Cycles: Fix one-tile UDIM rendering

The code checked for the presence of more than one tile before
substituting the tile number into the filename, so if a one-tile
UDIM was used (or all but one tile were culled), the substitution
was skipped and as a result the file was not found.

With this change, the code explicitly tracks whether substitution
is required, avoiding this problem.

This also fixes another problem: The Environment texture never
does substitution since it doesn't support UDIMs, but before the
syncing code still inserted the placeholder into the filename if the
user selected a tiled background image.

1 files changed, 1 insertions, 0 deletions

diff --git a/intern/cycles/render/nodes.h b/intern/cycles/render/nodes.h
index a8fe7644957..5b23ef6929e 100644
--- a/intern/cycles/render/nodes.h
+++ b/intern/cycles/render/nodes.h
@@ -114,6 +114,7 @@ class ImageTextureNode : public ImageSlotTextureNode {
   bool animated;
   float3 vector;
   ccl::vector<int> tiles;
+  bool is_tiled;
 
   /* Runtime. */
   bool is_float;