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Diffstat (limited to 'src/mbgl/util/geometry_within.cpp')
-rw-r--r-- | src/mbgl/util/geometry_within.cpp | 143 |
1 files changed, 0 insertions, 143 deletions
diff --git a/src/mbgl/util/geometry_within.cpp b/src/mbgl/util/geometry_within.cpp deleted file mode 100644 index 618567a8e1..0000000000 --- a/src/mbgl/util/geometry_within.cpp +++ /dev/null @@ -1,143 +0,0 @@ -#include <mbgl/util/geometry_within.hpp> - -#include <algorithm> - -namespace mbgl { - -namespace { -bool rayIntersect(const Point<int64_t>& p, const Point<int64_t>& p1, const Point<int64_t>& p2) { - return ((p1.y > p.y) != (p2.y > p.y)) && (p.x < (p2.x - p1.x) * (p.y - p1.y) / (p2.y - p1.y) + p1.x); -} - -// check if point p in on line segment with end points p1 and p2 -bool onBoundary(const Point<int64_t>& p, const Point<int64_t>& p1, const Point<int64_t>& p2) { - // requirements of point p on line segment: - // 1. colinear: cross product of vector p->p1(x1, y1) and vector p->p2(x2, y2) equals to 0 - // 2. p is between p1 and p2 - const auto x1 = p.x - p1.x; - const auto y1 = p.y - p1.y; - const auto x2 = p.x - p2.x; - const auto y2 = p.y - p2.y; - return (x1 * y2 - x2 * y1 == 0) && (x1 * x2 <= 0) && (y1 * y2 <= 0); -} - -// a, b are end points for line segment1, c and d are end points for line segment2 -bool lineIntersectLine(const Point<int64_t>& a, - const Point<int64_t>& b, - const Point<int64_t>& c, - const Point<int64_t>& d) { - const auto perp = [](const Point<int64_t>& v1, const Point<int64_t>& v2) { return (v1.x * v2.y - v1.y * v2.x); }; - - // check if two segments are parallel or not - // precondition is end point a, b is inside polygon, if line a->b is - // parallel to polygon edge c->d, then a->b won't intersect with c->d - auto vectorP = Point<int64_t>(b.x - a.x, b.y - a.y); - auto vectorQ = Point<int64_t>(d.x - c.x, d.y - c.y); - if (perp(vectorQ, vectorP) == 0) return false; - - // check if p1 and p2 are in different sides of line segment q1->q2 - const auto twoSided = - [](const Point<int64_t>& p1, const Point<int64_t>& p2, const Point<int64_t>& q1, const Point<int64_t>& q2) { - int64_t x1; - int64_t y1; - int64_t x2; - int64_t y2; - int64_t x3; - int64_t y3; - - // q1->p1 (x1, y1), q1->p2 (x2, y2), q1->q2 (x3, y3) - x1 = p1.x - q1.x; - y1 = p1.y - q1.y; - x2 = p2.x - q1.x; - y2 = p2.y - q1.y; - x3 = q2.x - q1.x; - y3 = q2.y - q1.y; - auto ret1 = (x1 * y3 - x3 * y1); - auto ret2 = (x2 * y3 - x3 * y2); - return (ret1 > 0 && ret2 < 0) || (ret1 < 0 && ret2 > 0); - }; - - // If lines are intersecting with each other, the relative location should be: - // a and b lie in different sides of segment c->d - // c and d lie in different sides of segment a->b - return twoSided(a, b, c, d) && twoSided(c, d, a, b); -} - -bool lineIntersectPolygon(const Point<int64_t>& p1, const Point<int64_t>& p2, const Polygon<int64_t>& polygon) { - for (auto ring : polygon) { - auto length = ring.size(); - // loop through every edge of the ring - for (std::size_t i = 0; i < length - 1; ++i) { - if (lineIntersectLine(p1, p2, ring[i], ring[i + 1])) { - return true; - } - } - } - return false; -} - -} // namespace - -void updateBBox(WithinBBox& bbox, const Point<int64_t>& p) { - bbox[0] = std::min(p.x, bbox[0]); - bbox[1] = std::min(p.y, bbox[1]); - bbox[2] = std::max(p.x, bbox[2]); - bbox[3] = std::max(p.y, bbox[3]); -} - -bool boxWithinBox(const WithinBBox& bbox1, const WithinBBox& bbox2) { - if (bbox1[0] <= bbox2[0]) return false; - if (bbox1[2] >= bbox2[2]) return false; - if (bbox1[1] <= bbox2[1]) return false; - if (bbox1[3] >= bbox2[3]) return false; - return true; -} - -// ray casting algorithm for detecting if point is in polygon -bool pointWithinPolygon(const Point<int64_t>& point, const Polygon<int64_t>& polygon) { - bool within = false; - for (const auto& ring : polygon) { - const auto length = ring.size(); - // loop through every edge of the ring - for (std::size_t i = 0; i < length - 1; ++i) { - if (onBoundary(point, ring[i], ring[i + 1])) return false; - if (rayIntersect(point, ring[i], ring[i + 1])) { - within = !within; - } - } - } - return within; -} - -bool pointWithinPolygons(const Point<int64_t>& point, const MultiPolygon<int64_t>& polygons) { - for (const auto& polygon : polygons) { - if (pointWithinPolygon(point, polygon)) return true; - } - return false; -} - -bool lineStringWithinPolygon(const LineString<int64_t>& line, const Polygon<int64_t>& polygon) { - const auto length = line.size(); - // First, check if geometry points of line segments are all inside polygon - for (std::size_t i = 0; i < length; ++i) { - if (!pointWithinPolygon(line[i], polygon)) { - return false; - } - } - - // Second, check if there is line segment intersecting polygon edge - for (std::size_t i = 0; i < length - 1; ++i) { - if (lineIntersectPolygon(line[i], line[i + 1], polygon)) { - return false; - } - } - return true; -} - -bool lineStringWithinPolygons(const LineString<int64_t>& line, const MultiPolygon<int64_t>& polygons) { - for (const auto& polygon : polygons) { - if (lineStringWithinPolygon(line, polygon)) return true; - } - return false; -} -} // namespace mbgl |