| 1 | /* |
| 2 | * Copyright (C) 2008 Patrik Gornicz, Gornicz_P (at) hotmail (dot) com. |
| 3 | * |
| 4 | * This program is free software: you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation, either version 3 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 16 | */ |
| 17 | |
| 18 | #include "mathw.h" |
| 19 | |
| 20 | |
| 21 | /// ***** Public Methods ***** |
| 22 | |
| 23 | int mod(int x, int y) |
| 24 | { |
| 25 | return x % y + (x < 0 ? y : 0); |
| 26 | } |
| 27 | |
| 28 | // Vector2 Math |
| 29 | |
| 30 | Vector2 vectorToLine |
| 31 | ( |
| 32 | const Vector2& vec, |
| 33 | float x1, |
| 34 | float y1, |
| 35 | float x2, |
| 36 | float y2 |
| 37 | ) |
| 38 | { |
| 39 | float lineSize = (float) sqrt((x1 - x2) * (x1 - x2) |
| 40 | + (y1 - y2) * (y1 - y2)); |
| 41 | if (lineSize == 0) |
| 42 | return Vector2(x1 - vec.x, y1 - vec.y); |
| 43 | |
| 44 | float u = ((vec.x - x1) * (x2 - x1) |
| 45 | + (vec.y - y1) * (y2 - y1)) / (lineSize * lineSize); |
| 46 | |
| 47 | if (u < 0) |
| 48 | return Vector2(x1 - vec.x, y1 - vec.y); |
| 49 | else if (u > 1) |
| 50 | return Vector2(x2 - vec.x, y2 - vec.y); |
| 51 | else |
| 52 | { |
| 53 | float ix = x1 + u * (x2 - x1); |
| 54 | float iy = y1 + u * (y2 - y1); |
| 55 | return Vector2(ix - vec.x, iy - vec.y); |
| 56 | } |
| 57 | } |
| 58 | |
| 59 | Vector2 perp(const Vector2& vec) |
| 60 | { |
| 61 | return Vector2(-vec.y, vec.x); |
| 62 | } |
| 63 | |
| 64 | float dot(const Vector2& vec1, const Vector2& vec2) |
| 65 | { |
| 66 | return vec1.x * vec2.x + vec1.y * vec2.y; |
| 67 | } |
| 68 | |
| 69 | //TODO float Vector2::projectionCoeff(const Vector2* vec) const; |
| 70 | //TODO Vector2* Vector2::projection(const Vector2* vec) const; |
| 71 | |