Compositor: Full-frame base system

This patch adds the base code needed to make the full-frame system work for both current tiled/per-pixel implementation of operations and full-frame.

Two execution models:
- Tiled: Current implementation. Renders execution groups in tiles from outputs to input. Not all operations are buffered. Runs the tiled/per-pixel implementation.
- FullFrame: All operations are buffered. Fully renders operations from inputs to outputs. Runs full-frame implementation of operations if available otherwise the current tiled/per-pixel. Creates output buffers on first read and free them as soon as all its readers have finished, reducing peak memory usage of complex/long trees. Operations are multi-threaded but do not run in parallel as Tiled (will be done in another patch).

This should allow us to convert operations to full-frame in small steps with the system already working and solve the problem of high memory usage.

FullFrame breaking changes respect Tiled system, mainly:
- Translate, Rotate, Scale, and Transform take effect immediately instead of next buffered operation.
- Any sampling is always done over inputs instead of last buffered operation.

Reviewed By: jbakker

Differential Revision: https://developer.blender.org/D11113

1 files changed, 84 insertions, 0 deletions

diff --git a/source/blender/compositor/intern/COM_ExecutionModel.h b/source/blender/compositor/intern/COM_ExecutionModel.h
new file mode 100644
index 00000000000..9e8466b9282
--- /dev/null
+++ b/source/blender/compositor/intern/COM_ExecutionModel.h
@@ -0,0 +1,84 @@
+/*
+ * 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.
+ *
+ * Copyright 2021, Blender Foundation.
+ */
+
+#pragma once
+
+#include "BLI_rect.h"
+#include "BLI_vector.hh"
+
+#include "COM_ExecutionSystem.h"
+
+#include <functional>
+
+#ifdef WITH_CXX_GUARDEDALLOC
+#  include "MEM_guardedalloc.h"
+#endif
+
+namespace blender::compositor {
+
+class NodeOperation;
+
+/**
+ * Base class for execution models. Contains shared implementation.
+ */
+class ExecutionModel {
+ protected:
+  /**
+   * Render and viewer border info. Coordinates are normalized.
+   */
+  struct {
+    bool use_render_border;
+    const rctf *render_border;
+    bool use_viewer_border;
+    const rctf *viewer_border;
+  } border_;
+
+  /**
+   * Context used during execution.
+   */
+  CompositorContext &context_;
+
+  /**
+   * All operations being executed.
+   */
+  Span<NodeOperation *> operations_;
+
+ public:
+  ExecutionModel(CompositorContext &context, Span<NodeOperation *> operations);
+
+  virtual ~ExecutionModel()
+  {
+  }
+
+  virtual void execute(ExecutionSystem &exec_system) = 0;
+
+  virtual void execute_work(const rcti &UNUSED(work_rect),
+                            std::function<void(const rcti &split_rect)> UNUSED(work_func))
+  {
+    BLI_assert(!"Method not supported by current execution model");
+  }
+
+ protected:
+  bool is_breaked() const;
+
+#ifdef WITH_CXX_GUARDEDALLOC
+  MEM_CXX_CLASS_ALLOC_FUNCS("COM:BaseExecutionModel")
+#endif
+};
+
+}  // namespace blender::compositor