Shading: Add Volume Info node.

The Volume Info node provides the Color, Desnity, Flame, and Temperature
of smoke domains.

Reviewers: brecht

Differential Revision: https://developer.blender.org/D5551

intern/cycles/blender/blender_shader.cpp

@@ -607,6 +607,9 @@ static ShaderNode *add_node(Scene *scene,
   else if (b_node.is_a(&RNA_ShaderNodeHairInfo)) {
     node = new HairInfoNode();
   }
+  else if (b_node.is_a(&RNA_ShaderNodeVolumeInfo)) {
+    node = new VolumeInfoNode();
+  }
   else if (b_node.is_a(&RNA_ShaderNodeBump)) {
     BL::ShaderNodeBump b_bump_node(b_node);
     BumpNode *bump = new BumpNode();

intern/cycles/render/nodes.cpp

@@ -4168,6 +4168,90 @@ void HairInfoNode::compile(OSLCompiler &compiler)
   compiler.add(this, "node_hair_info");
 }
 
+/* Volume Info */
+
+NODE_DEFINE(VolumeInfoNode)
+{
+  NodeType *type = NodeType::add("volume_info", create, NodeType::SHADER);
+
+  SOCKET_OUT_COLOR(color, "Color");
+  SOCKET_OUT_FLOAT(density, "Density");
+  SOCKET_OUT_FLOAT(flame, "Flame");
+  SOCKET_OUT_FLOAT(temperature, "Temperature");
+
+  return type;
+}
+
+VolumeInfoNode::VolumeInfoNode() : ShaderNode(node_type)
+{
+}
+
+/* The requested attributes are not updated after node expansion.
+ * So we explicitly request the required attributes.
+ */
+void VolumeInfoNode::attributes(Shader *shader, AttributeRequestSet *attributes)
+{
+  if (shader->has_volume) {
+    if (!output("Color")->links.empty()) {
+      attributes->add(ATTR_STD_VOLUME_COLOR);
+    }
+    if (!output("Density")->links.empty()) {
+      attributes->add(ATTR_STD_VOLUME_DENSITY);
+    }
+    if (!output("Flame")->links.empty()) {
+      attributes->add(ATTR_STD_VOLUME_FLAME);
+    }
+    if (!output("Temperature")->links.empty()) {
+      attributes->add(ATTR_STD_VOLUME_TEMPERATURE);
+    }
+    attributes->add(ATTR_STD_GENERATED_TRANSFORM);
+  }
+  ShaderNode::attributes(shader, attributes);
+}
+
+void VolumeInfoNode::expand(ShaderGraph *graph)
+{
+  ShaderOutput *color_out = output("Color");
+  if (!color_out->links.empty()) {
+    AttributeNode *attr = new AttributeNode();
+    attr->attribute = "color";
+    graph->add(attr);
+    graph->relink(color_out, attr->output("Color"));
+  }
+
+  ShaderOutput *density_out = output("Density");
+  if (!density_out->links.empty()) {
+    AttributeNode *attr = new AttributeNode();
+    attr->attribute = "density";
+    graph->add(attr);
+    graph->relink(density_out, attr->output("Fac"));
+  }
+
+  ShaderOutput *flame_out = output("Flame");
+  if (!flame_out->links.empty()) {
+    AttributeNode *attr = new AttributeNode();
+    attr->attribute = "flame";
+    graph->add(attr);
+    graph->relink(flame_out, attr->output("Fac"));
+  }
+
+  ShaderOutput *temperature_out = output("Temperature");
+  if (!temperature_out->links.empty()) {
+    AttributeNode *attr = new AttributeNode();
+    attr->attribute = "temperature";
+    graph->add(attr);
+    graph->relink(temperature_out, attr->output("Fac"));
+  }
+}
+
+void VolumeInfoNode::compile(SVMCompiler &)
+{
+}
+
+void VolumeInfoNode::compile(OSLCompiler &)
+{
+}
+
 /* Value */
 
 NODE_DEFINE(ValueNode)

intern/cycles/render/nodes.h

@@ -961,6 +961,21 @@ class HairInfoNode : public ShaderNode {
   }
 };
 
+class VolumeInfoNode : public ShaderNode {
+ public:
+  SHADER_NODE_CLASS(VolumeInfoNode)
+  void attributes(Shader *shader, AttributeRequestSet *attributes);
+  bool has_attribute_dependency()
+  {
+    return true;
+  }
+  bool has_spatial_varying()
+  {
+    return true;
+  }
+  void expand(ShaderGraph *graph);
+};
+
 class ValueNode : public ShaderNode {
  public:
   SHADER_NODE_CLASS(ValueNode)

release/scripts/startup/nodeitems_builtins.py

@@ -186,6 +186,7 @@ shader_node_categories = [
         NodeItem("ShaderNodeAmbientOcclusion"),
         NodeItem("ShaderNodeObjectInfo"),
         NodeItem("ShaderNodeHairInfo"),
+        NodeItem("ShaderNodeVolumeInfo"),
         NodeItem("ShaderNodeParticleInfo"),
         NodeItem("ShaderNodeCameraData"),
         NodeItem("ShaderNodeUVMap"),

source/blender/blenkernel/BKE_node.h

@@ -979,6 +979,7 @@ void BKE_nodetree_remove_layer_n(struct bNodeTree *ntree,
 #define SH_NODE_MAP_RANGE 702
 #define SH_NODE_CLAMP 703
 #define SH_NODE_TEX_WHITE_NOISE 704
+#define SH_NODE_VOLUME_INFO 705
 
 /* custom defines options for Material node */
 #define SH_NODE_MAT_DIFF 1

source/blender/blenkernel/intern/node.c

@@ -3960,6 +3960,7 @@ static void registerTextureNodes(void)
   register_node_type_sh_tangent();
   register_node_type_sh_normal_map();
   register_node_type_sh_hair_info();
+  register_node_type_sh_volume_info();
 
   register_node_type_tex_checker();
   register_node_type_tex_texture();

source/blender/gpu/shaders/gpu_shader_material.glsl

@@ -2322,6 +2322,35 @@ void node_attribute_volume_temperature(
   outcol = vec4(outf, outf, outf, 1.0);
 }
 
+void node_volume_info(sampler3D densitySampler,
+                      sampler3D flameSampler,
+                      vec2 temperature,
+                      out vec4 outColor,
+                      out float outDensity,
+                      out float outFlame,
+                      out float outTemprature)
+{
+#if defined(MESH_SHADER) && defined(VOLUMETRICS)
+  vec3 p = volumeObjectLocalCoord;
+#else
+  vec3 p = vec3(0.0);
+#endif
+
+  vec4 density = texture(densitySampler, p);
+  outDensity = density.a;
+
+  /* Density is premultiplied for interpolation, divide it out here. */
+  if (density.a > 1e-8) {
+    density.rgb /= density.a;
+  }
+  outColor = vec4(density.rgb * volumeColor, 1.0);
+
+  float flame = texture(flameSampler, p).r;
+  outFlame = flame;
+
+  outTemprature = (flame > 0.01) ? temperature.x + flame * (temperature.y - temperature.x) : 0.0;
+}
+
 void node_attribute(vec3 attr, out vec4 outcol, out vec3 outvec, out float outf)
 {
   outcol = vec4(attr, 1.0);

source/blender/nodes/CMakeLists.txt

@@ -209,6 +209,7 @@ set(SRC
   shader/nodes/node_shader_vectTransform.c
   shader/nodes/node_shader_vector_displacement.c
   shader/nodes/node_shader_volume_absorption.c
+  shader/nodes/node_shader_volume_info.c
   shader/nodes/node_shader_volume_principled.c
   shader/nodes/node_shader_volume_scatter.c
   shader/nodes/node_shader_wavelength.c

source/blender/nodes/NOD_shader.h

@@ -81,6 +81,7 @@ void register_node_type_sh_layer_weight(void);
 void register_node_type_sh_tex_coord(void);
 void register_node_type_sh_particle_info(void);
 void register_node_type_sh_hair_info(void);
+void register_node_type_sh_volume_info(void);
 void register_node_type_sh_script(void);
 void register_node_type_sh_normal_map(void);
 void register_node_type_sh_tangent(void);

source/blender/nodes/NOD_static_types.h

@@ -96,6 +96,7 @@ DefNode(ShaderNode,     SH_NODE_LIGHT_FALLOFF,      0,                      "LIG
 DefNode(ShaderNode,     SH_NODE_OBJECT_INFO,        0,                      "OBJECT_INFO",        ObjectInfo,       "Object Info",       ""       )
 DefNode(ShaderNode,     SH_NODE_PARTICLE_INFO,      0,                      "PARTICLE_INFO",      ParticleInfo,     "Particle Info",     ""       )
 DefNode(ShaderNode,     SH_NODE_HAIR_INFO,          0,                      "HAIR_INFO",          HairInfo,         "Hair Info",         ""       )
+DefNode(ShaderNode,     SH_NODE_VOLUME_INFO,        0,                      "VOLUME_INFO",        VolumeInfo,       "Volume Info",       ""       )
 DefNode(ShaderNode,     SH_NODE_WIREFRAME,          def_sh_tex_wireframe,   "WIREFRAME",          Wireframe,        "Wireframe",         ""       )
 DefNode(ShaderNode,     SH_NODE_WAVELENGTH,         0,                      "WAVELENGTH",         Wavelength,       "Wavelength",        ""       )
 DefNode(ShaderNode,     SH_NODE_BLACKBODY,          0,                      "BLACKBODY",          Blackbody,        "Blackbody",         ""       )

source/blender/nodes/shader/nodes/node_shader_volume_info.c

@@ -0,0 +1,56 @@
+/*
+ * 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) 2005 Blender Foundation.
+ * All rights reserved.
+ */
+
+#include "../node_shader_util.h"
+
+static bNodeSocketTemplate sh_node_volume_info_out[] = {
+    {SOCK_RGBA, 0, N_("Color")},
+    {SOCK_FLOAT, 0, N_("Density")},
+    {SOCK_FLOAT, 0, N_("Flame")},
+    {SOCK_FLOAT, 0, N_("Temperature")},
+    {-1, 0, ""},
+};
+
+static int node_shader_gpu_volume_info(GPUMaterial *mat,
+                                       bNode *node,
+                                       bNodeExecData *UNUSED(execdata),
+                                       GPUNodeStack *in,
+                                       GPUNodeStack *out)
+{
+
+  return GPU_stack_link(mat,
+                        node,
+                        "node_volume_info",
+                        in,
+                        out,
+                        GPU_builtin(GPU_VOLUME_DENSITY),
+                        GPU_builtin(GPU_VOLUME_FLAME),
+                        GPU_builtin(GPU_VOLUME_TEMPERATURE));
+}
+
+void register_node_type_sh_volume_info(void)
+{
+  static bNodeType ntype;
+
+  sh_node_type_base(&ntype, SH_NODE_VOLUME_INFO, "Volume Info", NODE_CLASS_INPUT, 0);
+  node_type_socket_templates(&ntype, NULL, sh_node_volume_info_out);
+  node_type_gpu(&ntype, node_shader_gpu_volume_info);
+
+  nodeRegisterType(&ntype);
+}