Fix T99733: Objects with driven visibility are evaluated when not needed

The issue was caused by the fact that objects with driven or animated
visibility were considered visible by the dependency graph evaluation.

This change makes it so the dependency graph evaluation is aware of
visibility which might be changing. This is achieved by evaluating the
path of the graph which affects objects visibility and adjusts to it
before evaluating the rest of the graph.

There is some time penalty to this, but there does not seem to be a
way to fully avoid this penalty.

With the production shot from the heist project the FPS drops by a
tenth of a frame (~9.4 vs ~9.3 fps) when adding a driver to an object
which keeps it visible. Note that this is a bit hard to measure since
the FPS fluctuates quite a bit throughout the playback. On the other
hand, having a driver on a visibility of a heavy object from character
and setting visibility to false gives big speedup.

Also worth noting that there is no penalty at all when there are no
animated visibilities in the scene.

Differential Revision: https://developer.blender.org/D15498

1 files changed, 61 insertions, 21 deletions

diff --git a/source/blender/depsgraph/intern/eval/deg_eval.cc b/source/blender/depsgraph/intern/eval/deg_eval.cc
index 47f2a8ca219..426e04a5cf9 100644
--- a/source/blender/depsgraph/intern/eval/deg_eval.cc
+++ b/source/blender/depsgraph/intern/eval/deg_eval.cc
@@ -37,6 +37,7 @@
 #include "intern/eval/deg_eval_copy_on_write.h"
 #include "intern/eval/deg_eval_flush.h"
 #include "intern/eval/deg_eval_stats.h"
+#include "intern/eval/deg_eval_visibility.h"
 #include "intern/node/deg_node.h"
 #include "intern/node/deg_node_component.h"
 #include "intern/node/deg_node_id.h"
@@ -69,6 +70,9 @@ enum class EvaluationStage {
    * involved. */
   COPY_ON_WRITE,
 
+  /* Evaluate actual ID nodes visiblity based on the current state of animation and drivers. */
+  DYNAMIC_VISIBILITY,
+
   /* Threaded evaluation of all possible operations. */
   THREADED_EVALUATION,
 
@@ -83,7 +87,8 @@ struct DepsgraphEvalState {
   Depsgraph *graph;
   bool do_stats;
   EvaluationStage stage;
-  bool need_single_thread_pass;
+  bool need_update_pending_parents = true;
+  bool need_single_thread_pass = false;
 };
 
 void evaluate_node(const DepsgraphEvalState *state, OperationNode *operation_node)
@@ -122,24 +127,31 @@ void deg_task_run_func(TaskPool *pool, void *taskdata)
   schedule_children(state, operation_node, schedule_node_to_pool, pool);
 }
 
-bool check_operation_node_visible(OperationNode *op_node)
+bool check_operation_node_visible(const DepsgraphEvalState *state, OperationNode *op_node)
 {
   const ComponentNode *comp_node = op_node->owner;
-  /* Special exception, copy on write component is to be always evaluated,
-   * to keep copied "database" in a consistent state. */
+  /* Special case for copy on write component: it is to be always evaluated, to keep copied
+   * "database" in a consistent state. */
   if (comp_node->type == NodeType::COPY_ON_WRITE) {
     return true;
   }
-  return comp_node->affects_directly_visible;
+
+  /* Special case for dynamic visiblity pass: the actual visibility is not yet known, so limit to
+   * only operations which affects visibility. */
+  if (state->stage == EvaluationStage::DYNAMIC_VISIBILITY) {
+    return op_node->flag & OperationFlag::DEPSOP_FLAG_AFFECTS_VISIBILITY;
+  }
+
+  return comp_node->affects_visible_id;
 }
 
-void calculate_pending_parents_for_node(OperationNode *node)
+void calculate_pending_parents_for_node(const DepsgraphEvalState *state, OperationNode *node)
 {
   /* Update counters, applies for both visible and invisible IDs. */
   node->num_links_pending = 0;
   node->scheduled = false;
   /* Invisible IDs requires no pending operations. */
-  if (!check_operation_node_visible(node)) {
+  if (!check_operation_node_visible(state, node)) {
     return;
   }
   /* No need to bother with anything if node is not tagged for update. */
@@ -153,7 +165,7 @@ void calculate_pending_parents_for_node(OperationNode *node)
        * calculation, but how is it possible that visible object depends
        * on an invisible? This is something what is prohibited after
        * deg_graph_build_flush_layers(). */
-      if (!check_operation_node_visible(from)) {
+      if (!check_operation_node_visible(state, from)) {
         continue;
       }
       /* No need to wait for operation which is up to date. */
@@ -165,20 +177,24 @@ void calculate_pending_parents_for_node(OperationNode *node)
   }
 }
 
-void calculate_pending_parents(Depsgraph *graph)
+void calculate_pending_parents_if_needed(DepsgraphEvalState *state)
 {
-  for (OperationNode *node : graph->operations) {
-    calculate_pending_parents_for_node(node);
+  if (!state->need_update_pending_parents) {
+    return;
   }
+
+  for (OperationNode *node : state->graph->operations) {
+    calculate_pending_parents_for_node(state, node);
+  }
+
+  state->need_update_pending_parents = false;
 }
 
 void initialize_execution(DepsgraphEvalState *state, Depsgraph *graph)
 {
-  const bool do_stats = state->do_stats;
-  calculate_pending_parents(graph);
   /* Clear tags and other things which needs to be clear. */
-  for (OperationNode *node : graph->operations) {
-    if (do_stats) {
+  if (state->do_stats) {
+    for (OperationNode *node : graph->operations) {
       node->stats.reset_current();
     }
   }
@@ -203,11 +219,10 @@ bool need_evaluate_operation_at_stage(DepsgraphEvalState *state,
     case EvaluationStage::COPY_ON_WRITE:
       return (component_node->type == NodeType::COPY_ON_WRITE);
 
+    case EvaluationStage::DYNAMIC_VISIBILITY:
+      return operation_node->flag & OperationFlag::DEPSOP_FLAG_AFFECTS_VISIBILITY;
+
     case EvaluationStage::THREADED_EVALUATION:
-      /* Sanity check: copy-on-write node should be evaluated already. This will be indicated by
-       * scheduled flag (we assume that scheduled operations have been actually handled by previous
-       * stage). */
-      BLI_assert(operation_node->scheduled || component_node->type != NodeType::COPY_ON_WRITE);
       if (is_metaball_object_operation(operation_node)) {
         state->need_single_thread_pass = true;
         return false;
@@ -233,7 +248,7 @@ void schedule_node(DepsgraphEvalState *state,
                    ScheduleFunctionArgs... schedule_function_args)
 {
   /* No need to schedule nodes of invisible ID. */
-  if (!check_operation_node_visible(node)) {
+  if (!check_operation_node_visible(state, node)) {
     return;
   }
   /* No need to schedule operations which are not tagged for update, they are
@@ -317,6 +332,8 @@ void evaluate_graph_threaded_stage(DepsgraphEvalState *state,
 {
   state->stage = stage;
 
+  calculate_pending_parents_if_needed(state);
+
   schedule_graph(state, schedule_node_to_pool, task_pool);
   BLI_task_pool_work_and_wait(task_pool);
 }
@@ -328,6 +345,8 @@ void evaluate_graph_single_threaded_if_needed(DepsgraphEvalState *state)
     return;
   }
 
+  BLI_assert(!state->need_update_pending_parents);
+
   state->stage = EvaluationStage::SINGLE_THREADED_WORKAROUND;
 
   GSQueue *evaluation_queue = BLI_gsqueue_new(sizeof(OperationNode *));
@@ -392,7 +411,6 @@ void deg_evaluate_on_refresh(Depsgraph *graph)
   DepsgraphEvalState state;
   state.graph = graph;
   state.do_stats = graph->debug.do_time_debug();
-  state.need_single_thread_pass = false;
 
   /* Prepare all nodes for evaluation. */
   initialize_execution(&state, graph);
@@ -403,6 +421,10 @@ void deg_evaluate_on_refresh(Depsgraph *graph)
    *   that if a dependency graph has a cycle evaluation functions will always "see" valid expanded
    *   datablock. It might not be evaluated yet, but at least the datablock will be valid.
    *
+   * - If there is potentially dynamically changing visibility in the graph update the actual
+   *   nodes visibilities, so that actual heavy data evaluation can benefit from knowledge that
+   *   something heavy is not currently visible.
+   *
    * - Multi-threaded evaluation of all possible nodes.
    *   Certain operations (and their subtrees) could be ignored. For example, meta-balls are not
    *   safe from threading point of view, so the threaded evaluation will stop at the metaball
@@ -413,6 +435,24 @@ void deg_evaluate_on_refresh(Depsgraph *graph)
   TaskPool *task_pool = deg_evaluate_task_pool_create(&state);
 
   evaluate_graph_threaded_stage(&state, task_pool, EvaluationStage::COPY_ON_WRITE);
+
+  if (graph->has_animated_visibility) {
+    /* Update pending parents including only the ones which are affecting operations which are
+     * affecting visibility. */
+    state.need_update_pending_parents = true;
+
+    evaluate_graph_threaded_stage(&state, task_pool, EvaluationStage::DYNAMIC_VISIBILITY);
+
+    deg_graph_flush_visibility_flags_if_needed(graph);
+
+    /* Update parents to an updated visibility and evaluation stage.
+     *
+     * Need to do it regardless of whether visibility is actually changed or not: current state of
+     * the pending parents are all zeroes because it was previously calculated for only visibility
+     * related nodes and those are fully evaluated by now. */
+    state.need_update_pending_parents = true;
+  }
+
   evaluate_graph_threaded_stage(&state, task_pool, EvaluationStage::THREADED_EVALUATION);
 
   BLI_task_pool_free(task_pool);