Fix T49534: 2.78 Wrong texture scaling in material viewport

Seems to be a bug in original implementation of a830280: code was always
using tangent space instead of UV map because it had the same name. Now
prefer UVMap over tangent because this is how Cycles works. At least it's
closer to.

Not sure it the save+reload issue is still relevant after this fix, that
needs to be double-checked.

Thanks @dfelinto for looking into the report and simplifying the case.

Should be included into 2.78a.

1 files changed, 4 insertions, 4 deletions

diff --git a/source/blender/blenkernel/intern/DerivedMesh.c b/source/blender/blenkernel/intern/DerivedMesh.c
index 8168817491f..f75b3c0df85 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.c
+++ b/source/blender/blenkernel/intern/DerivedMesh.c
@@ -3675,15 +3675,15 @@ void DM_vertex_attributes_from_gpu(DerivedMesh *dm, GPUVertexAttribs *gattribs,
 			 * We do it based on the specified name.
 			 */
 			if (gattribs->layer[b].name[0]) {
-				layer = CustomData_get_named_layer_index(&dm->loopData, CD_TANGENT, gattribs->layer[b].name);
-				type = CD_TANGENT;
+				layer = CustomData_get_named_layer_index(ldata, CD_MLOOPUV, gattribs->layer[b].name);
+				type = CD_MTFACE;
 				if (layer == -1) {
 					layer = CustomData_get_named_layer_index(ldata, CD_MLOOPCOL, gattribs->layer[b].name);
 					type = CD_MCOL;
 				}
 				if (layer == -1) {
-					layer = CustomData_get_named_layer_index(ldata, CD_MLOOPUV, gattribs->layer[b].name);
-					type = CD_MTFACE;
+					layer = CustomData_get_named_layer_index(&dm->loopData, CD_TANGENT, gattribs->layer[b].name);
+					type = CD_TANGENT;
 				}
 				if (layer == -1) {
 					continue;