[2912] | 1 | #include "Polyhedron.h"
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| 2 | #include "common.h"
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| 3 | #include "Polygon3.h"
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| 4 | #include "Plane3.h"
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| 5 |
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| 6 |
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[3021] | 7 | #ifdef _CRT_SET
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| 8 | #define _CRTDBG_MAP_ALLOC
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| 9 | #include <stdlib.h>
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| 10 | #include <crtdbg.h>
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| 11 |
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| 12 | // redefine new operator
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| 13 | #define DEBUG_NEW new(_NORMAL_BLOCK, __FILE__, __LINE__)
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| 14 | #define new DEBUG_NEW
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| 15 | #endif
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| 16 |
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| 17 |
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[2912] | 18 | using namespace std;
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| 19 |
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| 20 |
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| 21 | namespace CHCDemoEngine
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| 22 | {
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| 23 |
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| 24 | static const float epsilon = 1e-6f;
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| 25 |
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[2929] | 26 |
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| 27 |
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[2931] | 28 | /************************************************************/
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| 29 | /* class Polyhedron Implementation */
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| 30 | /************************************************************/
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[2912] | 31 |
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| 32 |
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| 33 | Polyhedron::Polyhedron()
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| 34 | {
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| 35 | mBox.Initialize();
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| 36 | }
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| 37 |
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| 38 |
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| 39 | Polyhedron::Polyhedron(const PolygonContainer &polys)
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| 40 | {
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| 41 | mPolygons = polys;
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| 42 |
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| 43 | mBox.Initialize();
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| 44 | mBox.Include(mPolygons);
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| 45 | }
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| 46 |
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| 47 |
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| 48 | Polyhedron::Polyhedron(const Polyhedron &rhs)
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| 49 | {
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| 50 | mPolygons.reserve(rhs.mPolygons.size());
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| 51 | mBox = rhs.mBox;
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| 52 |
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| 53 | PolygonContainer::const_iterator it, it_end = rhs.mPolygons.end();
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| 54 |
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| 55 | for (it = rhs.mPolygons.begin(); it != it_end; ++ it)
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| 56 | Add(new Polygon3(*(*it)));
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| 57 | }
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| 58 |
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| 59 |
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[2929] | 60 | Polyhedron *Polyhedron::CreatePolyhedron(const vector<Plane3> &planes,
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| 61 | const AxisAlignedBox3 &sceneBox)
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| 62 | {
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| 63 | // add the bounding box
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| 64 | PolygonContainer polygons;
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| 65 | sceneBox.ExtractPolygons(polygons);
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| 66 |
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| 67 | Polyhedron *oldPolyhedron = new Polyhedron(polygons);
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| 68 |
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| 69 | if (!oldPolyhedron->Valid()) cerr << "******************* not valid!! ************* " << endl;
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| 70 |
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| 71 | vector<Plane3>::const_iterator it, it_end = planes.end();
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| 72 |
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| 73 | Polyhedron *newPolyhedron = NULL;
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| 74 |
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| 75 | // intersect bounding box with planes
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| 76 | for (it = planes.begin(); it != it_end; ++ it)
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| 77 | {
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| 78 | Plane3 plane = *it;
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| 79 |
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| 80 | newPolyhedron = oldPolyhedron->CalcIntersection(plane);
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| 81 |
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| 82 | if (!newPolyhedron)
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| 83 | {
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[2944] | 84 | //cerr << "polyhedron not valid or NULL!" << endl;
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[2929] | 85 | return NULL;
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| 86 | }
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| 87 |
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| 88 | DEL_PTR(oldPolyhedron);
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| 89 | oldPolyhedron = newPolyhedron;
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| 90 | }
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| 91 |
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| 92 | return newPolyhedron;
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| 93 | }
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| 94 |
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| 95 |
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[2912] | 96 | Polyhedron::~Polyhedron()
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| 97 | {
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| 98 | CLEAR_CONTAINER(mPolygons);
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| 99 | }
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| 100 |
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| 101 |
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| 102 | int Polyhedron::NumPolygons() const
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| 103 | {
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| 104 | return (int)mPolygons.size();
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| 105 | }
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| 106 |
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| 107 |
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| 108 | void Polyhedron::Add(Polygon3 *p)
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| 109 | {
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| 110 | mPolygons.push_back(p);
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| 111 | mBox.Include(*p);
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| 112 | }
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| 113 |
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| 114 |
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| 115 | const PolygonContainer &Polyhedron::GetPolygons() const
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| 116 | {
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| 117 | return mPolygons;
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| 118 | }
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| 119 |
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| 120 |
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| 121 | float Polyhedron::GetArea() const
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| 122 | {
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| 123 | float area = 0;
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| 124 |
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| 125 | for (size_t i = 0; i < mPolygons.size(); ++ i)
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| 126 | {
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| 127 | area += mPolygons[i]->GetArea();
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| 128 | }
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| 129 |
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| 130 | return area;
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| 131 | }
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| 132 |
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| 133 |
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[2913] | 134 |
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[2912] | 135 | float Polyhedron::GetVolume() const
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| 136 | {
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| 137 | // computes volume by tetrahedralization of the geometry
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| 138 | // We just compute the sum of the tetrahedron volumes
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| 139 | float volume = 0;
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| 140 | const float f = 1.0f / 6.0f;
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| 141 |
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| 142 | PolygonContainer::const_iterator pit, pit_end = mPolygons.end();
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| 143 |
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| 144 | // note: can take arbitrary point, e.g., the origin. However,
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| 145 | // we rather take the center of mass to prevents precision errors
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| 146 | const Vector3 center = CenterOfMass();
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| 147 |
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| 148 | for (pit = mPolygons.begin(); pit != pit_end; ++ pit)
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| 149 | {
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| 150 | Polygon3 *poly = *pit;
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| 151 | const Vector3 v0 = poly->mVertices[0] - center;
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| 152 |
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| 153 | for (int i = 1; i < (int)poly->mVertices.size() - 1; ++ i)
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| 154 | {
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| 155 | const Vector3 v1 = poly->mVertices[i] - center;
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| 156 | const Vector3 v2 = poly->mVertices[i + 1] - center;
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| 157 |
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| 158 | // more robust version using abs and the center of mass
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| 159 | volume += fabs (f * (DotProd(v0, CrossProd(v1, v2))));
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| 160 | }
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| 161 | }
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| 162 |
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| 163 | return volume;
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| 164 | }
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| 165 |
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| 166 |
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| 167 | AxisAlignedBox3 Polyhedron::GetBoundingBox() const
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| 168 | {
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| 169 | return mBox;
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| 170 | }
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| 171 |
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| 172 |
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| 173 | int Polyhedron::Side(const Plane3 &plane) const
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| 174 | {
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| 175 | int boxSide = mBox.Side(plane);
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[2913] | 176 |
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[2912] | 177 | // plane does not intersect bounding box
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| 178 | if (boxSide != 0) return boxSide;
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| 179 |
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| 180 | PolygonContainer::const_iterator it, it_end = mPolygons.end();
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| 181 |
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| 182 | int s = 0;
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| 183 |
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| 184 | for (it = mPolygons.begin(); it != it_end; ++ it)
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| 185 | {
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| 186 | const int side = (*it)->Side(plane, epsilon);
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| 187 |
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[2913] | 188 | if (side == 0) // intersects polygon => intersects
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| 189 | return 0;
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| 190 | else if (side != 0)
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[2912] | 191 | {
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| 192 | if (side == -s)
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| 193 | return 0; // sign changed => intersects
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| 194 |
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| 195 | s = side;
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| 196 | }
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| 197 | }
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| 198 |
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| 199 | return s;
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| 200 | }
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| 201 |
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| 202 |
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| 203 | Vector3 Polyhedron::CenterOfMass() const
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| 204 | {
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| 205 | int n = 0;
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| 206 |
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| 207 | Vector3 center(0,0,0);
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| 208 |
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| 209 | PolygonContainer::const_iterator pit, pit_end = mPolygons.end();
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| 210 |
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| 211 | for (pit = mPolygons.begin(); pit != pit_end; ++ pit)
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| 212 | {
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| 213 | Polygon3 *poly = *pit;
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| 214 |
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| 215 | VertexArray::const_iterator vit, vit_end = poly->mVertices.end();
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| 216 |
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| 217 | for(vit = poly->mVertices.begin(); vit != vit_end; ++ vit)
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| 218 | {
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| 219 | center += *vit;
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| 220 | ++ n;
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| 221 | }
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| 222 | }
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| 223 |
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| 224 | return center / (float)n;
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| 225 | }
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| 226 |
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| 227 |
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| 228 | bool Polyhedron::Valid() const
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| 229 | {
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| 230 | // polyhedron is degenerated
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| 231 | if (mPolygons.size() < 3)
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| 232 | return false;
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[2913] | 233 |
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| 234 | const Vector3 center = CenterOfMass();
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| 235 |
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| 236 | PolygonContainer::const_iterator pit, pit_end = mPolygons.end();
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| 237 |
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| 238 | for (pit = mPolygons.begin(); pit != pit_end; ++ pit)
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| 239 | {
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| 240 | Polygon3 *poly = *pit;
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| 241 | Plane3 plane = poly->GetSupportingPlane();
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| 242 |
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| 243 | float dist = plane.Distance(center);
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| 244 | //cout << "dist: " << dist<< endl;
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| 245 | if (dist > 0)
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| 246 | return false;
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| 247 | }
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| 248 | return true;
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[2912] | 249 | }
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| 250 |
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| 251 |
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| 252 | Polyhedron *Polyhedron::CalcIntersection(const Plane3 &splitPlane) const
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| 253 | {
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| 254 | // first test plane intersection with geometry
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| 255 | const int intersect = Side(splitPlane);
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| 256 |
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| 257 | if (intersect == 1)
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[2913] | 258 | {
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[2912] | 259 | // on the other side of the plane, the intersection is empty
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[2913] | 260 | return NULL;
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| 261 | }
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[2912] | 262 | else if (intersect == -1)
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[2913] | 263 | {
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[2912] | 264 | // does not intersect, just return a copy
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[2913] | 265 | return new Polyhedron(*this);
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| 266 | }
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[2912] | 267 |
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[2913] | 268 | // polyhedron is intersected: create new polyhedron
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| 269 | Polyhedron *clippedPolyhedron = new Polyhedron();
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[2912] | 270 |
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[2913] | 271 |
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[2912] | 272 | //////////
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[2913] | 273 | //-- create and add new polygon to close polyhedron
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[2912] | 274 |
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| 275 | // get cross section of new polygon
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| 276 | Polygon3 *planePoly = mBox.CrossSection(splitPlane);
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| 277 |
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| 278 | // create new face: split polygon with all other polygons
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| 279 | planePoly = SplitPolygon(planePoly);
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| 280 |
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[2943] | 281 | if (planePoly)
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| 282 | {
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| 283 | // we can now savely add the new polygon
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| 284 | clippedPolyhedron->Add(planePoly);
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| 285 | }
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| 286 | else if (0)
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| 287 | {
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| 288 | // something is wrong, probably some numerical error
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| 289 | cerr << "no polygon: should not happen" << endl;
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[2913] | 290 | return new Polyhedron(*this);
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[2912] | 291 | }
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[2943] | 292 |
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[2912] | 293 |
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| 294 | /////////////
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[2913] | 295 | //-- clip polyhedron: plane splits all polygons
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[2912] | 296 |
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[2936] | 297 | for (size_t i = 0; i < mPolygons.size(); ++ i)
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[2912] | 298 | {
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| 299 | Polygon3 *poly = mPolygons[i];
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| 300 |
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| 301 | const int cf = mPolygons[i]->ClassifyPlane(splitPlane, epsilon);
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| 302 |
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| 303 | switch (cf)
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| 304 | {
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| 305 | // split case: split polygon and add it
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| 306 | case Polygon3::SPLIT:
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| 307 | {
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| 308 | Polygon3 *poly = mPolygons[i];
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| 309 |
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| 310 | Polygon3 *frontPoly = new Polygon3();
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| 311 | Polygon3 *backPoly = new Polygon3();
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| 312 |
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| 313 | poly->Split(splitPlane, *frontPoly, *backPoly, epsilon);
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| 314 |
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| 315 | // we are only interested in the polytope behind the plane
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| 316 | DEL_PTR(frontPoly);
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| 317 |
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| 318 | if (backPoly->Valid(epsilon))
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| 319 | clippedPolyhedron->Add(backPoly);
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| 320 | else
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| 321 | DEL_PTR(backPoly);
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| 322 | }
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| 323 |
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| 324 | break;
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| 325 | case Polygon3::BACK_SIDE:
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| 326 | case Polygon3::COINCIDENT:
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| 327 | clippedPolyhedron->Add(new Polygon3(mPolygons[i]->mVertices));
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| 328 | break;
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| 329 | default:
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| 330 | // polygon is not in intersection
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| 331 | break;
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| 332 | }
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| 333 | }
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| 334 |
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| 335 | return clippedPolyhedron;
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| 336 | }
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| 337 |
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| 338 |
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| 339 | Polygon3 *Polyhedron::SplitPolygon(Polygon3 *polygon) const
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| 340 | {
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| 341 | if (!polygon->Valid(epsilon)) DEL_PTR(polygon);
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| 342 |
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| 343 | // polygon is split by all other planes
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| 344 | for (size_t i = 0; (i < mPolygons.size()) && polygon; ++ i)
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| 345 | {
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| 346 | const Plane3 plane = mPolygons[i]->GetSupportingPlane();
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| 347 |
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| 348 | int cf = polygon->ClassifyPlane(plane, epsilon);
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| 349 |
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| 350 | // split new polygon with all previous planes
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| 351 | switch (cf)
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| 352 | {
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| 353 | case Polygon3::SPLIT:
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| 354 | {
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| 355 | Polygon3 *frontPoly = new Polygon3();
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| 356 | Polygon3 *backPoly = new Polygon3();
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| 357 |
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| 358 | polygon->Split(plane, *frontPoly, *backPoly, epsilon);
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| 359 |
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| 360 | // don't need these anymore
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| 361 | DEL_PTR(frontPoly);
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| 362 | DEL_PTR(polygon);
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| 363 |
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| 364 | // back polygon belongs to geometry
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| 365 | if (backPoly->Valid(epsilon))
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| 366 | polygon = backPoly;
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| 367 | else
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| 368 | DEL_PTR(backPoly);
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| 369 | }
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| 370 | break;
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| 371 | case Polygon3::FRONT_SIDE:
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[2943] | 372 | //cerr << "SplitPolygon: should not come here" << endl;
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[2912] | 373 | DEL_PTR(polygon);
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| 374 | break;
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| 375 | // polygon is taken as it is
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| 376 | case Polygon3::BACK_SIDE:
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| 377 | case Polygon3::COINCIDENT:
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| 378 | default:
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| 379 | break;
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| 380 | }
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| 381 | }
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| 382 |
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| 383 | return polygon;
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| 384 | }
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| 385 |
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| 386 |
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| 387 | void Polyhedron::CollectVertices(VertexArray &vertices) const
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| 388 | {
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| 389 | PolygonContainer::const_iterator it, it_end = mPolygons.end();
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| 390 |
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| 391 | for (it = mPolygons.begin(); it != it_end; ++ it)
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| 392 | {
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| 393 | Polygon3 *poly = *it;
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| 394 |
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| 395 | VertexArray::const_iterator vit, vit_end = poly->mVertices.end();
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| 396 |
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| 397 | for (vit = poly->mVertices.begin(); vit != vit_end; ++ vit)
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| 398 | {
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| 399 | vertices.push_back(*vit);
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| 400 | }
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| 401 | }
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| 402 | }
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| 403 |
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| 404 |
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| 405 | }
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