1 files changed, 213 insertions, 0 deletions
diff --git a/source/blender/nodes/geometry/nodes/node_geo_attribute_randomize.cc b/source/blender/nodes/geometry/nodes/node_geo_attribute_randomize.cc
new file mode 100644
index 00000000000..2c3acfc9735
--- /dev/null
+++ b/source/blender/nodes/geometry/nodes/node_geo_attribute_randomize.cc
@@ -0,0 +1,213 @@
+/*
+ * 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 "node_geometry_util.hh"
+
+#include "BLI_hash.h"
+#include "BLI_rand.hh"
+
+#include "DNA_mesh_types.h"
+#include "DNA_pointcloud_types.h"
+
+static bNodeSocketTemplate geo_node_attribute_randomize_in[] = {
+    {SOCK_GEOMETRY, N_("Geometry")},
+    {SOCK_STRING, N_("Attribute")},
+    {SOCK_VECTOR, N_("Min"), 0.0f, 0.0f, 0.0f, 0.0f, -FLT_MAX, FLT_MAX},
+    {SOCK_VECTOR, N_("Max"), 1.0f, 1.0f, 1.0f, 0.0f, -FLT_MAX, FLT_MAX},
+    {SOCK_FLOAT, N_("Min"), 0.0f, 0.0f, 0.0f, 0.0f, -FLT_MAX, FLT_MAX},
+    {SOCK_FLOAT, N_("Max"), 1.0f, 0.0f, 0.0f, 0.0f, -FLT_MAX, FLT_MAX},
+    {SOCK_INT, N_("Seed"), 0, 0, 0, 0, -10000, 10000},
+    {-1, ""},
+};
+
+static bNodeSocketTemplate geo_node_attribute_randomize_out[] = {
+    {SOCK_GEOMETRY, N_("Geometry")},
+    {-1, ""},
+};
+
+static void geo_node_attribute_randomize_init(bNodeTree *UNUSED(tree), bNode *node)
+{
+  node->custom1 = CD_PROP_FLOAT;
+}
+
+static void geo_node_attribute_randomize_update(bNodeTree *UNUSED(ntree), bNode *node)
+{
+  bNodeSocket *sock_min_vector = (bNodeSocket *)BLI_findlink(&node->inputs, 2);
+  bNodeSocket *sock_max_vector = sock_min_vector->next;
+  bNodeSocket *sock_min_float = sock_max_vector->next;
+  bNodeSocket *sock_max_float = sock_min_float->next;
+
+  const int data_type = node->custom1;
+
+  nodeSetSocketAvailability(sock_min_vector, data_type == CD_PROP_FLOAT3);
+  nodeSetSocketAvailability(sock_max_vector, data_type == CD_PROP_FLOAT3);
+  nodeSetSocketAvailability(sock_min_float, data_type == CD_PROP_FLOAT);
+  nodeSetSocketAvailability(sock_max_float, data_type == CD_PROP_FLOAT);
+}
+
+namespace blender::nodes {
+
+/** Rehash to combine the seed with the "id" hash and a mutator for each dimension. */
+static float noise_from_index_and_mutator(const int seed, const int hash, const int mutator)
+{
+  const int combined_hash = BLI_hash_int_3d(seed, hash, mutator);
+  return BLI_hash_int_01(combined_hash);
+}
+
+/** Rehash to combine the seed with the "id" hash. */
+static float noise_from_index(const int seed, const int hash)
+{
+  const int combined_hash = BLI_hash_int_2d(seed, hash);
+  return BLI_hash_int_01(combined_hash);
+}
+
+static void randomize_attribute(BooleanWriteAttribute &attribute, Span<int> hashes, const int seed)
+{
+  MutableSpan<bool> attribute_span = attribute.get_span();
+  for (const int i : IndexRange(attribute.size())) {
+    const bool value = noise_from_index(seed, hashes[i]) > 0.5f;
+    attribute_span[i] = value;
+  }
+  attribute.apply_span();
+}
+
+static void randomize_attribute(
+    FloatWriteAttribute &attribute, float min, float max, Span<int> hashes, const int seed)
+{
+  MutableSpan<float> attribute_span = attribute.get_span();
+  for (const int i : IndexRange(attribute.size())) {
+    const float value = noise_from_index(seed, hashes[i]) * (max - min) + min;
+    attribute_span[i] = value;
+  }
+  attribute.apply_span();
+}
+
+static void randomize_attribute(
+    Float3WriteAttribute &attribute, float3 min, float3 max, Span<int> hashes, const int seed)
+{
+  MutableSpan<float3> attribute_span = attribute.get_span();
+  for (const int i : IndexRange(attribute.size())) {
+    const float x = noise_from_index_and_mutator(seed, hashes[i], 47);
+    const float y = noise_from_index_and_mutator(seed, hashes[i], 8);
+    const float z = noise_from_index_and_mutator(seed, hashes[i], 64);
+    const float3 value = float3(x, y, z) * (max - min) + min;
+    attribute_span[i] = value;
+  }
+  attribute.apply_span();
+}
+
+static Array<int> get_element_hashes(GeometryComponent &component,
+                                     const AttributeDomain domain,
+                                     const int attribute_size)
+{
+  /* Hash the reserved name attribute "id" as a (hopefully) stable seed for each point. */
+  ReadAttributePtr hash_attribute = component.attribute_try_get_for_read("id", domain);
+  Array<int> hashes(attribute_size);
+  if (hash_attribute) {
+    BLI_assert(hashes.size() == hash_attribute->size());
+    const CPPType &cpp_type = hash_attribute->cpp_type();
+    fn::GSpan items = hash_attribute->get_span();
+    for (const int i : hashes.index_range()) {
+      hashes[i] = (int)cpp_type.hash(items[i]);
+    }
+  }
+  else {
+    /* If there is no "id" attribute for per-point variation, just create it here. */
+    RandomNumberGenerator rng;
+    rng.seed(0);
+    for (const int i : hashes.index_range()) {
+      hashes[i] = rng.get_int32();
+    }
+  }
+
+  return hashes;
+}
+
+static void randomize_attribute(GeometryComponent &component,
+                                const GeoNodeExecParams &params,
+                                const int seed)
+{
+  const bNode &node = params.node();
+  const CustomDataType data_type = static_cast<CustomDataType>(node.custom1);
+  const AttributeDomain domain = static_cast<AttributeDomain>(node.custom2);
+  const std::string attribute_name = params.get_input<std::string>("Attribute");
+  if (attribute_name.empty()) {
+    return;
+  }
+
+  WriteAttributePtr attribute = component.attribute_try_ensure_for_write(
+      attribute_name, domain, data_type);
+  if (!attribute) {
+    return;
+  }
+
+  Array<int> hashes = get_element_hashes(component, domain, attribute->size());
+
+  switch (data_type) {
+    case CD_PROP_FLOAT: {
+      FloatWriteAttribute float_attribute = std::move(attribute);
+      const float min_value = params.get_input<float>("Min_001");
+      const float max_value = params.get_input<float>("Max_001");
+      randomize_attribute(float_attribute, min_value, max_value, hashes, seed);
+      break;
+    }
+    case CD_PROP_FLOAT3: {
+      Float3WriteAttribute float3_attribute = std::move(attribute);
+      const float3 min_value = params.get_input<float3>("Min");
+      const float3 max_value = params.get_input<float3>("Max");
+      randomize_attribute(float3_attribute, min_value, max_value, hashes, seed);
+      break;
+    }
+    case CD_PROP_BOOL: {
+      BooleanWriteAttribute boolean_attribute = std::move(attribute);
+      randomize_attribute(boolean_attribute, hashes, seed);
+      break;
+    }
+    default:
+      break;
+  }
+}
+
+static void geo_node_random_attribute_exec(GeoNodeExecParams params)
+{
+  GeometrySet geometry_set = params.extract_input<GeometrySet>("Geometry");
+  const int seed = params.get_input<int>("Seed");
+
+  if (geometry_set.has<MeshComponent>()) {
+    randomize_attribute(geometry_set.get_component_for_write<MeshComponent>(), params, seed);
+  }
+  if (geometry_set.has<PointCloudComponent>()) {
+    randomize_attribute(geometry_set.get_component_for_write<PointCloudComponent>(), params, seed);
+  }
+
+  params.set_output("Geometry", geometry_set);
+}
+
+}  // namespace blender::nodes
+
+void register_node_type_geo_attribute_randomize()
+{
+  static bNodeType ntype;
+
+  geo_node_type_base(
+      &ntype, GEO_NODE_ATTRIBUTE_RANDOMIZE, "Attribute Randomize", NODE_CLASS_ATTRIBUTE, 0);
+  node_type_socket_templates(
+      &ntype, geo_node_attribute_randomize_in, geo_node_attribute_randomize_out);
+  node_type_init(&ntype, geo_node_attribute_randomize_init);
+  node_type_update(&ntype, geo_node_attribute_randomize_update);
+  ntype.geometry_node_execute = blender::nodes::geo_node_random_attribute_exec;
+  nodeRegisterType(&ntype);
+}