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Move point comparator lambda to function

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This avoids some code duplication
This commit is contained in:
karl 2020-12-28 12:17:44 +01:00
parent 0d8d6d7f6b
commit e7f18acc7d
1 changed files with 10 additions and 8 deletions
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18
kdtree.h
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@ -47,6 +47,14 @@ private:
int MAX_DEPTH = 500; int MAX_DEPTH = 500;
// Returns a comparator lambda for assessing which of the two points has a
// greater coordinate in the given axis.
auto get_point_comparator(int axis) {
return [axis](Point *p1, Point *p2) {
return p1->coordinates[axis] < p2->coordinates[axis];
};
}
Node *build(std::vector<Point *> points, int depth) { Node *build(std::vector<Point *> points, int depth) {
// Exit conditions // Exit conditions
if (points.empty() || depth > MAX_DEPTH) { if (points.empty() || depth > MAX_DEPTH) {
@ -59,9 +67,7 @@ private:
for (int it_axis = 0; it_axis < 3; it_axis++) { for (int it_axis = 0; it_axis < 3; it_axis++) {
// Get extent along this axis // Get extent along this axis
auto comparator = [it_axis](Point *p1, Point *p2) { auto comparator = get_point_comparator(it_axis);
return p1->coordinates[it_axis] < p2->coordinates[it_axis];
};
Point *min = *std::max_element(points.begin(), points.end(), comparator); Point *min = *std::max_element(points.begin(), points.end(), comparator);
Point *max = *std::max_element(points.begin(), points.end(), comparator); Point *max = *std::max_element(points.begin(), points.end(), comparator);
@ -80,12 +86,8 @@ private:
// left-of-median and right-of-median using nth_element // left-of-median and right-of-median using nth_element
int middle = points.size() / 2; int middle = points.size() / 2;
// TODO: Code duplication from the comparator in the earlier axis assessment
// loop
std::nth_element(points.begin(), points.begin() + middle, points.end(), std::nth_element(points.begin(), points.begin() + middle, points.end(),
[axis](Point *p1, Point *p2) { get_point_comparator(axis));
return p1->coordinates[axis] < p2->coordinates[axis];
});
Point *median; Point *median;
float pivot; float pivot;