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/*
This file is part of the MinGfx Project.
Copyright (c) 2017,2018 Regents of the University of Minnesota.
All Rights Reserved.
Original Author(s) of this File:
Dan Keefe, 2018, University of Minnesota
Author(s) of Significant Updates/Modifications to the File:
...
*/
#ifndef SRC_POINT2_H_
#define SRC_POINT2_H_
#include <iostream>
namespace mingfx {
/// Epsilon value used for == and != comparisons within MinGfx
#define MINGFX_MATH_EPSILON 1e-8
/** A 2D Point with floating point coordinates, used for storing 2D texture
coordinates, screen-space graphics, and mouse input.
*/
class Point2 {
public:
/// Default point at the origin
Point2();
/// Constructs a point given (x,y,1), where the 1 comes from the use of
/// homogeneous coordinates in computer graphics.
Point2(float x, float y);
/// Constructs a point given a pointer to x,y data
Point2(float *p);
/// Copy constructor for point
Point2(const Point2& p);
/// Point destructor
virtual ~Point2();
/// Check for "equality", taking floating point imprecision into account
bool operator==(const Point2& p) const;
/// Check for "inequality", taking floating point imprecision into account
bool operator!=(const Point2& p) const;
/// Assignment operator
Point2& operator=(const Point2& p);
/// Read only access to the ith coordinate of the point.
float operator[](const int i) const;
/// Returns a reference to the ith coordinate of the point. Use this
/// accessor if you wish to set the coordinate rather than just request
/// its value. Example:
/// ~~~
/// Point2 a;
/// a[0] = 5.0; // set the x-coordinate of the point
/// ~~~
float& operator[](const int i);
/// Read only access to the x coordinate. Can also use my_point[0]. Use
/// the my_point[0] = 1.0; form if you need to set the value.
float x() const { return p[0]; }
/// Read only access to the y coordinate. Can also use my_point[1]. Use
/// the my_point[1] = 1.0; form if you need to set the value.
float y() const { return p[1]; }
/// In homogeneous coordinates, the w coordinate for all points is 1.0.
float w() const { return 1.0; }
/// Returns a const pointer to the raw data array
const float * value_ptr() const;
/// Linear interpolation between this point and another. Alpha=0.0 returns
/// this point, and alpha=1.0 returns the other point, other values blend
/// between the two.
Point2 Lerp(const Point2 &b, float alpha) const;
/// (0,0) - a shortcut for a special point that is frequently needed
static const Point2& Origin();
/// (0,0) - a shortcut for a special point that is frequently needed
static const Point2& Zero();
/// (1,1) - a shortcut for a special point that is frequently needed
static const Point2& One();
/// Linear interpolation between two points. Alpha=0.0 returns 'a' and
/// alpha=1.0 returns 'b', other values blend between the two.
static Point2 Lerp(const Point2 &a, const Point2 &b, float alpha);
private:
float p[2];
};
std::ostream & operator<< ( std::ostream &os, const Point2 &p);
std::istream & operator>> ( std::istream &is, Point2 &p);
} // namespace
#endif
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