trisurf-ng.git - Gitblit

It works, png is output. The only problem is that some triangles are missing

Samo Penic

2014-06-13 a61c001cd35ff70a314ef417c4beda9c7e68d3ad

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0af0cf	1	#include<general.h>
SP	2	#include<cross-section.h>
	3	#include<coord.h>
a61c00	4	#include<cairo/cairo.h>
0af0cf	5	/** @brief Calculates cross-section of vesicle with plane.
SP	6	*
	7	* Function returns points of cross-section of vesicle with plane. Plane is described with equation $ax+by+cz+d=0$. Algorithm extracts coordinates of each vertex of a vesicle and then:
	8	*
	9	* if a distance of point to plane (given by equation $D=\frac{ax_0+by_0+cz_0+d}{\sqrt{a^2+b^2+c^2}}$, where $x_0$, $y_0$ and $z_0$ are coordinates of a given vertex) is less than maximal allowed distance between vertices {\tt sqrt(vesicle->dmax)} than vertex is a candidate for crossection calculation.
	10	*
	11	*/
d27c07	12	ts_coord_list get_crossection_with_plane(ts_vesicle vesicle,ts_double a,ts_double b,ts_double c, ts_double d){
0af0cf	13
SP	14
a61c00	15	ts_uint i, j,k;
0af0cf	16	ts_double pp,Dsq; // distance from the plane squared
a61c00	17	ts_double ppn1,ppn2; // distance from the plane squared of a neighbor
0af0cf	18	ts_double u; //factor to scale vector from first vector to the second to get intersection
SP	19	ts_vertex *vtx;
a61c00	20	ts_uint ntria=0; // number triangles
SP	21	ts_uint cnt=0;
	22	ts_triangle *tria[2]; // list of triangles
0af0cf	23	ts_coord_list *pts=init_coord_list();
d27c07	24	for(i=0;i<vesicle->vlist->n;i++){
0af0cf	25	vtx=vesicle->vlist->vtx[i];
SP	26
	27	pp=vtx->xa+vtx->yb+vtx->z*c+d;
	28	Dsq=pppp/(aa+bb+cc);
	29	if(Dsq<vesicle->dmax){
	30	for(j=0;j<vtx->neigh_no;j++){
a61c00	31	ppn1=vtx->neigh[j]->xa+vtx->neigh[j]->yb+vtx->neigh[j]->z*c+d;
SP	32	if(pp*ppn1<=0){ //the combination of vertices are good candidates for a crossection
	33	/* u=pp/(a(vtx->x-vtx->neigh[j]->x)+b(vtx->y-vtx->neigh[j]->y)+c*(vtx->z-vtx->neigh[j]->z));
d27c07	34	add_coord(pts, vtx->x+u*(vtx->neigh[j]->x - vtx->x),
SP	35	vtx->y+u*(vtx->neigh[j]->y - vtx->y),
	36	vtx->z+u*(vtx->neigh[j]->z - vtx->z),
0af0cf	37	TS_COORD_CARTESIAN);
a61c00	38
SP	39	*/
	40	//find triangle that belongs to the two vertices
	41	cnt=0;
	42	ntria=0;
	43	for(k=0;k<vtx->tristar_no;k++){
	44	if(vtx->tristar[k]->vertex[1]==vtx->neigh[j] && vtx->tristar[k]->vertex[0]==vtx){
	45	//triangle found.
	46	tria[ntria]=vtx->tristar[k];
	47	ntria++;
	48	}
	49	}
	50	// if ntria !=1 there is probably something wrong I would say...
	51	if(ntria==0) continue;
	52	if(ntria!=1) {
	53	fprintf(stderr,"ntria=%u\n",ntria);
	54	fatal ("Error in mesh. 1 triangle not found",123123);
	55	}
	56	//find the two intersections (in general) to form a intersection line
	57	/* we dont know which vertex is which, so we need to recalculate all previously calculated values*/
	58	pp=vtx->xa+vtx->yb+vtx->z*c+d;
	59	ppn1=vtx->neigh[j]->xa+vtx->neigh[j]->yb+vtx->neigh[j]->z*c+d;
	60
	61	u=pp/(a(vtx->x-vtx->neigh[j]->x)+b(vtx->y-vtx->neigh[j]->y)+c*(vtx->z-vtx->neigh[j]->z));
	62	add_coord(pts, vtx->x+u*(vtx->neigh[j]->x - vtx->x),
	63	vtx->y+u*(vtx->neigh[j]->y - vtx->y),
	64	vtx->z+u*(vtx->neigh[j]->z - vtx->z),
	65	TS_COORD_CARTESIAN);
	66	ppn2=tria[0]->vertex[2]->xa+tria[0]->vertex[2]->yb+tria[0]->vertex[2]->z*c+d;
	67	cnt++;
	68	//two more tries to find anothen pair of vertices, one above and one below the intersection plane */
	69	if(pp*ppn2<=0) {
	70	u=pp/(a(vtx->x-tria[0]->vertex[2]->x)+b(vtx->y-tria[0]->vertex[2]->y)+c*(vtx->z-tria[0]->vertex[2]->z));
	71	add_coord(pts, vtx->x+u*(tria[0]->vertex[2]->x - vtx->x),
	72	vtx->y+u*(tria[0]->vertex[2]->y - vtx->y),
	73	vtx->z+u*(tria[0]->vertex[2]->z - vtx->z),
	74	TS_COORD_CARTESIAN);
	75	cnt++;
	76	}
	77
	78	if(ppn2*ppn1<=0) {
	79	u=ppn1/(a(vtx->neigh[j]->x-tria[0]->vertex[2]->x)+b(vtx->neigh[j]->y-tria[0]->vertex[2]->y)+c*(vtx->neigh[j]->z-tria[0]->vertex[2]->z));
	80	add_coord(pts, vtx->neigh[j]->x+u*(tria[0]->vertex[2]->x - vtx->neigh[j]->x),
	81	vtx->neigh[j]->y+u*(tria[0]->vertex[2]->y - vtx->neigh[j]->y),
	82	vtx->neigh[j]->z+u*(tria[0]->vertex[2]->z - vtx->neigh[j]->z),
	83	TS_COORD_CARTESIAN);
	84	cnt++;
	85
	86	}
	87
	88
	89	if(cnt!=2){
	90	fprintf(stderr,"Hey, cnt=%u",cnt);
	91	}
0af0cf	92	}
SP	93	}
	94	}
	95	}
	96	return pts;
	97	}
	98
	99
a61c00	100	/** Saves calculated crossection as a png image */
SP	101	ts_bool crossection_to_png(ts_coord_list pts, char filename){
	102
	103	cairo_surface_t *surface;
	104	cairo_t *cr;
	105	ts_uint i;
	106	surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, 1800, 1800);
	107	cr = cairo_create (surface);
	108	cairo_rectangle(cr, 0.0, 0.0, 1800,1800);
	109	cairo_set_source_rgb(cr, 0.3, 0.3, 0.3);
	110	cairo_fill(cr);
	111	cairo_set_line_width (cr, 5.0/30.0);
	112	cairo_translate(cr, 900,900);
	113	cairo_scale (cr, 30, 30);
	114	cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
	115
	116	for(i=0;i<pts->n;i+=2){
	117	cairo_move_to(cr, pts->coord[i]->e1, pts->coord[i]->e2);
	118	cairo_line_to(cr, pts->coord[i+1]->e1, pts->coord[i+1]->e2);
	119	}
	120	cairo_stroke(cr);
	121	cairo_surface_write_to_png (surface,filename);
	122	cairo_surface_finish (surface);
	123	return TS_SUCCESS;
	124	}