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generate a polygon of the vertices

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This commit is contained in:
Trammell Hudson 2015-02-15 13:50:32 -05:00
parent c1e6633cd4
commit 3f102c5621
1 changed files with 59 additions and 17 deletions
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76
faces.c
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@ -67,28 +67,64 @@ svg_line(
}
void
draw_face(
/** Starting at a point, trace the coplanar polygon and return a
* list of vertices.
*/
int
trace_face(
const stl_3d_t * const stl,
const stl_face_t * const f,
int * const face_used,
const refframe_t * const ref
const stl_face_t * const f_start,
const stl_vertex_t ** vertex_list,
int * const face_used
)
{
if (face_used[f - stl->face]++)
return;
const stl_face_t * f = f_start;
int i = 0;
int vertex_count = 0;
for (int i = 0 ; i < 3 ; i++)
{
if (!f->face[i] || f->angle[i] != 0)
// preload the list with the starting point
vertex_list[vertex_count++] = f->vertex[i];
do {
const stl_vertex_t * const v1 = f->vertex[(i+0) % 3];
const stl_vertex_t * const v2 = f->vertex[(i+1) % 3];
const stl_face_t * const f_next = f->face[i];
fprintf(stderr, "%p %d: %f,%f,%f\n", f, i, v1->p.p[0], v1->p.p[1], v1->p.p[2]);
face_used[f - stl->face] = 1;
if (!f_next || f->angle[i] != 0)
{
// not coplanar (or missing?)
svg_line(ref, f->vertex[i]->p, f->vertex[(i+1)%3]->p);
} else {
// coplanar, recurse
draw_face(stl, f->face[i], face_used, ref);
// not coplanar or no connection.
// add the NEXT vertex on this face and continue
vertex_list[vertex_count++] = v2;
i = (i+1) % 3;
continue;
}
}
// coplanar; figure out which vertex on the next
// face we start at
int i_next = -1;
for (int j = 0 ; j < 3 ; j++)
{
if (f_next->vertex[j] != v1)
continue;
i_next = j;
break;
}
if (i_next == -1)
abort();
// move to the new face
f = f_next;
i = i_next;
// keep going until we reach our starting face
// at vertex 0.
} while (f != f_start || i != 0);
return vertex_count;
}
@ -108,6 +144,7 @@ main(void)
printf("<svg xmlns=\"http://www.w3.org/2000/svg\">\n");
printf("<g transform=\"scale(3.543307)\"><!-- scale to mm -->\n");
const stl_vertex_t ** const vertex_list = calloc(sizeof(*vertex_list), stl->num_vertex);
for(int i = 0 ; i < stl->num_face ; i++)
{
@ -115,6 +152,9 @@ main(void)
continue;
const stl_face_t * const f = &stl->face[i];
const int vertex_count = trace_face(stl, f, vertex_list, face_used);
fprintf(stderr, "%d: %d vertices\n", i, vertex_count);
// generate a refernce frame based on this face
refframe_t ref = {
@ -129,7 +169,9 @@ main(void)
ref.y = v3_norm(v3_cross(ref.x, ref.z));
printf("<!-- face %d --><g>\n", i);
draw_face(stl, f, face_used, &ref);
for (int j = 0 ; j < vertex_count-1 ; j++)
svg_line(&ref, vertex_list[j]->p, vertex_list[j+1]->p);
printf("</g>\n");
}