Functions: Multi Function Network

A multi-function network is a graph data structure, where nodes are
multi-functions (or dummies) and links represent data flow.
New multi-functions can be derived from such a network. For that
one just has to specify two sets of sockets in the network that
represent the inputs and outputs of the new function.

It is possible to do optimizations like constant folding on this
data structure, but that is not implemented in this patch yet.

In a next step, user generated node trees are converted into a
MFNetwork, so that they can be evaluated efficiently for many particles.

This patch also includes some tests that cover the majority of the code.
However, this seems to be the kind of code that is best tested by some
.blend files. Building graph structures in code is possible, but is
not easy to understand afterwards.

Reviewers: brecht

Differential Revision: https://developer.blender.org/D8049

1 files changed, 66 insertions, 0 deletions

diff --git a/source/blender/functions/FN_multi_function_network_evaluation.hh b/source/blender/functions/FN_multi_function_network_evaluation.hh
new file mode 100644
index 00000000000..85ccd1361ef
--- /dev/null
+++ b/source/blender/functions/FN_multi_function_network_evaluation.hh
@@ -0,0 +1,66 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __FN_MULTI_FUNCTION_NETWORK_EVALUATION_HH__
+#define __FN_MULTI_FUNCTION_NETWORK_EVALUATION_HH__
+
+/** \file
+ * \ingroup fn
+ */
+
+#include "FN_multi_function_network.hh"
+
+namespace blender {
+namespace fn {
+
+class MFNetworkEvaluationStorage;
+
+class MFNetworkEvaluator : public MultiFunction {
+ private:
+  Vector<const MFOutputSocket *> m_inputs;
+  Vector<const MFInputSocket *> m_outputs;
+
+ public:
+  MFNetworkEvaluator(Vector<const MFOutputSocket *> inputs, Vector<const MFInputSocket *> outputs);
+
+  void call(IndexMask mask, MFParams params, MFContext context) const override;
+
+ private:
+  using Storage = MFNetworkEvaluationStorage;
+
+  void copy_inputs_to_storage(MFParams params, Storage &storage) const;
+  void copy_outputs_to_storage(
+      MFParams params,
+      Storage &storage,
+      Vector<const MFInputSocket *> &outputs_to_initialize_in_the_end) const;
+
+  void evaluate_network_to_compute_outputs(MFContext &global_context, Storage &storage) const;
+
+  void evaluate_function(MFContext &global_context,
+                         const MFFunctionNode &function_node,
+                         Storage &storage) const;
+
+  bool can_do_single_value_evaluation(const MFFunctionNode &function_node, Storage &storage) const;
+
+  void initialize_remaining_outputs(MFParams params,
+                                    Storage &storage,
+                                    Span<const MFInputSocket *> remaining_outputs) const;
+};
+
+}  // namespace fn
+}  // namespace blender
+
+#endif /* __FN_MULTI_FUNCTION_NETWORK_EVALUATION_HH__ */