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Track nodes added at tile edges during clipping

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This commit is contained in:
Erica Fischer
2023-05-23 15:52:26 -07:00
parent 46e153e4a6
commit 65e276c27c
3 changed files with 87 additions and 26 deletions
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geometry.cpp
+77 -19
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@@ -547,16 +547,16 @@ drawvec close_poly(drawvec &geom) {
static bool inside(std::pair<double, double> d, int edge, long long minx, long long miny, long long maxx, long long maxy) {
switch (edge) {
case 0: // top
case 0: // top
return d.second > miny;
case 1: // right
case 1: // right
return d.first < maxx;
case 2: // bottom
case 2: // bottom
return d.second < maxy;
case 3: // left
case 3: // left
return d.first > minx;
}
@@ -566,16 +566,16 @@ static bool inside(std::pair<double, double> d, int edge, long long minx, long l
static std::pair<double, double> intersect(std::pair<double, double> a, std::pair<double, double> b, int edge, long long minx, long long miny, long long maxx, long long maxy) {
switch (edge) {
case 0: // top
case 0: // top
return std::pair<double, double>((a.first + (double) (b.first - a.first) * (miny - a.second) / (b.second - a.second)), miny);
case 1: // right
case 1: // right
return std::pair<double, double>(maxx, (a.second + (double) (b.second - a.second) * (maxx - a.first) / (b.first - a.first)));
case 2: // bottom
case 2: // bottom
return std::pair<double, double>((a.first + (double) (b.first - a.first) * (maxy - a.second) / (b.second - a.second)), maxy);
case 3: // left
case 3: // left
return std::pair<double, double>(minx, (a.second + (double) (b.second - a.second) * (minx - a.first) / (b.first - a.first)));
}
@@ -584,7 +584,9 @@ static std::pair<double, double> intersect(std::pair<double, double> a, std::pai
}
// http://en.wikipedia.org/wiki/Sutherland%E2%80%93Hodgman_algorithm
static std::vector<std::pair<double, double>> clip_poly1(std::vector<std::pair<double, double>> &geom, long long minx, long long miny, long long maxx, long long maxy) {
static std::vector<std::pair<double, double>> clip_poly1(std::vector<std::pair<double, double>> &geom,
long long minx, long long miny, long long maxx, long long maxy,
long long ax, long long ay, long long bx, long long by, drawvec &edge_nodes) {
std::vector<std::pair<double, double>> out = geom;
for (int edge = 0; edge < 4; edge++) {
@@ -597,13 +599,60 @@ static std::vector<std::pair<double, double>> clip_poly1(std::vector<std::pair<d
for (size_t e = 0; e < in.size(); e++) {
std::pair<double, double> E = in[e];
if (inside(E, edge, minx, miny, maxx, maxy)) {
if (!inside(S, edge, minx, miny, maxx, maxy)) {
out.push_back(intersect(S, E, edge, minx, miny, maxx, maxy));
if (!inside(S, edge, minx, miny, maxx, maxy)) {
// was outside the buffer
if (!inside(E, edge, minx, miny, maxx, maxy)) {
// still outside the buffer
} else if (!inside(E, edge, ax, ay, bx, by)) {
// outside the tile but inside the buffer
out.push_back(intersect(S, E, edge, minx, miny, maxx, maxy)); // on buffer edge
out.push_back(E);
} else {
out.push_back(intersect(S, E, edge, minx, miny, maxx, maxy)); // on buffer edge
if (prevent[P_SIMPLIFY_SHARED_NODES]) {
out.push_back(intersect(S, E, edge, ax, ay, bx, by)); // on tile boundary
edge_nodes.push_back(draw(VT_MOVETO, std::round(out.back().first), std::round(out.back().second)));
}
out.push_back(E);
}
} else if (!inside(S, edge, ax, ay, bx, by)) {
// was inside the buffer but outside the tile edge
if (!inside(E, edge, minx, miny, maxx, maxy)) {
// now outside the buffer
out.push_back(intersect(S, E, edge, minx, miny, maxx, maxy)); // on buffer edge
} else if (!inside(E, edge, ax, ay, bx, by)) {
// still outside the tile edge but inside the buffer
out.push_back(E);
} else {
// now inside the tile
if (prevent[P_SIMPLIFY_SHARED_NODES]) {
out.push_back(intersect(S, E, edge, ax, ay, bx, by)); // on tile boundary
edge_nodes.push_back(draw(VT_MOVETO, std::round(out.back().first), std::round(out.back().second)));
}
out.push_back(E);
}
} else {
// was inside the tile
if (!inside(E, edge, minx, miny, maxx, maxy)) {
// now outside the buffer
if (prevent[P_SIMPLIFY_SHARED_NODES]) {
out.push_back(intersect(S, E, edge, ax, ay, bx, by)); // on tile boundary
}
out.push_back(intersect(S, E, edge, minx, miny, maxx, maxy)); // on buffer edge
} else if (!inside(E, edge, ax, ay, bx, by)) {
// now inside the buffer but outside the tile edge
if (prevent[P_SIMPLIFY_SHARED_NODES]) {
out.push_back(intersect(S, E, edge, ax, ay, bx, by)); // on tile boundary
edge_nodes.push_back(draw(VT_MOVETO, std::round(out.back().first), std::round(out.back().second)));
}
out.push_back(E);
} else {
// still inside the tile
out.push_back(E);
}
out.push_back(E);
} else if (inside(S, edge, minx, miny, maxx, maxy)) {
out.push_back(intersect(S, E, edge, minx, miny, maxx, maxy));
}
S = E;
@@ -631,7 +680,8 @@ static std::vector<std::pair<double, double>> clip_poly1(std::vector<std::pair<d
return out;
}
drawvec simple_clip_poly(drawvec &geom, long long minx, long long miny, long long maxx, long long maxy) {
drawvec simple_clip_poly(drawvec &geom, long long minx, long long miny, long long maxx, long long maxy,
long long ax, long long ay, long long bx, long long by, drawvec &shared_nodes) {
drawvec out;
for (size_t i = 0; i < geom.size(); i++) {
@@ -649,7 +699,7 @@ drawvec simple_clip_poly(drawvec &geom, long long minx, long long miny, long lon
double y = geom[k].y;
tmp.emplace_back(x, y);
}
tmp = clip_poly1(tmp, minx, miny, maxx, maxy);
tmp = clip_poly1(tmp, minx, miny, maxx, maxy, ax, ay, bx, by, shared_nodes);
if (tmp.size() > 0) {
if (tmp[0].first != tmp[tmp.size() - 1].first || tmp[0].second != tmp[tmp.size() - 1].second) {
fprintf(stderr, "Internal error: Polygon ring not closed\n");
@@ -674,11 +724,17 @@ drawvec simple_clip_poly(drawvec &geom, long long minx, long long miny, long lon
return out;
}
drawvec simple_clip_poly(drawvec &geom, int z, int buffer) {
drawvec simple_clip_poly(drawvec &geom, long long minx, long long miny, long long maxx, long long maxy) {
drawvec dv;
return simple_clip_poly(geom, minx, miny, maxx, maxy, minx, miny, maxx, maxy, dv);
}
drawvec simple_clip_poly(drawvec &geom, int z, int buffer, drawvec &shared_nodes) {
long long area = 1LL << (32 - z);
long long clip_buffer = buffer * area / 256;
return simple_clip_poly(geom, -clip_buffer, -clip_buffer, area + clip_buffer, area + clip_buffer);
return simple_clip_poly(geom, -clip_buffer, -clip_buffer, area + clip_buffer, area + clip_buffer,
0, 0, area, area, shared_nodes);
}
drawvec reduce_tiny_poly(drawvec &geom, int z, int detail, bool *reduced, double *accum_area, serial_feature *this_feature, serial_feature *tiny_feature) {
@@ -1266,6 +1322,7 @@ drawvec fix_polygon(drawvec &geom) {
return out;
}
#if 0
std::vector<drawvec> chop_polygon(std::vector<drawvec> &geoms) {
while (1) {
bool again = false;
@@ -1344,6 +1401,7 @@ std::vector<drawvec> chop_polygon(std::vector<drawvec> &geoms) {
geoms = out;
}
}
#endif
#define INSIDE 0
#define LEFT 1