/**
* Triangulates the given (convex or concave) simple polygon to a list of triangle vertices.
* \param vertices pairs describing vertices of the polygon, in either clockwise or counterclockwise order.
* \return triples of triangle indices in clockwise order.
* Note the returned array is reused for later calls to the same method.
*/
void BLI_polyfill_calc_ex(
const float (*coords)[2],
const unsigned int coords_tot,
unsigned int (*r_tris)[3],
unsigned int *r_indices, eSign *r_coords_sign)
{
PolyFill pf;
/* localize */
unsigned int *indices = r_indices;
eSign *coords_sign = r_coords_sign;
unsigned int i;
/* assign all polyfill members here */
pf.indices = r_indices;
pf.coords = coords;
pf.coords_tot = coords_tot;
pf.coords_sign = r_coords_sign;
#ifdef USE_CONVEX_SKIP
pf.coords_tot_concave = 0;
#endif
pf.tris = r_tris;
pf.tris_tot = 0;
if ((coords_tot < 3) ||
cross_poly_v2((int)coords_tot, (float(*)[2])coords) > 0.0f)
{
for (i = 0; i < coords_tot; i++) {
indices[i] = i;
}
}
else {
/* reversed */
unsigned int n = coords_tot - 1;
for (i = 0; i < coords_tot; i++) {
indices[i] = (n - i);
}
}
for (i = 0; i < coords_tot; i++) {
coords_sign[i] = pf_coord_sign_calc(&pf, i);
#ifdef USE_CONVEX_SKIP
if (coords_sign[i] != CONVEX) {
pf.coords_tot_concave += 1;
}
#endif
}
pf_triangulate(&pf);
}
/**
* Triangulates the given (convex or concave) simple polygon to a list of triangle vertices.
*
* \param coords pairs describing vertices of the polygon, in either clockwise or counterclockwise order.
* \return triples of triangle indices in clockwise order.
* Note the returned array is reused for later calls to the same method.
*/
static void polyfill_prepare(
PolyFill *pf,
const float (*coords)[2],
const unsigned int coords_tot,
int coords_sign,
unsigned int (*r_tris)[3],
PolyIndex *r_indices)
{
/* localize */
PolyIndex *indices = r_indices;
unsigned int i;
/* assign all polyfill members here */
pf->indices = r_indices;
pf->coords = coords;
pf->coords_tot = coords_tot;
#ifdef USE_CONVEX_SKIP
pf->coords_tot_concave = 0;
#endif
pf->tris = r_tris;
pf->tris_tot = 0;
if (coords_sign == 0) {
coords_sign = (cross_poly_v2(coords, coords_tot) >= 0.0f) ? 1 : -1;
}
else {
/* chech we're passing in correcty args */
#ifndef NDEBUG
if (coords_sign == 1) {
BLI_assert(cross_poly_v2(coords, coords_tot) >= 0.0f);
}
else {
BLI_assert(cross_poly_v2(coords, coords_tot) <= 0.0f);
}
#endif
}
if (coords_sign == 1) {
for (i = 0; i < coords_tot; i++) {
indices[i].next = &indices[i + 1];
indices[i].prev = &indices[i - 1];
indices[i].index = i;
}
}
else {
/* reversed */
unsigned int n = coords_tot - 1;
for (i = 0; i < coords_tot; i++) {
indices[i].next = &indices[i + 1];
indices[i].prev = &indices[i - 1];
indices[i].index = (n - i);
}
}
indices[0].prev = &indices[coords_tot - 1];
indices[coords_tot - 1].next = &indices[0];
for (i = 0; i < coords_tot; i++) {
PolyIndex *pi = &indices[i];
pf_coord_sign_calc(pf, pi);
#ifdef USE_CONVEX_SKIP
if (pi->sign != CONVEX) {
pf->coords_tot_concave += 1;
}
#endif
}
}
static void pf_triangulate(PolyFill *pf)
{
/* localize */
PolyIndex *pi_ear;
#ifdef USE_CLIP_EVEN
PolyIndex *pi_ear_init = pf->indices;
#endif
#ifdef USE_CLIP_SWEEP
bool reverse = false;
#endif
while (pf->coords_tot > 3) {
PolyIndex *pi_prev, *pi_next;
eSign sign_orig_prev, sign_orig_next;
pi_ear = pf_ear_tip_find(
pf
#ifdef USE_CLIP_EVEN
, pi_ear_init
#endif
#ifdef USE_CLIP_SWEEP
, reverse
#endif
);
#ifdef USE_CLIP_SWEEP
#ifdef USE_CLIP_EVEN
if (pi_ear != pi_ear_init) {
reverse = !reverse;
}
#else
if (pi_ear != pf->indices) {
reverse = !reverse;
}
#endif
#endif
#ifdef USE_CONVEX_SKIP
if (pi_ear->sign != CONVEX) {
pf->coords_tot_concave -= 1;
}
#endif
pi_prev = pi_ear->prev;
pi_next = pi_ear->next;
pf_ear_tip_cut(pf, pi_ear);
/* The type of the two vertices adjacent to the clipped vertex may have changed. */
sign_orig_prev = pi_prev->sign;
sign_orig_next = pi_next->sign;
/* check if any verts became convex the (else if)
* case is highly unlikely but may happen with degenerate polygons */
if (sign_orig_prev != CONVEX) {
pf_coord_sign_calc(pf, pi_prev);
#ifdef USE_CONVEX_SKIP
if (pi_prev->sign == CONVEX) {
pf->coords_tot_concave -= 1;
#ifdef USE_KDTREE
kdtree2d_node_remove(&pf->kdtree, pi_prev->index);
#endif
}
#endif
}
if (sign_orig_next != CONVEX) {
pf_coord_sign_calc(pf, pi_next);
#ifdef USE_CONVEX_SKIP
if (pi_next->sign == CONVEX) {
pf->coords_tot_concave -= 1;
#ifdef USE_KDTREE
kdtree2d_node_remove(&pf->kdtree, pi_next->index);
#endif
}
#endif
}
#ifdef USE_CLIP_EVEN
#ifdef USE_CLIP_SWEEP
pi_ear_init = reverse ? pi_next->next : pi_prev->prev;
#else
pi_ear_init = pi_next->next;
#endif
#endif
}
if (pf->coords_tot == 3) {
unsigned int *tri = pf_tri_add(pf);
pi_ear = pf->indices;
tri[0] = pi_ear->index; pi_ear = pi_ear->next;
tri[1] = pi_ear->index; pi_ear = pi_ear->next;
tri[2] = pi_ear->index;
}
}
static void pf_triangulate(PolyFill *pf)
{
/* localize */
eSign *coords_sign = pf->coords_sign;
unsigned int index_ear_tip = 0;
while (pf->coords_tot > 3) {
unsigned int i_prev, i_next;
#ifdef USE_CONVEX_SKIP
eSign sign_orig_prev, sign_orig_next;
#endif
#ifdef USE_CLIP_EVEN
index_ear_tip = pf_ear_tip_find(pf, index_ear_tip);
#else
index_ear_tip = pf_ear_tip_find(pf);
#endif
#ifdef USE_CONVEX_SKIP
if (coords_sign[index_ear_tip] != CONVEX) {
pf->coords_tot_concave -= 1;
}
#endif
pf_ear_tip_cut(pf, index_ear_tip);
/* The type of the two vertices adjacent to the clipped vertex may have changed. */
i_prev = pf_index_prev(pf, index_ear_tip);
i_next = (index_ear_tip == pf->coords_tot) ? 0 : index_ear_tip;
#ifdef USE_CONVEX_SKIP
sign_orig_prev = coords_sign[i_prev];
sign_orig_next = coords_sign[i_next];
#endif
coords_sign[i_prev] = pf_coord_sign_calc(pf, i_prev);
coords_sign[i_next] = pf_coord_sign_calc(pf, i_next);
#ifdef USE_CONVEX_SKIP
/* check if any verts became convex the (else if)
* case is highly unlikely but may happen with degenerate polygons */
if ((sign_orig_prev != CONVEX) && (coords_sign[i_prev] == CONVEX)) pf->coords_tot_concave -= 1;
else if (UNLIKELY((sign_orig_prev == CONVEX) && (coords_sign[i_prev] != CONVEX))) pf->coords_tot_concave += 1;
if ((sign_orig_next != CONVEX) && (coords_sign[i_next] == CONVEX)) pf->coords_tot_concave -= 1;
else if (UNLIKELY((sign_orig_next == CONVEX) && (coords_sign[i_next] != CONVEX))) pf->coords_tot_concave += 1;
#endif
#ifdef USE_CLIP_EVEN
index_ear_tip = i_prev;
#endif
}
if (pf->coords_tot == 3) {
unsigned int *tri = pf_tri_add(pf);
tri[0] = pf->indices[0];
tri[1] = pf->indices[1];
tri[2] = pf->indices[2];
}
}