4 files changed, 116 insertions, 3 deletions

diff --git a/intern/cycles/blender/blender_object.cpp b/intern/cycles/blender/blender_object.cpp
index 2dbebac4cc3..a7eae421b55 100644
--- a/intern/cycles/blender/blender_object.cpp
+++ b/intern/cycles/blender/blender_object.cpp
@@ -523,6 +523,9 @@ void BlenderSync::sync_procedural(BL::Object &b_ob,
 
   procedural->set_scale(cache_file.scale());
 
+  procedural->set_use_prefetch(cache_file.use_prefetch());
+  procedural->set_prefetch_cache_size(cache_file.prefetch_cache_size());
+
   /* create or update existing AlembicObjects */
   ustring object_path = ustring(b_mesh_cache.object_path());
 
diff --git a/intern/cycles/render/alembic.cpp b/intern/cycles/render/alembic.cpp
index 81f47256739..69bc0712674 100644
--- a/intern/cycles/render/alembic.cpp
+++ b/intern/cycles/render/alembic.cpp
@@ -25,6 +25,7 @@
 #include "render/shader.h"
 
 #include "util/util_foreach.h"
+#include "util/util_logging.h"
 #include "util/util_progress.h"
 #include "util/util_transform.h"
 #include "util/util_vector.h"
@@ -211,6 +212,35 @@ void CachedData::set_time_sampling(TimeSampling time_sampling)
   }
 }
 
+size_t CachedData::memory_used() const
+{
+  size_t mem_used = 0;
+
+  mem_used += curve_first_key.memory_used();
+  mem_used += curve_keys.memory_used();
+  mem_used += curve_radius.memory_used();
+  mem_used += curve_shader.memory_used();
+  mem_used += num_ngons.memory_used();
+  mem_used += shader.memory_used();
+  mem_used += subd_creases_edge.memory_used();
+  mem_used += subd_creases_weight.memory_used();
+  mem_used += subd_face_corners.memory_used();
+  mem_used += subd_num_corners.memory_used();
+  mem_used += subd_ptex_offset.memory_used();
+  mem_used += subd_smooth.memory_used();
+  mem_used += subd_start_corner.memory_used();
+  mem_used += transforms.memory_used();
+  mem_used += triangles.memory_used();
+  mem_used += uv_loops.memory_used();
+  mem_used += vertices.memory_used();
+
+  for (const CachedAttribute &attr : attributes) {
+    mem_used += attr.data.memory_used();
+  }
+
+  return mem_used;
+}
+
 static M44d convert_yup_zup(const M44d &mtx, float scale_mult)
 {
   V3d scale, shear, rotation, translation;
@@ -706,6 +736,9 @@ NODE_DEFINE(AlembicProcedural)
 
   SOCKET_NODE_ARRAY(objects, "Objects", AlembicObject::get_node_type());
 
+  SOCKET_BOOLEAN(use_prefetch, "Use Prefetch", true);
+  SOCKET_INT(prefetch_cache_size, "Prefetch Cache Size", 4096);
+
   return type;
 }
 
@@ -823,6 +856,30 @@ void AlembicProcedural::generate(Scene *scene, Progress &progress)
     }
   }
 
+  if (use_prefetch_is_modified()) {
+    if (!use_prefetch) {
+      for (Node *node : objects) {
+        AlembicObject *object = static_cast<AlembicObject *>(node);
+        object->clear_cache();
+      }
+    }
+  }
+
+  if (prefetch_cache_size_is_modified()) {
+    /* Check whether the current memory usage fits in the new requested size,
+     * abort the render if it is any higher. */
+    size_t memory_used = 0ul;
+    for (Node *node : objects) {
+      AlembicObject *object = static_cast<AlembicObject *>(node);
+      memory_used += object->get_cached_data().memory_used();
+    }
+
+    if (memory_used > get_prefetch_cache_size_in_bytes()) {
+      progress.set_error("Error: Alembic Procedural memory limit reached");
+      return;
+    }
+  }
+
   build_caches(progress);
 
   foreach (Node *node, objects) {
@@ -1300,6 +1357,8 @@ void AlembicProcedural::walk_hierarchy(
 
 void AlembicProcedural::build_caches(Progress &progress)
 {
+  size_t memory_used = 0;
+
   for (Node *node : objects) {
     AlembicObject *object = static_cast<AlembicObject *>(node);
 
@@ -1353,7 +1412,18 @@ void AlembicProcedural::build_caches(Progress &progress)
     if (scale_is_modified() || object->get_cached_data().transforms.size() == 0) {
       object->setup_transform_cache(object->get_cached_data(), scale);
     }
+
+    memory_used += object->get_cached_data().memory_used();
+
+    if (use_prefetch) {
+      if (memory_used > get_prefetch_cache_size_in_bytes()) {
+        progress.set_error("Error: Alembic Procedural memory limit reached");
+        return;
+      }
+    }
   }
+
+  VLOG(1) << "AlembicProcedural memory usage : " << string_human_readable_size(memory_used);
 }
 
 CCL_NAMESPACE_END
diff --git a/intern/cycles/render/alembic.h b/intern/cycles/render/alembic.h
index 9c58af720f6..8e166a5ab04 100644
--- a/intern/cycles/render/alembic.h
+++ b/intern/cycles/render/alembic.h
@@ -272,6 +272,21 @@ template<typename T> class DataStore {
     node->set(*socket, value);
   }
 
+  size_t memory_used() const
+  {
+    if constexpr (is_array<T>::value) {
+      size_t mem_used = 0;
+
+      for (const T &array : data) {
+        mem_used += array.size() * sizeof(array[0]);
+      }
+
+      return mem_used;
+    }
+
+    return data.size() * sizeof(T);
+  }
+
  private:
   const TimeIndexPair &get_index_for_time(double time) const
   {
@@ -332,6 +347,8 @@ struct CachedData {
   void invalidate_last_loaded_time(bool attributes_only = false);
 
   void set_time_sampling(Alembic::AbcCoreAbstract::TimeSampling time_sampling);
+
+  size_t memory_used() const;
 };
 
 /* Representation of an Alembic object for the AlembicProcedural.
@@ -482,6 +499,13 @@ class AlembicProcedural : public Procedural {
    * software. */
   NODE_SOCKET_API(float, scale)
 
+  /* Cache controls */
+  NODE_SOCKET_API(bool, use_prefetch)
+
+  /* Memory limit for the cache, if the data does not fit within this limit, rendering is aborted.
+   */
+  NODE_SOCKET_API(int, prefetch_cache_size)
+
   AlembicProcedural();
   ~AlembicProcedural();
 
@@ -531,6 +555,12 @@ class AlembicProcedural : public Procedural {
   void read_subd(AlembicObject *abc_object, Alembic::AbcGeom::Abc::chrono_t frame_time);
 
   void build_caches(Progress &progress);
+
+  size_t get_prefetch_cache_size_in_bytes() const
+  {
+    /* prefetch_cache_size is in megabytes, so convert to bytes. */
+    return static_cast<size_t>(prefetch_cache_size) * 1024 * 1024;
+  }
 };
 
 CCL_NAMESPACE_END
diff --git a/intern/cycles/render/alembic_read.cpp b/intern/cycles/render/alembic_read.cpp
index c53ec668938..b105af63b44 100644
--- a/intern/cycles/render/alembic_read.cpp
+++ b/intern/cycles/render/alembic_read.cpp
@@ -44,9 +44,19 @@ static set<chrono_t> get_relevant_sample_times(AlembicProcedural *proc,
     return result;
   }
 
-  // load the data for the entire animation
-  const double start_frame = static_cast<double>(proc->get_start_frame());
-  const double end_frame = static_cast<double>(proc->get_end_frame());
+  double start_frame;
+  double end_frame;
+
+  if (proc->get_use_prefetch()) {
+    // load the data for the entire animation
+    start_frame = static_cast<double>(proc->get_start_frame());
+    end_frame = static_cast<double>(proc->get_end_frame());
+  }
+  else {
+    // load the data for the current frame
+    start_frame = static_cast<double>(proc->get_frame());
+    end_frame = start_frame;
+  }
 
   const double frame_rate = static_cast<double>(proc->get_frame_rate());
   const double start_time = start_frame / frame_rate;