source/blender/nodes/shader/CMakeLists.txt

@@ -164,6 +164,7 @@ if(WITH_MATERIALX)
     materialx/nodes/emission.cc
     materialx/nodes/huesatval.cc
     materialx/nodes/invert.cc
+    materialx/nodes/light_falloff.cc
     materialx/nodes/map_range.cc
     materialx/nodes/math.cc
     materialx/nodes/mix_rgb.cc

source/blender/nodes/shader/materialx/nodes/light_falloff.cc

@@ -0,0 +1,20 @@
+/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "node_parser.h"
+
+namespace blender::nodes::materialx {
+
+NodeItem LightFalloffNodeParser::compute()
+{
+  NodeItem strength = get_input_value("Strength", NodeItem::Type::Float);
+  NodeItem smooth = get_input_value("Smooth", NodeItem::Type::Float);
+
+  /* This node isn't supported by MaterialX. This formula was given from OSL shader code in Cycles node_light_falloff.osl. Considered ray_length=1.0f. */
+  strength = strength * val(1.0f) / (smooth + val(1.0f));
+
+  return strength;
+}
+
+}  // namespace blender::nodes::materialx

source/blender/nodes/shader/materialx/nodes/node_parser.cc

@@ -157,6 +157,7 @@ NodeItem NodeParser::get_input_link(const bNodeSocket &socket, NodeItem::Type to
     CASE_NODE_TYPE(SH_NODE_COMBXYZ, CombineXYZNodeParser)
     CASE_NODE_TYPE(SH_NODE_HUE_SAT, HueSatValNodeParser)
     CASE_NODE_TYPE(SH_NODE_INVERT, InvertNodeParser)
+    CASE_NODE_TYPE(SH_NODE_LIGHT_FALLOFF, LightFalloffNodeParser)
     CASE_NODE_TYPE(SH_NODE_MAP_RANGE, MapRangeNodeParser)
     CASE_NODE_TYPE(SH_NODE_MATH, MathNodeParser)
     CASE_NODE_TYPE(SH_NODE_MIX_RGB_LEGACY, MixRGBNodeParser)

source/blender/nodes/shader/materialx/nodes/node_parser.h

@@ -99,6 +99,7 @@ DECLARE_NODE_PARSER(CombineXYZNodeParser)
 DECLARE_NODE_PARSER(GammaNodeParser)
 DECLARE_NODE_PARSER(HueSatValNodeParser)
 DECLARE_NODE_PARSER(InvertNodeParser)
+DECLARE_NODE_PARSER(LightFalloffNodeParser)
 DECLARE_NODE_PARSER(MapRangeNodeParser)
 DECLARE_NODE_PARSER(MathNodeParser)
 DECLARE_NODE_PARSER(MixRGBNodeParser)