mgs/quickhull
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Change distance_to to distance_squared_to

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more efficiency! (and we only need it for comparisons anyways)
This commit is contained in:
karl 2020-11-29 01:38:07 +01:00
parent c0bba8b264
commit 6654519d84
2 changed files with 8 additions and 8 deletions
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8
Line.h
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@ -1,7 +1,5 @@
#pragma once
#include <cmath> // For abs, sqrt
#include "Point.h"
class Line
@ -51,12 +49,14 @@ public:
}
}
float distance_to(Point other) const
float distance_squared_to(Point other) const
{
float a = from().y() - to().y();
float b = to().x() - from().x();
float c = from().x() * to().y() - to().x() * from().y();
return abs(a * other.x() + b * other.y() + c) / sqrt(a * a + b * b);
float d = abs(a * other.x() + b * other.y() + c);
return (d * d) / (a * a + b * b);
}
};

8
Quickhull.h
View File

@ -67,7 +67,7 @@ private:
for (const Point &point : input)
{
float this_distance = line.distance_to(point);
float this_distance = line.distance_squared_to(point);
if (this_distance > furthest_distance)
{
furthest_distance = this_distance;
@ -85,17 +85,17 @@ private:
// Points inside the hull are added because of random lines.
for (const Point &point : input)
{
float this_distance = line.distance_to(point);
float this_distance = line.distance_squared_to(point);
// TODO: Both are required, otherwise only one side of the rectangle is
// taken -- why?
if (this_distance == furthest_distance || line.distance_to(point) == 0)
if (this_distance == furthest_distance || line.distance_squared_to(point) == 0)
{
output.emplace_back(point);
}
}
input.remove_if([furthest_distance, line](Point point)
{
return furthest_distance == line.distance_to(point);
return furthest_distance == line.distance_squared_to(point);
});
// Hotfix end