Fluid: Updated Mantaflow source files

This update introduces two improvements from the Mantaflow repository:

(1) Improved particle sampling:
- Liquid and secondary particles are sampled more predictably. With all parameters being equal, baked particles will be computed at the exact same position during every bake.
- Before, this was not guaranteed.

(2) Sparse grid caching:
- While saving grid data to disk, grids will from now on be saved in a sparse structure whenever possible (e.g. density, flame but not levelsets).
- With the sparse optimization grid cells with a value under the 'Empty Space' value (already present in domain settings) will not be cached.
- The main benefits of this optimization are: Smaller cache sizes and faster playback of simulation data in the viewport.
- This optimization works 'out-of-the-box'. There is no option in the UI to enable it.
- For now, only smoke simulation grids will take advantage of this optimization.

1 files changed, 23 insertions, 7 deletions

diff --git a/extern/mantaflow/preprocessed/grid.h b/extern/mantaflow/preprocessed/grid.h
index 1f3dc2789ac..cf942a19e9a 100644
--- a/extern/mantaflow/preprocessed/grid.h
+++ b/extern/mantaflow/preprocessed/grid.h
@@ -402,7 +402,7 @@ class GridBase : public PbClass {
 template<class T> class Grid : public GridBase {
  public:
   //! init new grid, values are set to zero
-  Grid(FluidSolver *parent, bool show = true);
+  Grid(FluidSolver *parent, bool show = true, bool sparse = false);
   static int _W_10(PyObject *_self, PyObject *_linargs, PyObject *_kwds)
   {
     PbClass *obj = Pb::objFromPy(_self);
@@ -416,7 +416,8 @@ template<class T> class Grid : public GridBase {
         ArgLocker _lock;
         FluidSolver *parent = _args.getPtr<FluidSolver>("parent", 0, &_lock);
         bool show = _args.getOpt<bool>("show", 1, true, &_lock);
-        obj = new Grid(parent, show);
+        bool sparse = _args.getOpt<bool>("sparse", 2, false, &_lock);
+        obj = new Grid(parent, show, sparse);
         obj->registerObject(_self, &_args);
         _args.check();
       }
@@ -581,6 +582,16 @@ template<class T> class Grid : public GridBase {
     DEBUG_ONLY(checkIndex(idx));
     return mData[idx];
   }
+  //! raw data access
+  inline T *getData() const
+  {
+    return mData;
+  }
+  //! query if this grid should be saved as a sparse grid
+  inline bool saveSparse()
+  {
+    return mSaveSparse;
+  }
 
   //! set data
   inline void set(int i, int j, int k, T &val)
@@ -1290,7 +1301,8 @@ template<class T> class Grid : public GridBase {
 
  protected:
   T *mData;
-  bool externalData;  // True if mData is managed outside of the Fluidsolver
+  bool mExternalData;  // True if mData is managed outside of the Fluidsolver
+  bool mSaveSparse;    // True if this grid may be cached in a sparse structure
  public:
   PbArgs _args;
 }
@@ -1302,7 +1314,8 @@ template<class T> class Grid : public GridBase {
 //! Special function for staggered grids
 class MACGrid : public Grid<Vec3> {
  public:
-  MACGrid(FluidSolver *parent, bool show = true) : Grid<Vec3>(parent, show)
+  MACGrid(FluidSolver *parent, bool show = true, bool sparse = false)
+      : Grid<Vec3>(parent, show, sparse)
   {
     mType = (GridType)(TypeMAC | TypeVec3);
   }
@@ -1319,7 +1332,8 @@ class MACGrid : public Grid<Vec3> {
         ArgLocker _lock;
         FluidSolver *parent = _args.getPtr<FluidSolver>("parent", 0, &_lock);
         bool show = _args.getOpt<bool>("show", 1, true, &_lock);
-        obj = new MACGrid(parent, show);
+        bool sparse = _args.getOpt<bool>("sparse", 2, false, &_lock);
+        obj = new MACGrid(parent, show, sparse);
         obj->registerObject(_self, &_args);
         _args.check();
       }
@@ -1425,7 +1439,8 @@ class MACGrid : public Grid<Vec3> {
 //! Special functions for FlagGrid
 class FlagGrid : public Grid<int> {
  public:
-  FlagGrid(FluidSolver *parent, int dim = 3, bool show = true) : Grid<int>(parent, show)
+  FlagGrid(FluidSolver *parent, int dim = 3, bool show = true, bool sparse = false)
+      : Grid<int>(parent, show, sparse)
   {
     mType = (GridType)(TypeFlags | TypeInt);
   }
@@ -1443,7 +1458,8 @@ class FlagGrid : public Grid<int> {
         FluidSolver *parent = _args.getPtr<FluidSolver>("parent", 0, &_lock);
         int dim = _args.getOpt<int>("dim", 1, 3, &_lock);
         bool show = _args.getOpt<bool>("show", 2, true, &_lock);
-        obj = new FlagGrid(parent, dim, show);
+        bool sparse = _args.getOpt<bool>("sparse", 3, false, &_lock);
+        obj = new FlagGrid(parent, dim, show, sparse);
         obj->registerObject(_self, &_args);
         _args.check();
       }