[167] | 1 | #include "Ray.h"
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[162] | 2 | #include "Mesh.h"
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| 3 |
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| 4 | int MeshInstance::mailID = 21843194198;
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| 5 |
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| 6 | void
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| 7 | Mesh::Preprocess()
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| 8 | {
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| 9 | mBoundingBox.Initialize();
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| 10 |
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| 11 | VertexContainer::const_iterator vi = mVertices.begin();
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| 12 | for (; vi != mVertices.end(); vi++) {
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| 13 | mBoundingBox.Include(*vi);
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| 14 | }
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| 15 |
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| 16 | mIsConvex = false;
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| 17 | }
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| 18 |
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| 19 |
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| 20 | int
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| 21 | Mesh::CastRay(
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| 22 | Ray &ray,
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| 23 | MeshInstance *instance
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| 24 | )
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| 25 | {
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| 26 | FaceContainer::const_iterator fi;
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| 27 | int faceIndex = 0;
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| 28 | int hits = 0;
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| 29 | float nearestT = MAX_FLOAT;
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| 30 | float nearestFace;
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| 31 |
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| 32 | if (ray.GetType() == Ray::LOCAL_RAY && ray.intersections.size())
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| 33 | nearestT = ray.intersections[0].mT;
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| 34 |
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| 35 |
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| 36 | for ( ;
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| 37 | faceIndex < mFaces.size();
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| 38 | faceIndex++) {
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| 39 | float t;
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| 40 | if (RayFaceIntersection(faceIndex, ray, t, nearestT) == Ray::INTERSECTION) {
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| 41 | switch (ray.GetType()) {
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| 42 | case Ray::GLOBAL_RAY:
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| 43 | ray.intersections.push_back(Ray::RayIntersection(t, instance, faceIndex));
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| 44 | hits++;
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| 45 | break;
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| 46 | case Ray::LOCAL_RAY:
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| 47 | hits++;
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| 48 | nearestT = t;
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| 49 | nearestFace = faceIndex;
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| 50 | break;
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| 51 | }
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| 52 | }
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| 53 | }
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| 54 |
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| 55 | if ( hits && ray.GetType() == Ray::LOCAL_RAY ) {
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| 56 | if (ray.intersections.size())
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| 57 | ray.intersections[0] = Ray::RayIntersection(nearestT, instance, nearestFace);
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| 58 | else
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| 59 | ray.intersections.push_back(Ray::RayIntersection(nearestT, instance, nearestFace));
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| 60 | }
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| 61 |
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| 62 | return hits;
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| 63 | }
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| 64 |
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| 65 |
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| 66 | // int_lineseg returns 1 if the given line segment intersects a 2D
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| 67 | // ray travelling in the positive X direction. This is used in the
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| 68 | // Jordan curve computation for polygon intersection.
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| 69 | inline int
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| 70 | int_lineseg(float px,
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| 71 | float py,
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| 72 | float u1,
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| 73 | float v1,
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| 74 | float u2,
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| 75 | float v2)
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| 76 | {
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| 77 | float t;
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| 78 | float ydiff;
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| 79 |
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| 80 | u1 -= px; u2 -= px; // translate line
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| 81 | v1 -= py; v2 -= py;
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| 82 |
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| 83 | if ((v1 > 0 && v2 > 0) ||
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| 84 | (v1 < 0 && v2 < 0) ||
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| 85 | (u1 < 0 && u2 < 0))
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| 86 | return 0;
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| 87 |
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| 88 | if (u1 > 0 && u2 > 0)
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| 89 | return 1;
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| 90 |
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| 91 | ydiff = v2 - v1;
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| 92 | if (fabs(ydiff) < Limits::Small) { // denominator near 0
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| 93 | if (((fabs(v1) > Limits::Small) ||
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| 94 | (u1 > 0) || (u2 > 0)))
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| 95 | return 0;
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| 96 | return 1;
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| 97 | }
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| 98 |
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| 99 | t = -v1 / ydiff; // Compute parameter
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| 100 |
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| 101 | return (u1 + t * (u2 - u1)) > 0;
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| 102 | }
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| 103 |
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| 104 |
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| 105 |
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| 106 | // intersection with the polygonal face of the mesh
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| 107 | int
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| 108 | Mesh::RayFaceIntersection(const int faceIndex,
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| 109 | const Ray &ray,
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| 110 | float &t,
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| 111 | const float nearestT
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| 112 | )
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| 113 | {
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| 114 | Face *face = mFaces[faceIndex];
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| 115 |
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| 116 | Plane3 plane = GetFacePlane(faceIndex);
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| 117 | float dot = DotProd(plane.mNormal, ray.GetDir());
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| 118 |
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| 119 | // Watch for near-zero denominator
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| 120 | // ONLY single sided polygons!!!!!
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| 121 | if (dot > -Limits::Small)
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| 122 | // if (fabs(dot) < Limits::Small)
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| 123 | return Ray::NO_INTERSECTION;
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| 124 |
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| 125 | t = (-plane.mD - DotProd(plane.mNormal, ray.GetLoc())) / dot;
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| 126 |
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| 127 | if (t <= Limits::Small)
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| 128 | return Ray::INTERSECTION_OUT_OF_LIMITS;
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| 129 |
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| 130 | if (t >= nearestT) {
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| 131 | return Ray::INTERSECTION_OUT_OF_LIMITS; // no intersection was found
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| 132 | }
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| 133 |
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| 134 | int count = 0;
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| 135 | float u, v, u1, v1, u2, v2;
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| 136 | int i;
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| 137 |
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| 138 | int paxis = plane.mNormal.DrivingAxis();
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| 139 |
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| 140 | // Project the intersection point onto the coordinate plane
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| 141 | // specified by which.
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| 142 | ray.Extrap(t).ExtractVerts(&u, &v, paxis);
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| 143 |
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| 144 |
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| 145 | mVertices[face->mVertexIndices[face->mVertexIndices.size() - 1]].
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| 146 | ExtractVerts(&u1, &v1, paxis );
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| 147 |
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| 148 | if (mIsConvex) {
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| 149 | // assume a convex face
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| 150 | for (i = 0; i < face->mVertexIndices.size(); i++) {
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| 151 | mVertices[face->mVertexIndices[i]].ExtractVerts(&u2, &v2, paxis);
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| 152 | // line u1, v1, u2, v2
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| 153 | if ((v2 - v1)*(u1 - u) > (u2 - u1)*(v1 - v))
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| 154 | return Ray::NO_INTERSECTION;
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| 155 | u1 = u2;
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| 156 | v1 = v2;
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| 157 | }
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| 158 |
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| 159 | return Ray::INTERSECTION;
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| 160 | }
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| 161 |
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| 162 | // We're stuck with the Jordan curve computation. Count number
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| 163 | // of intersections between the line segments the polygon comprises
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| 164 | // with a ray originating at the point of intersection and
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| 165 | // travelling in the positive X direction.
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| 166 | for (i = 0; i < face->mVertexIndices.size(); i++) {
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| 167 | mVertices[face->mVertexIndices[i]].ExtractVerts(&u2, &v2, paxis);
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| 168 | count += (int_lineseg(u, v, u1, v1, u2, v2) != 0);
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| 169 | u1 = u2;
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| 170 | v1 = v2;
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| 171 | }
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| 172 |
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| 173 | // We hit polygon if number of intersections is odd.
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| 174 | return (count & 1) ? Ray::INTERSECTION : Ray::NO_INTERSECTION;
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| 175 | }
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| 176 |
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| 177 |
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| 178 | int
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| 179 | MeshInstance::CastRay(
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| 180 | Ray &ray
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| 181 | )
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| 182 | {
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| 183 | int res = mMesh->CastRay(ray, this);
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| 184 | return res;
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| 185 | }
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| 186 |
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| 187 |
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| 188 | Plane3
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| 189 | Mesh::GetFacePlane(const int faceIndex)
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| 190 | {
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| 191 | Face *face = mFaces[faceIndex];
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| 192 | return Plane3(mVertices[face->mVertexIndices[0]],
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| 193 | mVertices[face->mVertexIndices[1]],
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| 194 | mVertices[face->mVertexIndices[2]]);
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| 195 | }
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| 196 |
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| 197 | int
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| 198 | MeshTransformedInstance::CastRay(
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| 199 | Ray &ray
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| 200 | )
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| 201 | {
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| 202 | ray.ApplyTransform(Invert(mWorldTransform));
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| 203 | int res = mMesh->CastRay(ray, this);
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| 204 | ray.ApplyTransform(mWorldTransform);
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| 205 |
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| 206 | return res;
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| 207 | }
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