comparison: src/geometry/plane.cpp
src/geometry/plane.cpp
- changeset 1390
- 3eace926af7f
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| 1389:3fb8ad4d27b1 | 1390:3eace926af7f |
|---|---|
| 1 /* | |
| 2 * LDForge: LDraw parts authoring CAD | |
| 3 * Copyright (C) 2013 - 2018 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 "plane.h" | |
| 20 | |
| 21 /* | |
| 22 * Constructs a plane from three points | |
| 23 */ | |
| 24 Plane Plane::fromPoints(const Vertex& v1, const Vertex& v2, const Vertex& v3) | |
| 25 { | |
| 26 Plane result; | |
| 27 result.normal = QVector3D::crossProduct(v2 - v1, v3 - v1); | |
| 28 result.point = v1; | |
| 29 return result; | |
| 30 } | |
| 31 | |
| 32 /* | |
| 33 * Returns whether or not this plane is valid. | |
| 34 */ | |
| 35 bool Plane::isValid() const | |
| 36 { | |
| 37 return not normal.isNull(); | |
| 38 } | |
| 39 | |
| 40 /* | |
| 41 * Finds the intersection of a line and a plane. Returns a structure containing whether or not | |
| 42 * there was an intersection as well as the intersected vertex if there was one. Can return a point | |
| 43 * outside of the line segment. | |
| 44 * | |
| 45 * C.f. https://en.wikipedia.org/wiki/Line%E2%80%93plane_intersection#Algebraic_form | |
| 46 */ | |
| 47 Plane::IntersectionResult Plane::intersection(const Line& line) const | |
| 48 { | |
| 49 if (isValid()) | |
| 50 { | |
| 51 QVector3D lineVector = line.v_2 - line.v_1; | |
| 52 qreal dot = QVector3D::dotProduct(lineVector, normal); | |
| 53 | |
| 54 if (not qFuzzyCompare(dot, 0.0)) | |
| 55 { | |
| 56 qreal factor = QVector3D::dotProduct(point - line.v_1, normal) / dot; | |
| 57 IntersectionResult result; | |
| 58 result.intersected = true; | |
| 59 result.vertex = Vertex::fromVector(lineVector * factor + (line.v_1 - Vertex {0, 0, 0})); | |
| 60 return result; | |
| 61 } | |
| 62 else | |
| 63 { | |
| 64 // did not intersect | |
| 65 return {}; | |
| 66 } | |
| 67 } | |
| 68 else | |
| 69 { | |
| 70 // plane is invalid | |
| 71 return {}; | |
| 72 } | |
| 73 } |
