UDIM: Support virtual filenames

This implements the design detailed in T92696 to support virtual
filenames for UDIM textures. Currently, the following 2 substitution
tokens are supported:

| Token | Meaning |
| ----- | ---- |
| <UDIM>   | 1001 + u-tile + v-tile * 10 |
| <UVTILE> | Equivalent to u<u-tile + 1>_v<v-tile + 1> |

Example for u-tile of 3 and v-tile of 1:
filename.<UDIM>_ver0023.png   --> filename.1014_ver0023.png
filename.<UVTILE>_ver0023.png --> filename.u4_v2_ver0023.png

For image loading, the existing workflow is unchanged. A user can select
one or more image files, belonging to one or more UDIM tile sets, and
have Blender load them all as it does today. Now the <UVTILE> format is
"guessed" just as the <UDIM> format was guessed before.

If guessing fails, the user can simply go into the Image Editor and type
the proper substitution in the filename. Once typing is complete,
Blender will reload the files and correctly fill the tiles. This
workflow is new as attempting to fix the guessing in current versions
did not really work, and the user was often stuck with a confusing
situation.

For image saving, the existing workflow is changed slightly. Currently,
when saving, a user has to be sure to type the filename of the first
tile (e.g. filename.1001.png) to save the entire UDIM set. The number
could differ if they start at a different tile etc. This is confusing.
Now, the user should type a filename containing the appropriate
substitution token. By default Blender will fill in a default name using
the <UDIM> token but the user is free to save out images using <UVTILE>
if they wish.

Differential Revision: https://developer.blender.org/D13057

1 files changed, 25 insertions, 28 deletions

diff --git a/source/blender/blenkernel/intern/image_save.c b/source/blender/blenkernel/intern/image_save.c
index f93ede517a9..329bc7b498b 100644
--- a/source/blender/blenkernel/intern/image_save.c
+++ b/source/blender/blenkernel/intern/image_save.c
@@ -30,6 +30,8 @@
 
 #include "DNA_image_types.h"
 
+#include "MEM_guardedalloc.h"
+
 #include "IMB_colormanagement.h"
 #include "IMB_imbuf.h"
 #include "IMB_imbuf_types.h"
@@ -402,15 +404,17 @@ bool BKE_image_save(
 
   bool colorspace_changed = false;
 
+  eUDIM_TILE_FORMAT tile_format;
+  char *udim_pattern = NULL;
+
   if (ima->source == IMA_SRC_TILED) {
-    /* Verify filepath for tiles images. */
-    ImageTile *first_tile = ima->tiles.first;
-    if (BLI_path_sequence_decode(opts->filepath, NULL, NULL, NULL) != first_tile->tile_number) {
+    /* Verify filepath for tiled images contains a valid UDIM marker. */
+    udim_pattern = BKE_image_get_tile_strformat(opts->filepath, &tile_format);
+    if (tile_format == UDIM_TILE_FORMAT_NONE) {
       BKE_reportf(reports,
                   RPT_ERROR,
-                  "When saving a tiled image, the path '%s' must contain the UDIM tile number %d",
-                  opts->filepath,
-                  first_tile->tile_number);
+                  "When saving a tiled image, the path '%s' must contain a valid UDIM marker",
+                  opts->filepath);
       return false;
     }
 
@@ -420,36 +424,29 @@ bool BKE_image_save(
     }
   }
 
-  /* Save image - or, for tiled images, the first tile. */
-  bool ok = image_save_single(reports, ima, iuser, opts, &colorspace_changed);
-
-  if (ok && ima->source == IMA_SRC_TILED) {
+  /* Save images */
+  bool ok = false;
+  if (ima->source != IMA_SRC_TILED) {
+    ok = image_save_single(reports, ima, iuser, opts, &colorspace_changed);
+  }
+  else {
     char filepath[FILE_MAX];
     BLI_strncpy(filepath, opts->filepath, sizeof(filepath));
 
-    char head[FILE_MAX], tail[FILE_MAX];
-    unsigned short numlen;
-    BLI_path_sequence_decode(filepath, head, tail, &numlen);
-
-    /* Save all other tiles. */
-    int index;
-    LISTBASE_FOREACH_INDEX (ImageTile *, tile, &ima->tiles, index) {
-      /* First tile was already saved before the loop. */
-      if (index == 0) {
-        continue;
-      }
+    /* Save all the tiles. */
+    LISTBASE_FOREACH (ImageTile *, tile, &ima->tiles) {
+      BKE_image_set_filepath_from_tile_number(
+          opts->filepath, udim_pattern, tile_format, tile->tile_number);
 
+      iuser->tile = tile->tile_number;
+      ok = image_save_single(reports, ima, iuser, opts, &colorspace_changed);
       if (!ok) {
-        continue;
+        break;
       }
-
-      /* Build filepath of the tile. */
-      BLI_path_sequence_encode(opts->filepath, head, tail, numlen, tile->tile_number);
-
-      iuser->tile = tile->tile_number;
-      ok = ok && image_save_single(reports, ima, iuser, opts, &colorspace_changed);
     }
+    BLI_strncpy(ima->filepath, filepath, sizeof(ima->filepath));
     BLI_strncpy(opts->filepath, filepath, sizeof(opts->filepath));
+    MEM_freeN(udim_pattern);
   }
 
   if (colorspace_changed) {