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//==================================================================
// Copyright 2002, softSurfer (www.softsurfer.com)
// This code may be freely used and modified for any purpose
// providing that this copyright notice is included with it.
// SoftSurfer makes no warranty for this code, and cannot be held
// liable for any real or imagined damage resulting from it's use.
// Users of this code must verify correctness for their application.
//==================================================================
// Heavily modified by Randal A. Koene, 20050111
#include "Point2D.hh"
#include "Vector2D.hh"
// Read input Point2D format: "(%f)" or "(%f, %f)"
istream& operator>>( istream& input, Point2D& P) {
char c;
input >> c; // skip '('
input >> P.x;
input >> c;
if (c == ')') {
P.y=0.0; // 1D coord
return input;
}
input >> P.y;
input >> c; // skip ')'
return input;
}
// Write output Point2D in format: "(%f, %f)"
ostream& operator<<( ostream& output, Point2D P) {
output << "(" << P.x << ", " << P.y << ")";
return output;
}
Vector2D Point2D::operator-( Point2D Q) // Vector2D diff of Point2Ds
{
Vector2D v;
v.x = x - Q.x;
v.y = y - Q.y;
return v;
}
Point2D Point2D::operator+( Vector2D v) // +ve translation
{
Point2D P;
P.x = x + v.x;
P.y = y + v.y;
return P;
}
Point2D Point2D::operator-( Vector2D v) // -ve translation
{
Point2D P;
P.x = x - v.x;
P.y = y - v.y;
return P;
}
Point2D& Point2D::operator+=( Vector2D v) // +ve translation
{
x += v.x;
y += v.y;
return *this;
}
Point2D& Point2D::operator-=( Vector2D v) // -ve translation
{
x -= v.x;
y -= v.y;
return *this;
}
//------------------------------------------------------------------
// Point2D Scalar Operations (convenient but often illegal)
// are not valid for points in general,
// unless they are 'affine' as coeffs of
// a sum in which all the coeffs add to 1,
// such as: the sum (a*P + b*Q) with (a+b == 1).
// The programmer must enforce this (if they want to).
//------------------------------------------------------------------
Point2D operator*( int c, Point2D Q) {
Point2D P;
P.x = c * Q.x;
P.y = c * Q.y;
return P;
}
Point2D operator*( double c, Point2D Q) {
Point2D P;
P.x = c * Q.x;
P.y = c * Q.y;
return P;
}
Point2D operator*( Point2D Q, int c) {
Point2D P;
P.x = c * Q.x;
P.y = c * Q.y;
return P;
}
Point2D operator*( Point2D Q, double c) {
Point2D P;
P.x = c * Q.x;
P.y = c * Q.y;
return P;
}
Point2D operator/( Point2D Q, int c) {
Point2D P;
P.x = Q.x / c;
P.y = Q.y / c;
return P;
}
Point2D operator/( Point2D Q, double c) {
Point2D P;
P.x = Q.x / c;
P.y = Q.y / c;
return P;
}
//------------------------------------------------------------------
// Point2D Addition (also convenient but often illegal)
// is not valid unless part of an affine sum.
// The programmer must enforce this (if they want to).
//------------------------------------------------------------------
Point2D operator+( Point2D Q, Point2D R)
{
Point2D P;
P.x = Q.x + R.x;
P.y = Q.y + R.y;
return P;
}
//------------------------------------------------------------------
// Affine Sums
// Returns weighted sum, even when not affine, but...
// Tests if coeffs add to 1. If not, sets: err = Esum.
//------------------------------------------------------------------
Point2D asum( int n, int c[], Point2D Q[], int * err) {
int cs = 0;
Point2D P;
if (err) {
*err = 0;
for (int i=0; i<n; i++) cs += c[i];
if (cs != 1) // not an affine sum
*err = -1; // flag error, but compute sum anyway
}
for (int i=0; i<n; i++) {
P.x += c[i] * Q[i].x;
P.y += c[i] * Q[i].y;
}
return P;
}
Point2D asum( int n, double c[], Point2D Q[], int * err) {
double cs = 0.0;
Point2D P;
if (err) {
*err = 0;
for (int i=0; i<n; i++) cs += c[i];
if (cs != 1) // not an affine sum
*err = -1; // flag error, but compute sum anyway
}
for (int i=0; i<n; i++) {
P.x += c[i] * Q[i].x;
P.y += c[i] * Q[i].y;
}
return P;
}
//------------------------------------------------------------------
// Distance between Point2Ds
//------------------------------------------------------------------
double Point2D::distance( Point2D & P ) { // Euclidean distance
double dx = P.x - x;
double dy = P.y - y;
return sqrt(dx*dx + dy*dy);
}
double distance( Point2D P, Point2D Q) { // Euclidean distance
double dx = P.x - Q.x;
double dy = P.y - Q.y;
return sqrt(dx*dx + dy*dy);
}
double distance2( Point2D P, Point2D Q) { // squared distance (more efficient)
double dx = P.x - Q.x;
double dy = P.y - Q.y;
return (dx*dx + dy*dy);
}
//------------------------------------------------------------------
// Sidedness of a Point2D wrt a directed line P1->P2
// - makes sense in 2D only
//------------------------------------------------------------------
double Point2D::isLeft( Point2D P1, Point2D P2, int * err) {
if (err) *err = 0;
return ((P1.x - x) * (P2.y - y) - (P2.x - x) * (P1.y - y));
}
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