class Point2D

Defined in: C4Vector2D.h

The Point2D class encapsulates a 2D point.

Definition

class Point2D : public Vector2D

Constructor

Point2D();

Point2D(float r, float s);

Parameters

`r`	The value of the x coordinate.
`s`	The value of the y coordinate.

Description

The Point2D class is used to store a two-dimensional point having floating-point components x and y. The difference between a point and a vector is that a point is assumed to have a w coordinate of 1 whenever it needs to be converted to a four-dimensional representation, whereas a vector is assumed to have a w coordinate of 0. Such a conversion occurs when a vector or point is assigned to a Vector4D object or is multiplied by a Transform4D object.

The default constructor leaves the components of the vector undefined. If the values r and s are supplied, then they are assigned to the x and y components of the base vector object, respectively.

The difference between two points produces a direction vector. A two-dimensional direction vector is converted to a point by adding it to the identifier Origin2D.

Overloaded Operators

`Point2D& operator *=(float t);`	Multiplies by the scalar `t`.
`Point2D& operator /=(float t);`	Divides by the scalar `t`.

Nonmember Operations

`Point2D operator -(const Point2D& p);`	Returns the negation of the point `p`.
`Point2D operator +(const Point2D& p1, const Point2D& p2);`	Returns the sum of the points `p1` and `p2`.
`Point2D operator +(const Point2D& p, const Vector2D& v);`	Returns the sum of the point `p` and the vector `v`.
`Point2D operator -(const Point2D& p, const Vector2D& v);`	Returns the difference of the point `p` and the vector `v`.
`Vector2D operator -(const Point2D& p1, const Point2D& p2);`	Returns the difference of the points `p1` and `p2`.
`Point2D operator *(const Point2D& p, float t);`	Returns the product of the point `p` and the scalar `t`.
`Point2D operator *(float t, const Point2D& p);`	Returns the product of the point `p` and the scalar `t`.
`Point2D operator /(const Point2D& p, float t) const;`	Returns the product of the point `p` and the inverse of the scalar `t`.

Base Classes

Vector2D A Point2D object behaves much like a Vector2D object, but some properties are altered.