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      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 "SkScalar.h"
     12 
     13 struct 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 the dot product of a and b, treating them as 3D vectors
    111     */
    112     static SkScalar DotProduct(const SkPoint3& a, const SkPoint3& b) {
    113         return a.fX * b.fX + a.fY * b.fY + a.fZ * b.fZ;
    114     }
    115 
    116     SkScalar dot(const SkPoint3& vec) const {
    117         return DotProduct(*this, vec);
    118     }
    119 };
    120 
    121 typedef SkPoint3 SkVector3;
    122 typedef SkPoint3 SkColor3f;
    123 
    124 #endif
    125