Add support for tiled images and the UDIM naming scheme

This patch contains the work that I did during my week at the Code Quest - adding support for tiled images to Blender.

With this patch, images now contain a list of tiles. By default, this just contains one tile, but if the source type is set to Tiled, the user can add additional tiles. When acquiring an ImBuf, the tile to be loaded is specified in the ImageUser.
Therefore, code that is not yet aware of tiles will just access the default tile as usual.

The filenames of the additional tiles are derived from the original filename according to the UDIM naming scheme - the filename contains an index that is calculated as (1001 + 10*<y coordinate of the tile> + <x coordinate of the tile>), where the x coordinate never goes above 9.
Internally, the various tiles are stored in a cache just like sequences. When acquired for the first time, the code will try to load the corresponding file from disk. Alternatively, a new operator can be used to initialize the tile similar to the New Image operator.

The following features are supported so far:
- Automatic detection and loading of all tiles when opening the first tile (1001)
- Saving all tiles
- Adding and removing tiles
- Filling tiles with generated images
- Drawing all tiles in the Image Editor
- Viewing a tiled grid even if no image is selected
- Rendering tiled images in Eevee
- Rendering tiled images in Cycles (in SVM mode)
- Automatically skipping loading of unused tiles in Cycles
- 2D texture painting (also across tiles)
- 3D texture painting (also across tiles, only limitation: individual faces can not cross tile borders)
- Assigning custom labels to individual tiles (drawn in the Image Editor instead of the ID)
- Different resolutions between tiles

There still are some missing features that will be added later (see T72390):
- Workbench engine support
- Packing/Unpacking support
- Baking support
- Cycles OSL support
- many other Blender features that rely on images

Thanks to Brecht for the review and to all who tested the intermediate versions!

Differential Revision: https://developer.blender.org/D3509

1 files changed, 94 insertions, 24 deletions

diff --git a/source/blender/editors/sculpt_paint/paint_image_proj.c b/source/blender/editors/sculpt_paint/paint_image_proj.c
index c57490041bc..6a67c469955 100644
--- a/source/blender/editors/sculpt_paint/paint_image_proj.c
+++ b/source/blender/editors/sculpt_paint/paint_image_proj.c
@@ -197,6 +197,7 @@ BLI_INLINE unsigned char f_to_char(const float val)
  */
 typedef struct ProjPaintImage {
   Image *ima;
+  ImageUser iuser;
   ImBuf *ibuf;
   ImagePaintPartialRedraw *partRedrawRect;
   /** Only used to build undo tiles during painting. */
@@ -530,6 +531,18 @@ BLI_INLINE const MPoly *ps_tri_index_to_mpoly(const ProjPaintState *ps, int tri_
 
 /* Finish projection painting structs */
 
+static int project_paint_face_paint_tile(Image *ima, const float *uv)
+{
+  if (ima == NULL || ima->source != IMA_SRC_TILED) {
+    return 0;
+  }
+
+  /* Currently, faces are assumed to belong to one tile, so checking the first loop is enough. */
+  int tx = (int)uv[0];
+  int ty = (int)uv[1];
+  return 1001 + 10 * ty + tx;
+}
+
 static TexPaintSlot *project_paint_face_paint_slot(const ProjPaintState *ps, int tri_index)
 {
   const MPoly *mp = ps_tri_index_to_mpoly(ps, tri_index);
@@ -729,9 +742,17 @@ static bool project_paint_PickColor(const ProjPaintState *ps,
 
   ima = project_paint_face_paint_image(ps, tri_index);
   /** we must have got the imbuf before getting here. */
-  ibuf = BKE_image_get_first_ibuf(ima);
-  if (!ibuf) {
-    return 0;
+  int tile_number = project_paint_face_paint_tile(ima, lt_tri_uv[0]);
+  ImageUser iuser;
+  BKE_imageuser_default(&iuser);
+  iuser.tile = tile_number;
+  ibuf = BKE_image_acquire_ibuf(ima, &iuser, NULL);
+  if (ibuf == NULL) {
+    iuser.tile = 0;
+    ibuf = BKE_image_acquire_ibuf(ima, &iuser, NULL);
+    if (ibuf == NULL) {
+      return 0;
+    }
   }
 
   if (interp) {
@@ -1154,6 +1175,8 @@ static bool check_seam(const ProjPaintState *ps,
         const float *lt_tri_uv[3] = {PS_LOOPTRI_AS_UV_3(ps->poly_to_loop_uv, lt)};
         Image *tpage = project_paint_face_paint_image(ps, tri_index);
         Image *orig_tpage = project_paint_face_paint_image(ps, orig_face);
+        int tile = project_paint_face_paint_tile(tpage, lt_tri_uv[0]);
+        int orig_tile = project_paint_face_paint_tile(orig_tpage, orig_lt_tri_uv[0]);
 
         BLI_assert(i1_fidx != -1);
 
@@ -1171,7 +1194,8 @@ static bool check_seam(const ProjPaintState *ps,
         }
 
         /* first test if they have the same image */
-        if ((orig_tpage == tpage) && cmp_uv(orig_lt_tri_uv[orig_i1_fidx], lt_tri_uv[i1_fidx]) &&
+        if ((orig_tpage == tpage) && (orig_tile == tile) &&
+            cmp_uv(orig_lt_tri_uv[orig_i1_fidx], lt_tri_uv[i1_fidx]) &&
             cmp_uv(orig_lt_tri_uv[orig_i2_fidx], lt_tri_uv[i2_fidx])) {
           /* if faces don't have the same winding in uv space,
            * they are on the same side so edge is boundary */
@@ -1817,6 +1841,7 @@ static int project_paint_undo_subtiles(const TileInfo *tinf, int tx, int ty)
                                           pjIma->ima,
                                           pjIma->ibuf,
                                           tinf->tmpibuf,
+                                          pjIma->iuser.tile,
                                           tx,
                                           ty,
                                           &pjIma->maskRect[tile_index],
@@ -1829,6 +1854,7 @@ static int project_paint_undo_subtiles(const TileInfo *tinf, int tx, int ty)
                                           pjIma->ima,
                                           pjIma->ibuf,
                                           tinf->tmpibuf,
+                                          pjIma->iuser.tile,
                                           tx,
                                           ty,
                                           NULL,
@@ -3486,6 +3512,7 @@ static void project_bucket_init(const ProjPaintState *ps,
   ImBuf *ibuf = NULL;
   Image *tpage_last = NULL, *tpage;
   ImBuf *tmpibuf = NULL;
+  int tile_last = 0;
 
   if (ps->image_tot == 1) {
     /* Simple loop, no context switching */
@@ -3509,17 +3536,34 @@ static void project_bucket_init(const ProjPaintState *ps,
     for (node = ps->bucketFaces[bucket_index]; node; node = node->next) {
       tri_index = POINTER_AS_INT(node->link);
 
+      const MLoopTri *lt = &ps->mlooptri_eval[tri_index];
+      const float *lt_tri_uv[3] = {PS_LOOPTRI_AS_UV_3(ps->poly_to_loop_uv, lt)};
+
       /* Image context switching */
       tpage = project_paint_face_paint_image(ps, tri_index);
-      if (tpage_last != tpage) {
+      int tile = project_paint_face_paint_tile(tpage, lt_tri_uv[0]);
+      if (tpage_last != tpage || tile_last != tile) {
         tpage_last = tpage;
+        tile_last = tile;
 
+        ibuf = NULL;
         for (image_index = 0; image_index < ps->image_tot; image_index++) {
-          if (ps->projImages[image_index].ima == tpage_last) {
-            ibuf = ps->projImages[image_index].ibuf;
+          ProjPaintImage *projIma = &ps->projImages[image_index];
+          if ((projIma->ima == tpage) && (projIma->iuser.tile == tile)) {
+            ibuf = projIma->ibuf;
             break;
           }
         }
+        if (ibuf == NULL) {
+          /* Failed to find the specific tile, fall back to the primary tile. */
+          for (image_index = 0; image_index < ps->image_tot; image_index++) {
+            ProjPaintImage *projIma = &ps->projImages[image_index];
+            if ((projIma->ima == tpage) && (projIma->iuser.tile == 0)) {
+              ibuf = projIma->ibuf;
+              break;
+            }
+          }
+        }
       }
       /* context switching done */
 
@@ -4232,22 +4276,36 @@ static bool project_paint_winclip(const ProjPaintState *ps, const ProjPaintFaceC
 }
 #endif  // PROJ_DEBUG_WINCLIP
 
+typedef struct PrepareImageEntry {
+  struct PrepareImageEntry *next, *prev;
+  Image *ima;
+  int tile;
+} PrepareImageEntry;
+
 static void project_paint_build_proj_ima(ProjPaintState *ps,
                                          MemArena *arena,
-                                         LinkNode *image_LinkList)
+                                         ListBase *used_images)
 {
   ProjPaintImage *projIma;
-  LinkNode *node;
+  PrepareImageEntry *entry;
   int i;
 
   /* build an array of images we use */
   projIma = ps->projImages = BLI_memarena_alloc(arena, sizeof(ProjPaintImage) * ps->image_tot);
 
-  for (node = image_LinkList, i = 0; node; node = node->next, i++, projIma++) {
+  for (entry = used_images->first, i = 0; entry; entry = entry->next, i++, projIma++) {
+    memset(&projIma->iuser, 0, sizeof(ImageUser));
+    BKE_imageuser_default(&projIma->iuser);
+    projIma->iuser.tile = entry->tile;
     int size;
-    projIma->ima = node->link;
+    projIma->ima = entry->ima;
     projIma->touch = 0;
-    projIma->ibuf = BKE_image_acquire_ibuf(projIma->ima, NULL, NULL);
+    projIma->ibuf = BKE_image_acquire_ibuf(projIma->ima, &projIma->iuser, NULL);
+    if (projIma->ibuf == NULL) {
+      projIma->iuser.tile = 0;
+      projIma->ibuf = BKE_image_acquire_ibuf(projIma->ima, &projIma->iuser, NULL);
+      BLI_assert(projIma->ibuf != NULL);
+    }
     size = sizeof(void **) * ED_IMAGE_UNDO_TILE_NUMBER(projIma->ibuf->x) *
            ED_IMAGE_UNDO_TILE_NUMBER(projIma->ibuf->y);
     projIma->partRedrawRect = BLI_memarena_alloc(
@@ -4270,15 +4328,18 @@ static void project_paint_prepare_all_faces(ProjPaintState *ps,
                                             const bool is_multi_view)
 {
   /* Image Vars - keep track of images we have used */
-  LinkNodePair image_LinkList = {NULL, NULL};
+  ListBase used_images = {NULL};
 
   Image *tpage_last = NULL, *tpage;
   TexPaintSlot *slot_last = NULL;
   TexPaintSlot *slot = NULL;
+  int tile_last = -1, tile;
   const MLoopTri *lt;
   int image_index = -1, tri_index;
   int prev_poly = -1;
 
+  BLI_assert(ps->image_tot == 0);
+
   for (tri_index = 0, lt = ps->mlooptri_eval; tri_index < ps->totlooptri_eval; tri_index++, lt++) {
     bool is_face_sel;
     bool skip_tri = false;
@@ -4321,6 +4382,8 @@ static void project_paint_prepare_all_faces(ProjPaintState *ps,
 
     ps->poly_to_loop_uv[lt->poly] = mloopuv_base;
 
+    tile = project_paint_face_paint_tile(tpage, mloopuv_base[lt->tri[0]].uv);
+
 #ifndef PROJ_DEBUG_NOSEAMBLEED
     project_paint_bleed_add_face_user(ps, arena, lt, tri_index);
 #endif
@@ -4382,18 +4445,24 @@ static void project_paint_prepare_all_faces(ProjPaintState *ps,
         }
       }
 
-      if (tpage_last != tpage) {
-
-        image_index = BLI_linklist_index(image_LinkList.list, tpage);
+      if (tpage_last != tpage || tile_last != tile) {
+        image_index = 0;
+        for (PrepareImageEntry *e = used_images.first; e; e = e->next, image_index++) {
+          if (e->ima == tpage && e->tile == tile) {
+            break;
+          }
+        }
 
-        if (image_index == -1 && BKE_image_has_ibuf(tpage, NULL)) {
-          /* MemArena doesn't have an append func */
-          BLI_linklist_append(&image_LinkList, tpage);
-          image_index = ps->image_tot;
+        if (image_index == ps->image_tot) {
+          PrepareImageEntry *e = MEM_callocN(sizeof(PrepareImageEntry), "PrepareImageEntry");
+          e->ima = tpage;
+          e->tile = tile;
+          BLI_addtail(&used_images, e);
           ps->image_tot++;
         }
 
         tpage_last = tpage;
+        tile_last = tile;
       }
 
       if (image_index != -1) {
@@ -4406,11 +4475,11 @@ static void project_paint_prepare_all_faces(ProjPaintState *ps,
 
   /* build an array of images we use*/
   if (ps->is_shared_user == false) {
-    project_paint_build_proj_ima(ps, arena, image_LinkList.list);
+    project_paint_build_proj_ima(ps, arena, &used_images);
   }
 
   /* we have built the array, discard the linked list */
-  BLI_linklist_free(image_LinkList.list, NULL);
+  BLI_freelistN(&used_images);
 }
 
 /* run once per stroke before projection painting */
@@ -4675,7 +4744,7 @@ static bool project_image_refresh_tagged(ProjPaintState *ps)
         pr = &(projIma->partRedrawRect[i]);
         if (pr->x2 != -1) { /* TODO - use 'enabled' ? */
           set_imapaintpartial(pr);
-          imapaint_image_update(NULL, projIma->ima, projIma->ibuf, true);
+          imapaint_image_update(NULL, projIma->ima, projIma->ibuf, &projIma->iuser, true);
           redraw = 1;
         }
 
@@ -6441,7 +6510,8 @@ static Image *proj_paint_image_create(wmOperator *op, Main *bmain, bool is_data)
                                 gen_type,
                                 color,
                                 false,
-                                is_data);
+                                is_data,
+                                false); /* TODO(lukas): Add option */
 
   return ima;
 }