1// Copyright (c) 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef UI_GFX_GEOMETRY_MATRIX3_F_H_
6#define UI_GFX_GEOMETRY_MATRIX3_F_H_
7
8#include "base/logging.h"
9#include "ui/gfx/geometry/vector3d_f.h"
10
11namespace gfx {
12
13class GFX_EXPORT Matrix3F {
14 public:
15  ~Matrix3F();
16
17  static Matrix3F Zeros();
18  static Matrix3F Ones();
19  static Matrix3F Identity();
20  static Matrix3F FromOuterProduct(const Vector3dF& a, const Vector3dF& bt);
21
22  bool IsEqual(const Matrix3F& rhs) const;
23
24  // Element-wise comparison with given precision.
25  bool IsNear(const Matrix3F& rhs, float precision) const;
26
27  float get(int i, int j) const {
28    return data_[MatrixToArrayCoords(i, j)];
29  }
30
31  void set(int i, int j, float v) {
32    data_[MatrixToArrayCoords(i, j)] = v;
33  }
34
35  void set(float m00, float m01, float m02,
36           float m10, float m11, float m12,
37           float m20, float m21, float m22) {
38    data_[0] = m00;
39    data_[1] = m01;
40    data_[2] = m02;
41    data_[3] = m10;
42    data_[4] = m11;
43    data_[5] = m12;
44    data_[6] = m20;
45    data_[7] = m21;
46    data_[8] = m22;
47  }
48
49  Vector3dF get_column(int i) const {
50    return Vector3dF(
51      data_[MatrixToArrayCoords(0, i)],
52      data_[MatrixToArrayCoords(1, i)],
53      data_[MatrixToArrayCoords(2, i)]);
54  }
55
56  void set_column(int i, const Vector3dF& c) {
57    data_[MatrixToArrayCoords(0, i)] = c.x();
58    data_[MatrixToArrayCoords(1, i)] = c.y();
59    data_[MatrixToArrayCoords(2, i)] = c.z();
60  }
61
62  // Returns an inverse of this if the matrix is non-singular, zero (== Zero())
63  // otherwise.
64  Matrix3F Inverse() const;
65
66  // Value of the determinant of the matrix.
67  float Determinant() const;
68
69  // Trace (sum of diagonal elements) of the matrix.
70  float Trace() const {
71    return data_[MatrixToArrayCoords(0, 0)] +
72        data_[MatrixToArrayCoords(1, 1)] +
73        data_[MatrixToArrayCoords(2, 2)];
74  }
75
76  // Compute eigenvalues and (optionally) normalized eigenvectors of
77  // a positive defnite matrix *this. Eigenvectors are computed only if
78  // non-null |eigenvectors| matrix is passed. If it is NULL, the routine
79  // will not attempt to compute eigenvectors but will still return eigenvalues
80  // if they can be computed.
81  // If eigenvalues cannot be computed (the matrix does not meet constraints)
82  // the 0-vector is returned. Note that to retrieve eigenvalues, the matrix
83  // only needs to be symmetric while eigenvectors require it to be
84  // positive-definite. Passing a non-positive definite matrix will result in
85  // NaNs in vectors which cannot be computed.
86  // Eigenvectors are placed as column in |eigenvectors| in order corresponding
87  // to eigenvalues.
88  Vector3dF SolveEigenproblem(Matrix3F* eigenvectors) const;
89
90 private:
91  Matrix3F();  // Uninitialized default.
92
93  static int MatrixToArrayCoords(int i, int j) {
94    DCHECK(i >= 0 && i < 3);
95    DCHECK(j >= 0 && j < 3);
96    return i * 3 + j;
97  }
98
99  float data_[9];
100};
101
102inline bool operator==(const Matrix3F& lhs, const Matrix3F& rhs) {
103  return lhs.IsEqual(rhs);
104}
105
106}  // namespace gfx
107
108#endif  // UI_GFX_GEOMETRY_MATRIX3_F_H_
109