trisurf-ng.git - Gitblit

Samo Penic

2012-06-07 eb86057daf38a5964f0dc570243b8e60d299f2ac

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d7639a	1	#include<stdlib.h>
SP	2	#include<stdio.h>
	3	#include "general.h"
	4	#include "triangle.h"
	5	#include<math.h>
	6
bb77ca	7	/** @brief Prepares the list for triangles.
SP	8	*
	9	* Create empty list for holding the information on triangles. Triangles are
	10	* added later on with triangle_add().
	11	* Returns pointer to the tlist datastructure it has created. This pointer must
	12	* be assigned to some variable or it will be lost.
	13	*
	14	*
	15	* Example of usage:
	16	* ts_triangle_list *tlist;
	17	* tlist=triangle_data_free();
	18	*
	19	* Initalized data structure for holding the information on triangles.
	20	*
	21	*/
a2a676	22	ts_triangle_list *init_triangle_list(){
SP	23	ts_triangle_list tlist=(ts_triangle_list )malloc(sizeof(ts_triangle_list));
d7639a	24	tlist->n = 0;
a2a676	25	tlist->tria=NULL;
SP	26	return tlist;
d7639a	27	}
SP	28
bb77ca	29	/** @brief Add the triangle to the triangle list and create necessary data
SP	30	* structures.
	31	*
	32	* Add the triangle ts_triangle with ts_triangle_data to the ts_triangle_list.
	33	* The triangle list is resized, the ts_triangle is allocated and
	34	* ts_triangle_data is allocated and zeroed. The function receives 4 arguments:
	35	* ts_triangle_list tlist as list of triangles and 3 ts_vertex vtx as
	36	* vertices that are used to form a triangle. Returns a pointer to newly
	37	* created triangle. This pointer doesn't need assigning, since it is
	38	* referenced by triangle list.
	39	*
	40	* WARNING: Function can be accelerated a bit by removing the NULL checks.
	41	* However the time gained by removal doesn't justify the time spent by
	42	* debugging stupid NULL pointers.
	43	*
	44	* Example of usage:
	45	* triangle_add(tlist, vlist->vtx[1], vlist->vtx[2], vlist->vtx[3]);
	46	*
	47	* Creates a triangle with given vertices and puts it into the list.
	48	*
	49	*/
a2a676	50	ts_triangle triangle_add(ts_triangle_list tlist, ts_vertex vtx1, ts_vertex vtx2, ts_vertex *vtx3){
SP	51	if(vtx1==NULL \|\| vtx2==NULL \|\| vtx3==NULL){
	52	return NULL;
	53	}
d7639a	54	tlist->n++;
a2a676	55	tlist->tria=(ts_triangle *)realloc(tlist->tria,tlist->nsizeof(ts_triangle *));
SP	56	if(tlist->tria==NULL) fatal("Cannot reallocate memory for additional ts_triangle.",5);
	57
	58	tlist->tria[tlist->n-1]=(ts_triangle *)calloc(1,sizeof(ts_triangle));
	59	if(tlist->tria[tlist->n-1]==NULL) fatal("Cannot reallocate memory for additional ts_triangle.",5);
41a035	60	// tlist->tria[tlist->n-1]->data=(ts_triangle_data *)calloc(1,sizeof(ts_triangle_data));
a2a676	61
d7639a	62	//NOW insert vertices!
a2a676	63	tlist->tria[tlist->n - 1]->idx=tlist->n-1;
41a035	64	tlist->tria[tlist->n - 1]->vertex[0]=vtx1;
SP	65	tlist->tria[tlist->n - 1]->vertex[1]=vtx2;
	66	tlist->tria[tlist->n - 1]->vertex[2]=vtx3;
a2a676	67	return tlist->tria[tlist->n-1];
d7639a	68	}
SP	69
bb77ca	70	/** @brief Add the neigbour to triangles.
SP	71	*
	72	* Add the neigbour to the list of neighbouring triangles. The
	73	* neighbouring triangles are those, who share two vertices. Function resizes
	74	* the list and adds the pointer to neighbour. It receives two arguments of
dac2e5	75	* ts_triangle type. It then adds second triangle to the list of first
SP	76	* triangle, but not the opposite. Upon
bb77ca	77	* success it returns TS_SUCCESS, upon detecting NULL pointers
SP	78	* returns TS_FAIL and it FATALY ends when the data structure
	79	* cannot be resized.
	80	*
	81	*
	82	* WARNING: Function can be accelerated a bit by removing the NULL checks.
	83	* However the time gained by removal doesn't justify the time spent by
	84	* debugging stupid NULL pointers.
	85	*
	86	* Example of usage:
	87	* triangle_remove_neighbour(tlist->tria[3], tlist->tria[4]);
	88	*
	89	* Triangles 3 and 4 are not neighbours anymore.
	90	*
	91	*/
d7639a	92
SP	93	ts_bool triangle_add_neighbour(ts_triangle tria, ts_triangle ntria){
a2a676	94	if(tria==NULL \|\| ntria==NULL) return TS_FAIL;
SP	95	/*TODO: check if the neighbour already exists! Now there is no such check
	96	* because of the performance issue. */
41a035	97	tria->neigh_no++;
SP	98	tria->neigh=realloc(tria->neigh,tria->neigh_nosizeof(ts_triangle ));
	99	if(tria->neigh == NULL)
d7639a	100	fatal("Reallocation of memory failed during insertion of triangle neighbour in triangle_add_neighbour",3);
41a035	101	tria->neigh[tria->neigh_no-1]=ntria;
3131dc	102
SP	103
a2a676	104	/* we repeat the procedure for the neighbour */
3131dc	105	/* ntria->data->neigh_no++;
a2a676	106	ntria->data->neigh=realloc(ntria->data->neigh,ntria->data->neigh_nosizeof(ts_triangle ));
SP	107	if(ntria->data->neigh == NULL)
	108	fatal("Reallocation of memory failed during insertion of triangle neighbour in triangle_add_neighbour",3);
	109	ntria->data->neigh[ntria->data->neigh_no-1]=tria;
3131dc	110	*/
d7639a	111	return TS_SUCCESS;
SP	112	}
	113
bb77ca	114	/** @brief Remove the neigbours from triangle.
SP	115	*
	116	* Removes the neigbour from the list of neighbouring triangles. The
	117	* neighbouring triangles are those, who share two vertices. Function resizes
	118	* the list and deletes the pointer to neighbour. It receives two arguments of
	119	* ts_triangle type. It then removes eachother form eachother's list. Upon
	120	* success it returns TS_SUCCESS, upon failure to find the triangle in the
	121	* neighbour list returns TS_FAIL and it FATALY ends when the datastructure
	122	* cannot be resized.
	123	*
	124	* WARNING: The function doesn't check whether the pointer is NULL or invalid. It is the
	125	* job of programmer to make sure the pointer is valid.
	126	*
	127	* WARNING: Function is slow. Do not use it often!
	128	*
	129	* Example of usage:
	130	* triangle_remove_neighbour(tlist->tria[3], tlist->tria[4]);
	131	*
	132	* Triangles 3 and 4 are not neighbours anymore.
	133	*
	134	*/
d7639a	135	ts_bool triangle_remove_neighbour(ts_triangle tria, ts_triangle ntria){
a2a676	136	ts_uint i,j=0;
SP	137	if(tria==NULL \|\| ntria==NULL) return TS_FAIL;
	138
41a035	139	for(i=0;i<tria->neigh_no;i++){
SP	140	if(tria->neigh[i]!=ntria){
	141	tria->neigh[j]=tria->neigh[i];
d7639a	142	j++;
SP	143	}
	144	}
a2a676	145	if(j==i) {
SP	146	return TS_FAIL;
	147	//fatal("In triangle_remove_neighbour: Specified neighbour does not exist for given triangle",3);
	148	}
41a035	149	tria->neigh_no--;
SP	150	tria->neigh=(ts_triangle *)realloc(tria->neigh,tria->neigh_nosizeof(ts_triangle *));
	151	if(tria->neigh == NULL){
a2a676	152	fatal("Reallocation of memory failed during removal of vertex neighbour in triangle_remove_neighbour",100);
SP	153	}
	154	/* we repeat the procedure for neighbour */
41a035	155	for(i=0;i<ntria->neigh_no;i++){
SP	156	if(ntria->neigh[i]!=tria){
	157	ntria->neigh[j]=ntria->neigh[i];
a2a676	158	j++;
SP	159	}
	160	}
	161	if(j==i) {
	162	return TS_FAIL;
	163	//fatal("In triangle_remove_neighbour: Specified neighbour does not exist for given triangle",3);
	164	}
41a035	165	ntria->neigh_no--;
SP	166	ntria->neigh=(ts_triangle *)realloc(ntria->neigh,ntria->neigh_nosizeof(ts_triangle *));
	167	if(ntria->neigh == NULL){
a2a676	168	fatal("Reallocation of memory failed during removal of vertex neighbour in triangle_remove_neighbour",100);
SP	169	}
d7639a	170	return TS_SUCCESS;
SP	171	}
	172
bb77ca	173
SP	174	/** @brief Calculates normal vector of the triangle.
	175
	176	*
	177	* Calculate normal vector of the triangle (xnorm, ynorm and znorm) and stores
	178	* information in underlying ts_triangle_data data_structure.
	179	*
	180	* Function receives one argument of type ts_triangle. It should be corectly
	181	* initialized with underlying data structure of type ts_triangle_data. the
	182	* result is stored in triangle->data->xnorm, triangle->data->ynorm,
	183	* triangle->data->znorm. Returns TS_SUCCESS on completion.
	184	*
	185	* NOTE: Function uses math.h library. pow function implementation is selected
	186	* accordind to the setting in genreal.h
	187	*
	188	* Example of usage:
	189	* triangle_normal_vector(tlist->tria[3]);
	190	*
	191	* Computes normals and stores information into tlist->tria[3]->xnorm,
	192	* tlist->tria[3]->ynorm, tlist->tria[3]->znorm.
	193	*
	194	*/
d7639a	195	ts_bool triangle_normal_vector(ts_triangle *tria){
SP	196	ts_double x21,x31,y21,y31,z21,z31,xden;
8f6a69	197	x21=tria->vertex[1]->x - tria->vertex[0]->x;
SP	198	x31=tria->vertex[2]->x - tria->vertex[0]->x;
	199	y21=tria->vertex[1]->y - tria->vertex[0]->y;
	200	y31=tria->vertex[2]->y - tria->vertex[0]->y;
	201	z21=tria->vertex[1]->z - tria->vertex[0]->z;
	202	z31=tria->vertex[2]->z - tria->vertex[0]->z;
d7639a	203
41a035	204	tria->xnorm=y21z31 - z21y31;
SP	205	tria->ynorm=z21x31 - x21z31;
	206	tria->znorm=x21y31 - y21x31;
	207	xden=tria->xnorm*tria->xnorm +
	208	tria->ynorm*tria->ynorm +
	209	tria->znorm*tria->znorm;
d7639a	210	#ifdef TS_DOUBLE_DOUBLE
SP	211	xden=sqrt(xden);
	212	#endif
	213	#ifdef TS_DOUBLE_FLOAT
	214	xden=sqrtf(xden);
	215	#endif
	216	#ifdef TS_DOUBLE_LONGDOUBLE
	217	xden=sqrtl(xden);
	218	#endif
41a035	219	tria->xnorm=tria->xnorm/xden;
SP	220	tria->ynorm=tria->ynorm/xden;
	221	tria->znorm=tria->znorm/xden;
d7639a	222	return TS_SUCCESS;
SP	223	}
	224
	225
bb77ca	226
SP	227
	228
d7639a	229
bb77ca	230	/** @brief Frees the memory allocated for data structure of triangle list
SP	231	* (ts_triangle_list)
	232	*
	233	* Function frees the memory of ts_triangle_list previously allocated. It
	234	* accepts one argument, the address of data structure. It destroys all
	235	* ts_triangle's in the list with underlying data (by calling
	236	* triangle_data_free()), and the list itself.
	237	*
	238	* Should be used eveytime the deletion of triangle list (created by
	239	* init_triangle_list() and altered by add_triangle() or remove_triangle()) is desired.
	240	*
	241	* WARNING: The function doesn't check whether the pointer is NULL or invalid. It is the
	242	* job of programmer to make sure the pointer is valid.
	243	*
	244	* WARNING: Careful when destroying triangle lists. There could be pointers to
	245	* that information remaining in structures like vertex_data. This pointers
	246	* will be rendered invalid by this operation and should not be used anymore.
	247	*
	248	* Example of usage:
	249	* triangle_list_free(tlist);
	250	*
	251	* Clears all the information on triangles.
	252	*
	253	*/
d7639a	254	ts_bool triangle_list_free(ts_triangle_list *tlist){
a2a676	255	ts_uint i;
d7639a	256	for(i=0;i<tlist->n;i++){
41a035	257	if(tlist->tria[i]->neigh!=NULL) free(tlist->tria[i]->neigh);
a2a676	258	free(tlist->tria[i]);
d7639a	259	}
a2a676	260	free(tlist->tria);
SP	261	free(tlist);
d7639a	262	return TS_SUCCESS;
SP	263	}
	264