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Keyframe::GetClosestPoint(): Use binary search

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This commit is contained in:
Daniel Jour
2019-11-30 11:58:51 +01:00
parent 54e8e37d2d
commit 65cb3dfde9
1 changed files with 23 additions and 30 deletions
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53
src/KeyFrame.cpp
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@@ -121,39 +121,32 @@ bool Keyframe::Contains(Point p) const {
// Get current point (or closest point) from the X coordinate (i.e. the frame number)
Point Keyframe::GetClosestPoint(Point p, bool useLeft) const {
Point closest(-1, -1);
// loop through points, and find a matching coordinate
for (int64_t x = 0; x < Points.size(); x++) {
// Get each point
Point existing_point = Points[x];
// find a match
if (existing_point.co.X >= p.co.X && !useLeft) {
// New closest point found (to the Right)
closest = existing_point;
break;
} else if (existing_point.co.X < p.co.X && useLeft) {
// New closest point found (to the Left)
closest = existing_point;
} else if (existing_point.co.X >= p.co.X && useLeft) {
// We've gone past the left point... so break
break;
}
if (Points.size() == 0) {
return Point(-1, -1);
}
// Handle edge cases (if no point was found)
if (closest.co.X == -1) {
if (p.co.X <= 1 && Points.size() > 0)
// Assign 1st point
closest = Points[0];
else if (Points.size() > 0)
// Assign last point
closest = Points[Points.size() - 1];
}
// Finds a point with an X coordinate which is "not less" (greater
// or equal) than the queried X coordinate.
std::vector<Point>::const_iterator candidate =
std::lower_bound(begin(Points), end(Points), p.co.X, IsPointBeforeX);
// no matching point found
return closest;
if (candidate == end(Points)) {
// All points are before the queried point.
//
// Note: Behavior the same regardless of useLeft!
return Points.back();
}
if (candidate == begin(Points)) {
// First point is greater or equal to the queried point.
//
// Note: Behavior the same regardless of useLeft!
return Points.front();
}
if (useLeft) {
return *(candidate - 1);
} else {
return *candidate;
}
}
// Get current point (or closest point to the right) from the X coordinate (i.e. the frame number)