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104 lines
3.1 KiB
C++
104 lines
3.1 KiB
C++
#include "geometry.hpp"
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#include "mapbox/geometry/earcut.hpp"
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using Coord = long long;
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using N = size_t;
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using Point = std::array<Coord, 2>;
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drawvec reinforce(drawvec const &pts, std::vector<std::vector<Point>> polygon, double scale) {
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std::vector<N> indices = mapbox::earcut<N>(polygon);
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drawvec out2;
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for (size_t i = 0; i + 2 < indices.size(); i += 3) {
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std::vector<double> lengths;
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for (size_t j = 0; j < 3; j++) {
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size_t v1 = i + j;
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size_t v2 = i + ((j + 1) % 3);
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size_t v3 = i + ((j + 2) % 3);
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double px, py;
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if (distance_from_line(pts[indices[v1]].x, pts[indices[v1]].y, // the point
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pts[indices[v2]].x, pts[indices[v2]].y, // start of opposite side
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pts[indices[v3]].x, pts[indices[v3]].y, // end of opposite side
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&px, &py) < 2 * scale) {
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double ang = atan2(pts[indices[v1]].y - py, pts[indices[v1]].x - px);
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// make a new triangle that is not so flat
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out2.push_back(draw(VT_MOVETO, pts[indices[v2]].x, pts[indices[v2]].y));
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out2.push_back(draw(VT_LINETO, pts[indices[v3]].x, pts[indices[v3]].y));
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out2.push_back(draw(VT_LINETO, px + scale * 2 * cos(ang), py + scale * 2 * sin(ang)));
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out2.push_back(draw(VT_LINETO, pts[indices[v2]].x, pts[indices[v2]].y));
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}
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#if 0
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long long dx = pts[indices[v2]].x - pts[indices[v1]].x;
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long long dy = pts[indices[v2]].y - pts[indices[v1]].y;
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double d = sqrt(dx * dx + dy * dy);
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if (d < sqrt(2) * scale) {
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// make a new triangle with a longer side
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double ang = atan2(dy, dx);
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out2.push_back(draw(VT_MOVETO, pts[indices[v3]].x, pts[indices[v3]].y));
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out2.push_back(draw(VT_LINETO, pts[indices[v1]].x - sqrt(2) * scale * cos(ang), pts[indices[v1]].y - sqrt(2) * scale * sin(ang)));
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out2.push_back(draw(VT_LINETO, pts[indices[v2]].x + sqrt(2) * scale * cos(ang), pts[indices[v2]].y + sqrt(2) * scale * sin(ang)));
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out2.push_back(draw(VT_LINETO, pts[indices[v3]].x, pts[indices[v3]].y));
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}
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#endif
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}
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}
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return out2;
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}
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drawvec fix_by_triangulation(drawvec const &dv, int z, int detail) {
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std::vector<std::vector<Point>> polygon;
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drawvec out, out2;
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double scale = 1LL << (32 - z - detail);
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for (size_t i = 0; i < dv.size(); i++) {
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if (dv[i].op == VT_MOVETO) {
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size_t j;
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for (j = i + 1; j < dv.size(); j++) {
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if (dv[j].op != VT_LINETO) {
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break;
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}
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}
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if (get_area(dv, i, j) > 0) {
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// outer ring, so process whatever we have so far
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drawvec additional = reinforce(out, polygon, scale);
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for (auto const &d : additional) {
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out2.push_back(d);
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}
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polygon.clear();
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out.clear();
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}
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std::vector<Point> ring;
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// j - 1 because earcut docs indicate that it doesn't expect
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// a duplicate last point in each ring
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for (size_t k = i; k < j - 1; k++) {
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Point p = {(long long) dv[k].x, (long long) dv[k].y};
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ring.push_back(p);
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out.push_back(dv[k]);
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}
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polygon.push_back(ring);
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i = j - 1;
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}
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}
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drawvec additional = reinforce(out, polygon, scale);
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for (auto const &d : additional) {
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out2.push_back(d);
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}
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for (auto const &d : dv) {
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out2.push_back(d);
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}
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return out2;
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}
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