From f6b42772ebb1266c243a567ee81b36092302b953 Mon Sep 17 00:00:00 2001 From: ganovelli Date: Thu, 22 Jan 2009 14:34:27 +0000 Subject: [PATCH] added IntersectionLineTriangle --- vcg/space/intersection3.h | 213 +++++++++++++------------------------- 1 file changed, 71 insertions(+), 142 deletions(-) diff --git a/vcg/space/intersection3.h b/vcg/space/intersection3.h index f744846a..3c44f455 100644 --- a/vcg/space/intersection3.h +++ b/vcg/space/intersection3.h @@ -434,152 +434,80 @@ namespace vcg { ); } - - // ray-triangle, gives barycentric coords of intersection and distance along ray +#endif + + /* + * Function computing the intersection between a line and a triangle. + * from: + * Tomas Möller and Ben Trumbore, + * ``Fast, Minimum Storage Ray-Triangle Intersection'', + * journal of graphics tools, vol. 2, no. 1, pp. 21-28, 1997 + * @param[in] line + * @param[in] triangle vertices + * @param[out] intersection the intersection point, meaningful only if the line intersects the triangle + * + */ + template -bool Intersection( const Line3 & ray, const Point3 & vert0, +bool IntersectionLineTriangle( const Line3 & line, const Point3 & vert0, const Point3 & vert1, const Point3 & vert2, - T & a ,T & b, T & dist) -{ - // small (hum) borders around triangle - const T EPSILON2= T(1e-8); - - const T EPSILON = T(1e-8); - - Point3 edge1 = vert1 - vert0; - Point3 edge2 = vert2 - vert0; + T & t ,T & u, T & v) +{ + #define EPSIL 0.000001 + + vcg::Point3 edge1, edge2, tvec, pvec, qvec; + T det,inv_det; + + /* find vectors for two edges sharing vert0 */ + edge1 = vert1 - vert0; + edge2 = vert2 - vert0; + + /* begin calculating determinant - also used to calculate U parameter */ + pvec = line.Direction() ^ edge2; + + /* if determinant is near zero, line lies in plane of triangle */ + det = edge1 * pvec; + + /* calculate distance from vert0 to line origin */ + tvec = line.Origin() - vert0; + inv_det = 1.0 / det; + + qvec = tvec ^ edge1; + + if (det > EPSIL) + { + u = tvec * pvec ; + if ( u < 0.0 || u > det) + return 0; + + /* calculate V parameter and test bounds */ + v = line.Direction() * qvec; + if ( v < 0.0 || u + v > det) + return 0; + + } + else if(det < -EPSIL) + { + /* calculate U parameter and test bounds */ + u = tvec * pvec ; + if ( u > 0.0 || u < det) + return 0; + + /* calculate V parameter and test bounds */ + v = line.Direction() * qvec ; + if ( v > 0.0 || u + v < det) + return 0; + } + else return 0; /* line is parallell to the plane of the triangle */ + + t = edge2 * qvec * inv_det; + ( u) *= inv_det; + ( v) *= inv_det; + + return 1; +} - // determinant - Point3 pvec = ray.Direction() ^ edge2; - T det = edge1*pvec; - - // if determinant is near zero, ray lies in plane of triangle - if (fabs(det) < EPSILON) return false; - - // calculate distance from vert0 to ray origin - Point3 tvec = ray.Origin()- vert0; - - // calculate A parameter and test bounds - a = tvec * pvec; - if (a < -EPSILON2*det || a > det+det*EPSILON2) return false; - - // prepare to test V parameter - Point3 qvec = tvec ^ edge1; - - // calculate B parameter and test bounds - b = ray.Direction() * qvec ; - if (b < -EPSILON2*det || b + a > det+det*EPSILON2) return false; - - // calculate t, scale parameters, ray intersects triangle - dist = edge2 * qvec; - if (dist<0) return false; - T inv_det = T(1.0) / det; - dist *= inv_det; - a *= inv_det; - b *= inv_det; - - return true; -} - - // ray-triangle, gives barycentric coords of intersection and distance along ray. - // Ray3 type used. -template -bool Intersection( const Ray3 & ray, const Point3 & vert0, - const Point3 & vert1, const Point3 & vert2, - T & a ,T & b, T & dist) -{ - // small (hum) borders around triangle - const T EPSILON2= T(1e-8); - - const T EPSILON = T(1e-8); - - Point3 edge1 = vert1 - vert0; - Point3 edge2 = vert2 - vert0; - - // determinant - Point3 pvec = ray.Direction() ^ edge2; - - T det = edge1*pvec; - - // if determinant is near zero, ray lies in plane of triangle - if (fabs(det) < EPSILON) return false; - - // calculate distance from vert0 to ray origin - Point3 tvec = ray.Origin()- vert0; - - // calculate A parameter and test bounds - a = tvec * pvec; - if (a < -EPSILON2*det || a > det+det*EPSILON2) return false; - - // prepare to test V parameter - Point3 qvec = tvec ^ edge1; - - // calculate B parameter and test bounds - b = ray.Direction() * qvec ; - if (b < -EPSILON2*det || b + a > det+det*EPSILON2) return false; - - // calculate t, scale parameters, ray intersects triangle - dist = edge2 * qvec; - if (dist<0) return false; - T inv_det = T(1.0) / det; - dist *= inv_det; - a *= inv_det; - b *= inv_det; - - return true; -} -#endif -#if 0 -// ray-triangle, gives intersection 3d point and distance along ray -template -bool Intersection( const Line3 & ray, const Point3 & vert0, - const Point3 & vert1, const Point3 & vert2, - Point3 & inte) -{ - - // small (hum) borders around triangle - const T EPSILON2= T(1e-8); - - const T EPSILON = T(1e-8); - - Point3 edge1 = vert1 - vert0; - Point3 edge2 = vert2 - vert0; - - // determinant - Point3 pvec = ray.Direction() ^ edge2; - - T det = edge1*pvec; - - // if determinant is near zero, ray lies in plane of triangle - if (fabs(det) < EPSILON) return false; - - // calculate distance from vert0 to ray origin - Point3 tvec = ray.Origin() - vert0; - - // calculate A parameter and test bounds - T a = tvec * pvec; - if (a < -EPSILON2*det || a > det+det*EPSILON2) return false; - - // prepare to test V parameter - Point3 qvec = tvec ^ edge1; - - // calculate B parameter and test bounds - T b = ray.Direction() * qvec ; - if (b < -EPSILON2*det || b + a > det+det*EPSILON2) return false; - - // calculate t, scale parameters, ray intersects triangle - double dist = edge2 * qvec; - //if (dist<0) return false; - T inv_det = 1.0 / det; - dist *= inv_det; - a *= inv_det; - b *= inv_det; - - inte = vert0 + edge1*a + edge2*b; - return true; -} -#endif // line-box template bool Intersection_Line_Box( const Box3 & box, const Line3 & r, Point3 & coord ) @@ -933,5 +861,6 @@ public: /*@}*/ + } // end namespace #endif