Untitled

#include<iostream>
#include<conio.h>

using namespace std;

// Clamp n to lie within the range [min, max]
float Clamp(float n, float min, float max)
{
    if (n < min) return min;
    if (n > max) return max;
  return n;
}
// Computes closest points C1 and C2 of S1(s)=P1+s*(Q1-P1) and
// S2(t)=P2+t*(Q2-P2), returning s and t. Function result is squared
// distance between between S1(s) and S2(t)
float ClosestPtSegmentSegment(Point p1, Point q1, Point p2, Point q2,
float &s, float &t, Point &c1, Point &c2)
{
Vector d1 = q1 - p1; // Direction vector of segment S1
Vector d2 = q2 - p2; // Direction vector of segment S2
Vector r = p1 - p2;
float a = Dot(d1, d1); // Squared length of segment S1, always nonnegative
float e = Dot(d2, d2); // Squared length of segment S2, always nonnegative
float f = Dot(d2, r);
// Check if either or both segments degenerate into points
if (a <= EPSILON && e <= EPSILON) {
// Both segments degenerate into points
s = t = 0.0f;
c1 = p1;
c2 = p2;

return Dot(c1 - c2, c1 - c2);
}
if (a <= EPSILON) {
// First segment degenerates into a point
s = 0.0f;
t = f / e; // s = 0 => t = (b*s + f) / e = f / e
t = Clamp(t, 0.0f, 1.0f);
} else {
float c = Dot(d1, r);
if (e <= EPSILON) {
// Second segment degenerates into a point
t = 0.0f;
s = Clamp(-c / a, 0.0f, 1.0f); // t = 0 => s = (b*t - c) / a = -c / a
} else {
// The general nondegenerate case starts here
float b = Dot(d1, d2);
float denom = a*e-b*b; // Always nonnegative
// If segments not parallel, compute closest point on L1 to L2 and
// clamp to segment S1. Else pick arbitrary s (here 0)
if (denom != 0.0f) {
s = Clamp((b*f - c*e) / denom, 0.0f, 1.0f);
} else s = 0.0f;
// Compute point on L2 closest to S1(s) using
// t = Dot((P1 + D1*s) - P2,D2) / Dot(D2,D2) = (b*s + f) / e
t = (b*s + f) / e;
// If t in [0,1] done. Else clamp t, recompute s for the new value
// of t using s = Dot((P2 + D2*t) - P1,D1) / Dot(D1,D1)= (t*b - c) / a
// and clamp s to [0, 1]
if (t < 0.0f) {
t = 0.0f;
s = Clamp(-c / a, 0.0f, 1.0f);
} else if (t > 1.0f) {
t = 1.0f;
s = Clamp((b - c) / a, 0.0f, 1.0f);
}
}
}
c1 = p1 + d1 * s;
c2 = p2 + d2 * t;
return Dot(c1 - c2, c1 - c2);
}

void main()
{

_getch();
return;
}