1 files changed, 169 insertions, 0 deletions
diff --git a/source/blender/bmesh/intern/bmesh_query_uv.c b/source/blender/bmesh/intern/bmesh_query_uv.c
new file mode 100644
index 00000000000..b9ea51f0c4d
--- /dev/null
+++ b/source/blender/bmesh/intern/bmesh_query_uv.c
@@ -0,0 +1,169 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+/** \file
+ * \ingroup bmesh
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_alloca.h"
+#include "BLI_linklist.h"
+#include "BLI_math.h"
+#include "BLI_utildefines_stack.h"
+
+#include "BKE_customdata.h"
+
+#include "DNA_meshdata_types.h"
+
+#include "bmesh.h"
+#include "intern/bmesh_private.h"
+
+static void uv_aspect(const BMLoop *l,
+                      const float aspect[2],
+                      const int cd_loop_uv_offset,
+                      float r_uv[2])
+{
+  const float *uv = ((const MLoopUV *)BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset))->uv;
+  r_uv[0] = uv[0] * aspect[0];
+  r_uv[1] = uv[1] * aspect[1];
+}
+
+/**
+ * Typically we avoid hiding arguments,
+ * make this an exception since it reads poorly with so many repeated arguments.
+ */
+#define UV_ASPECT(l, r_uv) uv_aspect(l, aspect, cd_loop_uv_offset, r_uv)
+
+/**
+ * Computes the UV center of a face, using the mean average weighted by edge length.
+ *
+ * See #BM_face_calc_center_median_weighted for matching spatial functionality.
+ *
+ * \param aspect: Calculate the center scaling by these values, and finally dividing.
+ * Since correct weighting depends on having the correct aspect.
+ */
+void BM_face_uv_calc_center_median_weighted(const BMFace *f,
+                                            const float aspect[2],
+                                            const int cd_loop_uv_offset,
+                                            float r_cent[2])
+{
+  const BMLoop *l_iter;
+  const BMLoop *l_first;
+  float totw = 0.0f;
+  float w_prev;
+
+  zero_v2(r_cent);
+
+  l_iter = l_first = BM_FACE_FIRST_LOOP(f);
+
+  float uv_prev[2], uv_curr[2];
+  UV_ASPECT(l_iter->prev, uv_prev);
+  UV_ASPECT(l_iter, uv_curr);
+  w_prev = len_v2v2(uv_prev, uv_curr);
+  do {
+    float uv_next[2];
+    UV_ASPECT(l_iter->next, uv_next);
+    const float w_curr = len_v2v2(uv_curr, uv_next);
+    const float w = (w_curr + w_prev);
+    madd_v2_v2fl(r_cent, uv_curr, w);
+    totw += w;
+    w_prev = w_curr;
+    copy_v2_v2(uv_curr, uv_next);
+  } while ((l_iter = l_iter->next) != l_first);
+
+  if (totw != 0.0f) {
+    mul_v2_fl(r_cent, 1.0f / (float)totw);
+  }
+  /* Reverse aspect. */
+  r_cent[0] /= aspect[0];
+  r_cent[1] /= aspect[1];
+}
+
+#undef UV_ASPECT
+
+/**
+ * Calculate the UV cross product (use the sign to check the winding).
+ */
+float BM_face_uv_calc_cross(const BMFace *f, const int cd_loop_uv_offset)
+{
+  float(*uvs)[2] = BLI_array_alloca(uvs, f->len);
+  const BMLoop *l_iter;
+  const BMLoop *l_first;
+  int i = 0;
+  l_iter = l_first = BM_FACE_FIRST_LOOP(f);
+  do {
+    const MLoopUV *luv = BM_ELEM_CD_GET_VOID_P(l_iter, cd_loop_uv_offset);
+    copy_v2_v2(uvs[i++], luv->uv);
+  } while ((l_iter = l_iter->next) != l_first);
+  return cross_poly_v2(uvs, f->len);
+}
+
+/**
+ * Check if two loops that share an edge also have the same UV coordinates.
+ */
+bool BM_loop_uv_share_edge_check(BMLoop *l_a, BMLoop *l_b, const int cd_loop_uv_offset)
+{
+  BLI_assert(l_a->e == l_b->e);
+  MLoopUV *luv_a_curr = BM_ELEM_CD_GET_VOID_P(l_a, cd_loop_uv_offset);
+  MLoopUV *luv_a_next = BM_ELEM_CD_GET_VOID_P(l_a->next, cd_loop_uv_offset);
+  MLoopUV *luv_b_curr = BM_ELEM_CD_GET_VOID_P(l_b, cd_loop_uv_offset);
+  MLoopUV *luv_b_next = BM_ELEM_CD_GET_VOID_P(l_b->next, cd_loop_uv_offset);
+  if (l_a->v != l_b->v) {
+    SWAP(MLoopUV *, luv_b_curr, luv_b_next);
+  }
+  return (equals_v2v2(luv_a_curr->uv, luv_b_curr->uv) &&
+          equals_v2v2(luv_a_next->uv, luv_b_next->uv));
+}
+
+/**
+ * Check if two loops that share a vertex also have the same UV coordinates.
+ */
+bool BM_loop_uv_share_vert_check(BMLoop *l_a, BMLoop *l_b, const int cd_loop_uv_offset)
+{
+  BLI_assert(l_a->v == l_b->v);
+  const MLoopUV *luv_a = BM_ELEM_CD_GET_VOID_P(l_a, cd_loop_uv_offset);
+  const MLoopUV *luv_b = BM_ELEM_CD_GET_VOID_P(l_b, cd_loop_uv_offset);
+  if (!equals_v2v2(luv_a->uv, luv_b->uv)) {
+    return false;
+  }
+  return true;
+}
+
+/**
+ * Check if two loops that share a vertex also have the same UV coordinates.
+ */
+bool BM_edge_uv_share_vert_check(BMEdge *e, BMLoop *l_a, BMLoop *l_b, const int cd_loop_uv_offset)
+{
+  BLI_assert(l_a->v == l_b->v);
+  if (!BM_loop_uv_share_vert_check(l_a, l_b, cd_loop_uv_offset)) {
+    return false;
+  }
+
+  /* No need for NULL checks, these will always succeed. */
+  const BMLoop *l_other_a = BM_loop_other_vert_loop_by_edge(l_a, e);
+  const BMLoop *l_other_b = BM_loop_other_vert_loop_by_edge(l_b, e);
+
+  {
+    const MLoopUV *luv_other_a = BM_ELEM_CD_GET_VOID_P(l_other_a, cd_loop_uv_offset);
+    const MLoopUV *luv_other_b = BM_ELEM_CD_GET_VOID_P(l_other_b, cd_loop_uv_offset);
+    if (!equals_v2v2(luv_other_a->uv, luv_other_b->uv)) {
+      return false;
+    }
+  }
+
+  return true;
+}