Geometry Nodes: new Attribute Sample Texture node

This node allows sampling a texture for every vertex based on some
mapping attribute. Typical attribute names are the name of a uv map
(e.g. "UVMap") and "position". However, every attribute that can be
converted to a vector implicitly is supported.

It should be noted that as of right now, uv map attributes can only be
accessed after a Point Distribute node.

Ref T82584.

Differential Revision: https://developer.blender.org/D10121

5 files changed, 112 insertions, 0 deletions

diff --git a/source/blender/nodes/CMakeLists.txt b/source/blender/nodes/CMakeLists.txt
index 9057e4c6be8..d796c7c309c 100644
--- a/source/blender/nodes/CMakeLists.txt
+++ b/source/blender/nodes/CMakeLists.txt
@@ -146,6 +146,7 @@ set(SRC
   geometry/nodes/node_geo_attribute_fill.cc
   geometry/nodes/node_geo_attribute_math.cc
   geometry/nodes/node_geo_attribute_mix.cc
+  geometry/nodes/node_geo_attribute_sample_texture.cc
   geometry/nodes/node_geo_attribute_randomize.cc
   geometry/nodes/node_geo_attribute_vector_math.cc
   geometry/nodes/node_geo_boolean.cc
diff --git a/source/blender/nodes/NOD_geometry.h b/source/blender/nodes/NOD_geometry.h
index 523d0cfa24d..1b3a8200beb 100644
--- a/source/blender/nodes/NOD_geometry.h
+++ b/source/blender/nodes/NOD_geometry.h
@@ -47,6 +47,7 @@ void register_node_type_geo_attribute_mix(void);
 void register_node_type_geo_attribute_color_ramp(void);
 void register_node_type_geo_point_rotate(void);
 void register_node_type_geo_align_rotation_to_vector(void);
+void register_node_type_geo_sample_texture(void);
 
 #ifdef __cplusplus
 }
diff --git a/source/blender/nodes/NOD_geometry_exec.hh b/source/blender/nodes/NOD_geometry_exec.hh
index 3820c0f0009..454c9e96246 100644
--- a/source/blender/nodes/NOD_geometry_exec.hh
+++ b/source/blender/nodes/NOD_geometry_exec.hh
@@ -32,6 +32,8 @@ using bke::BooleanReadAttribute;
 using bke::BooleanWriteAttribute;
 using bke::Color4fReadAttribute;
 using bke::Color4fWriteAttribute;
+using bke::Float2ReadAttribute;
+using bke::Float2WriteAttribute;
 using bke::Float3ReadAttribute;
 using bke::Float3WriteAttribute;
 using bke::FloatReadAttribute;
diff --git a/source/blender/nodes/NOD_static_types.h b/source/blender/nodes/NOD_static_types.h
index e91b385a87e..4c300916357 100644
--- a/source/blender/nodes/NOD_static_types.h
+++ b/source/blender/nodes/NOD_static_types.h
@@ -289,6 +289,7 @@ DefNode(GeometryNode, GEO_NODE_ATTRIBUTE_VECTOR_MATH, def_geo_attribute_vector_m
 DefNode(GeometryNode, GEO_NODE_ALIGN_ROTATION_TO_VECTOR, def_geo_align_rotation_to_vector, "ALIGN_ROTATION_TO_VECTOR", AlignRotationToVector, "Align Rotation to Vector", "")
 DefNode(GeometryNode, GEO_NODE_POINT_SCALE, def_geo_point_scale, "POINT_SCALE", PointScale, "Point Scale", "")
 DefNode(GeometryNode, GEO_NODE_POINT_TRANSLATE, def_geo_point_translate, "POINT_TRANSLATE", PointTranslate, "Point Translate", "")
+DefNode(GeometryNode, GEO_NODE_ATTRIBUTE_SAMPLE_TEXTURE, def_geo_attribute_sample_texture, "ATTRIBUTE_SAMPLE_TEXTURE", AttributeSampleTexture, "Attribute Sample Texture", "")
 
 /* undefine macros */
 #undef DefNode
diff --git a/source/blender/nodes/geometry/nodes/node_geo_attribute_sample_texture.cc b/source/blender/nodes/geometry/nodes/node_geo_attribute_sample_texture.cc
new file mode 100644
index 00000000000..66495bfa53b
--- /dev/null
+++ b/source/blender/nodes/geometry/nodes/node_geo_attribute_sample_texture.cc
@@ -0,0 +1,107 @@
+/*
+ * 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 "BLI_compiler_attrs.h"
+
+#include "DNA_texture_types.h"
+
+#include "BKE_texture.h"
+
+#include "RE_texture.h"
+
+#include "node_geometry_util.hh"
+
+static bNodeSocketTemplate geo_node_attribute_sample_texture_in[] = {
+    {SOCK_GEOMETRY, N_("Geometry")},
+    {SOCK_STRING, N_("Mapping")},
+    {SOCK_STRING, N_("Result")},
+    {-1, ""},
+};
+
+static bNodeSocketTemplate geo_node_attribute_sample_texture_out[] = {
+    {SOCK_GEOMETRY, N_("Geometry")},
+    {-1, ""},
+};
+
+namespace blender::nodes {
+
+static void execute_on_component(GeometryComponent &component, const GeoNodeExecParams &params)
+{
+  const bNode &node = params.node();
+  Tex *texture = reinterpret_cast<Tex *>(node.id);
+  const std::string result_attribute_name = params.get_input<std::string>("Result");
+
+  if (texture == nullptr) {
+    return;
+  }
+
+  const std::string mapping_name = params.get_input<std::string>("Mapping");
+  if (!component.attribute_exists(mapping_name)) {
+    return;
+  }
+
+  OutputAttributePtr attribute_out = component.attribute_try_get_for_output(
+      result_attribute_name, ATTR_DOMAIN_POINT, CD_PROP_COLOR);
+  if (!attribute_out) {
+    return;
+  }
+
+  Float3ReadAttribute mapping_attribute = component.attribute_get_for_read<float3>(
+      mapping_name, ATTR_DOMAIN_POINT, {0, 0, 0});
+
+  MutableSpan<Color4f> colors = attribute_out->get_span<Color4f>();
+  for (const int i : IndexRange(mapping_attribute.size())) {
+    TexResult texture_result = {0};
+    const float3 position = mapping_attribute[i];
+    /* For legacy reasons we have to map [0, 1] to [-1, 1] to support uv mappings. */
+    const float3 remapped_position = position * 2.0f - float3(1.0f);
+    BKE_texture_get_value(nullptr, texture, remapped_position, &texture_result, false);
+    colors[i] = {texture_result.tr, texture_result.tg, texture_result.tb, texture_result.ta};
+  }
+  attribute_out.apply_span_and_save();
+}
+
+static void geo_node_attribute_sample_texture_exec(GeoNodeExecParams params)
+{
+  GeometrySet geometry_set = params.extract_input<GeometrySet>("Geometry");
+
+  if (geometry_set.has<MeshComponent>()) {
+    execute_on_component(geometry_set.get_component_for_write<MeshComponent>(), params);
+  }
+  if (geometry_set.has<PointCloudComponent>()) {
+    execute_on_component(geometry_set.get_component_for_write<PointCloudComponent>(), params);
+  }
+
+  params.set_output("Geometry", geometry_set);
+}
+
+}  // namespace blender::nodes
+
+void register_node_type_geo_sample_texture()
+{
+  static bNodeType ntype;
+
+  geo_node_type_base(&ntype,
+                     GEO_NODE_ATTRIBUTE_SAMPLE_TEXTURE,
+                     "Attribute Sample Texture",
+                     NODE_CLASS_ATTRIBUTE,
+                     0);
+  node_type_size_preset(&ntype, NODE_SIZE_LARGE);
+  node_type_socket_templates(
+      &ntype, geo_node_attribute_sample_texture_in, geo_node_attribute_sample_texture_out);
+  ntype.geometry_node_execute = blender::nodes::geo_node_attribute_sample_texture_exec;
+  nodeRegisterType(&ntype);
+}