Cycles / OSL:

* Add Light Falloff Node.

intern/cycles/kernel/osl/nodes/CMakeLists.txt

@@ -30,6 +30,7 @@ set(SRC_OSL
 	node_image_texture.osl
 	node_invert.osl
 	node_light_path.osl
+	node_light_falloff.osl
 	node_magic_texture.osl
 	node_mapping.osl
 	node_math.osl

intern/cycles/kernel/osl/nodes/node_light_falloff.osl

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012, 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.
+ */
+
+#include "stdosl.h"
+
+shader node_light_falloff(
+	float Strength = 0.0,
+	float Smooth = 0.0,
+	output float Quadratic = 0.0,
+	output float Linear = 0.0,
+	output float Constant = 0.0)
+{
+	float ray_length = 0.0;
+	float strength = Strength;
+	getattribute("std::ray_length", ray_length);
+
+	if(Smooth > 0.0) {
+		float squared = ray_length*ray_length;
+		strength *= squared/(Smooth + squared);
+	}
+
+	/* Quadratic */ 
+	Quadratic = strength;
+	
+	/* Linear */
+	Linear = (strength*ray_length);
+
+	/* Constant */
+	Constant = (strength*ray_length*ray_length);
+}
+