gctl/lib/geometry/triangle.h
2024-09-10 15:45:07 +08:00

226 lines
7.3 KiB
C++

/********************************************************
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* Geophysical Computational Tools & Library (GCTL)
*
* Copyright (c) 2023 Yi Zhang (yizhang-geo@zju.edu.cn)
*
* GCTL is distributed under a dual licensing scheme. 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 2
* of the License, or (at your option) any later version. You should have
* received a copy of the GNU Lesser General Public License along with this
* program. If not, see <http://www.gnu.org/licenses/>.
*
* If the terms and conditions of the LGPL v.2. would prevent you from using
* the GCTL, please consider the option to obtain a commercial license for a
* fee. These licenses are offered by the GCTL's original author. As a rule,
* licenses are provided "as-is", unlimited in time for a one time fee. Please
* send corresponding requests to: yizhang-geo@zju.edu.cn. Please do not forget
* to include some description of your company and the realm of its activities.
* Also add information on how to contact you by electronic and paper mail.
******************************************************/
#ifndef _GCTL_TRIANGLE_H
#define _GCTL_TRIANGLE_H
#include "vertex.h"
#include "entity.h"
namespace gctl
{
// Declaration of the basic triangle type
template <typename A> struct type_triangle;
// triangle type of attribute type of void
typedef type_triangle<void> triangle;
/**
* @brief Structure of a triangle.
*
* 三维直角坐标中的三角形结构体。
*/
template <typename A>
struct type_triangle : public entity<vertex3dc, 3, A>
{
/**
* 构造函数
*/
type_triangle();
/**
* @brief Set object from parameters
*
* @warning This function will locate memories to store vertice
*
* @param[in] p0 The first point
* @param[in] p1 The second point
* @param[in] p2 The third point
* @param[in] index The element index
*/
type_triangle(const point3dc &p0, const point3dc &p1, const point3dc &p2, int index = 0);
/**
* @brief 构造函数重载
*
* @param[in] index 索引值
* @param vert0 顶点0的指针
* @param vert1 顶点1的指针
* @param vert2 顶点2的指针
*/
type_triangle(vertex3dc &vert0, vertex3dc &vert1, vertex3dc &vert2, int index = 0);
/**
* @brief 析构函数
*/
virtual ~type_triangle(){}
/**
* @brief Set object from parameters
*
* @warning This function will locate memories to store vertice
*
* @param[in] p0 The first point
* @param[in] p1 The second point
* @param[in] p2 The third point
* @param[in] index The element index
*/
void set(const point3dc &p0, const point3dc &p1, const point3dc &p2, int index = 0);
/**
* @brief 设置三角形的索引与顶点列表
*
* @param[in] index 索引值
* @param vert0 顶点0的指针
* @param vert1 顶点1的指针
* @param vert2 顶点2的指针
*/
void set(vertex3dc &vert0, vertex3dc &vert1, vertex3dc &vert2, int index = 0);
/**
* @brief Calculate the triangle's area
*
* @return area
*/
double area();
/**
* @brief Calculate the center of the tetrahedron
*
* @return point3dc center position
*/
point3dc center();
/**
* @brief Calculate the local coordinates of the triangle
*
* (hgt_x, hgt_y)
* / \
* / | \
* / | \
* / | \
* /---------\
* (0,0) (len, 0)
*
* @param len bottom length the triangle which equals to the longest edge length
* @param hgt_x local x coordinate of the height of the triangle
* @param hgt_y local y coordinate of the height of the triangle
* @param c_id local index of the vertex ar the origin
*/
void local_coordinates(double &len, double &hgt_x, double &hgt_y, size_t &c_id);
};
template <typename A>
type_triangle<A>::type_triangle() : entity<vertex3dc, 3, A>::entity(){}
template <typename A>
type_triangle<A>::type_triangle(const point3dc &p0, const point3dc &p1, const point3dc &p2, int index) : type_triangle()
{
set(p0, p1, p2, index);
}
template <typename A>
type_triangle<A>::type_triangle(vertex3dc &vert0, vertex3dc &vert1,
vertex3dc &vert2, int index) : type_triangle()
{
set(vert0, vert1, vert2, index);
}
template <typename A>
void type_triangle<A>::set(const point3dc &p0, const point3dc &p1, const point3dc &p2, int index)
{
if (index < 0)
{
throw out_of_range("Invalid index number, From type_triangle::set(...)");
}
for (int i = 0; i < 3; ++i)
{
this->vert[i] = new vertex3dc;
}
this->self_host = true;
this->id = index;
this->vert[0]->set(p0, 0);
this->vert[1]->set(p1, 1);
this->vert[2]->set(p2, 2);
return;
}
template <typename A>
void type_triangle<A>::set(vertex3dc &vert0, vertex3dc &vert1,
vertex3dc &vert2, int index)
{
if (index < 0)
{
throw out_of_range("Invalid index number, From type_triangle::set(...)");
}
this->id = index;
this->vert[0] = &vert0;
this->vert[1] = &vert1;
this->vert[2] = &vert2;
return;
}
template <typename A>
double type_triangle<A>::area()
{
double edge_len[3] = {0.0, 0.0, 0.0};
edge_len[0] = distance(*this->vert[0], *this->vert[1]);
edge_len[1] = distance(*this->vert[1], *this->vert[2]);
edge_len[2] = distance(*this->vert[2], *this->vert[0]);
// calculate element's area
double p = 0.5*(edge_len[0] + edge_len[1] + edge_len[2]);
return sqrt(p*(p-edge_len[0])*(p-edge_len[1])*(p-edge_len[2]));
}
template <typename A>
point3dc type_triangle<A>::center()
{
point3dc vc;
vc = (1.0/3.0)*(*this->vert[0] + *this->vert[1] + *this->vert[2]);
return vc;
}
template <typename A>
void type_triangle<A>::local_coordinates(double &len, double &hgt_x, double &hgt_y, size_t &c_id)
{
double edge_len[3] = {0.0, 0.0, 0.0};
edge_len[0] = distance(*this->vert[0], *this->vert[1]);
edge_len[1] = distance(*this->vert[1], *this->vert[2]);
edge_len[2] = distance(*this->vert[2], *this->vert[0]);
if (edge_len[1] >= edge_len[0]) c_id = 1;
else c_id = 0;
if (edge_len[2] > edge_len[c_id]) c_id = 2;
// calculate element's area
double p = 0.5*(edge_len[0] + edge_len[1] + edge_len[2]);
double area = sqrt(p*(p-edge_len[0])*(p-edge_len[1])*(p-edge_len[2]));
len = edge_len[c_id];
hgt_y = 2.0*area/len;
hgt_x = sqrt(edge_len[(c_id+2)%3]*edge_len[(c_id+2)%3] - hgt_y*hgt_y);
return;
}
}
#endif // _GCTL_TRIANGLE_H