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).

4 files changed, 66 insertions, 1 deletions

diff --git a/source/blender/nodes/CMakeLists.txt b/source/blender/nodes/CMakeLists.txt
index 6fed0d16848..e09a0892370 100644
--- a/source/blender/nodes/CMakeLists.txt
+++ b/source/blender/nodes/CMakeLists.txt
@@ -105,6 +105,7 @@ set(SRC
 	composite/nodes/node_composite_setalpha.c
 	composite/nodes/node_composite_splitViewer.c
 	composite/nodes/node_composite_stabilize2d.c
+	composite/nodes/node_composite_sunbeams.c
 	composite/nodes/node_composite_texture.c
 	composite/nodes/node_composite_tonemap.c
 	composite/nodes/node_composite_trackpos.c
diff --git a/source/blender/nodes/NOD_composite.h b/source/blender/nodes/NOD_composite.h
index ad5f35b8faa..961fdbfc0fb 100644
--- a/source/blender/nodes/NOD_composite.h
+++ b/source/blender/nodes/NOD_composite.h
@@ -125,7 +125,7 @@ void register_node_type_cmp_mask(void);
 void register_node_type_cmp_glare(void);
 void register_node_type_cmp_tonemap(void);
 void register_node_type_cmp_lensdist(void);
-
+void register_node_type_cmp_sunbeams(void);
 
 void register_node_type_cmp_colorcorrection(void);
 void register_node_type_cmp_boxmask(void);
diff --git a/source/blender/nodes/NOD_static_types.h b/source/blender/nodes/NOD_static_types.h
index 8d6c4abaef6..be87abd7b7e 100644
--- a/source/blender/nodes/NOD_static_types.h
+++ b/source/blender/nodes/NOD_static_types.h
@@ -208,6 +208,7 @@ DefNode( CompositorNode, CMP_NODE_TRACKPOS,       def_cmp_trackpos,       "TRACK
 DefNode( CompositorNode, CMP_NODE_PIXELATE,       0,                      "PIXELATE",       Pixelate,         "Pixelate",          ""              )
 DefNode( CompositorNode, CMP_NODE_PLANETRACKDEFORM,def_cmp_planetrackdeform,"PLANETRACKDEFORM",PlaneTrackDeform,"Plane Track Deform",""              )
 DefNode( CompositorNode, CMP_NODE_CORNERPIN,      0,                      "CORNERPIN",      CornerPin,        "Corner Pin",        ""              )
+DefNode( CompositorNode, CMP_NODE_SUNBEAMS,       def_cmp_sunbeams,       "SUNBEAMS",       SunBeams,         "Sun Beams",         ""              )
 
 DefNode( TextureNode,    TEX_NODE_OUTPUT,         def_tex_output,         "OUTPUT",         Output,           "Output",            ""              )
 DefNode( TextureNode,    TEX_NODE_CHECKER,        0,                      "CHECKER",        Checker,          "Checker",           ""              )
diff --git a/source/blender/nodes/composite/nodes/node_composite_sunbeams.c b/source/blender/nodes/composite/nodes/node_composite_sunbeams.c
new file mode 100644
index 00000000000..4d937d63b75
--- /dev/null
+++ b/source/blender/nodes/composite/nodes/node_composite_sunbeams.c
@@ -0,0 +1,63 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * 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.
+ *
+ * The Original Code is Copyright (C) 2014 Blender Foundation.
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * Contributor(s): Lukas Toenne
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/nodes/composite/nodes/node_composite_sunbeams.c
+ *  \ingroup cmpnodes
+ */
+
+#include "node_composite_util.h"
+
+static bNodeSocketTemplate inputs[] = {
+	{	SOCK_RGBA, 1, N_("Image"),			1.0f, 1.0f, 1.0f, 1.0f},
+	{	-1, 0, ""	}
+};
+static bNodeSocketTemplate outputs[] = {
+	{	SOCK_RGBA, 0, N_("Image")},
+	{	-1, 0, ""	}
+};
+
+static void init(bNodeTree *UNUSED(ntree), bNode *node)
+{
+	NodeSunBeams *data = MEM_callocN(sizeof(NodeSunBeams), "sun beams node");
+
+	data->source[0] = 0.5f;
+	data->source[1] = 0.5f;
+
+	node->storage = data;
+}
+
+void register_node_type_cmp_sunbeams(void)
+{
+	static bNodeType ntype;
+
+	cmp_node_type_base(&ntype, CMP_NODE_SUNBEAMS, "Sun Beams", NODE_CLASS_OP_FILTER, 0);
+	node_type_socket_templates(&ntype, inputs, outputs);
+	node_type_init(&ntype, init);
+	node_type_storage(&ntype, "NodeSunBeams", node_free_standard_storage, node_copy_standard_storage);
+
+	nodeRegisterType(&ntype);
+}