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

5 files changed, 124 insertions, 32 deletions

diff --git a/source/blender/gpu/GPU_material.h b/source/blender/gpu/GPU_material.h
index 4dc0019978a..a5363c7a42c 100644
--- a/source/blender/gpu/GPU_material.h
+++ b/source/blender/gpu/GPU_material.h
@@ -142,7 +142,7 @@ typedef enum eGPUMaterialStatus {
 GPUNodeLink *GPU_attribute(CustomDataType type, const char *name);
 GPUNodeLink *GPU_constant(float *num);
 GPUNodeLink *GPU_uniform(float *num);
-GPUNodeLink *GPU_image(struct Image *ima, struct ImageUser *iuser);
+GPUNodeLink *GPU_image(struct Image *ima, struct ImageUser *iuser, int tile);
 GPUNodeLink *GPU_color_band(GPUMaterial *mat, int size, float *pixels, float *layer);
 GPUNodeLink *GPU_builtin(eGPUBuiltin builtin);
 
diff --git a/source/blender/gpu/intern/gpu_codegen.c b/source/blender/gpu/intern/gpu_codegen.c
index 410e23c9576..23ea9a62ef8 100644
--- a/source/blender/gpu/intern/gpu_codegen.c
+++ b/source/blender/gpu/intern/gpu_codegen.c
@@ -581,17 +581,19 @@ const char *GPU_builtin_name(eGPUBuiltin builtin)
 }
 
 /* assign only one texid per buffer to avoid sampling the same texture twice */
-static void codegen_set_texid(GHash *bindhash, GPUInput *input, int *texid, void *key)
+static void codegen_set_texid(GHash *bindhash, GPUInput *input, int *texid, void *key1, int key2)
 {
-  if (BLI_ghash_haskey(bindhash, key)) {
+  GHashPair pair = {key1, POINTER_FROM_INT(key2)};
+  if (BLI_ghash_haskey(bindhash, &pair)) {
     /* Reuse existing texid */
-    input->texid = POINTER_AS_INT(BLI_ghash_lookup(bindhash, key));
+    input->texid = POINTER_AS_INT(BLI_ghash_lookup(bindhash, &pair));
   }
   else {
     /* Allocate new texid */
     input->texid = *texid;
     (*texid)++;
     input->bindtex = true;
+    void *key = BLI_ghashutil_pairalloc(key1, POINTER_FROM_INT(key2));
     BLI_ghash_insert(bindhash, key, POINTER_FROM_INT(input->texid));
   }
 }
@@ -604,7 +606,7 @@ static void codegen_set_unique_ids(ListBase *nodes)
   GPUOutput *output;
   int id = 1, texid = 0;
 
-  bindhash = BLI_ghash_ptr_new("codegen_set_unique_ids1 gh");
+  bindhash = BLI_ghash_pair_new("codegen_set_unique_ids1 gh");
 
   for (node = nodes->first; node; node = node->next) {
     for (input = node->inputs.first; input; input = input->next) {
@@ -616,11 +618,11 @@ static void codegen_set_unique_ids(ListBase *nodes)
         input->bindtex = false;
         if (input->ima) {
           /* input is texture from image */
-          codegen_set_texid(bindhash, input, &texid, input->ima);
+          codegen_set_texid(bindhash, input, &texid, input->ima, input->image_tile);
         }
         else if (input->coba) {
           /* input is color band texture, check coba pointer */
-          codegen_set_texid(bindhash, input, &texid, input->coba);
+          codegen_set_texid(bindhash, input, &texid, input->coba, 0);
         }
         else {
           /* Either input->ima or input->coba should be non-NULL. */
@@ -635,7 +637,7 @@ static void codegen_set_unique_ids(ListBase *nodes)
     }
   }
 
-  BLI_ghash_free(bindhash, NULL, NULL);
+  BLI_ghash_free(bindhash, BLI_ghashutil_pairfree, NULL);
 }
 
 /**
@@ -1545,6 +1547,7 @@ static void gpu_node_input_link(GPUNode *node, GPUNodeLink *link, const eGPUType
       input->source = GPU_SOURCE_TEX;
       input->ima = link->ima;
       input->iuser = link->iuser;
+      input->image_tile = link->image_tile;
       break;
     case GPU_NODE_LINK_ATTR:
       input->source = GPU_SOURCE_ATTR;
@@ -1789,12 +1792,13 @@ GPUNodeLink *GPU_uniform(float *num)
   return link;
 }
 
-GPUNodeLink *GPU_image(Image *ima, ImageUser *iuser)
+GPUNodeLink *GPU_image(Image *ima, ImageUser *iuser, int tile)
 {
   GPUNodeLink *link = GPU_node_link_create();
   link->link_type = GPU_NODE_LINK_IMAGE_BLENDER;
   link->ima = ima;
   link->iuser = iuser;
+  link->image_tile = tile;
   return link;
 }
 
diff --git a/source/blender/gpu/intern/gpu_codegen.h b/source/blender/gpu/intern/gpu_codegen.h
index 4e09f16ebf8..0e6982c603e 100644
--- a/source/blender/gpu/intern/gpu_codegen.h
+++ b/source/blender/gpu/intern/gpu_codegen.h
@@ -99,6 +99,7 @@ struct GPUNodeLink {
     struct {
       struct Image *ima;
       struct ImageUser *iuser;
+      int image_tile;
     };
   };
 };
@@ -138,6 +139,7 @@ typedef struct GPUInput {
       struct ImageUser *iuser;  /* image user */
       bool bindtex;             /* input is responsible for binding the texture? */
       int texid;                /* number for multitexture, starting from zero */
+      int image_tile;           /* image tile */
       eGPUType textype;         /* texture type (2D, 1D Array ...) */
     };
     /* GPU_SOURCE_ATTR */
diff --git a/source/blender/gpu/intern/gpu_draw.c b/source/blender/gpu/intern/gpu_draw.c
index 7fa2eb6424c..2d70ce009e2 100644
--- a/source/blender/gpu/intern/gpu_draw.c
+++ b/source/blender/gpu/intern/gpu_draw.c
@@ -195,13 +195,13 @@ float GPU_get_anisotropic(void)
 
 /* Set OpenGL state for an MTFace */
 
-static GPUTexture **gpu_get_image_gputexture(Image *ima, GLenum textarget)
+static GPUTexture **gpu_get_tile_gputexture(ImageTile *tile, GLenum textarget)
 {
   if (textarget == GL_TEXTURE_2D) {
-    return &ima->gputexture[TEXTARGET_TEXTURE_2D];
+    return &tile->gputexture[TEXTARGET_TEXTURE_2D];
   }
   else if (textarget == GL_TEXTURE_CUBE_MAP) {
-    return &ima->gputexture[TEXTARGET_TEXTURE_CUBE_MAP];
+    return &tile->gputexture[TEXTARGET_TEXTURE_CUBE_MAP];
   }
 
   return NULL;
@@ -476,8 +476,19 @@ GPUTexture *GPU_texture_from_blender(Image *ima, ImageUser *iuser, int textarget
   /* Tag as in active use for garbage collector. */
   BKE_image_tag_time(ima);
 
+  ImageTile *tile = BKE_image_get_tile_from_iuser(ima, iuser);
+
+  if (tile == NULL) {
+    /* TODO(lukas): When a tile gets deleted, the materials using the image
+     * aren't rebuilt and therefore continue to use it.
+     * This workaround isn't ideal, the result should be a pink color
+     * (for a missing tile). With the current behaviour, new tiles also won't
+     * be detected. */
+    tile = BKE_image_get_tile(ima, 0);
+  }
+
   /* Test if we already have a texture. */
-  GPUTexture **tex = gpu_get_image_gputexture(ima, textarget);
+  GPUTexture **tex = gpu_get_tile_gputexture(tile, textarget);
   if (*tex) {
     return *tex;
   }
@@ -485,7 +496,7 @@ GPUTexture *GPU_texture_from_blender(Image *ima, ImageUser *iuser, int textarget
   /* Check if we have a valid image. If not, we return a dummy
    * texture with zero bindcode so we don't keep trying. */
   uint bindcode = 0;
-  if (ima->ok == 0) {
+  if (tile->ok == 0) {
     *tex = GPU_texture_from_bindcode(textarget, bindcode);
     return *tex;
   }
@@ -861,11 +872,14 @@ void GPU_paint_set_mipmap(Main *bmain, bool mipmap)
     for (Image *ima = bmain->images.first; ima; ima = ima->id.next) {
       if (BKE_image_has_opengl_texture(ima)) {
         if (ima->gpuflag & IMA_GPU_MIPMAP_COMPLETE) {
-          if (ima->gputexture[TEXTARGET_TEXTURE_2D]) {
-            GPU_texture_bind(ima->gputexture[TEXTARGET_TEXTURE_2D], 0);
-            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, gpu_get_mipmap_filter(0));
-            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, gpu_get_mipmap_filter(1));
-            GPU_texture_unbind(ima->gputexture[TEXTARGET_TEXTURE_2D]);
+          LISTBASE_FOREACH (ImageTile *, tile, &ima->tiles) {
+            GPUTexture *tex = tile->gputexture[TEXTARGET_TEXTURE_2D];
+            if (tex != NULL) {
+              GPU_texture_bind(tex, 0);
+              glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, gpu_get_mipmap_filter(0));
+              glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, gpu_get_mipmap_filter(1));
+              GPU_texture_unbind(tex);
+            }
           }
         }
         else {
@@ -880,11 +894,14 @@ void GPU_paint_set_mipmap(Main *bmain, bool mipmap)
   else {
     for (Image *ima = bmain->images.first; ima; ima = ima->id.next) {
       if (BKE_image_has_opengl_texture(ima)) {
-        if (ima->gputexture[TEXTARGET_TEXTURE_2D]) {
-          GPU_texture_bind(ima->gputexture[TEXTARGET_TEXTURE_2D], 0);
-          glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-          glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, gpu_get_mipmap_filter(1));
-          GPU_texture_unbind(ima->gputexture[TEXTARGET_TEXTURE_2D]);
+        LISTBASE_FOREACH (ImageTile *, tile, &ima->tiles) {
+          GPUTexture *tex = tile->gputexture[TEXTARGET_TEXTURE_2D];
+          if (tex != NULL) {
+            GPU_texture_bind(tex, 0);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, gpu_get_mipmap_filter(1));
+            GPU_texture_unbind(tex);
+          }
         }
       }
       else {
@@ -897,14 +914,16 @@ void GPU_paint_set_mipmap(Main *bmain, bool mipmap)
 void GPU_paint_update_image(Image *ima, ImageUser *iuser, int x, int y, int w, int h)
 {
   ImBuf *ibuf = BKE_image_acquire_ibuf(ima, iuser, NULL);
+  ImageTile *tile = BKE_image_get_tile_from_iuser(ima, iuser);
+  GPUTexture *tex = tile->gputexture[TEXTARGET_TEXTURE_2D];
 
-  if ((ima->gputexture[TEXTARGET_TEXTURE_2D] == NULL) || (ibuf == NULL) || (w == 0) || (h == 0)) {
+  if ((tex == NULL) || (ibuf == NULL) || (w == 0) || (h == 0)) {
     /* Full reload of texture. */
     GPU_free_image(ima);
   }
   else {
     /* Partial update of texture. */
-    GPU_texture_bind(ima->gputexture[TEXTARGET_TEXTURE_2D], 0);
+    GPU_texture_bind(tex, 0);
 
     gpu_texture_update_from_ibuf(ima, ibuf, x, y, w, h);
 
@@ -915,7 +934,7 @@ void GPU_paint_update_image(Image *ima, ImageUser *iuser, int x, int y, int w, i
       ima->gpuflag &= ~IMA_GPU_MIPMAP_COMPLETE;
     }
 
-    GPU_texture_unbind(ima->gputexture[TEXTARGET_TEXTURE_2D]);
+    GPU_texture_unbind(tex);
   }
 
   BKE_image_release_ibuf(ima, ibuf, NULL);
@@ -1323,11 +1342,13 @@ void GPU_free_unused_buffers(Main *bmain)
 
 static void gpu_free_image_immediate(Image *ima)
 {
-  for (int i = 0; i < TEXTARGET_COUNT; i++) {
-    /* free glsl image binding */
-    if (ima->gputexture[i]) {
-      GPU_texture_free(ima->gputexture[i]);
-      ima->gputexture[i] = NULL;
+  LISTBASE_FOREACH (ImageTile *, tile, &ima->tiles) {
+    for (int i = 0; i < TEXTARGET_COUNT; i++) {
+      /* free glsl image binding */
+      if (tile->gputexture[i] != NULL) {
+        GPU_texture_free(tile->gputexture[i]);
+        tile->gputexture[i] = NULL;
+      }
     }
   }
 
diff --git a/source/blender/gpu/shaders/material/gpu_shader_material_tex_image.glsl b/source/blender/gpu/shaders/material/gpu_shader_material_tex_image.glsl
index bc2bf998145..fadb3b92df4 100644
--- a/source/blender/gpu/shaders/material/gpu_shader_material_tex_image.glsl
+++ b/source/blender/gpu/shaders/material/gpu_shader_material_tex_image.glsl
@@ -353,3 +353,68 @@ void node_tex_image_empty(vec3 co, out vec4 color, out float alpha)
   color = vec4(0.0);
   alpha = 0.0;
 }
+
+void node_tex_tile_map(vec3 co, out vec4 color, out vec3 map)
+{
+  float tx = floor(co.x);
+  float ty = floor(co.y);
+
+  if (tx < 0 || ty < 0 || tx >= 10)
+    map = vec3(0, 0, -1);
+  else
+    map = vec3(co.x - tx, co.y - ty, 1001 + 10 * ty + tx);
+
+  color = vec4(1.0, 0.0, 1.0, 1.0);
+}
+
+void node_tex_tile_linear(
+    vec3 map, float tile_id, sampler2D ima, vec4 in_color, out vec4 color, out float alpha)
+{
+  if (map.z == tile_id) {
+    vec3 co = map.xyy;
+    node_tex_image_linear(co, ima, color, alpha);
+  }
+  else {
+    color = in_color;
+    alpha = color.a;
+  }
+}
+
+void node_tex_tile_nearest(
+    vec3 map, float tile_id, sampler2D ima, vec4 in_color, out vec4 color, out float alpha)
+{
+  if (map.z == tile_id) {
+    vec3 co = map.xyy;
+    node_tex_image_nearest(co, ima, color, alpha);
+  }
+  else {
+    color = in_color;
+    alpha = color.a;
+  }
+}
+
+void node_tex_tile_cubic(
+    vec3 map, float tile_id, sampler2D ima, vec4 in_color, out vec4 color, out float alpha)
+{
+  if (map.z == tile_id) {
+    vec3 co = map.xyy;
+    node_tex_image_cubic(co, ima, color, alpha);
+  }
+  else {
+    color = in_color;
+    alpha = color.a;
+  }
+}
+
+void node_tex_tile_smart(
+    vec3 map, float tile_id, sampler2D ima, vec4 in_color, out vec4 color, out float alpha)
+{
+  if (map.z == tile_id) {
+    vec3 co = map.xyy;
+    node_tex_image_smart(co, ima, color, alpha);
+  }
+  else {
+    color = in_color;
+    alpha = color.a;
+  }
+}