bloomenthal.cpp

快速fft变换的c实现

	if (l->i == i && l->j == j && l->k == k) {
	    c->value = l->value;
	    return c;
	    }
    l = (CORNERLIST *) mycalloc(1, sizeof(CORNERLIST));
    l->i = i; l->j = j; l->k = k;
    l->value = c->value = function(c->x, c->y, c->z);
    l->next = p->corners[index];
    p->corners[index] = l;
    return c;
}

/* find: search for point with value of given sign (0: neg, 1: pos) */


Bloomenthal::TEST Bloomenthal::find1(int sign, PROCESS *p, double x, double y, double z)
{
	int i;
    TEST test;
    double range = p->size;
    test.ok = 1;
    for (i = 0; i < 10000; i++) {
	test.p.x = x+range*(RAND()-0.5);
	test.p.y = y+range*(RAND()-0.5);
	test.p.z = z+range*(RAND()-0.5);
	test.value = function(test.p.x, test.p.y, test.p.z);
	if (sign == (test.value > 0.0)) return test;
	range = range*1.0005; /* slowly expand search outwards */
    }
    test.ok = 0;
    return test;
}

/**** Tetrahedral Polygonization ****/

/* dotet: triangulate the tetrahedron
 * b, c, d should appear clockwise when viewed from a
 * return 0 if client aborts, 1 otherwise */

int Bloomenthal::dotet(CUBE *cube, int c1, int c2, int c3, int c4, PROCESS *p)
{
	CORNER *a = cube->corners[c1];
    CORNER *b = cube->corners[c2];
    CORNER *c = cube->corners[c3];
    CORNER *d = cube->corners[c4];
    int index = 0, apos, bpos, cpos, dpos, e1, e2, e3, e4, e5, e6;
    if (apos = (a->value > 0.0)) index += 8;
    if (bpos = (b->value > 0.0)) index += 4;
    if (cpos = (c->value > 0.0)) index += 2;
    if (dpos = (d->value > 0.0)) index += 1;
    /* index is now 4-bit number representing one of the 16 possible cases */
    if (apos != bpos) e1 = vertid(a, b, p);
    if (apos != cpos) e2 = vertid(a, c, p);
    if (apos != dpos) e3 = vertid(a, d, p);
    if (bpos != cpos) e4 = vertid(b, c, p);
    if (bpos != dpos) e5 = vertid(b, d, p);
    if (cpos != dpos) e6 = vertid(c, d, p);
    /* 14 productive tetrahedral cases (0000 and 1111 do not yield polygons */
    switch (index) {
	case 1:	 return triproc(e5, e6, e3, p->vertices);
	case 2:	 return triproc(e2, e6, e4, p->vertices);
	case 3:	 return triproc(e3, e5, e4, p->vertices) &&
			triproc(e3, e4, e2, p->vertices);
	case 4:	 return triproc(e1, e4, e5, p->vertices);
	case 5:	 return triproc(e3, e1, e4, p->vertices) &&
			triproc(e3, e4, e6, p->vertices);
	case 6:	 return triproc(e1, e2, e6, p->vertices) &&
			triproc(e1, e6, e5, p->vertices);
	case 7:	 return triproc(e1, e2, e3, p->vertices);
	case 8:	 return triproc(e1, e3, e2, p->vertices);
	case 9:	 return triproc(e1, e5, e6, p->vertices) &&
			triproc(e1, e6, e2, p->vertices);
	case 10: return triproc(e1, e3, e6, p->vertices) &&
			triproc(e1, e6, e4, p->vertices);
	case 11: return triproc(e1, e5, e4, p->vertices);
	case 12: return triproc(e3, e2, e4, p->vertices) &&
			triproc(e3, e4, e5, p->vertices);
	case 13: return triproc(e6, e2, e4, p->vertices);
	case 14: return triproc(e5, e3, e6, p->vertices);
    }
    return 1;
}

/**** Cubical Polygonization (optional) ****/

/* docube: triangulate the cube directly, without decomposition */

int Bloomenthal::docube(CUBE *cube, PROCESS *p)
{
	INTLISTS *polys;
    int i, index = 0;
    for (i = 0; i < 8; i++) if (cube->corners[i]->value > 0.0) index += (1<<i);
    for (polys = cubetable[index]; polys; polys = polys->next) {
	INTLIST *edges;
	int a = -1, b = -1, count = 0;
	for (edges = polys->list; edges; edges = edges->next) {
	    CORNER *c1 = cube->corners[corner1[edges->i]];
	    CORNER *c2 = cube->corners[corner2[edges->i]];
	    int c = vertid(c1, c2, p);
	    if (++count > 2 && ! triproc(a, b, c, p->vertices)) return 0;
	    if (count < 3) a = b;
	    b = c;
	}
    }
    return 1;
}

/* nextcwedge: return next clockwise edge from given edge around given face */

 Bloomenthal::nextcwedge(int edge, int face)
{
	switch (edge) {
	case LB: return (face == L)? LF : BN;
	case LT: return (face == L)? LN : TF;
	case LN: return (face == L)? LB : TN;
	case LF: return (face == L)? LT : BF;
	case RB: return (face == R)? RN : BF;
	case RT: return (face == R)? RF : TN;
	case RN: return (face == R)? RT : BN;
	case RF: return (face == R)? RB : TF;
	case BN: return (face == B)? RB : LN;
	case BF: return (face == B)? LB : RF;
	case TN: return (face == T)? LT : RN;
	case TF: return (face == T)? RT : LF;
	default: return 0;
    }
}

/* otherface: return face adjoining edge that is not the given face */

int Bloomenthal::otherface(int edge, int face)
{
	int other = leftface[edge];
    return face == other? rightface[edge] : other;
}

/* makecubetable: create the 256 entry table for cubical polygonization */

void Bloomenthal::makecubetable()
{
	static int visited = 0;

	if (visited)
		return;

	visited = 1;

	int i, e, c, done[12], pos[8];
    for (i = 0; i < 256; i++) {
	for (e = 0; e < 12; e++) done[e] = 0;
	for (c = 0; c < 8; c++) pos[c] = BIT(i, c);
	for (e = 0; e < 12; e++)
	    if (!done[e] && (pos[corner1[e]] != pos[corner2[e]])) {
		INTLIST *ints = 0;
		INTLISTS *lists = (INTLISTS *) mycalloc(1, sizeof(INTLISTS));
		int start = e, edge = e;
		/* get face that is to right of edge from pos to neg corner: */
		int face = pos[corner1[e]]? rightface[e] : leftface[e];
		while (1) {
		    edge = nextcwedge(edge, face);
		    done[edge] = 1;
		    if (pos[corner1[edge]] != pos[corner2[edge]]) {
			INTLIST *tmp = ints;
			ints = (INTLIST *) mycalloc(1, sizeof(INTLIST));
			ints->i = edge;
			ints->next = tmp; /* add edge to head of list */
			if (edge == start) break;
			face = otherface(edge, face);
		    }
		}
		lists->list = ints; /* add ints to head of table entry */
		lists->next = cubetable[i];
		cubetable[i] = lists;
	    }
    }
}

/**** Storage ****/

/* mycalloc: return successful calloc or exit program */

char * Bloomenthal::mycalloc(int nitems, int nbytes)
{
	char *ptr = (char*)calloc(nitems, nbytes);
	if (ptr != NULL) return ptr;
	fprintf(stderr, "can't calloc %d bytes\n", nitems*nbytes);
	exit(1);
}

/* setcenter: set (i,j,k) entry of table[]
 * return 1 if already set; otherwise, set and return 0 */

int Bloomenthal::setcenter(CENTERLIST *table[], int i, int j, int k)
{
	int index = HASH(i, j, k);
    CENTERLIST *new1, *l, *q = table[index];
    for (l = q; l != NULL; l = l->next)
	if (l->i == i && l->j == j && l->k == k) return 1;
    new1 = (CENTERLIST *) mycalloc(1, sizeof(CENTERLIST));
    new1->i = i; new1->j = j; new1->k = k; new1->next = q;
    table[index] = new1;
    return 0;
}

/* setedge: set vertex id for edge */

void Bloomenthal::setedge(EDGELIST *table[], int i1, int j1, int k1, int i2, int j2, int k2, int vid)
{
	unsigned int index;
    EDGELIST *new1;
    if (i1>i2 || (i1==i2 && (j1>j2 || (j1==j2 && k1>k2)))) {
	int t=i1; i1=i2; i2=t; t=j1; j1=j2; j2=t; t=k1; k1=k2; k2=t;
    }
    index = HASH(i1, j1, k1) + HASH(i2, j2, k2);
    new1 = (EDGELIST *) mycalloc(1, sizeof(EDGELIST));
    new1->i1 = i1; new1->j1 = j1; new1->k1 = k1;
    new1->i2 = i2; new1->j2 = j2; new1->k2 = k2;
    new1->vid = vid;
    new1->next = table[index];
    table[index] = new1;	
}

/* getedge: return vertex id for edge; return -1 if not set */

int Bloomenthal::getedge(EDGELIST *table[], int i1, int j1, int k1, int i2, int j2, int k2)
{
	EDGELIST *q;
    if (i1>i2 || (i1==i2 && (j1>j2 || (j1==j2 && k1>k2)))) {
	int t=i1; i1=i2; i2=t; t=j1; j1=j2; j2=t; t=k1; k1=k2; k2=t;
    };
    q = table[HASH(i1, j1, k1)+HASH(i2, j2, k2)];
    for (; q != NULL; q = q->next)
	if (q->i1 == i1 && q->j1 == j1 && q->k1 == k1 &&
	    q->i2 == i2 && q->j2 == j2 && q->k2 == k2)
	    return q->vid;
    return -1;
}

/**** Vertices ****/


/* vertid: return index for vertex on edge:
 * c1->value and c2->value are presumed of different sign
 * return saved index if any; else compute vertex and save */

int Bloomenthal::vertid(CORNER *c1, CORNER *c2, PROCESS *p)
{
	VERTEX v;
    POINT1 a, b;
    int vid = getedge(p->edges, c1->i, c1->j, c1->k, c2->i, c2->j, c2->k);
    if (vid != -1) return vid;			     /* previously computed */
    a.x = c1->x; a.y = c1->y; a.z = c1->z;
    b.x = c2->x; b.y = c2->y; b.z = c2->z;

	double x1, y1, z1, x2, y2, z2, f1, f2;
	if(c1->value > 0){
		f1 = c1->value;
		x1 = c1->x; y1 = c1->y; z1 = c1->z;
		f2 = c2->value;
		x2 = c2->x; y2 = c2->y; z2 = c2->z;
	}
	else{
		f1 = c2->value;
		x1 = c2->x; y1 = c2->y; z1 = c2->z;
		f2 = c1->value;
		x2 = c1->x; y2 = c1->y; z2 = c1->z;
	}

	//Repeated Linear Interpolation
	double x, y, z, f;
	for(int i=0; i<10; i++){
		double w1 = fabs(f1);
		double w2 = fabs(f2);
		x = (w2*x1 + w1*x2)/(w1+w2);
		y = (w2*y1 + w1*y2)/(w1+w2);
		z = (w2*z1 + w1*z2)/(w1+w2);
		break;

		f = function(x,y,z);
		if(fabs(f) < 0.00001)
			break;
		if(f > 0){
			f1 = f;
			x1 = x;  y1 = y;  z1 = z;
		}
		else{
			f2 = f;
			x2 = x;  y2 = y;  z2 = z;
		}
	}
	v.position.x = x;
	v.position.y = y;
	v.position.z = z;

	

    //converge(&a, &b, c1->value, &v.position); /* position */
    //vnormal(&v.position, p, &v.normal);			   /* normal */
    addtovertices(&p->vertices, v);			   /* save vertex */
    vid = p->vertices.count-1;
    setedge(p->edges, c1->i, c1->j, c1->k, c2->i, c2->j, c2->k, vid);
    return vid;
}

/* addtovertices: add v to sequence of vertices */

void Bloomenthal::addtovertices(VERTICES *vertices, VERTEX v)
{
	if(FILEOUT){
		fprintf(ver_file, "%f %f %f\n", v.position.x, v.position.y, v.position.z);
		vertices->count++;
	}
	else{
		if(vertices->count == vertices->max) {
			int i;
			VERTEX *new1;
			vertices->max = vertices->count == 0 ? 10 : 2*vertices->count;
			new1 = (VERTEX *) mycalloc((unsigned) vertices->max, sizeof(VERTEX));
			for (i = 0; i < vertices->count; i++) new1[i] = vertices->ptr[i];
			if (vertices->ptr != NULL) free((char *)vertices->ptr);
			vertices->ptr = new1;
		}
		vertices->ptr[vertices->count++] = v;
	}
}

/* vnormal: compute unit length surface normal at point */

void Bloomenthal::vnormal(POINT1 *point, PROCESS *p, POINT1 *v)
{
	double f = function(point->x, point->y, point->z);
    v->x = function(point->x+p->delta, point->y, point->z)-f;
    v->y = function(point->x, point->y+p->delta, point->z)-f;
    v->z = function(point->x, point->y, point->z+p->delta)-f;
    f = sqrt(v->x*v->x + v->y*v->y + v->z*v->z);
    if (f != 0.0) {v->x /= f; v->y /= f; v->z /= f;}
}

/* converge: from two points of differing sign, converge to zero crossing */
void Bloomenthal::converge(POINT1 *p1, POINT1 *p2, double v, POINT1 *p)
{
	int i = 0;
    POINT1 pos, neg;
    if (v < 0) {
	pos.x = p2->x; pos.y = p2->y; pos.z = p2->z;
	neg.x = p1->x; neg.y = p1->y; neg.z = p1->z;
    }
    else {
	pos.x = p1->x; pos.y = p1->y; pos.z = p1->z;
	neg.x = p2->x; neg.y = p2->y; neg.z = p2->z;
    }
    while (1) {
	p->x = 0.5*(pos.x + neg.x);
	p->y = 0.5*(pos.y + neg.y);
	p->z = 0.5*(pos.z + neg.z);
	if (i++ == RES) return;
	if ((function(p->x, p->y, p->z)) > 0.0)
	     {pos.x = p->x; pos.y = p->y; pos.z = p->z;}
	else {neg.x = p->x; neg.y = p->y; neg.z = p->z;}
    }
}

double Bloomenthal::function(double x, double y, double z)
{
	return func->GetValue((float)x, (float)y, (float)z);
}