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Back to floating point Douglas-Peucker to fix undersimplification

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This commit is contained in:
Erica Fischer
2023-09-14 11:22:05 -07:00
parent afef561cf0
commit 01d1de243c
76 changed files with 20061 additions and 20031 deletions
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geometry.cpp
+23 -38
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@@ -334,44 +334,31 @@ bool point_within_tile(long long x, long long y, int z) {
return x >= 0 && y >= 0 && x < area && y < area;
}
long long distance_from_line(long long point_x, long long point_y, long long segA_x, long long segA_y, long long segB_x, long long segB_y, long long divisor) {
double distance_from_line(long long point_x, long long point_y, long long segA_x, long long segA_y, long long segB_x, long long segB_y) {
// long long fpversion = square_distance_from_line_fp(point_x, point_y, segA_x, segA_y, segB_x, segB_y);
if (divisor != 1) {
point_x /= divisor;
point_y /= divisor;
segA_x /= divisor;
segA_y /= divisor;
segB_x /= divisor;
segB_y /= divisor;
}
const long long scale = 1024;
long long p2x = segB_x - segA_x;
long long p2y = segB_y - segA_y;
long long something = p2x * p2x + p2y * p2y;
double u = 0 == (something / scale) ? 0 : ((point_x - segA_x) * p2x + (point_y - segA_y) * p2y) / (something / scale);
double something = p2x * p2x + p2y * p2y;
double u = (0 == something) ? 0 : ((point_x - segA_x) * p2x + (point_y - segA_y) * p2y) / (something);
if (u > scale) {
u = scale;
if (u > 1) {
u = 1;
} else if (u < 0) {
u = 0;
}
long long x = std::round(segA_x + u * p2x / scale);
long long y = std::round(segA_y + u * p2y / scale);
double x = std::round(segA_x + u * p2x);
double y = std::round(segA_y + u * p2y);
long long dx = x - point_x;
long long dy = y - point_y;
double dx = x - point_x;
double dy = y - point_y;
long long out = dx * dx + dy * dy;
out = std::round(sqrt(out)) * divisor;
return out;
return sqrt(dx * dx + dy * dy);
}
// 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) {
static void douglas_peucker(drawvec &geom, int start, int n, double e, size_t kept, size_t retain) {
std::stack<int> recursion_stack;
if (!geom[start + 0].necessary || !geom[start + n - 1].necessary) {
@@ -385,8 +372,11 @@ static void douglas_peucker(drawvec &geom, int start, int n, double e, size_t ke
recursion_stack.push(prev);
recursion_stack.push(here);
prev = here;
if (retain > 0) {
retain--;
if (prevent[P_SIMPLIFY_SHARED_NODES]) {
if (retain > 0) {
retain--;
}
}
}
}
@@ -403,7 +393,7 @@ static void douglas_peucker(drawvec &geom, int start, int n, double e, size_t ke
int first = recursion_stack.top();
recursion_stack.pop();
long long max_distance = -1;
double max_distance = -1;
int farthest_element_index;
// find index idx of element with max_distance
@@ -411,9 +401,9 @@ static void douglas_peucker(drawvec &geom, int start, int n, double e, size_t ke
if (geom[start + first] < geom[start + second]) {
farthest_element_index = first;
for (i = first + 1; i < second; i++) {
long long temp_dist = 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);
double temp_dist = 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);
long long distance = std::llabs(temp_dist);
double distance = std::fabs(temp_dist);
if ((distance > e || kept < retain) && (distance > max_distance || (distance == max_distance && geom[start + i] < geom[start + farthest_element_index]))) {
farthest_element_index = i;
@@ -423,9 +413,9 @@ static void douglas_peucker(drawvec &geom, int start, int n, double e, size_t ke
} else {
farthest_element_index = second;
for (i = second - 1; i > first; i--) {
long long temp_dist = 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);
double temp_dist = 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);
long long distance = std::llabs(temp_dist);
double distance = std::fabs(temp_dist);
if ((distance > e || kept < retain) && (distance > max_distance || (distance == max_distance && geom[start + i] < geom[start + farthest_element_index]))) {
farthest_element_index = i;
@@ -551,11 +541,7 @@ drawvec simplify_lines(drawvec &geom, int z, int detail, bool mark_tile_bounds,
if (additional[A_VISVALINGAM]) {
visvalingam(geom, i, j, scale, retain);
} else {
long long divisor = 1;
if (z < 18) {
divisor = 1LL << (18 - z);
}
douglas_peucker(geom, i, j - i, res * simplification, 2, retain, divisor);
douglas_peucker(geom, i, j - i, res * simplification, 2, retain);
}
}
i = j - 1;
@@ -1038,8 +1024,7 @@ double label_goodness(const drawvec &dv, long long x, long long y) {
}
if (i > 0 && dv[i].op == VT_LINETO) {
// division by 16 to avoid overflow with z0 coordinates
dist = distance_from_line(x, y, dv[i - 1].x, dv[i - 1].y, dv[i].x, dv[i].y, 16);
dist = distance_from_line(x, y, dv[i - 1].x, dv[i - 1].y, dv[i].x, dv[i].y);
if (dist < closest) {
closest = dist;
}