Fix [#37394] UV Map cannot be renamed.

Own epic failure! CustomData_get_named_layer() returns a relative index, not an absolute one. :(

1 files changed, 12 insertions, 6 deletions

diff --git a/source/blender/blenkernel/intern/mesh.c b/source/blender/blenkernel/intern/mesh.c
index a77f768835a..844252c583c 100644
--- a/source/blender/blenkernel/intern/mesh.c
+++ b/source/blender/blenkernel/intern/mesh.c
@@ -708,26 +708,32 @@ bool BKE_mesh_uv_cdlayer_rename(Mesh *me, const char *old_name, const char *new_
 					return false;
 				}
 				else {
-					lidx = lidx_start + (fidx - fidx_start);
+					lidx = fidx;
 				}
 			}
-			pidx = pidx_start + (lidx - lidx_start);
+			pidx = lidx;
 		}
 		else {
 			if (lidx == -1) {
-				lidx = lidx_start + (pidx - pidx_start);
+				lidx = pidx;
 			}
 			if (fidx == -1 && do_tessface) {
-				fidx = fidx_start + (pidx - pidx_start);
+				fidx = pidx;
 			}
 		}
 #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);
+		else if (pidx != lidx) {
+			lidx = pidx;
 		}
 #endif
 
+		/* Go back to absolute indices! */
+		pidx += pidx_start;
+		lidx += lidx_start;
+		if (fidx != -1)
+			fidx += fidx_start;
+
 		return BKE_mesh_uv_cdlayer_rename_index(me, pidx, lidx, fidx, new_name, do_tessface);
 	}
 }