Fix T51746: normal map tangents not working correctly when there are no UV maps.

Patch by Alexander, with some refactoring by Brecht.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D2709

2 files changed, 4 insertions, 5 deletions

diff --git a/source/blender/render/intern/include/render_types.h b/source/blender/render/intern/include/render_types.h
index f0323340899..f9942bef61f 100644
--- a/source/blender/render/intern/include/render_types.h
+++ b/source/blender/render/intern/include/render_types.h
@@ -335,7 +335,7 @@ typedef struct ObjectRen {
 	char (*mcol)[MAX_CUSTOMDATA_LAYER_NAME];
 	int  actmtface, actmcol, bakemtface;
 
-	char tangent_mask; /* which tangent layer should be calculated */
+	short tangent_mask; /* which tangent layer should be calculated */
 
 	float obmat[4][4];	/* only used in convertblender.c, for instancing */
 
diff --git a/source/blender/render/intern/source/convertblender.c b/source/blender/render/intern/source/convertblender.c
index 41ff8e046e7..4876d2d193e 100644
--- a/source/blender/render/intern/source/convertblender.c
+++ b/source/blender/render/intern/source/convertblender.c
@@ -3439,10 +3439,9 @@ static void init_render_mesh(Render *re, ObjectRen *obr, int timeoffset)
 										if (need_nmap_tangent_concrete || need_tangent) {
 											int uv_start = CustomData_get_layer_index(&dm->faceData, CD_MTFACE);
 											int uv_index = CustomData_get_named_layer_index(&dm->faceData, CD_MTFACE, layer->name);
-											BLI_assert(uv_start >= 0 && uv_index >= 0);
-											if ((uv_start < 0 || uv_index < 0))
-												continue;
-											int n = uv_index - uv_start;
+
+											/* if there are no UVs, orco tangents are in first slot */
+											int n = (uv_start >= 0 && uv_index >= 0) ? uv_index - uv_start : 0;
 
 											const float *tangent = (const float *) layer->data;
 											float *ftang = RE_vlakren_get_nmap_tangent(obr, vlr, n, true);