[191] | 1 | #include "Triangle3.h"
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[1328] | 2 | #include "Ray.h"
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| 3 | #include "AxisAlignedBox3.h"
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[1344] | 4 | #include "Containers.h"
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| 5 | #include "Polygon3.h"
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[191] | 6 |
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[1328] | 7 |
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[863] | 8 | namespace GtpVisibilityPreprocessor {
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[860] | 9 |
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[1328] | 10 |
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| 11 | Triangle3::Triangle3(const Vector3 &a, const Vector3 &b, const Vector3 &c)
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[191] | 12 | {
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[1328] | 13 | Init(a, b, c);
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[191] | 14 | }
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[860] | 15 |
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[1328] | 16 |
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| 17 | void Triangle3::Init(const Vector3 &a, const Vector3 &b, const Vector3 &c)
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| 18 | {
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| 19 | mVertices[0] = a;
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| 20 | mVertices[1] = b;
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| 21 | mVertices[2] = c;
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| 22 | }
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| 23 |
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| 24 |
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| 25 | float Triangle3::GetSpatialAngle(const Vector3 &point) const
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| 26 | {
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| 27 | return 0.0f;
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| 28 | }
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| 29 |
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| 30 |
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[1344] | 31 | int Triangle3::CastRay(const Ray &ray, float &t, const float nearestT, Vector3 &normal) const
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[1328] | 32 | {
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[1420] | 33 | #if 0
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| 34 | VertexContainer vertices;
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[1344] | 35 | vertices.push_back(mVertices[0]);
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| 36 | vertices.push_back(mVertices[1]);
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| 37 | vertices.push_back(mVertices[2]);
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| 38 |
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| 39 | Polygon3 poly(vertices);
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| 40 |
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| 41 | int dummy = poly.CastRay(ray, t, nearestT);
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| 42 |
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[1420] | 43 | cout << "polyversion code: " << dummy << " t: " << t << " nearestT: " << nearestT << endl;
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| 44 | return dummy;
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| 45 | #endif
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| 46 |
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| 47 | //////////////
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| 48 | // specialised triangle ray casting version
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[1586] | 49 | // using ray-plane intersection
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[1344] | 50 |
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[1328] | 51 | // get triangle edge vectors and plane normal
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[1344] | 52 | const Vector3 u = mVertices[0] - mVertices[1];
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| 53 | const Vector3 v = mVertices[2] - mVertices[1];
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[1328] | 54 |
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[1420] | 55 | // cross product
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| 56 | normal = Normalize(CrossProd(v, u));
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[1328] | 57 |
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[1420] | 58 | // ray direction vector
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| 59 | const Vector3 dir = ray.GetDir();
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[1344] | 60 | const Vector3 w0 = ray.GetLoc() - mVertices[1];
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[1328] | 61 |
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| 62 | // params to calc ray-plane intersect
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[1344] | 63 | const float a = -DotProd(normal, w0);
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| 64 | const float b = DotProd(normal, dir);
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[1328] | 65 |
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[1344] | 66 | // check for division by zero
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[1328] | 67 | if (fabs(b) < Limits::Small)
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| 68 | {
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| 69 | // ray is parallel to triangle plane
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[1420] | 70 | if (a == 0)
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[1328] | 71 | {
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[1420] | 72 | // ray lies in triangle plane
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[1328] | 73 | return Ray::INTERSECTION_OUT_OF_LIMITS;
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| 74 | }
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| 75 | else
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| 76 | {
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[1420] | 77 | // ray disjoint from plane
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| 78 | return Ray::NO_INTERSECTION;
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[1328] | 79 | }
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| 80 | }
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| 81 |
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[1344] | 82 | // distance from origin of ray to plane
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[1328] | 83 | t = a / b;
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| 84 |
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| 85 | if (t < 0.0) // ray goes away from triangle
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| 86 | {
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[1344] | 87 | return Ray::NO_INTERSECTION; // => no intersect
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[1328] | 88 | }
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[1344] | 89 | // already found nearer intersection
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| 90 | else if ((ray.GetType() == Ray::LOCAL_RAY) && (t >= nearestT))
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| 91 | {
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| 92 | return Ray::NO_INTERSECTION;
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| 93 | }
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[1328] | 94 |
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[1420] | 95 | /////////////////
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[1344] | 96 | //-- found intersection point
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| 97 | //-- check if it is inside triangle
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| 98 |
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| 99 | const Vector3 pt = ray.GetLoc() + t * dir;
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[1421] | 100 | #if _DEBUG
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[1420] | 101 | if (!pt.CheckValidity())
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| 102 | {
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| 103 | cout << "tr: " << *this << endl;
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| 104 | cout << "v: " << pt << " t: " << t << " a: " << a << " b: " << b << " n: " << normal << endl;
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| 105 | }
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[1421] | 106 | #endif
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[1344] | 107 | const Vector3 w = pt - mVertices[1];
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[1328] | 108 |
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| 109 | const float uu = DotProd(u, u);
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| 110 | const float uv = DotProd(u, v);
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| 111 | const float vv = DotProd(v, v);
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| 112 |
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| 113 | const float wu = DotProd(w, u);
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| 114 | const float wv = DotProd(w, v);
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| 115 | const float D = uv * uv - uu * vv;
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| 116 |
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| 117 | // get and test parametric coords
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| 118 | const float s = (uv * wv - vv * wu) / D;
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| 119 |
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[1344] | 120 | if ((s < 0.0) || (s > 1.0)) // pt is outside triangle
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| 121 | {
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[1328] | 122 | return Ray::NO_INTERSECTION;
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| 123 | }
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| 124 |
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| 125 | const float s2 = (uv * wu - uu * wv) / D;
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| 126 |
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[1344] | 127 | if ((s2 < 0.0) || ((s + s2) > 1.0)) // pt is outside triangle
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| 128 | {
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[1328] | 129 | return Ray::NO_INTERSECTION;
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| 130 | }
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| 131 |
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| 132 | return Ray::INTERSECTION; // I is in T
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| 133 | }
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| 134 |
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| 135 |
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| 136 | AxisAlignedBox3 Triangle3::GetBoundingBox() const
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| 137 | {
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| 138 | AxisAlignedBox3 box;
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| 139 | box.Initialize();
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| 140 |
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| 141 | box.Include(mVertices[0]);
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| 142 | box.Include(mVertices[1]);
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| 143 | box.Include(mVertices[2]);
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| 144 |
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| 145 | return box;
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| 146 | }
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| 147 |
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| 148 |
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| 149 | Vector3 Triangle3::GetNormal() const
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| 150 | {
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| 151 | const Vector3 v1 = mVertices[0] - mVertices[1];
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[1344] | 152 | const Vector3 v2 = mVertices[2] - mVertices[1];
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[1328] | 153 |
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| 154 | return Normalize(CrossProd(v2, v1));
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| 155 | }
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| 156 |
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| 157 |
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| 158 | Vector3 Triangle3::GetCenter() const
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| 159 | {
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| 160 | return (mVertices[0] + mVertices[1] + mVertices[2]) / 3.0f;
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| 161 | }
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| 162 |
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| 163 |
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| 164 | float Triangle3::GetArea() const
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| 165 | {
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[1344] | 166 | Vector3 v1 = mVertices[0] - mVertices[1], v2=mVertices[2] - mVertices[1];
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[1328] | 167 | return 0.5f * Magnitude(CrossProd(v2, v1));
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| 168 | }
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| 169 |
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| 170 |
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[1420] | 171 | bool Triangle3::CheckValidity() const
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| 172 | {
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| 173 | return !(
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| 174 | EpsilonEqualV3(mVertices[0], mVertices[1]) ||
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| 175 | EpsilonEqualV3(mVertices[0], mVertices[2]) ||
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| 176 | EpsilonEqualV3(mVertices[1], mVertices[2])
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| 177 | );
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| 178 | }
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| 179 |
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[860] | 180 | } |
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