UDIM: Add support for packing inside .blend files

This completes support for tiled texture packing on the Blender / Cycles
side of things.

Most of these changes fall into one of three categories:
- Updating Image handling code to pack/unpack tiled and multi-view images
- Updating Cycles to handle tiled textures through BlenderImageLoader
- Updating OSL to properly handle textures with multiple slots

Differential Revision: https://developer.blender.org/D14395

2 files changed, 45 insertions, 7 deletions

diff --git a/intern/cycles/kernel/osl/services.cpp b/intern/cycles/kernel/osl/services.cpp
index 832498f1f73..e2e10b5b83f 100644
--- a/intern/cycles/kernel/osl/services.cpp
+++ b/intern/cycles/kernel/osl/services.cpp
@@ -1304,8 +1304,38 @@ bool OSLRenderServices::texture(ustring filename,
       break;
     }
     case OSLTextureHandle::SVM: {
-      /* Packed texture. */
-      float4 rgba = kernel_tex_image_interp(kernel_globals, handle->svm_slot, s, 1.0f - t);
+      int id = -1;
+      if (handle->svm_slots[0].w == -1) {
+        /* Packed single texture. */
+        id = handle->svm_slots[0].y;
+      }
+      else {
+        /* Packed tiled texture. */
+        int tx = (int)s;
+        int ty = (int)t;
+        int tile = 1001 + 10 * ty + tx;
+        for (int4 tile_node : handle->svm_slots) {
+          if (tile_node.x == tile) {
+            id = tile_node.y;
+            break;
+          }
+          if (tile_node.z == tile) {
+            id = tile_node.w;
+            break;
+          }
+        }
+        s -= tx;
+        t -= ty;
+      }
+
+      float4 rgba;
+      if (id == -1) {
+        rgba = make_float4(
+            TEX_IMAGE_MISSING_R, TEX_IMAGE_MISSING_G, TEX_IMAGE_MISSING_B, TEX_IMAGE_MISSING_A);
+      }
+      else {
+        rgba = kernel_tex_image_interp(kernel_globals, id, s, 1.0f - t);
+      }
 
       result[0] = rgba[0];
       if (nchannels > 1)
@@ -1319,7 +1349,7 @@ bool OSLRenderServices::texture(ustring filename,
     }
     case OSLTextureHandle::IES: {
       /* IES light. */
-      result[0] = kernel_ies_interp(kernel_globals, handle->svm_slot, s, t);
+      result[0] = kernel_ies_interp(kernel_globals, handle->svm_slots[0].y, s, t);
       status = true;
       break;
     }
@@ -1413,7 +1443,7 @@ bool OSLRenderServices::texture3d(ustring filename,
       /* Packed texture. */
       ShaderData *sd = (ShaderData *)(sg->renderstate);
       KernelGlobals kernel_globals = sd->osl_globals;
-      int slot = handle->svm_slot;
+      int slot = handle->svm_slots[0].y;
       float3 P_float3 = make_float3(P.x, P.y, P.z);
       float4 rgba = kernel_tex_image_interp_3d(kernel_globals, slot, P_float3, INTERPOLATION_NONE);
 
diff --git a/intern/cycles/kernel/osl/services.h b/intern/cycles/kernel/osl/services.h
index 653fa017140..27d7f7fb8e1 100644
--- a/intern/cycles/kernel/osl/services.h
+++ b/intern/cycles/kernel/osl/services.h
@@ -39,18 +39,26 @@ struct KernelGlobalsCPU;
  * with additional data.
  *
  * These are stored in a concurrent hash map, because OSL can compile multiple
- * shaders in parallel. */
+ * shaders in parallel.
+ *
+ * Note: The svm_slots array contains a compressed mapping of tile to svm_slot pairs
+ * stored as follows: x:tile_a, y:svm_slot_a, z:tile_b, w:svm_slot_b etc. */
 
 struct OSLTextureHandle : public OIIO::RefCnt {
   enum Type { OIIO, SVM, IES, BEVEL, AO };
 
+  OSLTextureHandle(Type type, const vector<int4> &svm_slots)
+      : type(type), svm_slots(svm_slots), oiio_handle(NULL), processor(NULL)
+  {
+  }
+
   OSLTextureHandle(Type type = OIIO, int svm_slot = -1)
-      : type(type), svm_slot(svm_slot), oiio_handle(NULL), processor(NULL)
+      : OSLTextureHandle(type, {make_int4(0, svm_slot, -1, -1)})
   {
   }
 
   Type type;
-  int svm_slot;
+  vector<int4> svm_slots;
   OSL::TextureSystem::TextureHandle *oiio_handle;
   ColorSpaceProcessor *processor;
 };