static int stl_check_normal_vector(stl_file *stl, int facet_num, int normal_fix_flag) {
/* Returns 0 if the normal is within tolerance */
/* Returns 1 if the normal is not within tolerance, but direction is OK */
/* Returns 2 if the normal is not within tolerance and backwards */
/* Returns 4 if the status is unknown. */
stl_facet *facet;
facet = &stl->facet_start[facet_num];
stl_normal normal;
stl_calculate_normal(normal, facet);
stl_normalize_vector(normal);
stl_normal normal_dif = (normal - facet->normal).cwiseAbs();
const float eps = 0.001f;
if (normal_dif(0) < eps && normal_dif(1) < eps && normal_dif(2) < eps) {
/* It is not really necessary to change the values here */
/* but just for consistency, I will. */
facet->normal = normal;
return 0;
}
stl_normal test_norm = facet->normal;
stl_normalize_vector(test_norm);
normal_dif = (normal - test_norm).cwiseAbs();
if (normal_dif(0) < eps && normal_dif(1) < eps && normal_dif(2) < eps) {
if(normal_fix_flag) {
facet->normal = normal;
stl->stats.normals_fixed += 1;
}
return 1;
}
test_norm *= -1.f;
normal_dif = (normal - test_norm).cwiseAbs();
if (normal_dif(0) < eps && normal_dif(1) < eps && normal_dif(2) < eps) {
// Facet is backwards.
if(normal_fix_flag) {
facet->normal = normal;
stl->stats.normals_fixed += 1;
}
return 2;
}
if(normal_fix_flag) {
facet->normal = normal;
stl->stats.normals_fixed += 1;
}
return 4;
}
static float get_area(stl_facet *facet)
{
float cross[3][3];
float sum[3];
float n[3];
float area;
int i;
for(i = 0; i < 3; i++){
cross[i][0]=((facet->vertex[i].y * facet->vertex[(i + 1) % 3].z) -
(facet->vertex[i].z * facet->vertex[(i + 1) % 3].y));
cross[i][1]=((facet->vertex[i].z * facet->vertex[(i + 1) % 3].x) -
(facet->vertex[i].x * facet->vertex[(i + 1) % 3].z));
cross[i][2]=((facet->vertex[i].x * facet->vertex[(i + 1) % 3].y) -
(facet->vertex[i].y * facet->vertex[(i + 1) % 3].x));
}
sum[0] = cross[0][0] + cross[1][0] + cross[2][0];
sum[1] = cross[0][1] + cross[1][1] + cross[2][1];
sum[2] = cross[0][2] + cross[1][2] + cross[2][2];
/* This should already be done. But just in case, let's do it again */
stl_calculate_normal(n, facet);
stl_normalize_vector(n);
area = 0.5 * (n[0] * sum[0] + n[1] * sum[1] + n[2] * sum[2]);
return area;
}
void stl_reverse_all_facets(stl_file *stl)
{
if (stl->error)
return;
stl_normal normal;
for(int i = 0; i < stl->stats.number_of_facets; i++) {
stl_reverse_facet(stl, i);
stl_calculate_normal(normal, &stl->facet_start[i]);
stl_normalize_vector(normal);
stl->facet_start[i].normal = normal;
}
}
static void calculate_normals(stl_file *stl)
{
long i;
float normal[3];
for(i = 0; i < stl->stats.number_of_facets; i++){
stl_calculate_normal(normal, &stl->facet_start[i]);
stl_normalize_vector(normal);
stl->facet_start[i].normal.x = normal[0];
stl->facet_start[i].normal.y = normal[1];
stl->facet_start[i].normal.z = normal[2];
}
}
void
stl_reverse_all_facets(stl_file *stl)
{
int i;
float normal[3];
for(i = 0; i < stl->stats.number_of_facets; i++)
{
stl_reverse_facet(stl, i);
stl_calculate_normal(normal, &stl->facet_start[i]);
stl_normalize_vector(normal);
stl->facet_start[i].normal.x = normal[0];
stl->facet_start[i].normal.y = normal[1];
stl->facet_start[i].normal.z = normal[2];
}
}
int
stl_check_normal_vector(stl_file *stl, int facet_num, int normal_fix_flag)
{
/* Returns 0 if the normal is within tolerance */
/* Returns 1 if the normal is not within tolerance, but direction is OK */
/* Returns 2 if the normal is not within tolerance and backwards */
/* Returns 4 if the status is unknown. */
float normal[3];
float test_norm[3];
stl_facet *facet;
facet = &stl->facet_start[facet_num];
stl_calculate_normal(normal, facet);
stl_normalize_vector(normal);
if( (ABS(normal[0] - facet->normal.x) < 0.001)
&& (ABS(normal[1] - facet->normal.y) < 0.001)
&& (ABS(normal[2] - facet->normal.z) < 0.001))
{
/* It is not really necessary to change the values here */
/* but just for consistency, I will. */
facet->normal.x = normal[0];
facet->normal.y = normal[1];
facet->normal.z = normal[2];
return 0;
}
test_norm[0] = facet->normal.x;
test_norm[1] = facet->normal.y;
test_norm[2] = facet->normal.z;
stl_normalize_vector(test_norm);
if( (ABS(normal[0] - test_norm[0]) < 0.001)
&& (ABS(normal[1] - test_norm[1]) < 0.001)
&& (ABS(normal[2] - test_norm[2]) < 0.001))
{
if(normal_fix_flag)
{
facet->normal.x = normal[0];
facet->normal.y = normal[1];
facet->normal.z = normal[2];
stl->stats.normals_fixed += 1;
}
return 1;
}
stl_reverse_vector(test_norm);
if( (ABS(normal[0] - test_norm[0]) < 0.001)
&& (ABS(normal[1] - test_norm[1]) < 0.001)
&& (ABS(normal[2] - test_norm[2]) < 0.001))
{
/* Facet is backwards. */
if(normal_fix_flag)
{
facet->normal.x = normal[0];
facet->normal.y = normal[1];
facet->normal.z = normal[2];
stl->stats.normals_fixed += 1;
}
return 2;
}
if(normal_fix_flag)
{
facet->normal.x = normal[0];
facet->normal.y = normal[1];
facet->normal.z = normal[2];
stl->stats.normals_fixed += 1;
}
return 4;
}
