Revision: 64307
http://sourceforge.net/p/brlcad/code/64307
Author: starseeker
Date: 2015-02-26 23:46:36 +0000 (Thu, 26 Feb 2015)
Log Message:
-----------
Clean up and document the brep_to_bot routine
Modified Paths:
--------------
brlcad/trunk/src/librt/test_shape_recognition.cpp
Modified: brlcad/trunk/src/librt/test_shape_recognition.cpp
===================================================================
--- brlcad/trunk/src/librt/test_shape_recognition.cpp 2015-02-26 23:26:11 UTC
(rev 64306)
+++ brlcad/trunk/src/librt/test_shape_recognition.cpp 2015-02-26 23:46:36 UTC
(rev 64307)
@@ -22,22 +22,48 @@
void
brep_to_bot(struct subbrep_object_data *data, struct rt_wdb *wdbp)
{
- std::cout << "bot build for brep " << bu_vls_addr(data->key) << "\n";
/* Triangulate faces and write out as a bot */
struct bu_vls prim_name = BU_VLS_INIT_ZERO;
int all_faces_cnt = 0;
+ int face_error = 0;
+ int *final_faces = NULL;
+
+ // Accumulate faces in a std::vector, since we don't know how many we're
going to get
+ std::vector<int> all_faces;
+
+ /* Set up an inital comprehensive vertex array that will be used in
+ * the final BoT build - all face definitions will ultimately index
+ * into this array */
point_t *all_verts = (point_t *)bu_calloc(data->brep->m_V.Count(),
sizeof(point_t), "bot verts");
for (int vi = 0; vi < data->brep->m_V.Count(); vi++) {
VMOVE(all_verts[vi], data->brep->m_V[vi].Point());
}
- std::vector<int> all_faces;
+
+ // Iterate over all faces in the brep. TODO - should probably protect
this with some planar checks...
for (int s_it = 0; s_it < data->brep->m_F.Count(); s_it++) {
- int loop_length = 0;
+ int num_faces;
+ int *faces;
const ON_BrepFace *b_face = &(data->brep->m_F[s_it]);
+
+ /* There should be only an outer loop by this point in the process */
+ /* TODO - should probably check that as an error-out condition... */
const ON_BrepLoop *b_loop = b_face->OuterLoop();
- point_t *verts = (point_t *)bu_calloc(b_loop->m_ti.Count(),
sizeof(point_t), "bot verts");
+
+ /* We need to build a 2D vertex list for the triangulation, and as long
+ * as we make sure the vertex mapping accounts for flipped trims in 3D,
+ * the point indices returned for the 2D triangulation will correspond
+ * to the correct 3D points without any additional work. In essence,
+ * we use the fact that the BRep gives us a ready-made 2D point
+ * parameterization to same some work.*/
point2d_t *verts2d = (point2d_t *)bu_calloc(b_loop->m_ti.Count(),
sizeof(point2d_t), "bot verts");
+
+ /* The triangulation will use only the points in the temporay verts2d
+ * array and return with faces indexed accordingly, so we need a map to
+ * translate them back to our final vert array */
std::map<int, int> local_to_verts;
+
+ /* Now the fun begins. If we have an outer loop that isn't CCW, we
+ * need to assemble our verts2d polygon backwards */
if
(data->brep->LoopDirection(data->local_brep->m_L[b_loop->m_loop_index]) != 1) {
for (int ti = 0; ti < b_loop->m_ti.Count(); ti++) {
int ti_rev = b_loop->m_ti.Count() - 1 - ti;
@@ -47,14 +73,11 @@
ON_2dPoint cp = trim_curve->PointAt(trim_curve->Domain().Min());
V2MOVE(verts2d[ti], cp);
if (trim->m_bRev3d) {
- VMOVE(verts[ti], edge->Vertex(1)->Point());
local_to_verts[ti] = edge->Vertex(1)->m_vertex_index;
} else {
- VMOVE(verts[ti], edge->Vertex(0)->Point());
local_to_verts[ti] = edge->Vertex(0)->m_vertex_index;
}
}
-
} else {
for (int ti = 0; ti < b_loop->m_ti.Count(); ti++) {
const ON_BrepTrim *trim =
&(b_face->Brep()->m_T[b_loop->m_ti[ti]]);
@@ -63,23 +86,24 @@
ON_2dPoint cp = trim_curve->PointAt(trim_curve->Domain().Max());
V2MOVE(verts2d[ti], cp);
if (trim->m_bRev3d) {
- VMOVE(verts[ti], edge->Vertex(0)->Point());
local_to_verts[ti] = edge->Vertex(0)->m_vertex_index;
} else {
- VMOVE(verts[ti], edge->Vertex(1)->Point());
local_to_verts[ti] = edge->Vertex(1)->m_vertex_index;
}
}
}
- int num_faces;
- int *faces;
- //std::cout << "bot build for face " << b_face->m_face_index << "...\n";
- //if (b_face->m_bRev) std::cout << "(face is flipped)\n";
- int face_error = bn_polygon_triangulate(&faces, &num_faces, (const
point2d_t *)verts2d, b_loop->m_ti.Count());
+
+ /* The real work - triangulate the 2D polygon to find out triangles for
+ * this particular B-Rep face */
+ face_error = bn_polygon_triangulate(&faces, &num_faces, (const
point2d_t *)verts2d, b_loop->m_ti.Count());
if (face_error || !faces) {
std::cout << "bot build failed for face " << b_face->m_face_index
<< "\n";
+ bu_free(verts2d, "free tmp 2d vertex array");
+ bu_free(all_verts, "free top level vertex array");
return;
} else {
+ /* We aren't done with the reversing fun - if the face is reversed,
we need
+ * to flip our triangles as well */
if (b_face->m_bRev) {
for (int f_ind = 0; f_ind < num_faces; f_ind++) {
int itmp = faces[f_ind * 3 + 2];
@@ -87,22 +111,31 @@
faces[f_ind * 3 + 1] = itmp;
}
}
+ /* Now that we have our faces, map them from the local vertex
+ * indices to the global ones and insert the faces into the
+ * all_faces array */
for (int f_ind = 0; f_ind < num_faces*3; f_ind++) {
all_faces.push_back(local_to_verts[faces[f_ind]]);
}
all_faces_cnt += num_faces;
+ bu_free(verts2d, "free tmp 2d vertex array");
}
-#if 0
+
+ /* Uncomment this code to create per-face bots for debugging purposes */
+ /*
bu_vls_sprintf(&prim_name, "bot_%s_face_%d.s", bu_vls_addr(data->key),
b_face->m_face_index);
if (mk_bot(wdbp, bu_vls_addr(&prim_name), RT_BOT_SOLID,
RT_BOT_UNORIENTED, 0, b_loop->m_ti.Count(), num_faces, (fastf_t *)verts, faces,
(fastf_t *)NULL, (struct bu_bitv *)NULL)) {
std::cout << "mk_bot failed for face " << b_face->m_face_index <<
"\n";
- }
-#endif
+ }*/
}
- int *final_faces = (int *)bu_calloc(all_faces_cnt * 3, sizeof(int), "final
bot verts");
- for (size_t i = 0; i < all_faces_cnt*3; i++) {
+
+ /* Now we can build the final faces array for mk_bot */
+ final_faces = (int *)bu_calloc(all_faces_cnt * 3, sizeof(int), "final bot
verts");
+ for (int i = 0; i < all_faces_cnt*3; i++) {
final_faces[i] = all_faces[i];
}
+
+ /* Make the bot, using the data key for a unique name */
bu_vls_sprintf(&prim_name, "bot_%s.s", bu_vls_addr(data->key));
if (mk_bot(wdbp, bu_vls_addr(&prim_name), RT_BOT_SOLID, RT_BOT_UNORIENTED,
0, data->brep->m_V.Count(), all_faces_cnt, (fastf_t *)all_verts, final_faces,
(fastf_t *)NULL, (struct bu_bitv *)NULL)) {
std::cout << "mk_bot failed for overall bot\n";
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