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Prescan for small deltas before doing proper simplification

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This commit is contained in:
Erica Fischer
2024-08-06 09:14:41 -07:00
parent b329489dee
commit d1d8238b83
2 changed files with 64 additions and 12 deletions
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geometry.cpp
+49 -3
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@@ -239,6 +239,48 @@ drawvec impose_tile_boundaries(const drawvec &geom, long long extent) {
return out;
}
static void mark_unnecessary(drawvec &geom, size_t start, size_t end, double e) {
double ee = e * e;
if (geom[start] < geom[end]) {
size_t last = start;
for (size_t i = start + 1; i < end; i++) {
long long dx = geom[i].x - geom[last].x;
long long dy = geom[i].y - geom[last].y;
if (dx * dx + dy * dy < ee) {
geom[i].necessary = -1;
} else {
last = i;
}
}
} else {
size_t last = end;
for (size_t i = end - 1; i > start; i--) {
long long dx = geom[i].x - geom[last].x;
long long dy = geom[i].y - geom[last].y;
if (dx * dx + dy * dy < ee) {
geom[i].necessary = -1;
} else {
last = i;
}
}
}
}
static void mark_unnecessary(drawvec &geom, double e) {
for (size_t i = 0; i < geom.size(); i++) {
if (geom[i].necessary > 0) {
for (size_t j = i + 1; j < geom.size(); j++) {
if (geom[j].necessary > 0) {
mark_unnecessary(geom, i, j, e);
i = j - 1;
break;
}
}
}
}
}
drawvec simplify_lines(drawvec &geom, int z, int tx, int ty, int detail, bool mark_tile_bounds, double simplification, size_t retain, drawvec const &shared_nodes, struct node *shared_nodes_map, size_t nodepos, std::string const &shared_nodes_bloom) {
int res = 1 << (32 - detail - z);
long long area = 1LL << (32 - z);
@@ -265,7 +307,7 @@ drawvec simplify_lines(drawvec &geom, int z, int tx, int ty, int detail, bool ma
auto pt = std::lower_bound(shared_nodes.begin(), shared_nodes.end(), geom[i]);
if (pt != shared_nodes.end() && *pt == geom[i]) {
geom[i].necessary = true;
geom[i].necessary = 1;
}
if (nodepos > 0) {
@@ -284,7 +326,7 @@ drawvec simplify_lines(drawvec &geom, int z, int tx, int ty, int detail, bool ma
if (shared_nodes_bloom[bloom_ix] & bloom_mask) {
if (bsearch(&n, shared_nodes_map, nodepos / sizeof(node), sizeof(node), nodecmp) != NULL) {
geom[i].necessary = true;
geom[i].necessary = 1;
}
}
}
@@ -295,6 +337,10 @@ drawvec simplify_lines(drawvec &geom, int z, int tx, int ty, int detail, bool ma
geom = impose_tile_boundaries(geom, area);
}
if (!additional[A_VISVALINGAM]) {
mark_unnecessary(geom, res * simplification);
}
for (size_t i = 0; i < geom.size(); i++) {
if (geom[i].op == VT_MOVETO) {
size_t j;
@@ -327,7 +373,7 @@ drawvec simplify_lines(drawvec &geom, int z, int tx, int ty, int detail, bool ma
size_t out = 0;
for (size_t i = 0; i < geom.size(); i++) {
if (geom[i].necessary) {
if (geom[i].necessary > 0) {
geom[out++] = geom[i];
}
}