Realtime Compositor: Add evaluator and engine

This patch adds the core realtime compositor evaluator as well as a
compositor draw engine powered by the evaluator that operates in the
viewport. The realtime compositor is a new GPU accelerated compositor
that will be used to power the viewport compositor imminently as well as
the existing compositor in the future.

This patch only adds the evaluator and engine as an experimental
feature, the implementation of the nodes themselves will be committed
separately.

See T99210.

Differential Revision: https://developer.blender.org/D15206

Reviewed By: Clement Foucault

1 files changed, 21 insertions, 0 deletions

diff --git a/source/blender/compositor/realtime_compositor/COM_scheduler.hh b/source/blender/compositor/realtime_compositor/COM_scheduler.hh
new file mode 100644
index 00000000000..4f778b32145
--- /dev/null
+++ b/source/blender/compositor/realtime_compositor/COM_scheduler.hh
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#pragma once
+
+#include "BLI_vector_set.hh"
+
+#include "NOD_derived_node_tree.hh"
+
+namespace blender::realtime_compositor {
+
+using namespace nodes::derived_node_tree_types;
+
+/* A type representing the ordered set of nodes defining the schedule of node execution. */
+using Schedule = VectorSet<DNode>;
+
+/* Computes the execution schedule of the node tree. This is essentially a post-order depth first
+ * traversal of the node tree from the output node to the leaf input nodes, with informed order of
+ * traversal of dependencies based on a heuristic estimation of the number of needed buffers. */
+Schedule compute_schedule(DerivedNodeTree &tree);
+
+}  // namespace blender::realtime_compositor