/* rotates the vertices of a face in case v[2] or v[3] (vertex index) is = 0.
this is necessary to make the if(mface->v4) check for quads work */
int test_index_face(MFace *mface, CustomData *fdata, int mfindex, int nr)
{
/* first test if the face is legal */
if(mface->v3 && mface->v3==mface->v4) {
mface->v4= 0;
nr--;
}
if(mface->v2 && mface->v2==mface->v3) {
mface->v3= mface->v4;
mface->v4= 0;
nr--;
}
if(mface->v1==mface->v2) {
mface->v2= mface->v3;
mface->v3= mface->v4;
mface->v4= 0;
nr--;
}
/* prevent a zero at wrong index location */
if(nr==3) {
if(mface->v3==0) {
static int corner_indices[4] = {1, 2, 0, 3};
SWAP(int, mface->v1, mface->v2);
SWAP(int, mface->v2, mface->v3);
if(fdata)
CustomData_swap(fdata, mfindex, corner_indices);
}
}
else if(nr==4) {
/* rotates the vertices of a face in case v[2] or v[3] (vertex index) is = 0.
this is necessary to make the if(mface->v4) check for quads work */
int test_index_face(MFace *mface, CustomData *fdata, int mfindex, int nr)
{
/* first test if the face is legal */
if((mface->v3 || nr==4) && mface->v3==mface->v4) {
mface->v4= 0;
nr--;
}
if((mface->v2 || mface->v4) && mface->v2==mface->v3) {
mface->v3= mface->v4;
mface->v4= 0;
nr--;
}
if(mface->v1==mface->v2) {
mface->v2= mface->v3;
mface->v3= mface->v4;
mface->v4= 0;
nr--;
}
/* check corrupt cases, bowtie geometry, cant handle these because edge data wont exist so just return 0 */
if(nr==3) {
if(
/* real edges */
mface->v1==mface->v2 ||
mface->v2==mface->v3 ||
mface->v3==mface->v1
) {
return 0;
}
}
else if(nr==4) {
if(
/* real edges */
mface->v1==mface->v2 ||
mface->v2==mface->v3 ||
mface->v3==mface->v4 ||
mface->v4==mface->v1 ||
/* across the face */
mface->v1==mface->v3 ||
mface->v2==mface->v4
) {
return 0;
}
}
/* prevent a zero at wrong index location */
if(nr==3) {
if(mface->v3==0) {
static int corner_indices[4] = {1, 2, 0, 3};
SWAP(int, mface->v1, mface->v2);
SWAP(int, mface->v2, mface->v3);
if(fdata)
CustomData_swap(fdata, mfindex, corner_indices);
}
}
else if(nr==4) {
