Fluid: Added new viscosity solver

Mainly updated the Mantaflow version. It includes the new viscosity solver plugin based on the method from 'Accurate Viscous Free Surfaces for Buckling, Coiling, and Rotating Liquids' (Batty & Bridson).

In the UI, this update adds a new 'Viscosity' section to the fluid modifier UI (liquid domains only). For now, there is a single 'strength' value to control the viscosity of liquids.

2 files changed, 34 insertions, 15 deletions

diff --git a/source/blender/blenloader/intern/versioning_290.c b/source/blender/blenloader/intern/versioning_290.c
index 8a85278a931..63ef436d8e2 100644
--- a/source/blender/blenloader/intern/versioning_290.c
+++ b/source/blender/blenloader/intern/versioning_290.c
@@ -1430,18 +1430,7 @@ void blo_do_versions_290(FileData *fd, Library *UNUSED(lib), Main *bmain)
     }
   }
 
-  /**
-   * Versioning code until next subversion bump goes here.
-   *
-   * \note Be sure to check when bumping the version:
-   * - "versioning_userdef.c", #blo_do_versions_userdef
-   * - "versioning_userdef.c", #do_versions_theme
-   *
-   * \note Keep this message at the bottom of the function.
-   */
-  {
-    /* Keep this block, even when empty. */
-
+  if (!MAIN_VERSION_ATLEAST(bmain, 292, 9)) {
     FOREACH_NODETREE_BEGIN (bmain, ntree, id) {
       if (ntree->type == NTREE_GEOMETRY) {
         LISTBASE_FOREACH (bNode *, node, &ntree->nodes) {
@@ -1474,5 +1463,32 @@ void blo_do_versions_290(FileData *fd, Library *UNUSED(lib), Main *bmain)
         }
       }
     }
+
+    /* Ensure that new viscosity strength field is initialized correctly. */
+    if (!DNA_struct_elem_find(fd->filesdna, "FluidModifierData", "float", "viscosity_value")) {
+      LISTBASE_FOREACH (Object *, ob, &bmain->objects) {
+        LISTBASE_FOREACH (ModifierData *, md, &ob->modifiers) {
+          if (md->type == eModifierType_Fluid) {
+            FluidModifierData *fmd = (FluidModifierData *)md;
+            if (fmd->domain != NULL) {
+              fmd->domain->viscosity_value = 0.05;
+            }
+          }
+        }
+      }
+    }
+  }
+
+  /**
+   * Versioning code until next subversion bump goes here.
+   *
+   * \note Be sure to check when bumping the version:
+   * - "versioning_userdef.c", #blo_do_versions_userdef
+   * - "versioning_userdef.c", #do_versions_theme
+   *
+   * \note Keep this message at the bottom of the function.
+   */
+  {
+    /* Keep this block, even when empty. */
   }
 }
diff --git a/source/blender/blenloader/intern/versioning_userdef.c b/source/blender/blenloader/intern/versioning_userdef.c
index f1572c563bf..b9f09e0326d 100644
--- a/source/blender/blenloader/intern/versioning_userdef.c
+++ b/source/blender/blenloader/intern/versioning_userdef.c
@@ -820,6 +820,12 @@ void blo_do_versions_userdef(UserDef *userdef)
     userdef->uiflag &= ~USER_UIFLAG_UNUSED_3;
   }
 
+  if (!USER_VERSION_ATLEAST(292, 9)) {
+    if (BLI_listbase_is_empty(&userdef->asset_libraries)) {
+      BKE_preferences_asset_library_default_add(userdef);
+    }
+  }
+
   /**
    * Versioning code until next subversion bump goes here.
    *
@@ -831,9 +837,6 @@ void blo_do_versions_userdef(UserDef *userdef)
    */
   {
     /* Keep this block, even when empty. */
-    if (BLI_listbase_is_empty(&userdef->asset_libraries)) {
-      BKE_preferences_asset_library_default_add(userdef);
-    }
   }
 
   LISTBASE_FOREACH (bTheme *, btheme, &userdef->themes) {