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, 33 insertions, 3 deletions

diff --git a/source/blender/blenkernel/BKE_image.h b/source/blender/blenkernel/BKE_image.h
index 82c831ae8e0..e2bb1f988ca 100644
--- a/source/blender/blenkernel/BKE_image.h
+++ b/source/blender/blenkernel/BKE_image.h
@@ -33,6 +33,7 @@ struct ImBuf;
 struct Image;
 struct ImageFormatData;
 struct ImagePool;
+struct ImageTile;
 struct ImbFormatOptions;
 struct Main;
 struct Object;
@@ -43,6 +44,7 @@ struct StampData;
 struct anim;
 
 #define IMA_MAX_SPACE 64
+#define IMA_UDIM_MAX 1999
 
 void BKE_images_init(void);
 void BKE_images_exit(void);
@@ -206,7 +208,8 @@ struct Image *BKE_image_add_generated(struct Main *bmain,
                                       short gen_type,
                                       const float color[4],
                                       const bool stereo3d,
-                                      const bool is_data);
+                                      const bool is_data,
+                                      const bool tiled);
 /* adds image from imbuf, owns imbuf */
 struct Image *BKE_image_add_from_imbuf(struct Main *bmain, struct ImBuf *ibuf, const char *name);
 
@@ -302,6 +305,32 @@ bool BKE_image_has_alpha(struct Image *image);
 /* check if texture has gpu texture code */
 bool BKE_image_has_opengl_texture(struct Image *ima);
 
+/* get tile index for tiled images */
+void BKE_image_get_tile_label(struct Image *ima,
+                              struct ImageTile *tile,
+                              char *label,
+                              int len_label);
+
+struct ImageTile *BKE_image_add_tile(struct Image *ima, int tile_number, const char *label);
+bool BKE_image_remove_tile(struct Image *ima, struct ImageTile *tile);
+
+bool BKE_image_fill_tile(struct Image *ima,
+                         struct ImageTile *tile,
+                         int width,
+                         int height,
+                         const float color[4],
+                         int gen_type,
+                         int planes,
+                         bool is_float);
+
+struct ImageTile *BKE_image_get_tile(struct Image *ima, int tile_number);
+struct ImageTile *BKE_image_get_tile_from_iuser(struct Image *ima, struct ImageUser *iuser);
+
+int BKE_image_get_tile_from_pos(struct Image *ima,
+                                const float uv[2],
+                                float new_uv[2],
+                                float ofs[2]);
+
 void BKE_image_get_size(struct Image *image, struct ImageUser *iuser, int *width, int *height);
 void BKE_image_get_size_fl(struct Image *image, struct ImageUser *iuser, float size[2]);
 void BKE_image_get_aspect(struct Image *image, float *aspx, float *aspy);
@@ -316,8 +345,8 @@ void BKE_image_buf_fill_checker_color(unsigned char *rect,
                                       int height);
 
 /* Cycles hookup */
-unsigned char *BKE_image_get_pixels_for_frame(struct Image *image, int frame);
-float *BKE_image_get_float_pixels_for_frame(struct Image *image, int frame);
+unsigned char *BKE_image_get_pixels_for_frame(struct Image *image, int frame, int tile);
+float *BKE_image_get_float_pixels_for_frame(struct Image *image, int frame, int tile);
 
 /* Image modifications */
 bool BKE_image_is_dirty(struct Image *image);
@@ -331,6 +360,7 @@ bool BKE_image_has_anim(struct Image *image);
 bool BKE_image_has_packedfile(struct Image *image);
 bool BKE_image_has_filepath(struct Image *ima);
 bool BKE_image_is_animated(struct Image *image);
+bool BKE_image_has_multiple_ibufs(struct Image *image);
 void BKE_image_file_format_set(struct Image *image,
                                int ftype,
                                const struct ImbFormatOptions *options);