comparison: src/matrix.cpp
src/matrix.cpp
- changeset 33
- 4c41bfe2ec6e
- parent 32
- 767592024ec5
- child 34
- 1de2b8d64e9f
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| 32:767592024ec5 | 33:4c41bfe2ec6e |
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| 1 /* | |
| 2 * LDForge: LDraw parts authoring CAD | |
| 3 * Copyright (C) 2013 - 2020 Teemu Piippo | |
| 4 * | |
| 5 * This program is free software: you can redistribute it and/or modify | |
| 6 * it under the terms of the GNU General Public License as published by | |
| 7 * the Free Software Foundation, either version 3 of the License, or | |
| 8 * (at your option) any later version. | |
| 9 * | |
| 10 * This program is distributed in the hope that it will be useful, | |
| 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 13 * GNU General Public License for more details. | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License | |
| 16 * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
| 17 */ | |
| 18 | |
| 19 #include "matrix.h" | |
| 20 #include "vertex.h" | |
| 21 | |
| 22 Matrix4x4 combine(const Matrix3x3& topLeft, const Point3D& translation) | |
| 23 { | |
| 24 return {{ | |
| 25 {topLeft(0, 0), topLeft(0, 1), topLeft(0, 2), translation.x}, | |
| 26 {topLeft(1, 0), topLeft(1, 1), topLeft(1, 2), translation.y}, | |
| 27 {topLeft(2, 0), topLeft(2, 1), topLeft(2, 2), translation.z}, | |
| 28 {0, 0, 0, 1} | |
| 29 }}; | |
| 30 } | |
| 31 | |
| 32 /* | |
| 33 * Computes the determinant of a 3×3 matrix with each variable passed in row-major order. | |
| 34 */ | |
| 35 qreal math::det(qreal a, qreal b, qreal c, qreal d, qreal e, qreal f, qreal g, qreal h, qreal i) | |
| 36 { | |
| 37 return a*e*i + b*f*g + c*d*h - a*f*h - b*d*i - c*e*g; | |
| 38 } | |
| 39 | |
| 40 /* | |
| 41 * Computes the determinant of a 2×2 matrix. | |
| 42 */ | |
| 43 qreal math::det(const Matrix<2, 2>& matrix) | |
| 44 { | |
| 45 return matrix(0, 0) * matrix(1, 1) - matrix(0, 1) * matrix(1, 0); | |
| 46 } | |
| 47 | |
| 48 /* | |
| 49 * Computes the determinant of a 3×3 matrix. | |
| 50 */ | |
| 51 qreal math::det(const Matrix3x3& matrix) | |
| 52 { | |
| 53 return math::sum( | |
| 54 +matrix(0, 0) * matrix(1, 1) * matrix(2, 2), | |
| 55 -matrix(0, 0) * matrix(1, 2) * matrix(2, 1), | |
| 56 -matrix(0, 1) * matrix(1, 0) * matrix(2, 2), | |
| 57 +matrix(0, 1) * matrix(1, 2) * matrix(2, 0), | |
| 58 +matrix(0, 2) * matrix(1, 0) * matrix(2, 1), | |
| 59 -matrix(0, 2) * matrix(1, 1) * matrix(2, 0)); | |
| 60 } | |
| 61 | |
| 62 /* | |
| 63 * Computes the determinant of a 4×4 matrix. | |
| 64 */ | |
| 65 qreal math::det(const Matrix4x4& matrix) | |
| 66 { | |
| 67 qreal sum = 0; | |
| 68 | |
| 69 for (int column : {0, 1, 2, 3}) | |
| 70 { | |
| 71 int column_1 = (column >= 1) ? 0 : 1; | |
| 72 int column_2 = (column >= 2) ? 1 : 2; | |
| 73 int column_3 = (column >= 3) ? 2 : 3; | |
| 74 sum += ((column % 1) ? -1 : 1) * math::det( | |
| 75 matrix(1, column_1), matrix(1, column_2), matrix(1, column_3), | |
| 76 matrix(2, column_1), matrix(2, column_2), matrix(2, column_3), | |
| 77 matrix(3, column_1), matrix(3, column_2), matrix(3, column_3)); | |
| 78 } | |
| 79 | |
| 80 return sum; | |
| 81 } |
