Border for compositor viewer node feature

This adds border option to compositor, which affects on
a backdrop and viewer nodes, which is useful for faster
previews and tweaks.

Final compositing still happens for the whole frame, but
if it'll be needed it's not so difficult to support it
as well.

To use border there's Ctrl-B shortcut in the compositor
editor, which i used to define region you want to restrict
compositing to. There's also "Viewer Border" option in
the N-panel in case you'll want to disable border
compositing.

Some areas could be cleaned a bit, like ideally it shall
not be viewer image clearing in viewer_border_update RNA
callback, but currently it's not so much clear how to
make it the same fast as simple memset and glue it
somehow to compositor. Will think of nicer solution a
bit later.

1 files changed, 12 insertions, 0 deletions

diff --git a/source/blender/compositor/intern/COM_ExecutionGroup.h b/source/blender/compositor/intern/COM_ExecutionGroup.h
index 00104c24194..52f5bae4be9 100644
--- a/source/blender/compositor/intern/COM_ExecutionGroup.h
+++ b/source/blender/compositor/intern/COM_ExecutionGroup.h
@@ -161,6 +161,12 @@ private:
 	 * @see openCL
 	 */
 	bool m_initialized;
+
+	/**
+	 * @brief denotes boundary for border compositing
+	 * @note measured in pixel space
+	 */
+	rcti m_viewerBorder;
 	
 	// methods
 	/**
@@ -395,6 +401,12 @@ public:
 	 */
 	CompositorPriority getRenderPriotrity();
 
+	/**
+	 * @brief set border for viewer operation
+	 * @note all the coordinates are assumed to be in normalized space
+	 */
+	void setViewerBorder(float xmin, float xmax, float ymin, float ymax);
+
 #ifdef WITH_CXX_GUARDEDALLOC
 	MEM_CXX_CLASS_ALLOC_FUNCS("COM:ExecutionGroup")
 #endif