Fix [#36759] UV Project - Specified UV Map doesnt work properly

In fact, the issue was that names of mloopuv/mtespoly layers could very easily get out of sync (a simple rename was enough), while most tools (such as the UVProject modifier) expect matching layers to have the same name!

Now matching names are check on load, and renaming of a layer through RNA is guaranted to be synchronized with its counterparts.

Thanks to Brecht & Campbell for reviews.

1 files changed, 82 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/mesh.c b/source/blender/blenkernel/intern/mesh.c
index 63a7b8cd982..8c179d17901 100644
--- a/source/blender/blenkernel/intern/mesh.c
+++ b/source/blender/blenkernel/intern/mesh.c
@@ -40,6 +40,8 @@
 #include "BLI_math.h"
 #include "BLI_listbase.h"
 #include "BLI_edgehash.h"
+#include "BLI_string_utf8.h"
+#include "BLI_string.h"
 
 #include "BKE_animsys.h"
 #include "BKE_main.h"
@@ -622,6 +624,86 @@ void BKE_mesh_make_local(Mesh *me)
 	}
 }
 
+bool BKE_mesh_uv_cdlayer_rename_index(Mesh *me, const int poly_index, const int loop_index, const int face_index,
+                                      const char *new_name, const bool do_tessface)
+{
+	CustomData *pdata = &me->pdata, *ldata = &me->ldata, *fdata = &me->fdata;
+	CustomDataLayer *cdlp = &pdata->layers[poly_index];
+	CustomDataLayer *cdlu = &ldata->layers[loop_index];
+	CustomDataLayer *cdlf = do_tessface ? &fdata->layers[face_index] : NULL;
+	const int step = do_tessface ? 3 : 2;
+	int i;
+
+	BLI_strncpy(cdlp->name, new_name, sizeof(cdlp->name));
+	CustomData_set_layer_unique_name(pdata, cdlp - pdata->layers);
+
+	/* Loop until we do have exactly the same name for all layers! */
+	for (i = 1; (strcmp(cdlp->name, cdlu->name) != 0 || (cdlf && strcmp(cdlp->name, cdlf->name) != 0)); i++) {
+		switch (i % step) {
+			case 0:
+				BLI_strncpy(cdlp->name, cdlu->name, sizeof(cdlp->name));
+				CustomData_set_layer_unique_name(pdata, cdlp - pdata->layers);
+				break;
+			case 1:
+				BLI_strncpy(cdlu->name, cdlp->name, sizeof(cdlu->name));
+				CustomData_set_layer_unique_name(ldata, cdlu - ldata->layers);
+				break;
+			case 2:
+				BLI_strncpy(cdlf->name, cdlp->name, sizeof(cdlf->name));
+				CustomData_set_layer_unique_name(fdata, cdlf - fdata->layers);
+				break;
+		}
+	}
+
+	return true;
+}
+
+bool BKE_mesh_uv_cdlayer_rename(Mesh *me, const char *old_name, const char *new_name, bool do_tessface)
+{
+	CustomData *pdata = &me->pdata, *ldata = &me->ldata, *fdata = &me->fdata;
+	const int pidx_start = CustomData_get_layer_index(pdata, CD_MTEXPOLY);
+	const int lidx_start = CustomData_get_layer_index(ldata, CD_MLOOPUV);
+	const int fidx_start = do_tessface ? CustomData_get_layer_index(fdata, CD_MTFACE) : -1;
+	int pidx, lidx, fidx;
+
+	do_tessface = (do_tessface && fdata->totlayer);
+	pidx = CustomData_get_named_layer(pdata, CD_MTEXPOLY, old_name);
+	lidx = CustomData_get_named_layer(ldata, CD_MLOOPUV, old_name);
+	fidx = do_tessface ? CustomData_get_named_layer(fdata, CD_MTFACE, old_name) : -1;
+
+	/* None of those cases should happen, in theory!
+	 * Note this assume we have the same number of mtexpoly, mloopuv and mtface layers!
+	 */
+	if (pidx == -1) {
+		if (lidx == -1) {
+			if (fidx == -1) {
+				/* No layer found with this name! */
+				return false;
+			}
+			else {
+				lidx = lidx_start + (fidx - fidx_start);
+			}
+		}
+		pidx = pidx_start + (lidx - lidx_start);
+	}
+	else {
+		if (lidx == -1) {
+			lidx = lidx_start + (pidx - pidx_start);
+		}
+		if (fidx == -1 && do_tessface) {
+			fidx = fidx_start + (pidx - pidx_start);
+		}
+	}
+#if 0
+	/* For now, we do not consider mismatch in indices (i.e. same name leading to (relative) different indices). */
+	else if ((pidx - pidx_start) != (lidx - lidx_start)) {
+		lidx = lidx_start + (pidx - pidx_start);
+	}
+#endif
+
+	return BKE_mesh_uv_cdlayer_rename_index(me, pidx, lidx, fidx, new_name, do_tessface);
+}
+
 void BKE_mesh_boundbox_calc(Mesh *me, float r_loc[3], float r_size[3])
 {
 	BoundBox *bb;