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BMesh: move bridge tools stepping logic into macro 

Also use floor division since regular division was giving a bias
on negative error values.
This commit is contained in:
Campbell Barton 2017-09-18 00:06:29 +10:00
parent 8ca11b7084
commit 02b206780e
1 changed files with 49 additions and 51 deletions
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100
source/blender/bmesh/intern/bmesh_edgeloop.c
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@ -707,67 +707,65 @@ void BM_edgeloop_expand(
split_swap = !split_swap;
}
/* TODO, move to generic define? */
/**
* Even value distribution.
*
* \a src must be larger than \a dst,
* \a dst defines the number of iterations, their values are evenly spaced.
*
* The following pairs represent (src, dst) arguments and the values they loop over.
* <pre>
* (19, 4) -> [2, 7, 11. 16]
* (100, 5) -> [9, 29, 49, 69, 89]
* (100, 3) -> [16, 49, 83]
* (100, 100) -> [0..99]
* </pre>
* \note this is mainly useful for numbers that might not divide evenly into eachother.
*/
#define BLI_FOREACH_SPARSE_RANGE(src, dst, i) \
for (int _src = (src), _src2 = _src * 2, _dst2 = (dst) * 2, _error = _dst2 - _src, i = 0, _delta; \
((void)(_delta = divide_floor_i(_error, _dst2)), \
(void)(i -= _delta), \
(i < _src)); \
_error -= (_delta * _dst2) + _src2)
if (el_store->len < el_store_len) {
LinkData *node_curr = el_store->verts.first;
/**
* Bresenham's line algorithm is used for even spaced edge-loop distribution.
*
* Step over x until y reaches a large enough error and a new pivot is added.
* Note that x/y aren't meaningful in this context, but keep since logic matches line drawing.
*/
const int x_span = el_store->len;
const int y_span = el_store_len - el_store->len;
int iter_prev = 0;
BLI_FOREACH_SPARSE_RANGE(el_store->len, (el_store_len - el_store->len), iter) {
while (iter_prev < iter) {
node_curr = node_curr->next;
iter_prev += 1;
}
const int x_span_2x = x_span * 2;
const int y_span_2x = y_span * 2;
BLI_assert(x_span >= y_span);
/* error may go below zero */
int error = y_span_2x - x_span;
int x_iter = 0; /* traverse elements in 'el_store->len'. */
int y_iter = 0; /* each step on this variable represents a new pivot. */
while (x_iter != x_span) {
if (error >= 0) {
y_iter += 1;
error -= x_span_2x;
/* Split logic */
{
LinkData *node_curr_copy;
node_curr_copy = MEM_dupallocN(node_curr);
if (split == false) {
BLI_insertlinkafter(&el_store->verts, node_curr, node_curr_copy);
node_curr = node_curr_copy->next;
}
else {
if (node_curr->next || (el_store->flag & BM_EDGELOOP_IS_CLOSED)) {
EDGE_SPLIT(node_curr_copy,
node_curr->next ? node_curr->next : (LinkData *)el_store->verts.first);
BLI_insertlinkafter(&el_store->verts, node_curr, node_curr_copy);
node_curr = node_curr_copy->next;
}
else {
EDGE_SPLIT(node_curr_copy, node_curr->prev);
BLI_insertlinkbefore(&el_store->verts, node_curr, node_curr_copy);
node_curr = node_curr->next;
}
split_swap = !split_swap;
}
el_store->len++;
}
LinkData *node_curr_copy;
node_curr_copy = MEM_dupallocN(node_curr);
if (split == false) {
BLI_insertlinkafter(&el_store->verts, node_curr, node_curr_copy);
node_curr = node_curr_copy->next;
}
else {
node_curr = node_curr->next;
if (node_curr->next || (el_store->flag & BM_EDGELOOP_IS_CLOSED)) {
EDGE_SPLIT(node_curr_copy,
node_curr->next ? node_curr->next : (LinkData *)el_store->verts.first);
BLI_insertlinkafter(&el_store->verts, node_curr, node_curr_copy);
node_curr = node_curr_copy->next;
}
else {
EDGE_SPLIT(node_curr_copy, node_curr->prev);
BLI_insertlinkbefore(&el_store->verts, node_curr, node_curr_copy);
node_curr = node_curr->next;
}
split_swap = !split_swap;
}
x_iter += 1;
error += y_span_2x;
el_store->len++;
iter_prev += 1;
}
}
#undef BKE_FOREACH_SUBSET_OF_RANGE
#undef EDGE_SPLIT
BLI_assert(el_store->len == el_store_len);