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, 22 insertions, 3 deletions

diff --git a/source/blender/compositor/intern/COM_ExecutionSystem.h b/source/blender/compositor/intern/COM_ExecutionSystem.h
index e6170c48778..e106209651c 100644
--- a/source/blender/compositor/intern/COM_ExecutionSystem.h
+++ b/source/blender/compositor/intern/COM_ExecutionSystem.h
@@ -25,6 +25,7 @@ class ExecutionGroup;
 #include "COM_ExecutionGroup.h"
 #include "COM_Node.h"
 #include "COM_NodeOperation.h"
+#include "COM_SharedOperationBuffers.h"
 
 #include "DNA_color_types.h"
 #include "DNA_node_types.h"
@@ -115,13 +116,21 @@ namespace blender::compositor {
  * \see ExecutionGroup class representing the ExecutionGroup
  */
 
+/* Forward declarations. */
+class ExecutionModel;
+
 /**
  * \brief the ExecutionSystem contains the whole compositor tree.
  */
 class ExecutionSystem {
-
  private:
   /**
+   * Contains operations active buffers data. Buffers will be disposed once reader operations are
+   * finished.
+   */
+  SharedOperationBuffers active_buffers_;
+
+  /**
    * \brief the context used during execution
    */
   CompositorContext m_context;
@@ -136,6 +145,11 @@ class ExecutionSystem {
    */
   Vector<ExecutionGroup *> m_groups;
 
+  /**
+   * Active execution model implementation.
+   */
+  ExecutionModel *execution_model_;
+
  private:  // methods
  public:
   /**
@@ -178,9 +192,14 @@ class ExecutionSystem {
     return this->m_context;
   }
 
- private:
-  void execute_groups(eCompositorPriority priority);
+  SharedOperationBuffers &get_active_buffers()
+  {
+    return active_buffers_;
+  }
+
+  void execute_work(const rcti &work_rect, std::function<void(const rcti &split_rect)> work_func);
 
+ private:
   /* allow the DebugInfo class to look at internals */
   friend class DebugInfo;