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 "include/core/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 return { a.fX - b.fX, a.fY - b.fY, a.fZ - b.fZ };
82 }
83
84 /** Returns a new point whose coordinates are the sum of a and b (a + b)
85 */
86 friend SkPoint3 operator+(const SkPoint3& a, const SkPoint3& b) {
87 return { a.fX + b.fX, a.fY + b.fY, a.fZ + b.fZ };
88 }
89
90 /** Add v's coordinates to the point's
91 */
92 void operator+=(const SkPoint3& v) {
93 fX += v.fX;
94 fY += v.fY;
95 fZ += v.fZ;
96 }
97
98 /** Subtract v's coordinates from the point's
99 */
100 void operator-=(const SkPoint3& v) {
101 fX -= v.fX;
102 fY -= v.fY;
103 fZ -= v.fZ;
104 }
105
106 friend SkPoint3 operator*(SkScalar t, SkPoint3 p) {
107 return { t * p.fX, t * p.fY, t * p.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 /** Returns the cross product of a and b, treating them as 3D vectors
139 */
140 static SkPoint3 CrossProduct(const SkPoint3& a, const SkPoint3& b) {
141 SkPoint3 result;
142 result.fX = a.fY*b.fZ - a.fZ*b.fY;
143 result.fY = a.fZ*b.fX - a.fX*b.fZ;
144 result.fZ = a.fX*b.fY - a.fY*b.fX;
145
146 return result;
147 }
148
149 SkPoint3 cross(const SkPoint3& vec) const {
150 return CrossProduct(*this, vec);
151 }
152};
153
154typedef SkPoint3 SkVector3;
155typedef SkPoint3 SkColor3f;
156
157#endif
158