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@e-n-f
e-n-f committed Nov 13, 2023
1 parent ba9dbda commit c0866b9
Showing 1 changed file with 105 additions and 16 deletions.
121 changes: 105 additions & 16 deletions polygon.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -276,8 +276,8 @@ bool intersect(std::vector<segment> &segs, size_t s1, size_t s2) {
// at an endpoint in s1, so it doesn't need to be changed
} else {
// printf("introduce %f,%f in %f,%f to %f,%f (s1 %zu %zu)\n", x, y, segs[s1].first.x, segs[s1].first.y, segs[s1].second.x, segs[s1].second.y, s1, s2);
segs.push_back(std::make_pair(point(x, y), segs[s1].second));
segs[s1] = std::make_pair(segs[s1].first, point(x, y));
segs.push_back(std::make_pair(point(std::round(x), std::round(y)), segs[s1].second));
segs[s1] = std::make_pair(segs[s1].first, point(std::round(x), std::round(y)));
changed = true;
}

Expand All @@ -287,8 +287,8 @@ bool intersect(std::vector<segment> &segs, size_t s1, size_t s2) {
} else {
// printf("introduce %f,%f in %f,%f to %f,%f (s2 %zu %zu)\n", x, y, segs[s2].first.x, segs[s2].first.y, segs[s2].second.x, segs[s2].second.y, s1, s2);
// printf("introduce %lld,%lld in %lld,%lld to %lld,%lld (s2)\n", std::llround(x), std::llround(y), std::llround(segs[s2].first.x), std::llround(segs[s2].first.y), std::llround(segs[s2].second.x), std::llround(segs[s2].second.y));
segs.push_back(std::make_pair(point(x, y), segs[s2].second));
segs[s2] = std::make_pair(segs[s2].first, point(x, y));
segs.push_back(std::make_pair(point(std::round(x), std::round(y)), segs[s2].second));
segs[s2] = std::make_pair(segs[s2].first, point(std::round(x), std::round(y)));
changed = true;
}
} else if (intersections == SAME_SLOPE) {
Expand Down Expand Up @@ -416,10 +416,27 @@ struct ring_area {
drawvec geom;
double area;
std::vector<size_t> children;
long long ear_x;
long long ear_y;

ring_area(drawvec geom_, double area_) {
geom = geom_;
area = area_;

// search polygon ears to find an interior point
for (size_t i = 0; i + 2 < geom.size(); i++) {
long long x = (geom[i].x + geom[i + 1].x + geom[i + 2].x) / 3;
long long y = (geom[i].y + geom[i + 1].y + geom[i + 2].y) / 3;

if (pnpoly(geom, 0, geom.size(), x, y)) {
ear_x = x;
ear_y = y;
return;
}
}

fprintf(stderr, "Couldn't find an interior point\n");
exit(EXIT_IMPOSSIBLE);
}

bool operator<(ring_area const &s) const {
Expand All @@ -432,6 +449,8 @@ struct ring_area {
}
};

const int SCALE = 3;

std::vector<ring_area> reassemble(std::vector<segment> const &segs) {
std::multimap<point, segment> connections;
std::vector<ring_area> ret;
Expand Down Expand Up @@ -590,12 +609,12 @@ std::vector<ring_area> reassemble(std::vector<segment> const &segs) {
}

// these coordinates are doubled, so that `encloses` can always find
// an integer point at the center of an edge
// an interior point in each ring
drawvec out;
for (size_t i = 0; i < ring.size(); i++) {
out.emplace_back(i == 0 ? VT_MOVETO : VT_LINETO, std::round(ring[i].x) * 2, std::round(ring[i].y) * 2);
out.emplace_back(i == 0 ? VT_MOVETO : VT_LINETO, std::round(ring[i].x) * SCALE, std::round(ring[i].y) * SCALE);
}
out.emplace_back(VT_LINETO, std::round(ring[0].x) * 2, std::round(ring[0].y) * 2);
out.emplace_back(VT_LINETO, std::round(ring[0].x) * SCALE, std::round(ring[0].y) * SCALE);
if (out[0] != out[out.size() - 1]) {
fprintf(stderr, "Ring not closed???\n");
exit(EXIT_IMPOSSIBLE);
Expand All @@ -621,15 +640,41 @@ bool encloses(ring_area const &parent, ring_area const &child) {
exit(EXIT_IMPOSSIBLE);
}

// the edges of the child polygon are supposedly entirely contained within the parent
// (although the vertices may not be), so check the middle of an edge.
long long x = (child.geom[0].x + child.geom[1].x) / 2;
long long y = (child.geom[0].y + child.geom[1].y) / 2;
bool a = pnpoly(parent.geom, 0, parent.geom.size(), child.ear_x, child.ear_y);

return pnpoly(parent.geom, 0, parent.geom.size(), x, y);
#if 0
if (a != b) {
fprintf(stderr, "inconsistent pnpoly at %lld,%lld (%d) vs %lld,%lld (%d)\n", x, y, a, x2, y2, b);

printf("0 setlinewidth ");
for (auto const &g : parent.geom) {
printf("%lld %lld %s ", g.x, g.y, g.op == VT_MOVETO ? "moveto" : "lineto");
}
printf("stroke\n");
for (auto const &g : parent.geom) {
printf("%lld %lld .05 0 360 arc fill ", g.x, g.y);
}

for (auto const &g : child.geom) {
printf("%f %f %s ", g.x + 0.25, g.y + 0.25, g.op == VT_MOVETO ? "moveto" : "lineto");
}
printf("stroke\n");

printf("%lld %lld .5 0 360 arc fill\n", x, y);
printf("%lld %lld .5 0 360 arc fill\n", x2, y2);

exit(EXIT_FAILURE);
}
#endif

return a;
}

void flatten_rings(std::vector<ring_area> &rings, size_t i, drawvec &out, ssize_t winding, ssize_t parent) {
if (rings[i].geom.size() == 0) {
return;
}

// only the transition from winding order 0 to 1 or from 1 to 0
// is actually represented in the geometry.
//
Expand All @@ -638,7 +683,7 @@ void flatten_rings(std::vector<ring_area> &rings, size_t i, drawvec &out, ssize_
if ((winding == 0 && rings[i].area > 0) ||
(winding == 1 && rings[i].area < 0)) {
for (auto const &g : rings[i].geom) {
out.emplace_back(g.op, g.x / 2, g.y / 2);
out.emplace_back(g.op, g.x / SCALE, g.y / SCALE);
}
if (rings[i].geom.size() > 0 && rings[i].geom[0] != rings[i].geom[rings[i].geom.size() - 1]) {
fprintf(stderr, "Ring not closed\n");
Expand All @@ -655,6 +700,12 @@ void flatten_rings(std::vector<ring_area> &rings, size_t i, drawvec &out, ssize_
winding--;
}

fprintf(stderr, "ring %zu contains rings:", i);
for (size_t j = 0; j < rings[i].children.size(); j++) {
fprintf(stderr, " %zu", rings[i].children[j]);
}
fprintf(stderr, "\n");

for (size_t j = 0; j < rings[i].children.size(); j++) {
flatten_rings(rings, rings[i].children[j], out, winding, i);
}
Expand Down Expand Up @@ -706,18 +757,56 @@ drawvec clean_polygon(drawvec const &geom, int z, int detail) {
for (size_t i = 0; i < rings.size(); i++) { // from largest to smallest abs area
for (ssize_t j = i - 1; j >= 0; j--) { // from smallest to largest abs area of already examined
if (encloses(rings[j], rings[i])) {
printf("ring %zd (%f) encloses ring %zu (%f)\n", j, rings[j].area, i, rings[i].area);
rings[j].children.push_back(i);
if (rings[i].area < 0 && rings[j].area > 0) {
// inner ring inside an outer ring;
// attribute it to the outer ring
rings[j].children.push_back(i);
#if 0
fprintf(stderr, "inner within outer: ring %zd (%f) encloses ring %zu (%f) %s\n", j, rings[j].area, i, rings[i].area,
signbit(rings[j].area) == signbit(rings[i].area) ? "!!!!" : "");
#endif
} else if (rings[i].area < 0 && rings[j].area < 0) {
fprintf(stderr, "inner within inner: ring %zd (%f) encloses ring %zu (%f) %s\n", j, rings[j].area, i, rings[i].area,
signbit(rings[j].area) == signbit(rings[i].area) ? "!!!!" : "");
rings[i].geom.clear();
} else if (rings[i].area > 0 && rings[j].area > 0) {
fprintf(stderr, "outer within outer: ring %zd (%f) encloses ring %zu (%f) %s\n", j, rings[j].area, i, rings[i].area,
signbit(rings[j].area) == signbit(rings[i].area) ? "!!!!" : "");
rings[i].geom.clear();
} else {
// outer ring within an inner ring;
// this is OK, but it is treated as a new outer ring in the tile,
// not output in a hierarchy
}

break;
}
}
}

drawvec ret;
for (size_t i = 0; i < rings.size(); i++) {
flatten_rings(rings, i, ret, 0, -1);
for (auto const &g : rings[i].geom) {
ret.emplace_back(g.op, g.x / SCALE, g.y / SCALE);
}
for (auto child : rings[i].children) {
for (auto const &g : rings[child].geom) {
ret.emplace_back(g.op, g.x / SCALE, g.y / SCALE);
}
rings[child].geom.clear();
}
}

#if 0
for (size_t i = 0; i < rings.size(); i++) {
if (get_area(rings[i].geom, 0, rings[i].geom.size()) > 0) {
for (auto const &g : rings[i].geom) {
ret.emplace_back(g.op, g.x / SCALE, g.y / SCALE);
}
}
}
#endif

// remove collinear points?

#if 0
Expand Down

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