ScummVM API documentation
Line.h
1/* ScummVM - Graphic Adventure Engine
2 *
3 * ScummVM is the legal property of its developers, whose names
4 * are too numerous to list here. Please refer to the COPYRIGHT
5 * file distributed with this source distribution.
6 *
7 * This program is free software: you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, either version 3 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program. If not, see <http://www.gnu.org/licenses/>.
19 *
20 */
21
22/*
23 * This code is based on the CRAB engine
24 *
25 * Copyright (c) Arvind Raja Yadav
26 *
27 * Licensed under MIT
28 *
29 */
30
31#ifndef CRAB_LINE_H
32#define CRAB_LINE_H
33
34#include "crab/vectors.h"
35
36namespace Crab {
37
38// Find if 2 lines intersect and store the point of intersection
39template<typename T>
40bool collideLine(const T &p0X, const T &p0Y, const T &p1X, const T &p1Y,
41 const T &p2X, const T &p2Y, const T &p3X, const T &p3Y,
42 T *x = nullptr, T *y = nullptr) {
43 Vector2D<T> s1, s2;
44 s1.x = p1X - p0X;
45 s1.y = p1Y - p0Y;
46 s2.x = p3X - p2X;
47 s2.y = p3Y - p2Y;
48
49 float d = (-s2.x * s1.y + s1.x * s2.y);
50
51 if (d != 0) {
52 float s, t;
53 s = (-s1.y * (p0X - p2X) + s1.x * (p0Y - p2Y)) / d;
54 t = (s2.x * (p0Y - p2Y) - s2.y * (p0X - p2X)) / d;
55
56 if (s >= 0 && s <= 1 && t >= 0 && t <= 1) {
57 // Collision detected
58 if (x != nullptr)
59 *x = p0X + (t * s1.x);
60 if (y != nullptr)
61 *y = p0Y + (t * s1.y);
62
63 return true;
64 }
65 }
66
67 return false; // No collision
68}
69
70} // End of namespace Crab
71
72#endif // CRAB_LINE_H