Geometry Nodes: Curve Primitive Spiral

This node creates a curve spline and gives control for the number of
rotations, the number of points per rotation, start and end radius,
height, and direction. The "Reverse" input produces a visual change,
it doesn't just change the order of the control points.

Differential Revision: https://developer.blender.org/D11609

release/scripts/startup/nodeitems_builtins.py

@@ -511,6 +511,7 @@ geometry_node_categories = [
     ]),
     GeometryNodeCategory("GEO_PRIMITIVES_CURVE", "Curve Primitives", items=[
         NodeItem("GeometryNodeCurveStar"),
+        NodeItem("GeometryNodeCurveSpiral"),
     ]),
     GeometryNodeCategory("GEO_GEOMETRY", "Geometry", items=[
         NodeItem("GeometryNodeBoundBox"),

source/blender/blenkernel/BKE_node.h

@@ -1440,6 +1440,7 @@ int ntreeTexExecTree(struct bNodeTree *ntree,
 #define GEO_NODE_CURVE_SUBDIVIDE 1060
 #define GEO_NODE_RAYCAST 1061
 #define GEO_NODE_CURVE_PRIMITIVE_STAR 1062
+#define GEO_NODE_CURVE_PRIMITIVE_SPIRAL 1063
 
 /** \} */
 

source/blender/blenkernel/intern/node.cc

@@ -5054,6 +5054,7 @@ static void registerGeometryNodes()
   register_node_type_geo_collection_info();
   register_node_type_geo_convex_hull();
   register_node_type_geo_curve_length();
+  register_node_type_geo_curve_primitive_spiral();
   register_node_type_geo_curve_primitive_star();
   register_node_type_geo_curve_to_mesh();
   register_node_type_geo_curve_to_points();

source/blender/nodes/CMakeLists.txt

@@ -164,6 +164,7 @@ set(SRC
   geometry/nodes/node_geo_common.cc
   geometry/nodes/node_geo_convex_hull.cc
   geometry/nodes/node_geo_curve_length.cc  
+  geometry/nodes/node_geo_curve_primitive_spiral.cc
   geometry/nodes/node_geo_curve_primitive_star.cc
   geometry/nodes/node_geo_curve_to_mesh.cc
   geometry/nodes/node_geo_curve_to_points.cc

source/blender/nodes/NOD_geometry.h

@@ -52,6 +52,7 @@ void register_node_type_geo_bounding_box(void);
 void register_node_type_geo_collection_info(void);
 void register_node_type_geo_convex_hull(void);
 void register_node_type_geo_curve_length(void);
+void register_node_type_geo_curve_primitive_spiral(void);
 void register_node_type_geo_curve_primitive_star(void);
 void register_node_type_geo_curve_to_mesh(void);
 void register_node_type_geo_curve_to_points(void);

source/blender/nodes/NOD_static_types.h

@@ -292,6 +292,7 @@ DefNode(GeometryNode, GEO_NODE_COLLECTION_INFO, def_geo_collection_info, "COLLEC
 DefNode(GeometryNode, GEO_NODE_CONVEX_HULL, 0, "CONVEX_HULL", ConvexHull, "Convex Hull", "")
 DefNode(GeometryNode, GEO_NODE_CURVE_LENGTH, 0, "CURVE_LENGTH", CurveLength, "Curve Length", "")
 DefNode(GeometryNode, GEO_NODE_CURVE_PRIMITIVE_STAR, 0, "CURVE_PRIMITIVE_STAR", CurveStar, "Star", "")
+DefNode(GeometryNode, GEO_NODE_CURVE_PRIMITIVE_SPIRAL, 0, "CURVE_PRIMITIVE_SPIRAL", CurveSpiral, "Curve Spiral", "")
 DefNode(GeometryNode, GEO_NODE_CURVE_RESAMPLE, def_geo_curve_resample, "CURVE_RESAMPLE", CurveResample, "Resample Curve", "")
 DefNode(GeometryNode, GEO_NODE_CURVE_SUBDIVIDE, def_geo_curve_subdivide, "CURVE_SUBDIVIDE", CurveSubdivide, "Curve Subdivide", "")
 DefNode(GeometryNode, GEO_NODE_CURVE_TO_MESH, 0, "CURVE_TO_MESH", CurveToMesh, "Curve to Mesh", "")

source/blender/nodes/geometry/nodes/node_geo_curve_primitive_spiral.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 "BKE_spline.hh"
+
+#include "node_geometry_util.hh"
+
+static bNodeSocketTemplate geo_node_curve_primitive_spiral_in[] = {
+    {SOCK_INT, N_("Resolution"), 32.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1024.0f, PROP_UNSIGNED},
+    {SOCK_FLOAT, N_("Rotations"), 2.0f, 0.0f, 0.0f, 0.0f, 0.0f, FLT_MAX, PROP_FLOAT},
+    {SOCK_FLOAT, N_("Start Radius"), 1.0f, 0.0f, 0.0f, 0.0f, -FLT_MAX, FLT_MAX, PROP_DISTANCE},
+    {SOCK_FLOAT, N_("End Radius"), 2.0f, 0.0f, 0.0f, 0.0f, -FLT_MAX, FLT_MAX, PROP_DISTANCE},
+    {SOCK_FLOAT, N_("Height"), 2.0f, 0.0f, 0.0f, 0.0f, -FLT_MAX, FLT_MAX, PROP_DISTANCE},
+    {SOCK_BOOLEAN, N_("Reverse")},
+    {-1, ""},
+};
+
+static bNodeSocketTemplate geo_node_curve_primitive_spiral_out[] = {
+    {SOCK_GEOMETRY, N_("Curve")},
+    {-1, ""},
+};
+
+namespace blender::nodes {
+
+static std::unique_ptr<CurveEval> create_spiral_curve(const float rotations,
+                                                      const int resolution,
+                                                      const float start_radius,
+                                                      const float end_radius,
+                                                      const float height,
+                                                      const bool direction)
+{
+  std::unique_ptr<CurveEval> curve = std::make_unique<CurveEval>();
+  std::unique_ptr<PolySpline> spline = std::make_unique<PolySpline>();
+
+  const int totalpoints = resolution * rotations;
+  const float delta_radius = (end_radius - start_radius) / (float)totalpoints;
+  float radius = start_radius;
+  const float delta_height = height / (float)totalpoints;
+  const float delta_theta = (M_PI * 2 * rotations) / (float)totalpoints;
+  float theta = 0.0f;
+
+  for (const int i : IndexRange(totalpoints + 1)) {
+    const float x = radius * cos(theta);
+    const float y = radius * sin(theta);
+    const float z = delta_height * i;
+
+    spline->add_point(float3(x, y, z), 1.0f, 0.0f);
+
+    radius += delta_radius;
+
+    if (direction) {
+      theta += delta_theta;
+    }
+    else {
+      theta -= delta_theta;
+    }
+  }
+
+  spline->attributes.reallocate(spline->size());
+  curve->add_spline(std::move(spline));
+  curve->attributes.reallocate(curve->splines().size());
+  return curve;
+}
+
+static void geo_node_curve_primitive_spiral_exec(GeoNodeExecParams params)
+{
+  const float rotations = std::max(params.extract_input<float>("Rotations"), 0.0f);
+  if (rotations == 0.0f) {
+    params.set_output("Curve", GeometrySet());
+    return;
+  }
+
+  std::unique_ptr<CurveEval> curve = create_spiral_curve(
+      rotations,
+      std::max(params.extract_input<int>("Resolution"), 1),
+      params.extract_input<float>("Start Radius"),
+      params.extract_input<float>("End Radius"),
+      params.extract_input<float>("Height"),
+      params.extract_input<bool>("Reverse"));
+  params.set_output("Curve", GeometrySet::create_with_curve(curve.release()));
+}
+
+}  // namespace blender::nodes
+
+void register_node_type_geo_curve_primitive_spiral()
+{
+  static bNodeType ntype;
+
+  geo_node_type_base(&ntype, GEO_NODE_CURVE_PRIMITIVE_SPIRAL, "Spiral", NODE_CLASS_GEOMETRY, 0);
+  node_type_socket_templates(
+      &ntype, geo_node_curve_primitive_spiral_in, geo_node_curve_primitive_spiral_out);
+  ntype.geometry_node_execute = blender::nodes::geo_node_curve_primitive_spiral_exec;
+  nodeRegisterType(&ntype);
+}