src/cobalt/math/vector2d_f.h

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Defines a simple float vector class.  This class is used to indicate a
// distance in two dimensions between two points. Subtracting two points should
// produce a vector, and adding a vector to a point produces the point at the
// vector's distance from the original point.

#ifndef COBALT_MATH_VECTOR2D_F_H_
#define COBALT_MATH_VECTOR2D_F_H_

#include <iosfwd>
#include <string>

#include "base/logging.h"

namespace cobalt {
namespace math {

class Vector2dF {
 public:
  Vector2dF() : x_(0), y_(0) {}
  Vector2dF(float x, float y) : x_(x), y_(y) {}

  void SetVector(float x, float y) {
    x_ = x;
    y_ = y;
  }

  float x() const { return x_; }
  void set_x(float x) { x_ = x; }

  float y() const { return y_; }
  void set_y(float y) { y_ = y; }

  // True if both components of the vector are 0.
  bool IsZero() const;

  // Add the components of the |other| vector to the current vector.
  void Add(const Vector2dF& other);
  // Subtract the components of the |other| vector from the current vector.
  void Subtract(const Vector2dF& other);

  void operator+=(const Vector2dF& other) { Add(other); }
  void operator-=(const Vector2dF& other) { Subtract(other); }

  float operator[](int i) const {
    DCHECK_LE(0, i);
    DCHECK_GE(1, i);
    return i == 0 ? x_ : y_;
  }
  float& operator[](int i) {
    DCHECK_LE(0, i);
    DCHECK_GE(1, i);
    return i == 0 ? x_ : y_;
  }

  void SetToMin(const Vector2dF& other) {
    x_ = x_ <= other.x_ ? x_ : other.x_;
    y_ = y_ <= other.y_ ? y_ : other.y_;
  }

  void SetToMax(const Vector2dF& other) {
    x_ = x_ >= other.x_ ? x_ : other.x_;
    y_ = y_ >= other.y_ ? y_ : other.y_;
  }

  // Gives the square of the diagonal length of the vector.
  double LengthSquared() const;
  // Gives the diagonal length of the vector.
  float Length() const;

  // Scale the x and y components of the vector by |scale|.
  void Scale(float scale) { Scale(scale, scale); }
  // Scale the x and y components of the vector by |x_scale| and |y_scale|
  // respectively.
  void Scale(float x_scale, float y_scale);

  std::string ToString() const;

 private:
  float x_;
  float y_;
};

inline bool operator==(const Vector2dF& lhs, const Vector2dF& rhs) {
  return lhs.x() == rhs.x() && lhs.y() == rhs.y();
}

inline bool operator!=(const Vector2dF& lhs, const Vector2dF& rhs) {
  return !(lhs == rhs);
}

inline Vector2dF operator-(const Vector2dF& v) {
  return Vector2dF(-v.x(), -v.y());
}

inline Vector2dF operator+(const Vector2dF& lhs, const Vector2dF& rhs) {
  Vector2dF result = lhs;
  result.Add(rhs);
  return result;
}

inline Vector2dF operator-(const Vector2dF& lhs, const Vector2dF& rhs) {
  Vector2dF result = lhs;
  result.Add(-rhs);
  return result;
}

// Return the cross product of two vectors.
double CrossProduct(const Vector2dF& lhs, const Vector2dF& rhs);

// Return the dot product of two vectors.
double DotProduct(const Vector2dF& lhs, const Vector2dF& rhs);

// Return a vector that is |v| scaled by the given scale factors along each
// axis.
Vector2dF ScaleVector2d(const Vector2dF& v, float x_scale, float y_scale);

// Return a vector that is |v| scaled by the given scale factor.
inline Vector2dF ScaleVector2d(const Vector2dF& v, float scale) {
  return ScaleVector2d(v, scale, scale);
}

}  // namespace math
}  // namespace cobalt

#endif  // COBALT_MATH_VECTOR2D_F_H_