aboutsummaryrefslogtreecommitdiffstats
path: root/dev/MinGfx/src/point3.h
blob: 50783f03235a6a76ed0456b8916f2525604142d1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
/*
 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_POINT3_H_
#define SRC_POINT3_H_

#include <iostream>
#include <vector>

namespace mingfx {

/// Epsilon value used for == and != comparisons within MinGfx
#define MINGFX_MATH_EPSILON 1e-8

// forward declaration
class Vector3;
    
    
/** A 3D Point with floating point coordinates, used for storing vertices and
 all sorts of other 3D graphics operations.  Point3s can be transformed by a
 Matrix4.  Example:
 ~~~
 Point3 a(0,0,1);
 std::cout << a << std::endl;

 Matrix4 M = Matrix4::Translation(Vector3(0,0,-1));
 Point3 b = M * a;
 std::cout << b << std::endl;
 
 // you can access the individual components of the point in two ways:
 Point3 p(1,2,3);
 float option1 = p.x();
 float option2 = p[0];

 // to set an individual component of the point use the [] operator:
 Point3 p2;
 p2[0] = 0.4;
 p2[1] = 1.2;
 p2[2] = 3.1;
 ~~~
 */
class Point3 {
public:  
    /// Default point at the origin
    Point3();

    /// Constructs a point given (x,y,z,1), where the 1 comes from the use of
    /// homogeneous coordinates in computer graphics.
    Point3(float x, float y, float z);

    /// Constructs a point given a pointer to x,y,z data
    Point3(float *p);

    /// Copy constructor for point
    Point3(const Point3& p);

    /// Point destructor
    virtual ~Point3();

    /// Check for "equality", taking floating point imprecision into account
    bool operator==(const Point3& p) const;

    /// Check for "inequality", taking floating point imprecision into account
    bool operator!=(const Point3& p) const;

    /// Assignment operator
    Point3& operator=(const Point3& 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:
    /// ~~~
    /// Point3 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]; }
    
    /// Read only access to the z coordinate.  Can also use my_point[2].  Use
    /// the my_point[2] = 1.0; form if you need to set the value.
    float z() const { return p[2]; }
    
    /// 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.
    Point3 Lerp(const Point3 &b, float alpha) const;

    /// Returns the shortest (i.e., perpendicular) distance from this point to
    /// a plane defined by a point and a normal.
    float DistanceToPlane(const Point3 &plane_origin, const Vector3 &plane_normal);

    /// Returns the perpendicular projection of this point onto a plane defined
    /// by a point and a normal.
    Point3 ClosestPointOnPlane(const Point3 &plane_origin, const Vector3 &plane_normal);

    /// Given a list of points, returns the closest in the last to the current point.
    Point3 ClosestPoint(const std::vector<Point3> &point_list);
    
    
    
    /// (0,0,0) - a shortcut for a special point that is frequently needed
    static const Point3& Origin();

    /// (0,0,0) - a shortcut for a special point that is frequently needed
    static const Point3& Zero();
    
    /// (1,1,1) - a shortcut for a special point that is frequently needed
    static const Point3& One();
    
    /// Linear interpolation between two points.  Alpha=0.0 returns 'a' and
    /// alpha=1.0 returns 'b', other values blend between the two.
    static Point3 Lerp(const Point3 &a, const Point3 &b, float alpha);
    
    
    
private:
    float p[3];
};


std::ostream & operator<< ( std::ostream &os, const Point3 &p);
std::istream & operator>> ( std::istream &is, Point3 &p);


} // namespace
 
#endif