void
mat_make_look_at(struct matrix *m, const struct vector *o,
const struct vector *p)
{
struct vector n, u, v, t;
struct matrix a;
vec_sub(&n, p, o);
vec_normalize(&n);
/* v' = (0, 1, 0) */
vec_set(&v, 0.f, 1.f, 0.f);
/* v = v' - (v'*n)*n */
vec_scalar_mul_copy(&t, &n, vec_dot_product(&v, &n));
vec_sub_from(&v, &t);
vec_normalize(&v);
vec_cross_product(&u, &v, &n);
vec_normalize(&u);
m->m11 = u.x; m->m12 = u.y; m->m13 = u.z; m->m14 = 0.f;
m->m21 = v.x; m->m22 = v.y; m->m23 = v.z; m->m24 = 0.f;
m->m31 = n.x; m->m32 = n.y; m->m33 = n.z; m->m34 = 0.f;
mat_make_translation(&a, -o->x, -o->y, -o->z);
mat_mul(m, &a);
}
/**
* Calculate vertex normal vector
*/
int MeshData::calc_vex_norm(int vex_id, double *v)
{
int ele_n, *ele;
double v1[3], v2[3], v3[3];
int i1, i2, i3, ei;
int i, j;
double l;
// clear v
for(i=0; i<3; i++) v[i] = 0.0;
// get elements which contain given vertex
ele_n = 40;
ele = new int[ele_n];
get_ele_by_vex(vex_id, &ele_n, ele);
// for each element
for(i=0; i<ele_n; i++) {
ei = ele[i];
i1 = ele_arr[ei*3+0];
i2 = ele_arr[ei*3+1];
i3 = ele_arr[ei*3+2];
// v2 - v1
v1[0] = vex_arr[i2*3+0] - vex_arr[i1*3+0];
v1[1] = vex_arr[i2*3+1] - vex_arr[i1*3+1];
v1[2] = vex_arr[i2*3+2] - vex_arr[i1*3+2];
// v3 - v1
v2[0] = vex_arr[i3*3+0] - vex_arr[i1*3+0];
v2[1] = vex_arr[i3*3+1] - vex_arr[i1*3+1];
v2[2] = vex_arr[i3*3+2] - vex_arr[i1*3+2];
// (v2-v1)x(v3-v1)
vec_cross_product(v1, v2, v3);
v[0] += v3[0];
v[1] += v3[1];
v[2] += v3[2];
}
// average normal vector
v[0] /= ele_n;
v[1] /= ele_n;
v[2] /= ele_n;
// normalize length
l = sqrt(v[0]*v[0] + v[1]*v[1] + v[2]*v[2]);
v[0] /= l;
v[1] /= l;
v[2] /= l;
delete ele;
return 0;
}
static void createObjectCoordSystem(CoordinateSystem<float> *pXYZ,const float Z[3])
{
static const double cc=1./64.;
float X[3],Y[3];
if (Z[0]==0 && Z[1]==0 && Z[2]>=0) {
X[0]=1; X[1]=0; X[2]=0;
Y[0]=0; Y[1]=1; Y[2]=0;
} else if (Z[0]>-cc && Z[0]<cc && Z[1]>-cc && Z[1]<cc) {
/*X= [0 1 0] x Z*/
X[0]=Z[2]; X[1]=0; X[2]=-Z[0];
} else {
/*X= [0 0 1] x Z*/
X[0]=-Z[1]; X[1]=Z[0]; X[2]=0;
}
vec_cross_product(Y,Z,X);
pXYZ->setGlobal();
pXYZ->setAxis(X,Y,Z);
}
int MeshData::calc_ele_norm(void)
{
int i;
int i1, i2, i3;
double v1[3], v2[3], v3[3];
double vl;
if( ele_norm == NULL ) {
ele_norm = new double[ele_num*3];
}
// for each element
for(i=0; i<ele_num; i++) {
i1 = ele_arr[i*3+0];
i2 = ele_arr[i*3+1];
i3 = ele_arr[i*3+2];
// v2 - v1
v1[0] = vex_arr[i2*3+0] - vex_arr[i1*3+0];
v1[1] = vex_arr[i2*3+1] - vex_arr[i1*3+1];
v1[2] = vex_arr[i2*3+2] - vex_arr[i1*3+2];
// v3 - v1
v2[0] = vex_arr[i3*3+0] - vex_arr[i1*3+0];
v2[1] = vex_arr[i3*3+1] - vex_arr[i1*3+1];
v2[2] = vex_arr[i3*3+2] - vex_arr[i1*3+2];
// (v2-v1)x(v3-v1)
vec_cross_product(v1, v2, v3);
vl = sqrt(v3[0]*v3[0] + v3[1]*v3[1] + v3[2]*v3[2]);
ele_norm[i*3+0] = v3[0] / vl;
ele_norm[i*3+1] = v3[1] / vl;
ele_norm[i*3+2] = v3[2] / vl;
}
return 0;
}
void
mesh_init_poly_normals(struct mesh *mesh)
{
struct polygon *p, *end;
struct vector u, v;
int *vtx_index;
struct vertex *vtx;
vtx = mesh->vtx;
end = &mesh->poly[mesh->npoly];
for (p = mesh->poly; p != end; p++) {
assert(p->nvtx >= 3);
vtx_index = p->vtx_index;
vec_sub(&u, &vtx[vtx_index[1]].pos, &vtx[vtx_index[0]].pos);
vec_sub(&v, &vtx[vtx_index[2]].pos, &vtx[vtx_index[0]].pos);
vec_cross_product(&p->normal, &u, &v);
vec_normalize(&p->normal);
}
}
void BSplineSurf::recalcCoords(float ds,float dt)
{
float s,t;
float out[3];
int ns,nt;
myVector<float> sv;
myVector<float> tv;
for (s=U[0]; s<U[1]; s+=ds) {
sv.append(s);
}
sv.append(U[1]);
for (t=V[0]; t<V[1]; t+=dt) {
tv.append(t);
}
tv.append(V[1]);
total_coords=sv.length()*tv.length();
coords=(float(*)[3])malloc(total_coords*sizeof(float[3]));
total_coords=0;
for (ns=0; ns<sv.length(); ns++) {
s=sv.at(ns);
for (nt=0; nt<tv.length(); nt++) {
t=tv.at(nt);
getParamPoint(s,t,coords[total_coords]);
total_coords++;
}
}
myVector<int> N;
int striplen;
for (ns=0; ns<sv.length()-1; ns++) {
N.append(0);
striplen=N.length()-1;
for (nt=0; nt<tv.length(); nt++) {
N.append(nt+tv.length()*ns);
N.append(nt+ tv.length()*(ns+1));
}
N.at(striplen)=tv.length()*2;
}
N.append(0);
free(strip);
strip=(int*)malloc(N.length()*sizeof(int));
memcpy(strip,N.getData(),N.length()*sizeof(int));
free(normals);
normals=(float(*)[3])calloc(total_coords,sizeof(float[3]));
int *ar,totta,k;
ar=strip;
while (ar[0]) {
totta=ar[0]; ar++;
for (k=2; k<totta; k++) {
float g1[3],g2[3],g3[3];
vec_diff(g1,coords[ ar[k-2] ],coords[ ar[k-1] ]);
vec_diff(g2,coords[ ar[k-1] ],coords[ ar[k] ]);
vec_cross_product(g3,g1,g2);
vec_normalize(g3);
if (k&1) {
vec_flip(g3,g3);
}
vec_sum(normals[ ar[k] ],normals[ ar[k] ],g3);
if (k==2) {
vec_sum(normals[ ar[0] ],normals[ ar[0] ],g3);
vec_sum(normals[ ar[1] ],normals[ ar[1] ],g3);
}
}
ar+=totta;
}
for (k=0; k<total_coords; k++) {
vec_normalize(normals[k]);
}
}