Geometry Nodes: add Attribute Mix node

This node can be used to mix two attributes in various ways.
The blend modes are the same as in the MixRGB shader node.

Differential Revision: https://developer.blender.org/D9737

Ref T82374.

4 files changed, 222 insertions, 0 deletions

diff --git a/source/blender/nodes/CMakeLists.txt b/source/blender/nodes/CMakeLists.txt
index 87055a934fd..11852f6f723 100644
--- a/source/blender/nodes/CMakeLists.txt
+++ b/source/blender/nodes/CMakeLists.txt
@@ -144,6 +144,7 @@ set(SRC
   geometry/nodes/node_geo_common.cc
   geometry/nodes/node_geo_edge_split.cc
   geometry/nodes/node_geo_join_geometry.cc
+  geometry/nodes/node_geo_attribute_mix.cc
   geometry/nodes/node_geo_object_info.cc
   geometry/nodes/node_geo_point_distribute.cc
   geometry/nodes/node_geo_point_instance.cc
diff --git a/source/blender/nodes/NOD_geometry.h b/source/blender/nodes/NOD_geometry.h
index 6433841582b..e3ec0451832 100644
--- a/source/blender/nodes/NOD_geometry.h
+++ b/source/blender/nodes/NOD_geometry.h
@@ -38,6 +38,7 @@ void register_node_type_geo_object_info(void);
 void register_node_type_geo_random_attribute(void);
 void register_node_type_geo_attribute_math(void);
 void register_node_type_geo_join_geometry(void);
+void register_node_type_geo_attribute_mix(void);
 
 #ifdef __cplusplus
 }
diff --git a/source/blender/nodes/NOD_static_types.h b/source/blender/nodes/NOD_static_types.h
index 8ca978d1339..d1032647ba8 100644
--- a/source/blender/nodes/NOD_static_types.h
+++ b/source/blender/nodes/NOD_static_types.h
@@ -278,6 +278,7 @@ DefNode(GeometryNode, GEO_NODE_RANDOM_ATTRIBUTE, def_geo_random_attribute, "RAND
 DefNode(GeometryNode, GEO_NODE_ATTRIBUTE_MATH, def_geo_attribute_math, "ATTRIBUTE_MATH", AttributeMath, "Attribute Math", "")
 DefNode(GeometryNode, GEO_NODE_JOIN_GEOMETRY, 0, "JOIN_GEOMETRY", JoinGeometry, "Join Geometry", "")
 DefNode(GeometryNode, GEO_NODE_ATTRIBUTE_FILL, def_geo_attribute_fill, "ATTRIBUTE_FILL", AttributeFill, "Attribute Fill", "")
+DefNode(GeometryNode, GEO_NODE_ATTRIBUTE_MIX, def_geo_attribute_mix, "ATTRIBUTE_MIX", AttributeMix, "Attribute Mix", "")
 
 /* undefine macros */
 #undef DefNode
diff --git a/source/blender/nodes/geometry/nodes/node_geo_attribute_mix.cc b/source/blender/nodes/geometry/nodes/node_geo_attribute_mix.cc
new file mode 100644
index 00000000000..f96bc9f9e15
--- /dev/null
+++ b/source/blender/nodes/geometry/nodes/node_geo_attribute_mix.cc
@@ -0,0 +1,219 @@
+/*
+ * 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 "BKE_material.h"
+
+#include "node_geometry_util.hh"
+
+static bNodeSocketTemplate geo_node_attribute_mix_in[] = {
+    {SOCK_GEOMETRY, N_("Geometry")},
+    {SOCK_STRING, N_("Factor")},
+    {SOCK_FLOAT, N_("Factor"), 0.5, 0.0, 0.0, 0.0, 0.0, 1.0, PROP_FACTOR},
+    {SOCK_STRING, N_("A")},
+    {SOCK_FLOAT, N_("A"), 0.0, 0.0, 0.0, 0.0, -FLT_MAX, FLT_MAX},
+    {SOCK_VECTOR, N_("A"), 0.0, 0.0, 0.0, 0.0, -FLT_MAX, FLT_MAX},
+    {SOCK_RGBA, N_("A"), 0.5, 0.5, 0.5, 1.0},
+    {SOCK_STRING, N_("B")},
+    {SOCK_FLOAT, N_("B"), 0.0, 0.0, 0.0, 0.0, -FLT_MAX, FLT_MAX},
+    {SOCK_VECTOR, N_("B"), 0.0, 0.0, 0.0, 0.0, -FLT_MAX, FLT_MAX},
+    {SOCK_RGBA, N_("B"), 0.5, 0.5, 0.5, 1.0},
+    {SOCK_STRING, N_("Result")},
+    {-1, ""},
+};
+
+static bNodeSocketTemplate geo_node_mix_attribute_out[] = {
+    {SOCK_GEOMETRY, N_("Geometry")},
+    {-1, ""},
+};
+
+namespace blender::nodes {
+
+static void do_mix_operation_float(const int blend_mode,
+                                   const FloatReadAttribute &factors,
+                                   const FloatReadAttribute &inputs_a,
+                                   const FloatReadAttribute &inputs_b,
+                                   FloatWriteAttribute &results)
+{
+  const int size = results.size();
+  for (const int i : IndexRange(size)) {
+    const float factor = factors[i];
+    float3 a{inputs_a[i]};
+    const float3 b{inputs_b[i]};
+    ramp_blend(blend_mode, a, factor, b);
+    const float result = a.length();
+    results.set(i, result);
+  }
+}
+
+static void do_mix_operation_float3(const int blend_mode,
+                                    const FloatReadAttribute &factors,
+                                    const Float3ReadAttribute &inputs_a,
+                                    const Float3ReadAttribute &inputs_b,
+                                    Float3WriteAttribute &results)
+{
+  const int size = results.size();
+  for (const int i : IndexRange(size)) {
+    const float factor = factors[i];
+    float3 a = inputs_a[i];
+    const float3 b = inputs_b[i];
+    ramp_blend(blend_mode, a, factor, b);
+    results.set(i, a);
+  }
+}
+
+static void do_mix_operation_color4f(const int blend_mode,
+                                     const FloatReadAttribute &factors,
+                                     const Color4fReadAttribute &inputs_a,
+                                     const Color4fReadAttribute &inputs_b,
+                                     Color4fWriteAttribute &results)
+{
+  const int size = results.size();
+  for (const int i : IndexRange(size)) {
+    const float factor = factors[i];
+    Color4f a = inputs_a[i];
+    const Color4f b = inputs_b[i];
+    ramp_blend(blend_mode, a, factor, b);
+    results.set(i, a);
+  }
+}
+
+static void do_mix_operation(const CustomDataType result_type,
+                             int blend_mode,
+                             const FloatReadAttribute &attribute_factor,
+                             ReadAttributePtr attribute_a,
+                             ReadAttributePtr attribute_b,
+                             WriteAttributePtr attribute_result)
+{
+  if (result_type == CD_PROP_FLOAT) {
+    FloatReadAttribute attribute_a_float = std::move(attribute_a);
+    FloatReadAttribute attribute_b_float = std::move(attribute_b);
+    FloatWriteAttribute attribute_result_float = std::move(attribute_result);
+    do_mix_operation_float(blend_mode,
+                           attribute_factor,
+                           attribute_a_float,
+                           attribute_b_float,
+                           attribute_result_float);
+  }
+  else if (result_type == CD_PROP_FLOAT3) {
+    Float3ReadAttribute attribute_a_float3 = std::move(attribute_a);
+    Float3ReadAttribute attribute_b_float3 = std::move(attribute_b);
+    Float3WriteAttribute attribute_result_float3 = std::move(attribute_result);
+    do_mix_operation_float3(blend_mode,
+                            attribute_factor,
+                            attribute_a_float3,
+                            attribute_b_float3,
+                            attribute_result_float3);
+  }
+  else if (result_type == CD_PROP_COLOR) {
+    Color4fReadAttribute attribute_a_color4f = std::move(attribute_a);
+    Color4fReadAttribute attribute_b_color4f = std::move(attribute_b);
+    Color4fWriteAttribute attribute_result_color4f = std::move(attribute_result);
+    do_mix_operation_color4f(blend_mode,
+                             attribute_factor,
+                             attribute_a_color4f,
+                             attribute_b_color4f,
+                             attribute_result_color4f);
+  }
+}
+
+static void attribute_mix_calc(GeometryComponent &component, const GeoNodeExecParams &params)
+{
+  const bNode &node = params.node();
+  const NodeAttributeMix *node_storage = (const NodeAttributeMix *)node.storage;
+
+  CustomDataType result_type = CD_PROP_COLOR;
+  AttributeDomain result_domain = ATTR_DOMAIN_POINT;
+
+  /* Use type and domain from the result attribute, if it exists already. */
+  const std::string result_name = params.get_input<std::string>("Result");
+  const ReadAttributePtr result_attribute_read = component.attribute_try_get_for_read(result_name);
+  if (result_attribute_read) {
+    result_type = result_attribute_read->custom_data_type();
+    result_domain = result_attribute_read->domain();
+  }
+
+  WriteAttributePtr attribute_result = component.attribute_try_ensure_for_write(
+      result_name, result_domain, result_type);
+  if (!attribute_result) {
+    return;
+  }
+
+  FloatReadAttribute attribute_factor = params.get_input_attribute<float>(
+      "Factor", component, result_domain, 0.5f);
+  ReadAttributePtr attribute_a = params.get_input_attribute(
+      "A", component, result_domain, result_type, nullptr);
+  ReadAttributePtr attribute_b = params.get_input_attribute(
+      "B", component, result_domain, result_type, nullptr);
+
+  do_mix_operation(result_type,
+                   node_storage->blend_type,
+                   attribute_factor,
+                   std::move(attribute_a),
+                   std::move(attribute_b),
+                   std::move(attribute_result));
+}
+
+static void geo_node_attribute_mix_exec(GeoNodeExecParams params)
+{
+  GeometrySet geometry_set = params.extract_input<GeometrySet>("Geometry");
+
+  if (geometry_set.has<MeshComponent>()) {
+    attribute_mix_calc(geometry_set.get_component_for_write<MeshComponent>(), params);
+  }
+  if (geometry_set.has<PointCloudComponent>()) {
+    attribute_mix_calc(geometry_set.get_component_for_write<PointCloudComponent>(), params);
+  }
+
+  params.set_output("Geometry", geometry_set);
+}
+
+static void geo_node_attribute_mix_init(bNodeTree *UNUSED(ntree), bNode *node)
+{
+  NodeAttributeMix *data = (NodeAttributeMix *)MEM_callocN(sizeof(NodeAttributeMix),
+                                                           "attribute mix node");
+  data->blend_type = MA_RAMP_BLEND;
+  data->input_type_factor = GEO_NODE_ATTRIBUTE_INPUT_FLOAT;
+  data->input_type_a = GEO_NODE_ATTRIBUTE_INPUT_ATTRIBUTE;
+  data->input_type_b = GEO_NODE_ATTRIBUTE_INPUT_ATTRIBUTE;
+  node->storage = data;
+}
+
+static void geo_node_attribute_mix_update(bNodeTree *UNUSED(ntree), bNode *node)
+{
+  NodeAttributeMix *node_storage = (NodeAttributeMix *)node->storage;
+  update_attribute_input_socket_availabilities(
+      *node, "Factor", (GeometryNodeAttributeInputMode)node_storage->input_type_factor);
+  update_attribute_input_socket_availabilities(
+      *node, "A", (GeometryNodeAttributeInputMode)node_storage->input_type_a);
+  update_attribute_input_socket_availabilities(
+      *node, "B", (GeometryNodeAttributeInputMode)node_storage->input_type_b);
+}
+
+}  // namespace blender::nodes
+
+void register_node_type_geo_attribute_mix()
+{
+  static bNodeType ntype;
+
+  geo_node_type_base(&ntype, GEO_NODE_ATTRIBUTE_MIX, "Attribute Mix", NODE_CLASS_ATTRIBUTE, 0);
+  node_type_socket_templates(&ntype, geo_node_attribute_mix_in, geo_node_mix_attribute_out);
+  node_type_init(&ntype, blender::nodes::geo_node_attribute_mix_init);
+  node_type_update(&ntype, blender::nodes::geo_node_attribute_mix_update);
+  node_type_storage(
+      &ntype, "NodeAttributeMix", node_free_standard_storage, node_copy_standard_storage);
+  ntype.geometry_node_execute = blender::nodes::geo_node_attribute_mix_exec;
+  nodeRegisterType(&ntype);
+}