w = false; + if (slope_ == other.slope_) + return y_intercept_ > other.y_intercept_; - return w; -} - -bool -Building::conceals (Building const &other) const -{ - assert (iv_[LEFT] <= other.iv_[LEFT]); - return (iv_[RIGHT] >= other.iv_[RIGHT]) - && approx_greater_equal (height (other.iv_[LEFT]), other.height_[LEFT]) - && approx_greater_equal (height (other.iv_[RIGHT]), other.height_[RIGHT]); + /* their slopes were not equal, so there is an intersection point */ + Real i = intersection_x (other); + return (i <= x && slope_ > other.slope_) + || (i > x && slope_ < other.slope_); } void Skyline::internal_merge_skyline (list *s1, list *s2, list *const result) { + if (s1->empty () || s2->empty ()) + { + programming_error ("tried to merge an empty skyline"); + return; + } + + Real x = -infinity_f; while (!s1->empty ()) { - if (s2->front ().conceals_beginning (s1->front ())) + if (s2->front ().conceals (s1->front (), x)) swap (s1, s2); Building b = s1->front (); - while (!s2->empty () && b.conceals (s2->front ())) - s2->pop_front (); + Real end = first_intersection (b, s2, x); + if (s2->empty ()) { result->push_front (b); break; } - /* s2 either intersects with b or it ends after b */ - Real end = infinity_f; - Real s2_start_height = s2->front ().height_[LEFT]; - Real s2_end_height = s2->front ().height_[RIGHT]; - Real s1_start_height = b.height (s2->front ().iv_[LEFT]); - Real s1_end_height = b.height (s2->front ().iv_[RIGHT]); - if (approx_greater_than (s2_start_height, s1_start_height)) - end = s2->front ().iv_[LEFT]; - else if (approx_greater_than (s2_end_height, s1_end_height)) - end = b.intersection_x (s2->front ()); - end = min (end, b.iv_[RIGHT]); - - b.leading_part (end); - result->push_front (b); - - skyline_trailing_part (s1, end); - skyline_trailing_part (s2, end); + /* only include buildings wider than epsilon */ + if (end > x + EPS) + { + b.leading_part (end); + result->push_front (b); + } + + if (end >= s1->front ().end_) + s1->pop_front (); + + x = end; } result->reverse (); } @@ -306,62 +227,85 @@ empty_skyline (list *const ret) } static void -single_skyline (Building b, Real horizon_padding, list *const ret) +single_skyline (Building b, Real start, Real horizon_padding, list *const ret) { - b.iv_.widen (horizon_padding); - - if (!isinf (b.iv_[RIGHT])) - ret->push_front (Building (b.iv_[RIGHT], -infinity_f, + bool sloped_neighbours = horizon_padding > 0 && !isinf (start) && !isinf (b.end_); + if (!isinf (b.end_)) + ret->push_front (Building (b.end_ + horizon_padding, -infinity_f, -infinity_f, infinity_f)); - if (horizon_padding > 0 && !isinf (b.iv_.length ())) - ret->push_front (b.sloped_neighbour (horizon_padding, RIGHT)); + if (sloped_neighbours) + ret->push_front (b.sloped_neighbour (start, horizon_padding, RIGHT)); - if (b.iv_[RIGHT] > b.iv_[LEFT]) + if (b.end_ > start + EPS) ret->push_front (b); - if (horizon_padding > 0 && !isinf (b.iv_.length ())) - ret->push_front (b.sloped_neighbour (horizon_padding, LEFT)); - if (!isinf (b.iv_[LEFT])) + if (sloped_neighbours) + ret->push_front (b.sloped_neighbour (start, horizon_padding, LEFT)); + + if (!isinf (start)) ret->push_front (Building (-infinity_f, -infinity_f, - -infinity_f, b.iv_[LEFT])); + -infinity_f, start - horizon_padding)); } -/* remove a non-overlapping set of buildings from BUILDINGS and build a skyline +/* remove a non-overlapping set of boxes from BOXES and build a skyline out of them */ static list -non_overlapping_skyline (list *const buildings) +non_overlapping_skyline (list *const boxes, Real horizon_padding, Axis horizon_axis, Direction sky) { list result; Real last_end = -infinity_f; - list::iterator i = buildings->begin (); - while (i != buildings->end ()) + list::iterator i = boxes->begin (); + while (i != boxes->end ()) { - if (approx_less_than (i->iv_[LEFT], last_end)) + Interval iv = (*i)[horizon_axis]; + + if (iv[LEFT] - horizon_padding < last_end) { i++; continue; } - if (approx_greater_than (i->iv_[LEFT], last_end)) - result.push_back (Building (last_end, -infinity_f, -infinity_f, i->iv_[LEFT])); - else - i->iv_[LEFT] = last_end; + if (iv[LEFT] - horizon_padding > last_end + EPS) + result.push_front (Building (last_end, -infinity_f, -infinity_f, iv[LEFT] - 2*horizon_padding)); + + Building b (*i, horizon_padding, horizon_axis, sky); + bool sloped_neighbours = horizon_padding > 0 && !isinf (iv.length ()); + if (sloped_neighbours) + result.push_front (b.sloped_neighbour (iv[LEFT] - horizon_padding, horizon_padding, LEFT)); + result.push_front (b); + if (sloped_neighbours) + result.push_front (b.sloped_neighbour (iv[LEFT] - horizon_padding, horizon_padding, RIGHT)); - last_end = i->iv_[RIGHT]; - list::iterator j = i; - i++; - result.splice (result.end (), *buildings, j); + list::iterator j = i++; + boxes->erase (j); + last_end = result.front ().end_; } if (last_end < infinity_f) - result.push_back (Building (last_end, -infinity_f, -infinity_f, infinity_f)); - assert (is_legal_skyline (result)); + result.push_front (Building (last_end, -infinity_f, -infinity_f, infinity_f)); + result.reverse (); return result; } +class LessThanBox +{ + Axis a_; + +public: + LessThanBox (Axis a) + { + a_ = a; + } + + bool operator() (Box const &b1, Box const &b2) + { + return b1[a_][LEFT] < b2[a_][LEFT]; + } +}; + list -Skyline::internal_build_skyline (list *buildings) +Skyline::internal_build_skyline (list *boxes, Real horizon_padding, Axis horizon_axis, Direction sky) { - vsize size = buildings->size (); + vsize size = boxes->size (); if (size == 0) { @@ -372,16 +316,17 @@ Skyline::internal_build_skyline (list *buildings) else if (size == 1) { list result; - single_skyline (buildings->front (), 0, &result); + single_skyline (Building (boxes->front (), horizon_padding, horizon_axis, sky), + boxes->front ()[horizon_axis][LEFT], horizon_axis, &result); return result; } deque > partials; - buildings->sort (); - while (!buildings->empty ()) - partials.push_back (non_overlapping_skyline (buildings)); + boxes->sort (LessThanBox (horizon_axis)); + while (!boxes->empty ()) + partials.push_back (non_overlapping_skyline (boxes, horizon_padding, horizon_axis, sky)); - /* we'd like to say while (partials->size () > 1) but that's O(n). + /* we'd like to say while (partials->size () > 1) but that's O (n). Instead, we exit in the middle of the loop */ while (!partials.empty ()) { @@ -403,13 +348,14 @@ Skyline::internal_build_skyline (list *buildings) Skyline::Skyline () { sky_ = UP; - empty_skyline (&buildings_); + empty_skyline (&buildings_); } Skyline::Skyline (Skyline const &src) { sky_ = src.sky_; + /* doesn't a list's copy constructor do this? -- jneem */ for (list::const_iterator i = src.buildings_.begin (); i != src.buildings_.end (); i++) { @@ -434,32 +380,26 @@ Skyline::Skyline (Direction sky) */ Skyline::Skyline (vector const &boxes, Real horizon_padding, Axis horizon_axis, Direction sky) { - list bldgs; + list filtered_boxes; sky_ = sky; + Axis vert_axis = other_axis (horizon_axis); for (vsize i = 0; i < boxes.size (); i++) { - Building front (boxes[i], horizon_padding, horizon_axis, sky); - if (front.sane ()) - { - bldgs.push_front (front); - if (horizon_padding > 0 && !isinf (front.iv_.length ())) - { - bldgs.push_front (front.sloped_neighbour (horizon_padding, LEFT)); - bldgs.push_front (front.sloped_neighbour (horizon_padding, RIGHT)); - } - } + Interval iv = boxes[i][horizon_axis]; + iv.widen (horizon_padding); + if (iv.length () > EPS && !boxes[i][vert_axis].is_empty ()) + filtered_boxes.push_front (boxes[i]); } - buildings_ = internal_build_skyline (&bldgs); - assert (is_legal_skyline (buildings_)); + buildings_ = internal_build_skyline (&filtered_boxes, horizon_padding, horizon_axis, sky); } Skyline::Skyline (Box const &b, Real horizon_padding, Axis horizon_axis, Direction sky) { sky_ = sky; - Building front (b, 0, horizon_axis, sky); - single_skyline (front, horizon_padding, &buildings_); + Building front (b, horizon_padding, horizon_axis, sky); + single_skyline (front, b[horizon_axis][LEFT], horizon_padding, &buildings_); } void @@ -471,7 +411,6 @@ Skyline::merge (Skyline const &other) list my_bld; my_bld.splice (my_bld.begin (), buildings_); internal_merge_skyline (&other_bld, &my_bld, &buildings_); - assert (is_legal_skyline (buildings_)); } void @@ -480,10 +419,22 @@ Skyline::insert (Box const &b, Real horizon_padding, Axis a) list other_bld; list my_bld; + if (isnan (b[other_axis (a)][LEFT]) + || isnan (b[other_axis (a)][RIGHT])) + { + programming_error ("insane box for skyline"); + return; + } + + /* do the same filtering as in Skyline (vector const&, etc.) */ + Interval iv = b[a]; + iv.widen (horizon_padding); + if (iv.length () <= EPS || b[other_axis (a)].is_empty ()) + return; + my_bld.splice (my_bld.begin (), buildings_); - single_skyline (Building (b, 0, a, sky_), horizon_padding, &other_bld); + single_skyline (Building (b, horizon_padding, a, sky_), b[a][LEFT], horizon_padding, &other_bld); internal_merge_skyline (&other_bld, &my_bld, &buildings_); - assert (is_legal_skyline (buildings_)); } void @@ -491,22 +442,17 @@ Skyline::raise (Real r) { list::iterator end = buildings_.end (); for (list::iterator i = buildings_.begin (); i != end; i++) - { - i->height_[LEFT] += sky_ * r; - i->height_[RIGHT] += sky_ * r; - i->y_intercept_ += sky_ * r; - } - assert (is_legal_skyline (buildings_)); + i->y_intercept_ += sky_ * r; } void -Skyline::shift (Real r) +Skyline::shift (Real s) { list::iterator end = buildings_.end (); for (list::iterator i = buildings_.begin (); i != end; i++) { - i->iv_[LEFT] += r; - i->iv_[RIGHT] += r; + i->end_ += s; + i->y_intercept_ -= s * i->slope_; } } @@ -518,15 +464,18 @@ Skyline::distance (Skyline const &other) const list::const_iterator j = other.buildings_.begin (); Real dist = -infinity_f; + Real start = -infinity_f; while (i != buildings_.end () && j != other.buildings_.end ()) { - Interval iv = intersection (i->iv_, j->iv_); - dist = max (dist, max (i->height (iv[LEFT]) + j->height (iv[LEFT]), - i->height (iv[RIGHT]) + j->height (iv[RIGHT]))); - if (i->iv_[RIGHT] <= j->iv_[RIGHT]) + Real end = min (i->end_, j->end_); + Real start_dist = i->height (start) + j->height (start); + Real end_dist = i->height (end) + j->height (end); + dist = max (dist, max (start_dist, end_dist)); + if (i->end_ <= j->end_) i++; else j++; + start = end; } return dist; } @@ -539,7 +488,7 @@ Skyline::height (Real airplane) const list::const_iterator i; for (i = buildings_.begin (); i != buildings_.end (); i++) { - if (i->iv_[RIGHT] >= airplane) + if (i->end_ >= airplane) return sky_ * i->height (airplane); } @@ -559,83 +508,39 @@ void Skyline::set_minimum_height (Real h) { Skyline s (sky_); - s.buildings_.front ().height_[LEFT] = h * sky_; - s.buildings_.front ().height_[RIGHT] = h * sky_; s.buildings_.front ().y_intercept_ = h * sky_; merge (s); } vector -Skyline::to_points () const +Skyline::to_points (Axis horizon_axis) const { vector out; + Real start = -infinity_f; for (list::const_iterator i (buildings_.begin ()); i != buildings_.end (); i++) { - if (!isinf (i->iv_[LEFT]) && !isinf (i->height_[LEFT])) - out.push_back (Offset (i->iv_[LEFT], sky_ * i->height_[LEFT])); - if (!isinf (i->iv_[RIGHT]) && !isinf (i->height_[RIGHT])) - out.push_back (Offset (i->iv_[RIGHT], sky_ * i->height_[RIGHT])); + out.push_back (Offset (start, sky_ * i->height (start))); + out.push_back (Offset (i->end_, sky_ * i->height (i->end_))); + start = i->end_; } - return out; -} - -Skyline_pair::Skyline_pair () - : skylines_ (Skyline (DOWN), Skyline (UP)) -{ -} - -Skyline_pair::Skyline_pair (vector const &boxes, Real padding, Axis a) - : skylines_ (Skyline (boxes, padding, a, DOWN), Skyline (boxes, padding, a, UP)) -{ -} - -Skyline_pair::Skyline_pair (Box const &b, Real padding, Axis a) - : skylines_ (Skyline (b, padding, a, DOWN), Skyline (b, padding, a, UP)) -{ -} - -void -Skyline_pair::raise (Real r) -{ - skylines_[UP].raise (r); - skylines_[DOWN].raise (r); -} -void -Skyline_pair::shift (Real r) -{ - skylines_[UP].shift (r); - skylines_[DOWN].shift (r); -} + if (horizon_axis == Y_AXIS) + for (vsize i = 0; i < out.size (); i++) + out[i] = out[i].swapped (); -void -Skyline_pair::insert (Box const &b, Real padding, Axis a) -{ - skylines_[UP].insert (b, padding, a); - skylines_[DOWN].insert (b, padding, a); + return out; } -void -Skyline_pair::merge (Skyline_pair const &other) +bool +Skyline::is_empty () const { - skylines_[UP].merge (other[UP]); - skylines_[DOWN].merge (other[DOWN]); + Building b = buildings_.front (); + return b.end_ == infinity_f && b.y_intercept_ == -infinity_f; } -Skyline& -Skyline_pair::operator [] (Direction d) -{ - return skylines_[d]; -} - -Skyline const& -Skyline_pair::operator [] (Direction d) const -{ - return skylines_[d]; -} /****************************************************************/ @@ -644,13 +549,10 @@ IMPLEMENT_SIMPLE_SMOBS (Skyline); IMPLEMENT_TYPE_P (Skyline, "ly:skyline?"); IMPLEMENT_DEFAULT_EQUAL_P (Skyline); -IMPLEMENT_SIMPLE_SMOBS (Skyline_pair); -IMPLEMENT_TYPE_P (Skyline_pair, "ly:skyline-pair?"); -IMPLEMENT_DEFAULT_EQUAL_P (Skyline_pair); - SCM Skyline::mark_smob (SCM) { + ASSERT_LIVE_IS_ALLOWED (); return SCM_EOL; } @@ -664,19 +566,3 @@ Skyline::print_smob (SCM s, SCM port, scm_print_state *) return 1; } - -SCM -Skyline_pair::mark_smob (SCM) -{ - return SCM_EOL; -} - -int -Skyline_pair::print_smob (SCM s, SCM port, scm_print_state *) -{ - Skyline_pair *r = (Skyline_pair *) SCM_CELL_WORD_1 (s); - (void) r; - - scm_puts ("#", port); - return 1; -}