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Serenity Operating System
1/*
2 * Copyright (c) 2020, Shannon Booth <shannon.ml.booth@gmail.com>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <AK/Forward.h>
28#include <LibGfx/Point.h>
29
30namespace Gfx {
31
32class Triangle {
33public:
34 Triangle(Point a, Point b, Point c)
35 : m_a(a)
36 , m_b(b)
37 , m_c(c)
38 {
39 m_det = (m_b.x() - m_a.x()) * (m_c.y() - m_a.y()) - (m_b.y() - m_a.y()) * (m_c.x() - m_a.x());
40 }
41
42 Point a() const { return m_a; }
43 Point b() const { return m_b; }
44 Point c() const { return m_c; }
45
46 bool contains(Point p) const
47 {
48 int x = p.x();
49 int y = p.y();
50
51 int ax = m_a.x();
52 int bx = m_b.x();
53 int cx = m_c.x();
54
55 int ay = m_a.y();
56 int by = m_b.y();
57 int cy = m_c.y();
58
59 if (m_det * ((bx - ax) * (y - ay) - (by - ay) * (x - ax)) <= 0)
60 return false;
61 if (m_det * ((cx - bx) * (y - by) - (cy - by) * (x - bx)) <= 0)
62 return false;
63 if (m_det * ((ax - cx) * (y - cy) - (ay - cy) * (x - cx)) <= 0)
64 return false;
65 return true;
66 }
67
68 String to_string() const;
69
70private:
71 int m_det;
72 Point m_a;
73 Point m_b;
74 Point m_c;
75};
76
77const LogStream& operator<<(const LogStream&, const Triangle&);
78
79}