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more 'inflection_angle' to its own function

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Motiejus Jakštys 2021-04-03 09:38:52 +03:00
parent 0c7424ae25
commit 7475df5394
1 changed files with 30 additions and 29 deletions
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59
IV/wm.sql
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@ -170,18 +170,12 @@ create function self_crossing(
OUT mutated boolean
) as $$
declare
pi real;
i int4;
j int4;
prev_length int4;
pi real;
angle real;
p0 geometry;
p1 geometry;
p2 geometry;
p3 geometry;
a geometry;
b geometry;
bend geometry;
multi geometry;
begin
pi = radians(180);
@ -189,40 +183,20 @@ begin
-- go through the bends and find one where sum of inflection angle is >180
for i in 1..array_length(bends, 1) loop
angle = 0;
p1 = null;
p2 = null;
p3 = null;
for p0 in (
select geom from st_dumppoints(bends[i]) order by path[1] asc
) loop
p3 = p2;
p2 = p1;
p1 = p0;
continue when p3 is null;
angle = angle + abs(pi - st_angle(p1, p2, p3));
end loop;
continue when abs(angle) <= pi;
continue when abs(inflection_angle(bends[i])) <= pi;
-- sum of inflection angles for this bend is >180, so it may be
-- self-crossing. now try to find another bend in this line that
-- crosses an imaginary line of end-vertices
p0 = st_pointn(bends[i], 1);
p1 = st_pointn(bends[i], -1);
-- go through each bend in the given line, and see if has a potential to
-- cross bends[i]. optimization: we care only about bends which beginning
-- and end start at different sides of the plane, separated by endpoints
-- p0 and p1.
-- of the vertex.
j = 0;
while j < array_length(bends, 1) loop
j = j + 1;
continue when i = j;
p2 = st_pointn(bends[j], 1);
p3 = st_pointn(bends[j], -1);
-- do end vertices of bend[i] cross bend[j]?
a = st_pointn(bends[i], 1);
b = st_pointn(bends[i], -1);
@ -267,6 +241,33 @@ begin
end
$$ language plpgsql;
drop function if exists inflection_angle;
create function inflection_angle (IN bend geometry, OUT angle real) as $$
declare
pi real;
p0 geometry;
p1 geometry;
p2 geometry;
p3 geometry;
begin
pi = radians(180);
angle = 0;
p1 = null;
p2 = null;
p3 = null;
for p0 in (
select geom from st_dumppoints(bend) order by path[1] asc
) loop
p3 = p2;
p2 = p1;
p1 = p0;
continue when p3 is null;
angle = angle + abs(pi - st_angle(p1, p2, p3));
end loop;
end
$$ language plpgsql;
drop function if exists bend_attrs;
drop type if exists t_bend_attrs;
create type t_bend_attrs as (