Diffusion akantu (bugfixes/43-documentation-problem-with-latex-formatting) Browse

43-documentati…

aka_geometry.hh
View Options

			/**
			* @file aka_geometry.hh
			*
			* @author Alejandro M. Aragón <alejandro.aragon@epfl.ch>
			*
			* @date creation: Fri Jan 04 2013
			* @date last modification: Wed Dec 16 2015
			*
			* @brief geometric operations
			*
			* @section LICENSE
			*
			* Copyright (©) 2014, 2015 EPFL (Ecole Polytechnique Fédérale de Lausanne)
			* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
			*
			* Akantu is free software: you can redistribute it and/or modify it under the
			* terms of the GNU Lesser General Public License as published by the Free
			* Software Foundation, either version 3 of the License, or (at your option) any
			* later version.
			*
			* Akantu is distributed in the hope that it will be useful, but WITHOUT ANY
			* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
			* A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
			* details.
			*
			* You should have received a copy of the GNU Lesser General Public License
			* along with Akantu. If not, see <http://www.gnu.org/licenses/>.
			*
			*/

			/* -------------------------------------------------------------------------- */


			#ifndef __AKANTU_GEOMETRY_HH__
			#define __AKANTU_GEOMETRY_HH__

			#include <iostream>
			#include <tuple>
			#include "aka_point.hh"
			#include "aka_plane.hh"
			#include "aka_math.hh"

			__BEGIN_AKANTU__

			// predicates

			// combined tolerance test, from Christer Ericson
			template <typename T>
			typename std::enable_if<std::is_integral<T>::value, bool>::type
			equal(T x, T y)
			{ return x == y; }


			Real left_turn(const Point<2>& p, const Point<2>& q, const Point<2>& r);



			// closest point computations


			//! Computes the closest point laying on a segment to a point
			/*! Given segment \c ab and point \c c, computes closest point \c d on ab.
			* Also returns \c t for the position of the point: a + t*(b - a)
			*/
			template <int d, typename T>
			Point<d,T> closest_point_to_segment(const Point<d,T>& c,
			const Point<d,T>& a,
			const Point<d,T>& b) {

			Point<d,T> ab = b - a;


			// project c onto ab, computing parameterized position d(t) = a + t*(b – a)

			T t = (c - a)ab / sqrt(abab);

			// if outside segment, clamp t (and therefore d) to the closest endpoint
			if (t < 0.)
			t = 0.;
			else if (t > 1.)
			t = 1.;

			// compute projected position from the clamped t
			return a + t * ab;
			}

			//! Predicate that checks if a point has a projection on a line segment
			/*! Given segment \c ab and point \c c, checks if the point has a projection in the segment.
			*/
			template <int d, typename T>
			bool has_projection(const Point<d,T>& c,
			const Point<d,T>& a,
			const Point<d,T>& b) {

			Point<d,T> ab = b - a;
			// project c onto ab, computing parameterized position d(t) = a + t*(b – a)

			T t = (c - a)ab / (abab);
			return t > 0. && t < 1.;
			}

			//! Tests if a point has a projection to a triangle
			/*! This function uses the concept of Voronoi regions to determine
			* if a point has a projection within a triangle defined by points
			* \c a, \c b, and \c c.
			*/
			template <typename T>
			bool point_has_projection_to_triangle(const Point<3,T>& p,
			const Point<3,T>& a,
			const Point<3,T>& b,
			const Point<3,T>& c) {

			typedef Point<3,T> point_type;

			// obtain plane of the triangle
			Plane pi(a,b,c);

			// get point in the plane closest to p
			point_type q = closest_point_to_plane(p,pi);

			// return if point is within the triangle
			if (is_point_in_triangle(q, a, b, c))
			return true;
			return false;
			}

			//! Tests if point P lies inside a triangle
			/*! The triangle is defined by points \c a, \c b and \c c.
			*/

			template <typename T>
			bool is_point_in_triangle(const Point<3,T>& p,
			const Point<3,T>& a,
			const Point<3,T>& b,
			const Point<3,T>& c) {

			typedef Point<3,T> point_type;

			point_type v0 = b-a, v1 = c-a, v2 = p-a;

			Real d00 = v0*v0;
			Real d01 = v0*v1;
			Real d11 = v1*v1;
			Real d20 = v2*v0;
			Real d21 = v2*v1;
			Real denom = d00d11 - d01d01;

			// compute parametric coordinates
			Real v = (d11 * d20 - d01 * d21) / denom;
			Real w = (d00 * d21 - d01 * d20) / denom;
			return v >= 0. && w >= 0. && v + w <= 1.;
			}



			//! Compute the closest point to a triangle
			/*! This function uses the concept of Voronoi regions to determine
			* the closest point \c p to a triangle defined by points \c a, \c b
			* \c c.
			*/
			template <typename T>
			Point<3,T> closest_point_to_triangle(const Point<3,T>& p,
			const Point<3,T>& a,
			const Point<3,T>& b,
			const Point<3,T>& c) {

			typedef Point<3,T> point_type;

			// check if P in vertex region outside A
			point_type ab = b - a;
			point_type ac = c - a;
			point_type ap = p - a;

			// compute scalar products
			T d1 = ab * ap;
			T d2 = ac * ap;

			if (d1 <= 0. && d2 <= 0.)
			return a; // barycentric coordinates (1,0,0)

			// check if P in vertex region outside B
			point_type bp = p - b;

			T d3 = ab * bp;
			T d4 = ac * bp;

			if (d3 >= 0.0f && d4 <= d3)
			return b; // barycentric coordinates (0,1,0)

			// check if P in edge region of AB, if so return projection of P onto AB
			T vc = d1d4 - d3d2;
			if (vc <= 0. && d1 >= 0. && d3 <= 0.) {
			T v = d1 / (d1 - d3);
			return a + v * ab; // barycentric coordinates (1-v,v,0)
			}

			// check if P in vertex region outside C
			point_type cp = p - c;
			T d5 = ab * cp;
			T d6 = ac * cp;
			if (d6 >= 0.0f && d5 <= d6)
			return c; // barycentric coordinates (0,0,1)

			// check if P in edge region of AC, if so return projection of P onto AC
			T vb = d5d2 - d1d6;
			if (vb <= 0.0f && d2 >= 0.0f && d6 <= 0.0f) {
			T w = d2 / (d2 - d6);
			return a + w * ac; // barycentric coordinates (1-w,0,w)
			}

			// Check if P in edge region of BC, if so return projection of P onto BC
			T va = d3d6 - d5d4;
			if (va <= 0.0f && (d4 - d3) >= 0.0f && (d5 - d6) >= 0.0f) {
			T w = (d4 - d3) / ((d4 - d3) + (d5 - d6));
			return b + w * (c - b); // barycentric coordinates (0,1-w,w)
			}

			// P inside face region. Compute Q through its barycentric coordinates (u,v,w)
			T denom = 1.0f / (va + vb + vc);
			T v = vb * denom;
			T w = vc * denom;

			return a + abv + acw; // = ua + vb + wc, u = vadenom = 1.0f - v - w
			}


			template <typename T>
			Point<3,T> closest_point_to_plane(const Point<3,T>& q, const Plane& p) {

			typedef Point<3,T> point_type;

			const point_type& n = p.normal();

			T t = (nq - p.distance()) / (nn);
			return q - t * n;
			}

			//! Compute the closest point to a triangle
			/*! Obtains the plane of the triangle and checks if the point lies inside the
			* triangle. If not, it computes the closest point to each of the triangle
			* edges.
			*/
			template <typename T>
			Point<3,T> naive_closest_point_to_triangle(const Point<3,T>& p,
			const Point<3,T>& a,
			const Point<3,T>& b,
			const Point<3,T>& c) {

			typedef Point<3,T> point_type;

			// obtain plane of the triangle
			Plane pi(a,b,c);

			// get point in the plane closest to p
			point_type q = closest_point_to_plane(p,pi);

			// return if point is within the triangle
			if (is_point_in_triangle(q, a, b, c))
			return q;

			// else get the closest point taking into account all edges

			// first edge
			q = closest_point_to_segment(p, a, b);
			T d = (q-p).sq_norm();

			// second edge
			point_type r = closest_point_to_segment(p, b, c);

			T d2 = (r-p).sq_norm();
			if (d2 < d) {
			q = r;
			d = d2;
			}

			// third edge
			r = closest_point_to_segment(p,c,a);
			d2 = (r-p).sq_norm();
			if (d2 < d)
			q = r;

			// return closest point
			return q;
			}


			// intersect point p with velocity v with plane
			// the function returns collision time and point of contact
			// this function does not consider acceleration
			template <typename T>
			std::tuple<Real, Point<3,T> >
			moving_point_against_plane(const Point<3,T>& p, const Point<3,T>& v, Plane& pi) {

			typedef Point<3,T> point_type;

			// compute distance of point to plane
			Real dist = pi.normal()*p - pi.distance();

			// if point already in the plane
			if (std::abs(dist) <= 1e-10)
			return std::make_tuple(0., p);

			else {

			Real denom = pi.normal()*v;
			// no intersection as poin moving parallel to or away from plane
			if (denom * dist >= 0.)
			return std::make_tuple(inf, point_type());

			// point moving towards the plane
			else {
			// point is moving towards the plane
			Real t = -dist/denom;
			return std::make_tuple(t, p + t*v);
			}
			}
			}



			template <int dim, typename T>
			std::tuple<Real, Point<dim,T> >
			moving_point_against_point(const Point<dim,T>& s1, const Point<dim,T>& s2, /* point centers */
			const Point<dim,T>& v1, const Point<dim,T>& v2) /* point velocities */ {

			typedef Point<dim,T> point_type;
			typedef typename Point<dim,T>::value_type value_type;

			// vector between points
			point_type s = s2 - s1;
			// relative motion of s1 with respect to stationary s0
			point_type v = v2 - v1;
			value_type c = s*s;

			// if points within tolerance
			if (equal(s.sq_norm(), value_type()))
			return std::make_tuple(value_type(), s1);

			value_type epsilon = 2*std::numeric_limits<T>::epsilon();;

			value_type a = v*v;
			// if points not moving relative to each other
			if (a < epsilon)
			return std::make_tuple(inf, point_type());

			value_type b = v*s;
			// if points not moving towards each other
			if (b >= 0.)
			return std::make_tuple(inf, point_type());

			value_type d = bb - ac;
			// if no real-valued root (d < 0), points do not intersect
			if (d >= 0.) {
			value_type ts = (-b - sqrt(d))/a;
			point_type q = s1+v1*ts;
			return std::make_tuple(ts, q);
			}
			return std::make_tuple(inf, point_type());
			}


			__END_AKANTU__


			#endif /* __AKANTU_GEOMETRY_HH__ */

rAKA/extra_packages/contact_alejandro/src/common/aka_geometry.hhb285dab59995bugfixes/43-documentati…

aka_geometry.hhView Options

rAKA/extra_packages/contact_alejandro/src/common/aka_geometry.hh
b285dab59995bugfixes/43-documentati…

aka_geometry.hh
View Options