New compositor node "Sun Beams"

This allows adding a "fake" sun beam effect, simulating crepuscular rays
from light being scattered in a medium like the atmosphere or deep water.
Such effects can be created also by renderers using volumetric lighting,
but the compositor feature is a lot cheaper and is independent from 3D
rendering. This makes it ideally suited for motion graphics.

The implementation uses am optimized accumulation method for gathering
color values along a line segment. The inner buffer loop uses fixed
offset increments to avoid unnecessary multiplications and avoids
variables by using compile-time specialization (see inline comments
for further details).

1 files changed, 48 insertions, 0 deletions

diff --git a/source/blender/compositor/operations/COM_SunBeamsOperation.h b/source/blender/compositor/operations/COM_SunBeamsOperation.h
new file mode 100644
index 00000000000..ef80a31fe40
--- /dev/null
+++ b/source/blender/compositor/operations/COM_SunBeamsOperation.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2014, Blender Foundation.
+ *
+ * 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.
+ *
+ * Contributor:
+ *		Lukas Toenne
+ */
+
+#ifndef _COM_SunBeamsOperation_h
+#define _COM_SunBeamsOperation_h
+
+#include "COM_NodeOperation.h"
+
+class SunBeamsOperation : public NodeOperation {
+public:
+	SunBeamsOperation();
+
+	void executePixel(float output[4], int x, int y, void *data);
+
+	void initExecution();
+
+	void *initializeTileData(rcti *rect);
+
+	bool determineDependingAreaOfInterest(rcti *input, ReadBufferOperation *readOperation, rcti *output);
+
+	void setData(const NodeSunBeams &data) { m_data = data; }
+
+private:
+	NodeSunBeams m_data;
+
+	float m_source_px[2];
+	float m_ray_length_px;
+};
+
+#endif