[Bf-blender-cvs] [cfcdae5549f] blender-v2.91-release: Fix T82393: Volume to Mesh modifier with sequence fails during rendering

[Jacques Lucke]

Commit: cfcdae5549f37198fa8e66ee512f1093764ef022
Author: Jacques Lucke
Date:   Wed Nov 4 13:21:43 2020 +0100
Branches: blender-v2.91-release
https://developer.blender.org/rBcfcdae5549f37198fa8e66ee512f1093764ef022

Fix T82393: Volume to Mesh modifier with sequence fails during rendering

The issue was that the volume for the current frame
might not have been loaded already by the time the
modifier runs.

The solution is simply to make sure that the volume
is loaded. This is similar to the Volume Displace modifier.

===================================================================

M	source/blender/blenkernel/intern/volume.cc
M	source/blender/modifiers/intern/MOD_volume_to_mesh.cc

===================================================================

diff --git a/source/blender/blenkernel/intern/volume.cc b/source/blender/blenkernel/intern/volume.cc
index 5e6f0bb42ef..87993695486 100644
--- a/source/blender/blenkernel/intern/volume.cc
+++ b/source/blender/blenkernel/intern/volume.cc
@@ -1154,6 +1154,7 @@ VolumeGrid *BKE_volume_grid_active_get(const Volume *volume)
   return BKE_volume_grid_get(volume, index);
 }
 
+/* Tries to find a grid with the given name. Make sure that that the volume has been loaded. */
 VolumeGrid *BKE_volume_grid_find(const Volume *volume, const char *name)
 {
   int num_grids = BKE_volume_num_grids(volume);
diff --git a/source/blender/modifiers/intern/MOD_volume_to_mesh.cc b/source/blender/modifiers/intern/MOD_volume_to_mesh.cc
index 8146c4ca84a..11d30c1f173 100644
--- a/source/blender/modifiers/intern/MOD_volume_to_mesh.cc
+++ b/source/blender/modifiers/intern/MOD_volume_to_mesh.cc
@@ -45,6 +45,8 @@
 #include "BLI_span.hh"
 #include "BLI_timeit.hh"
 
+#include "DEG_depsgraph_query.h"
+
 #ifdef WITH_OPENVDB
 #  include <openvdb/tools/GridTransformer.h>
 #  include <openvdb/tools/VolumeToMesh.h>
@@ -281,6 +283,7 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
 
   Volume *volume = static_cast<Volume *>(vmmd->object->data);
 
+  BKE_volume_load(volume, DEG_get_bmain(ctx->depsgraph));
   VolumeGrid *volume_grid = BKE_volume_grid_find(volume, vmmd->grid_name);
   if (volume_grid == nullptr) {
     BKE_modifier_set_error(md, "Cannot find '%s' grid", vmmd->grid_name);