695 lines
19 KiB
C++
695 lines
19 KiB
C++
/**
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* @defgroup TIN
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*
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* @brief Generation of a Triangular Irregular Network (TIN) from a dense DEM grid.
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*
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* @author Yi Zhang
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* @date 2021-09-16
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*/
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#ifndef _TIN_DELAUNAY_H
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#define _TIN_DELAUNAY_H
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#include "cmath"
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#include "vector"
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#include "algorithm"
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#include "iostream"
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#define ZERO 1e-5
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// Start vertex definition
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struct vertex2dc
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{
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unsigned int id; // index of the vertex
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double x, y; // position of the vertex
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double elev; // elevation at the vertex
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vertex2dc() : x(NAN), y(NAN), elev(NAN), id(0) {}
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vertex2dc(double inx, double iny, double inelev, unsigned int inid) {set(inx, iny, inelev, inid);}
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void set(double inx, double iny, double inelev, unsigned int inid)
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{
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x = inx; y = iny; elev = inelev; id = inid;
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return;
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}
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};
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bool operator ==(const vertex2dc &a, const vertex2dc &b) // overload the == operator for vertex2dc type
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{
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if(fabs(a.x - b.x) <= ZERO && fabs(a.y - b.y) <= ZERO)
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{
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return true;
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}
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return false;
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}
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bool is_collinear(vertex2dc *a_ptr, vertex2dc *b_ptr, vertex2dc *c_ptr) // Test if the three points are on the same line
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{
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// ｜(y3−y1)(x2−x1)−(y2−y1)(x3−x1)｜
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if (fabs((c_ptr->y - a_ptr->y)*(b_ptr->x - a_ptr->x) - (b_ptr->y - a_ptr->y)*(c_ptr->x - a_ptr->x)) <= ZERO)
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{
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return true;
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}
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return false;
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}
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void circumcircle(vertex2dc *v0, vertex2dc *v1, vertex2dc *v2, double &cx, double &cy, double &cr) // calculate the circumcircle from three points
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{
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double s = 0.5 / ((v1->x - v0->x) * (v2->y - v0->y) - (v1->y - v0->y) * (v2->x - v0->x));
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double m = v1->x*v1->x - v0->x*v0->x + v1->y*v1->y - v0->y*v0->y;
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double u = v2->x*v2->x - v0->x*v0->x + v2->y*v2->y - v0->y*v0->y;
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cx = ((v2->y - v0->y)*m + (v0->y - v1->y)*u)*s;
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cy = ((v0->x - v2->x)*m + (v1->x - v0->x)*u)*s;
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cr = (v0->x - cx)*(v0->x - cx) + (v0->y - cy)*(v0->y - cy); // not need to calculate the squared root here
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return;
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}
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// End vertex definition
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// Start DEM definition
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struct triangle;
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struct dem_point
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{
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double x, y; // position of the DEM location
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double elev; // elevation at the DEM location
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double err; // error of the TIN with respect to the elevation
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triangle *host;
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dem_point() : x(NAN), y(NAN), elev(NAN), err(0.0), host(nullptr) {}
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dem_point(double inx, double iny, double inelev) {set(inx, iny, inelev);}
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void set(double inx, double iny, double inelev)
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{
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x = inx; y = iny; elev = inelev; err = 0.0; host = nullptr;
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return;
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}
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};
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bool compare_dem_point(dem_point *a, dem_point *b)
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{
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if (a->err > b->err) return true;
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return false;
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}
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// End DEM definition
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// Start triangle definition
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struct triangle
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{
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int id;
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vertex2dc *vert[3]; // vertex of the triangle
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triangle *neigh[3]; // neighbors of the triangle
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double cx, cy; // center of the triangle's circumcircle
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double cr; // radius of the circumcircle
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std::vector<dem_point*> hosted_dem;
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triangle() {vert[0] = vert[1] = vert[2] = nullptr; neigh[0] = neigh[1] = neigh[2] = nullptr;}
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triangle(vertex2dc *v0ptr, vertex2dc *v1ptr, vertex2dc *v2ptr) {set(v0ptr, v1ptr, v2ptr);}
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void set(vertex2dc *v0ptr, vertex2dc *v1ptr, vertex2dc *v2ptr)
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{
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vert[0] = v0ptr; vert[1] = v1ptr; vert[2] = v2ptr;
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neigh[0] = neigh[1] = neigh[2] = nullptr;
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circumcircle(vert[0], vert[1], vert[2], cx, cy, cr);
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return;
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}
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void set_neighbor(triangle *n0ptr, triangle *n1ptr, triangle *n2ptr)
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{
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neigh[0] = n0ptr; neigh[1] = n1ptr; neigh[2] = n2ptr;
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return;
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}
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bool bound_location(double inx, double iny) // Test if the location is inside the triangle
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{
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double l1x, l1y, l2x, l2y;
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for (int i = 0; i < 3; i++)
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{
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l1x = vert[(i+1)%3]->x - vert[i]->x;
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l1y = vert[(i+1)%3]->y - vert[i]->y;
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l2x = inx - vert[i]->x;
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l2y = iny - vert[i]->y;
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if ((l1x*l2y - l1y*l2x) < 0) // This condition includes points on the triangle's edge
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{
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return false;
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}
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}
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return true;
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}
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double interpolate(double inx, double iny) // Interpolate the elevation of the given location inside the triangle
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{
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double a1 = 0.5 * ((vert[1]->x - inx)*(vert[2]->y - iny) - (vert[1]->y - iny)*(vert[2]->x - inx));
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double a2 = 0.5 * ((vert[2]->x - inx)*(vert[0]->y - iny) - (vert[2]->y - iny)*(vert[0]->x - inx));
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double a3 = 0.5 * ((vert[0]->x - inx)*(vert[1]->y - iny) - (vert[0]->y - iny)*(vert[1]->x - inx));
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return (a1*vert[0]->elev + a2*vert[1]->elev + a3*vert[2]->elev)/(a1 + a2 + a3);
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}
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};
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/**
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* @brief Flip neighboring triangles and their neighbors
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*
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* original
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*
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* /\
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* / \
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* / \
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* / t \
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* t_id-------\ t_id (0, 1 or 2)
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* \--------/
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* \ /
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* \ n /
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* \ /
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* \/
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* n_id (0, 1 or 2)
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*
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* fliped
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*
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* /|\
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* / | \
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* / | \
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* / | \
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* t_id | \ t_id (0, 1 or 2)
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* \ t | n /
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* \ | /
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* \ | /
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* \ | /
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* \|/
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* n_id (0, 1 or 2)
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*
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* @param t target triangle
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* @param n neighboring triangle
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* @param t_vid reference index of the target triangle
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* @param n_vid reference index of the neighboring triangle
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*/
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void flip_neighboring_triangles(triangle *t, triangle *n, int t_id, int n_id)
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{
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t->vert[(t_id+1)%3] = n->vert[n_id]; // flip t
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circumcircle(t->vert[0], t->vert[1], t->vert[2], t->cx, t->cy, t->cr); // update circumcircle
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n->vert[(n_id+2)%3] = t->vert[(t_id+2)%3]; // flip n
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circumcircle(n->vert[0], n->vert[1], n->vert[2], n->cx, n->cy, n->cr); // update circumcircle
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// set side neighbors
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t->neigh[t_id] = n->neigh[(n_id+2)%3];
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n->neigh[(n_id+1)%3] = t->neigh[(t_id+1)%3];
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// set opposite neighbors
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t->neigh[(t_id+1)%3] = n;
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n->neigh[(n_id+2)%3] = t;
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// set oppsite neighbors
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if (t->neigh[t_id] != nullptr)
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{
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for (int i = 0; i < 3; i++)
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{
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if (t->neigh[t_id]->neigh[i] == n)
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{
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t->neigh[t_id]->neigh[i] = t;
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break;
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}
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}
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}
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if (n->neigh[(n_id+1)%3] != nullptr)
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{
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for (int i = 0; i < 3; i++)
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{
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if (n->neigh[(n_id+1)%3]->neigh[i] == t)
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{
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n->neigh[(n_id+1)%3]->neigh[i] = n;
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break;
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}
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}
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}
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// move hosted DEM points
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dem_point *tmp_dem;
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std::vector<dem_point*>::iterator d_iter;
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for (d_iter = t->hosted_dem.begin(); d_iter != t->hosted_dem.end(); )
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{
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tmp_dem = *d_iter;
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if (n->bound_location(tmp_dem->x, tmp_dem->y))
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{
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tmp_dem->host = n;
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n->hosted_dem.push_back(tmp_dem);
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d_iter = t->hosted_dem.erase(d_iter);
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}
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else d_iter++;
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}
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for (d_iter = n->hosted_dem.begin(); d_iter != n->hosted_dem.end(); )
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{
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tmp_dem = *d_iter;
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if (t->bound_location(tmp_dem->x, tmp_dem->y))
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{
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tmp_dem->host = t;
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t->hosted_dem.push_back(tmp_dem);
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d_iter = n->hosted_dem.erase(d_iter);
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}
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else d_iter++;
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}
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for (int i = 0; i < n->hosted_dem.size(); i++)
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{
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tmp_dem = n->hosted_dem[i];
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tmp_dem->err = fabs(n->interpolate(tmp_dem->x, tmp_dem->y) - tmp_dem->elev);
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}
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for (int i = 0; i < t->hosted_dem.size(); i++)
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{
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tmp_dem = t->hosted_dem[i];
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tmp_dem->err = fabs(t->interpolate(tmp_dem->x, tmp_dem->y) - tmp_dem->elev);
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}
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return;
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}
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/**
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* @brief Make sure that the input triangle meets the empty circumcircle condition
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*
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* @param t Input triangle
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*/
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void make_delaunay(triangle *t)
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{
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double dist;
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vertex2dc *n_vert;
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triangle *n_tri;
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dem_point *tmp_dem;
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for (int n = 0; n < 3; n++)
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{
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if (t->neigh[n] != nullptr) // must has neighbor on this side
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{
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n_tri = t->neigh[n];
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for (int v = 0; v < 3; v++)
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{
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n_vert = n_tri->vert[v];
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if (n_vert != t->vert[n] && n_vert != t->vert[(n+1)%3]) // find the opposite vertex
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{
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dist = (t->cx - n_vert->x) * (t->cx - n_vert->x) +
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(t->cy - n_vert->y) * (t->cy - n_vert->y);
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if ((dist - t->cr) < -1.0*ZERO) // need to be flipped
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{
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flip_neighboring_triangles(t, n_tri, n, v);
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// Make sure the triangles also meet the empty circumcircle condition after flipping
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make_delaunay(t);
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make_delaunay(n_tri);
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return; // Neighborhood changed. The current loop is not valid any more.
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}
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break; // no need to search more
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}
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}
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}
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}
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return;
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}
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triangle *split_triangle(vertex2dc *v, triangle *t, triangle *new_t[4])
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{
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vertex2dc *tmp_vert;
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triangle *tmp_tri;
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new_t[0] = new_t[1] = new_t[2] = new_t[3] = nullptr;
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// Check for collinear
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for (int i = 0; i < 3; i++)
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{
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if (is_collinear(t->vert[i], t->vert[(i+1)%3], v))
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{
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if (t->neigh[i] == nullptr)
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{
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tmp_tri = new triangle(t->vert[i], v, t->vert[(i+2)%3]); new_t[0] = tmp_tri;
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tmp_tri = new triangle(t->vert[(i+2)%3], v, t->vert[(i+1)%3]); new_t[1] = tmp_tri;
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new_t[0]->set_neighbor(nullptr, new_t[1], t->neigh[(i+2)%3]);
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new_t[1]->set_neighbor(new_t[0], nullptr, t->neigh[(i+1)%3]);
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for (int n = 0; n < 2; n++)
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{
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if (new_t[n]->neigh[2] != nullptr)
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{
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for (int k = 0; k < 3; ++k) // replace neighbor for the oppositing triangle
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{
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if (new_t[n]->neigh[2]->neigh[k] == t)
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{
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new_t[n]->neigh[2]->neigh[k] = new_t[n];
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break;
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}
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}
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}
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}
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return nullptr;
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}
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for (int k = 0; k < 3; k++)
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{
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tmp_vert = t->neigh[i]->vert[k];
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if (tmp_vert != t->vert[i] && tmp_vert != t->vert[(i+1)%3])
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{
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tmp_tri = new triangle(t->vert[i], v, t->vert[(i+2)%3]); new_t[0] = tmp_tri;
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tmp_tri = new triangle(t->vert[(i+2)%3], v, t->vert[(i+1)%3]); new_t[1] = tmp_tri;
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tmp_tri = new triangle(tmp_vert, v, t->vert[i]); new_t[2] = tmp_tri;
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tmp_tri = new triangle(t->vert[(i+1)%3], v, tmp_vert); new_t[3] = tmp_tri;
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new_t[0]->set_neighbor(new_t[2], new_t[1], t->neigh[(i+2)%3]);
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new_t[1]->set_neighbor(new_t[0], new_t[3], t->neigh[(i+1)%3]);
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new_t[2]->set_neighbor(new_t[3], new_t[0], t->neigh[i]->neigh[(k+2)%3]);
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new_t[3]->set_neighbor(new_t[1], new_t[2], t->neigh[i]->neigh[k]);
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for (int n = 0; n < 2; n++)
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{
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if (new_t[n]->neigh[2] != nullptr)
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{
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for (int k = 0; k < 3; ++k) // replace neighbor for the oppositing triangle
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{
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if (new_t[n]->neigh[2]->neigh[k] == t)
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{
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new_t[n]->neigh[2]->neigh[k] = new_t[n];
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break;
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}
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}
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}
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}
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for (int n = 2; n < 4; n++)
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{
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if (new_t[n]->neigh[2] != nullptr)
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{
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for (int k = 0; k < 3; ++k) // replace neighbor for the oppositing triangle
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{
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if (new_t[n]->neigh[2]->neigh[k] == t->neigh[i])
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{
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new_t[n]->neigh[2]->neigh[k] = new_t[n];
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break;
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}
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}
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}
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}
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break;
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}
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}
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return t->neigh[i];;
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}
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}
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for (int n = 0; n < 3; ++n)
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{
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tmp_tri = new triangle(t->vert[n], t->vert[(n+1)%3], v);
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new_t[n] = tmp_tri;
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}
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// sort neighbors for new triangles
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for (int n = 0; n < 3; ++n)
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{
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if (t->neigh[n] == nullptr)
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{
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new_t[n]->set_neighbor(nullptr, new_t[(n+1)%3], new_t[(n+2)%3]);
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}
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else
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{
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new_t[n]->set_neighbor(t->neigh[n], new_t[(n+1)%3], new_t[(n+2)%3]);
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for (int k = 0; k < 3; ++k) // replace neighbor for the oppositing triangle
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{
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if (t->neigh[n]->neigh[k] == t)
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{
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t->neigh[n]->neigh[k] = new_t[n];
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break;
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}
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}
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}
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}
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return nullptr;
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}
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// End triangle definition
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/**
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* @brief Generate the TIN from the DEM grid
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*
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* @param[in] dem Input DEM grid (Ordered from lower left corner to the upper right corner)
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* @param[in] xmin The minimal coordinate of the DEM grid on the x-axis
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* @param[in] xmax The maximal coordinate of the DEM grid on the x-axis
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* @param[in] ymin The minimal coordinate of the DEM grid on the y-axis
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* @param[in] ymax The maximal coordinate of the DEM grid on the y-axis
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* @param[in] dx Data spacing of the DEM grid on the x-axis
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* @param[in] dy Data spacing of the DEM grid on the y-axis
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* @param out_verts The output vector of vertex's pointers. The user need to destroy the memories allocated by the function before destroy the vector
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* @param out_tris The output vector of triangle's pointers. The user need to destroy the memories allocated by the function before destroy the vector
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* @param[in] maxi_err Threshold to quit the algorithm. The default is 1e-0
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* @param[in] err_records If this pointer is not NULL, record maximal error values after each insertion of vertex.
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*/
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void dem2tin(const std::vector<double> &dem, double xmin, double xmax, double ymin, double ymax,
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double dx, double dy, std::vector<vertex2dc*> &out_verts, std::vector<triangle*> &out_tris,
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double maxi_err = 1e-0, std::vector<double> *err_records = nullptr)
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{
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if (!out_verts.empty()) out_verts.clear();
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if (!out_tris.empty()) out_tris.clear();
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if (err_records != nullptr && !err_records->empty()) err_records->clear();
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if (dx <= 0.0 || dy <= 0.0 || maxi_err <= 0.0) return;
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if (xmin >= xmax || ymin >= ymax || (xmin + dx) > xmax || (ymin + dy) > ymax) return;
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int xnum = round((xmax - xmin)/dx) + 1;
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int ynum = round((ymax - ymin)/dy) + 1;
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if (dem.size() != xnum*ynum) return;
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// Prepare the DEM points
|
||
dem_point *tmp_dem = nullptr;
|
||
std::vector<dem_point*> cnst_dem;
|
||
std::vector<dem_point*> dem_grid(xnum*ynum);
|
||
std::vector<dem_point*>::iterator d_iter;
|
||
for (int i = 0; i < ynum; ++i)
|
||
{
|
||
for (int j = 0; j < xnum; ++j)
|
||
{
|
||
dem_grid[j + i*xnum] = new dem_point(xmin + dx*j, ymin + dy*i, dem[j + i*xnum]);
|
||
}
|
||
}
|
||
|
||
vertex2dc *tmp_vert = nullptr;
|
||
tmp_vert = new vertex2dc(xmin, ymin, dem_grid[0]->elev, out_verts.size()); // lower left corner
|
||
out_verts.push_back(tmp_vert);
|
||
|
||
d_iter = dem_grid.begin();
|
||
tmp_dem = *d_iter; delete tmp_dem;
|
||
dem_grid.erase(d_iter);
|
||
|
||
tmp_vert = new vertex2dc(xmax, ymin, dem_grid[xnum-2]->elev, out_verts.size()); // lower right corner. Note the first location is already erased
|
||
out_verts.push_back(tmp_vert);
|
||
|
||
d_iter = dem_grid.begin() + (xnum - 2);
|
||
tmp_dem = *d_iter; delete tmp_dem;
|
||
dem_grid.erase(d_iter);
|
||
|
||
tmp_vert = new vertex2dc(xmax, ymax, dem_grid[xnum*ynum-3]->elev, out_verts.size()); // upper right corner. Note the first two locations are already erased
|
||
out_verts.push_back(tmp_vert);
|
||
|
||
d_iter = dem_grid.begin() + (xnum*ynum - 3);
|
||
tmp_dem = *d_iter; delete tmp_dem;
|
||
dem_grid.erase(d_iter);
|
||
|
||
tmp_vert = new vertex2dc(xmin, ymax, dem_grid[xnum*(ynum-1) - 2]->elev, out_verts.size()); // upper left corner. Note the first two locations are already erased
|
||
out_verts.push_back(tmp_vert);
|
||
|
||
d_iter = dem_grid.begin() + (xnum*(ynum-1) - 2);
|
||
tmp_dem = *d_iter; delete tmp_dem;
|
||
dem_grid.erase(d_iter);
|
||
|
||
triangle *old_tri = nullptr, *tmp_tri = nullptr;
|
||
triangle *cnst_tri[4];
|
||
std::vector<triangle*>::iterator t_iter;
|
||
|
||
if (!is_collinear(out_verts[0], out_verts[1], out_verts[2])) // Do not create triangle if the vertexes are collinear
|
||
{
|
||
tmp_tri = new triangle(out_verts[0], out_verts[1], out_verts[2]); // order the vertex anti-clock wise
|
||
out_tris.push_back(tmp_tri); tmp_tri = nullptr;
|
||
}
|
||
|
||
if (!is_collinear(out_verts[0], out_verts[2], out_verts[3]))
|
||
{
|
||
tmp_tri = new triangle(out_verts[0], out_verts[2], out_verts[3]); // order the vertex anti-clock wise
|
||
out_tris.push_back(tmp_tri); tmp_tri = nullptr;
|
||
}
|
||
|
||
if (out_tris.size() != 2) return;
|
||
|
||
out_tris[0]->set_neighbor(nullptr, nullptr, out_tris[1]);
|
||
out_tris[1]->set_neighbor(out_tris[0], nullptr, nullptr);
|
||
|
||
// Find host triangle for all DEM locations
|
||
for (int i = 0; i < dem_grid.size(); ++i)
|
||
{
|
||
for (int t = 0; t < out_tris.size(); ++t)
|
||
{
|
||
if (out_tris[t]->bound_location(dem_grid[i]->x, dem_grid[i]->y))
|
||
{
|
||
dem_grid[i]->host = out_tris[t];
|
||
out_tris[t]->hosted_dem.push_back(dem_grid[i]);
|
||
break; // already found, no need to search more
|
||
}
|
||
}
|
||
}
|
||
|
||
// loop all DEM data to find the location with maximal error
|
||
for (int i = 0; i < dem_grid.size(); ++i)
|
||
{
|
||
dem_grid[i]->err = fabs(dem_grid[i]->host->interpolate(dem_grid[i]->x, dem_grid[i]->y) - dem_grid[i]->elev);
|
||
}
|
||
|
||
// Sort dem_grid in the desceding order with respect to the error
|
||
std::sort(dem_grid.begin(), dem_grid.end(), compare_dem_point);
|
||
|
||
while (dem_grid[0]->err >= maxi_err) // quit til the threshold is meet
|
||
{
|
||
if (err_records != nullptr)
|
||
{
|
||
err_records->push_back(dem_grid[0]->err);
|
||
}
|
||
|
||
// find the triangle that includes dem_grid[0] and remove it from out_tris
|
||
for (t_iter = out_tris.begin(); t_iter != out_tris.end(); )
|
||
{
|
||
old_tri = *t_iter;
|
||
if (old_tri == dem_grid[0]->host)
|
||
{
|
||
t_iter = out_tris.erase(t_iter);
|
||
break;
|
||
}
|
||
else t_iter++;
|
||
}
|
||
|
||
// remove dem_grid[0] from its host triangle's hosted DEM list
|
||
for (d_iter = old_tri->hosted_dem.begin(); d_iter != old_tri->hosted_dem.end(); )
|
||
{
|
||
if (dem_grid[0] == *d_iter)
|
||
{
|
||
d_iter = old_tri->hosted_dem.erase(d_iter);
|
||
break;
|
||
}
|
||
else d_iter++;
|
||
}
|
||
|
||
// create a new vertex
|
||
tmp_vert = new vertex2dc(dem_grid[0]->x, dem_grid[0]->y, dem_grid[0]->elev, out_verts.size());
|
||
out_verts.push_back(tmp_vert);
|
||
|
||
// Remove dem_grid[0] from the list and delete it
|
||
d_iter = dem_grid.begin();
|
||
tmp_dem = *d_iter; delete tmp_dem;
|
||
dem_grid.erase(d_iter);
|
||
|
||
// build new triangles
|
||
tmp_tri = split_triangle(tmp_vert, old_tri, cnst_tri);
|
||
for (int n = 0; n < 4; ++n)
|
||
{
|
||
if (cnst_tri[n] != nullptr)
|
||
{
|
||
out_tris.push_back(cnst_tri[n]);
|
||
}
|
||
}
|
||
|
||
if (tmp_tri != nullptr)
|
||
{
|
||
for (t_iter = out_tris.begin(); t_iter != out_tris.end(); )
|
||
{
|
||
if (tmp_tri == *t_iter)
|
||
{
|
||
t_iter = out_tris.erase(t_iter);
|
||
break;
|
||
}
|
||
else t_iter++;
|
||
}
|
||
|
||
// build hosted dem for the new triangles
|
||
for (int d = 0; d < old_tri->hosted_dem.size(); d++)
|
||
{
|
||
tmp_dem = old_tri->hosted_dem[d];
|
||
for (int n = 0; n < 4; n++)
|
||
{
|
||
if (cnst_tri[n] != nullptr && cnst_tri[n]->bound_location(tmp_dem->x, tmp_dem->y))
|
||
{
|
||
tmp_dem->host = cnst_tri[n];
|
||
tmp_dem->err = fabs(cnst_tri[n]->interpolate(tmp_dem->x, tmp_dem->y) - tmp_dem->elev);
|
||
cnst_tri[n]->hosted_dem.push_back(tmp_dem);
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
for (int d = 0; d < tmp_tri->hosted_dem.size(); d++)
|
||
{
|
||
tmp_dem = tmp_tri->hosted_dem[d];
|
||
for (int n = 0; n < 4; n++)
|
||
{
|
||
if (cnst_tri[n] != nullptr && cnst_tri[n]->bound_location(tmp_dem->x, tmp_dem->y))
|
||
{
|
||
tmp_dem->host = cnst_tri[n];
|
||
tmp_dem->err = fabs(cnst_tri[n]->interpolate(tmp_dem->x, tmp_dem->y) - tmp_dem->elev);
|
||
cnst_tri[n]->hosted_dem.push_back(tmp_dem);
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
// delete the old triangle
|
||
old_tri->hosted_dem.clear();
|
||
delete old_tri; old_tri = nullptr;
|
||
|
||
tmp_tri->hosted_dem.clear();
|
||
delete tmp_tri; tmp_tri = nullptr;
|
||
}
|
||
else
|
||
{
|
||
// build hosted dem for the new triangles
|
||
for (int d = 0; d < old_tri->hosted_dem.size(); d++)
|
||
{
|
||
tmp_dem = old_tri->hosted_dem[d];
|
||
for (int n = 0; n < 4; n++)
|
||
{
|
||
if (cnst_tri[n] != nullptr && cnst_tri[n]->bound_location(tmp_dem->x, tmp_dem->y))
|
||
{
|
||
tmp_dem->host = cnst_tri[n];
|
||
tmp_dem->err = fabs(cnst_tri[n]->interpolate(tmp_dem->x, tmp_dem->y) - tmp_dem->elev);
|
||
cnst_tri[n]->hosted_dem.push_back(tmp_dem);
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
// delete the old triangle
|
||
old_tri->hosted_dem.clear();
|
||
delete old_tri; old_tri = nullptr;
|
||
}
|
||
|
||
// Make sure cnst_tri meet the empty circumcircle condition
|
||
for (int n = 0; n < 4; ++n)
|
||
{
|
||
if (cnst_tri[n] != nullptr)
|
||
{
|
||
make_delaunay(cnst_tri[n]);
|
||
}
|
||
}
|
||
|
||
// Sort dem_grid in the desceding order with respect to the error
|
||
std::sort(dem_grid.begin(), dem_grid.end(), compare_dem_point);
|
||
}
|
||
|
||
if (err_records != nullptr)
|
||
{
|
||
err_records->push_back(dem_grid[0]->err);
|
||
}
|
||
|
||
// assign triangles index
|
||
for (int i = 0; i < out_tris.size(); i++)
|
||
{
|
||
out_tris[i]->id = i;
|
||
}
|
||
|
||
// destroy remaining DEM data
|
||
for (int i = 0; i < dem_grid.size(); ++i)
|
||
{
|
||
tmp_dem = dem_grid[i];
|
||
delete tmp_dem; tmp_dem = nullptr;
|
||
}
|
||
|
||
return;
|
||
}
|
||
|
||
#endif // _TIN_DELAUNAY_H
|