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Almost right, I think!

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Erica Fischer
2023-09-08 11:52:30 -07:00
parent 25265a9cdb
commit b5bf9d7dc5
1 changed files with 75 additions and 15 deletions
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geometry.cpp
+75 -15
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@@ -433,6 +433,22 @@ static long long square_distance_from_line(long long point_x, long long point_y,
return out;
}
#if 0
struct stackcmp {
drawvec &geom;
int offset;
stackcmp(drawvec &geom_), int offset_) geom : geom_, offset : offset_ { }
bool operator()(const int &a, const int &b) {
if (geom[offset + a] < geom[offset + b]) {
return true;
} else if (geom[offset + a]
return a.original_seq < b.original_seq;
}
};
#endif
// https://github.com/Project-OSRM/osrm-backend/blob/733d1384a40f/Algorithms/DouglasePeucker.cpp
static void douglas_peucker(drawvec &geom, int start, int n, double e, size_t kept, size_t retain, long long scale) {
e = e * e;
@@ -444,14 +460,25 @@ static void douglas_peucker(drawvec &geom, int start, int n, double e, size_t ke
exit(EXIT_IMPOSSIBLE);
}
printf("%d: ", n);
int prev = 0;
for (int here = 1; here < n; here++) {
if (geom[start + here].necessary) {
recursion_stack.push(prev);
recursion_stack.push(here);
if (geom[start + here] < geom[start + prev]) {
printf("%lld,%lld to %lld,%lld ", geom[start + here].x, geom[start + here].y, geom[start + prev].x, geom[start + prev].y);
} else {
printf("%lld,%lld to %lld,%lld ", geom[start + prev].x, geom[start + prev].y, geom[start + here].x, geom[start + here].y);
}
prev = here;
if (retain > 0) {
retain--;
}
}
}
printf("\n");
// std::sort(recursion_stack.begin(), recursion_stack.end(), stackcmp(geom, start));
while (!recursion_stack.empty()) {
// pop next element
@@ -464,36 +491,54 @@ static void douglas_peucker(drawvec &geom, int start, int n, double e, size_t ke
long long max_distance = -1;
int farthest_element_index;
if (geom[start + first] < geom[start + second]) {
farthest_element_index = second;
} else {
farthest_element_index = first;
}
// find index idx of element with max_distance
int i;
size_t looked = 0;
if (geom[start + first] < geom[start + second]) {
farthest_element_index = first;
for (i = first + 1; i < second; i++) {
looked++;
long long temp_dist = square_distance_from_line(geom[start + i].x, geom[start + i].y, geom[start + first].x, geom[start + first].y, geom[start + second].x, geom[start + second].y, scale);
long long distance = std::llabs(temp_dist);
printf("%d %lld,%lld to %lld,%lld try %lld,%lld %lld\n", n,
geom[start + first].x, geom[start + first].y,
geom[start + second].x, geom[start + second].y,
geom[start + i].x, geom[start + i].y,
distance);
if ((distance > e || kept < retain) && (distance > max_distance || (distance == max_distance && geom[start + i] < geom[start + farthest_element_index]))) {
farthest_element_index = i;
max_distance = distance;
}
}
printf("%d %lld,%lld to %lld,%lld choose %lld,%lld %lld %zu\n", n,
geom[start + first].x, geom[start + first].y,
geom[start + second].x, geom[start + second].y,
geom[start + farthest_element_index].x, geom[start + farthest_element_index].y, max_distance, looked);
} else {
farthest_element_index = second;
for (i = second - 1; i > first; i--) {
long long temp_dist = square_distance_from_line(geom[start + i].x, geom[start + i].y, geom[start + first].x, geom[start + first].y, geom[start + second].x, geom[start + second].y, scale);
looked++;
long long temp_dist = square_distance_from_line(geom[start + i].x, geom[start + i].y, geom[start + second].x, geom[start + second].y, geom[start + first].x, geom[start + first].y, scale);
long long distance = std::llabs(temp_dist);
printf("%d %lld,%lld to %lld,%lld try %lld,%lld %lld\n", n,
geom[start + second].x, geom[start + second].y,
geom[start + first].x, geom[start + first].y,
geom[start + i].x, geom[start + i].y,
distance);
if ((distance > e || kept < retain) && (distance > max_distance || (distance == max_distance && geom[start + i] < geom[start + farthest_element_index]))) {
farthest_element_index = i;
max_distance = distance;
}
}
printf("%d %lld,%lld to %lld,%lld choose %lld,%lld %lld rev %zu\n", n,
geom[start + second].x, geom[start + second].y,
geom[start + first].x, geom[start + first].y,
geom[start + farthest_element_index].x, geom[start + farthest_element_index].y, max_distance, looked);
}
if (max_distance >= 0) {
@@ -501,17 +546,32 @@ static void douglas_peucker(drawvec &geom, int start, int n, double e, size_t ke
geom[start + farthest_element_index].necessary = 1;
kept++;
if (1 < farthest_element_index - first) {
recursion_stack.push(first);
recursion_stack.push(farthest_element_index);
if (geom[start + first] < geom[start + second]) {
if (1 < farthest_element_index - first) {
recursion_stack.push(first);
recursion_stack.push(farthest_element_index);
// printf("split1: %d to %d, %d\n", first, farthest_element_index, farthest_element_index - first + 1);
}
if (1 < second - farthest_element_index) {
recursion_stack.push(farthest_element_index);
recursion_stack.push(second);
// printf("split1: %d to %d, %d\n", first, farthest_element_index, farthest_element_index - first + 1);
}
if (1 < second - farthest_element_index) {
recursion_stack.push(farthest_element_index);
recursion_stack.push(second);
// printf("split2: %d to %d, %d\n", farthest_element_index, second, second - farthest_element_index + 1);
// printf("split2: %d to %d, %d\n", farthest_element_index, second, second - farthest_element_index + 1);
}
} else {
if (1 < second - farthest_element_index) {
recursion_stack.push(farthest_element_index);
recursion_stack.push(second);
// printf("split2: %d to %d, %d\n", farthest_element_index, second, second - farthest_element_index + 1);
}
if (1 < farthest_element_index - first) {
recursion_stack.push(first);
recursion_stack.push(farthest_element_index);
// printf("split1: %d to %d, %d\n", first, farthest_element_index, farthest_element_index - first + 1);
}
}
}
}