Cycles: Add Support for IES files as textures for light strength

This patch adds support for IES files, a file format that is commonly used to store the directional intensity distribution of light sources.
The new IES node is supposed to be plugged into the Strength input of the Emission node of the lamp.

Since people generating IES files do not really seem to care about the standard, the parser is flexible enough to accept all test files I have tried.
Some common weirdnesses are distributing values over multiple lines that should go into one line, using commas instead of spaces as delimiters and adding various useless stuff at the end of the file.

The user interface of the node is similar to the script node, the user can either select an internal Text or load a file.
Internally, IES files are handled similar to Image textures: They are stored in slots by the LightManager and each unique IES is assigned to one slot.

The local coordinate system of the lamp is used, so that the direction of the light can be changed. For UI reasons, it's usually best to add an area light,
rotate it and then change its type, since especially the point light does not immediately show its local coordinate system in the viewport.

Reviewers: #cycles, dingto, sergey, brecht

Reviewed By: #cycles, dingto, brecht

Subscribers: OgDEV, crazyrobinhood, secundar, cardboard, pisuke, intrah, swerner, micah_denn, harvester, gottfried, disnel, campbellbarton, duarteframos, Lapineige, brecht, juicyfruit, dingto, marek, rickyblender, bliblubli, lockal, sergey

Differential Revision: https://developer.blender.org/D1543

4 files changed, 64 insertions, 0 deletions

diff --git a/source/blender/nodes/CMakeLists.txt b/source/blender/nodes/CMakeLists.txt
index 5247599bdf7..cc0bef30047 100644
--- a/source/blender/nodes/CMakeLists.txt
+++ b/source/blender/nodes/CMakeLists.txt
@@ -177,6 +177,7 @@ set(SRC
 	shader/nodes/node_shader_fresnel.c
 	shader/nodes/node_shader_geometry.c
 	shader/nodes/node_shader_holdout.c
+	shader/nodes/node_shader_ies_light.c
 	shader/nodes/node_shader_layer_weight.c
 	shader/nodes/node_shader_light_falloff.c
 	shader/nodes/node_shader_light_path.c
diff --git a/source/blender/nodes/NOD_shader.h b/source/blender/nodes/NOD_shader.h
index b00307ed7fb..7cb52cda550 100644
--- a/source/blender/nodes/NOD_shader.h
+++ b/source/blender/nodes/NOD_shader.h
@@ -138,6 +138,7 @@ void register_node_type_sh_tex_musgrave(void);
 void register_node_type_sh_tex_noise(void);
 void register_node_type_sh_tex_checker(void);
 void register_node_type_sh_bump(void);
+void register_node_type_sh_tex_ies(void);
 
 #endif
 
diff --git a/source/blender/nodes/NOD_static_types.h b/source/blender/nodes/NOD_static_types.h
index bc90e33ed03..5864b3deb39 100644
--- a/source/blender/nodes/NOD_static_types.h
+++ b/source/blender/nodes/NOD_static_types.h
@@ -130,6 +130,7 @@ DefNode( ShaderNode,     SH_NODE_COMBXYZ,            0,                      "CO
 DefNode( ShaderNode,     SH_NODE_BEVEL,              def_sh_bevel,           "BEVEL",              Bevel,            "Bevel",             ""       )
 DefNode( ShaderNode,     SH_NODE_DISPLACEMENT,       def_sh_displacement,    "DISPLACEMENT",       Displacement,     "Displacement",      ""       )
 DefNode( ShaderNode,     SH_NODE_VECTOR_DISPLACEMENT,def_sh_vector_displacement,"VECTOR_DISPLACEMENT",VectorDisplacement,"Vector Displacement",""  )
+DefNode( ShaderNode,     SH_NODE_TEX_IES,            def_sh_tex_ies,         "TEX_IES",            TexIES,           "IES Texture",       ""       )
 
 DefNode( CompositorNode, CMP_NODE_VIEWER,         def_cmp_viewer,         "VIEWER",         Viewer,           "Viewer",            ""              )
 DefNode( CompositorNode, CMP_NODE_RGB,            0,                      "RGB",            RGB,              "RGB",               ""              )
diff --git a/source/blender/nodes/shader/nodes/node_shader_ies_light.c b/source/blender/nodes/shader/nodes/node_shader_ies_light.c
new file mode 100644
index 00000000000..8084f445e34
--- /dev/null
+++ b/source/blender/nodes/shader/nodes/node_shader_ies_light.c
@@ -0,0 +1,61 @@
+/*
+ * ***** 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) 2018 Blender Foundation.
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * Contributor(s): none yet.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#include "../node_shader_util.h"
+
+/* **************** IES Light ******************** */
+
+static bNodeSocketTemplate sh_node_tex_ies_in[] = {
+	{	SOCK_VECTOR, 1, N_("Vector"),		0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, PROP_NONE, SOCK_HIDE_VALUE},
+	{	SOCK_FLOAT, 1, N_("Strength"),		1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1000000.0f, PROP_NONE},
+	{	-1, 0, ""	}
+};
+
+static bNodeSocketTemplate sh_node_tex_ies_out[] = {
+	{	SOCK_FLOAT, 0, N_("Fac")},
+	{	-1, 0, ""	}
+};
+
+static void node_shader_init_tex_ies(bNodeTree *UNUSED(ntree), bNode *node)
+{
+	NodeShaderTexIES *tex = MEM_callocN(sizeof(NodeShaderTexIES), "NodeShaderIESLight");
+	node->storage = tex;
+}
+
+/* node type definition */
+void register_node_type_sh_tex_ies(void)
+{
+	static bNodeType ntype;
+
+	sh_node_type_base(&ntype, SH_NODE_TEX_IES, "IES Texture", NODE_CLASS_TEXTURE, 0);
+	node_type_compatibility(&ntype, NODE_NEW_SHADING);
+	node_type_socket_templates(&ntype, sh_node_tex_ies_in, sh_node_tex_ies_out);
+	node_type_init(&ntype, node_shader_init_tex_ies);
+	node_type_storage(&ntype, "NodeShaderTexIES", node_free_standard_storage, node_copy_standard_storage);
+
+	nodeRegisterType(&ntype);
+}