1/*
2 * Copyright 2015 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkPoint3_DEFINED
9#define SkPoint3_DEFINED
10
11#include "SkPoint.h"
12
13struct SK_API SkPoint3 {
14    SkScalar fX, fY, fZ;
15
16    static SkPoint3 Make(SkScalar x, SkScalar y, SkScalar z) {
17        SkPoint3 pt;
18        pt.set(x, y, z);
19        return pt;
20    }
21
22    SkScalar x() const { return fX; }
23    SkScalar y() const { return fY; }
24    SkScalar z() const { return fZ; }
25
26    void set(SkScalar x, SkScalar y, SkScalar z) { fX = x; fY = y; fZ = z; }
27
28    friend bool operator==(const SkPoint3& a, const SkPoint3& b) {
29        return a.fX == b.fX && a.fY == b.fY && a.fZ == b.fZ;
30    }
31
32    friend bool operator!=(const SkPoint3& a, const SkPoint3& b) {
33        return !(a == b);
34    }
35
36    /** Returns the Euclidian distance from (0,0,0) to (x,y,z)
37    */
38    static SkScalar Length(SkScalar x, SkScalar y, SkScalar z);
39
40    /** Return the Euclidian distance from (0,0,0) to the point
41    */
42    SkScalar length() const { return SkPoint3::Length(fX, fY, fZ); }
43
44    /** Set the point (vector) to be unit-length in the same direction as it
45        already points.  If the point has a degenerate length (i.e., nearly 0)
46        then set it to (0,0,0) and return false; otherwise return true.
47    */
48    bool normalize();
49
50    /** Return a new point whose X, Y and Z coordinates are scaled.
51    */
52    SkPoint3 makeScale(SkScalar scale) const {
53        SkPoint3 p;
54        p.set(scale * fX, scale * fY, scale * fZ);
55        return p;
56    }
57
58    /** Scale the point's coordinates by scale.
59    */
60    void scale(SkScalar value) {
61        fX *= value;
62        fY *= value;
63        fZ *= value;
64    }
65
66    /** Return a new point whose X, Y and Z coordinates are the negative of the
67        original point's
68    */
69    SkPoint3 operator-() const {
70        SkPoint3 neg;
71        neg.fX = -fX;
72        neg.fY = -fY;
73        neg.fZ = -fZ;
74        return neg;
75    }
76
77    /** Returns a new point whose coordinates are the difference between
78        a and b (i.e., a - b)
79    */
80    friend SkPoint3 operator-(const SkPoint3& a, const SkPoint3& b) {
81        SkPoint3 v;
82        v.set(a.fX - b.fX, a.fY - b.fY, a.fZ - b.fZ);
83        return v;
84    }
85
86    /** Returns a new point whose coordinates are the sum of a and b (a + b)
87    */
88    friend SkPoint3 operator+(const SkPoint3& a, const SkPoint3& b) {
89        SkPoint3 v;
90        v.set(a.fX + b.fX, a.fY + b.fY, a.fZ + b.fZ);
91        return v;
92    }
93
94    /** Add v's coordinates to the point's
95    */
96    void operator+=(const SkPoint3& v) {
97        fX += v.fX;
98        fY += v.fY;
99        fZ += v.fZ;
100    }
101
102    /** Subtract v's coordinates from the point's
103    */
104    void operator-=(const SkPoint3& v) {
105        fX -= v.fX;
106        fY -= v.fY;
107        fZ -= v.fZ;
108    }
109
110    /** Returns true if fX, fY, and fZ are measurable values.
111
112     @return  true for values other than infinities and NaN
113     */
114    bool isFinite() const {
115        SkScalar accum = 0;
116        accum *= fX;
117        accum *= fY;
118        accum *= fZ;
119
120        // accum is either NaN or it is finite (zero).
121        SkASSERT(0 == accum || SkScalarIsNaN(accum));
122
123        // value==value will be true iff value is not NaN
124        // TODO: is it faster to say !accum or accum==accum?
125        return !SkScalarIsNaN(accum);
126    }
127
128    /** Returns the dot product of a and b, treating them as 3D vectors
129    */
130    static SkScalar DotProduct(const SkPoint3& a, const SkPoint3& b) {
131        return a.fX * b.fX + a.fY * b.fY + a.fZ * b.fZ;
132    }
133
134    SkScalar dot(const SkPoint3& vec) const {
135        return DotProduct(*this, vec);
136    }
137};
138
139typedef SkPoint3 SkVector3;
140typedef SkPoint3 SkColor3f;
141
142#endif
143