node_geo_curve_primitive_quadratic_bezier.cc

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#include "BKE_curves.hh"
#include "node_geometry_util.hh"
 
namespace blender::nodes::node_geo_curve_primitive_quadratic_bezier_cc {
 
static void node_declare(NodeDeclarationBuilder &b)
{
  b.add_input<decl::Int>("Resolution")
      .default_value(16)
      .min(3)
      .max(256)
      .subtype(PROP_UNSIGNED)
      .description("The number of edges on the curve");
  b.add_input<decl::Vector>("Start")
      .default_value({-1.0f, 0.0f, 0.0f})
      .subtype(PROP_TRANSLATION)
      .description("Position of the first control point");
  b.add_input<decl::Vector>("Middle")
      .default_value({0.0f, 2.0f, 0.0f})
      .subtype(PROP_TRANSLATION)
      .description("Position of the middle control point");
  b.add_input<decl::Vector>("End")
      .default_value({1.0f, 0.0f, 0.0f})
      .subtype(PROP_TRANSLATION)
      .description("Position of the last control point");
  b.add_output<decl::Geometry>("Curve");
}
 
static Curves *create_quadratic_bezier_curve(const float3 p1,
                                             const float3 p2,
                                             const float3 p3,
                                             const int resolution)
{
  Curves *curves_id = bke::curves_new_nomain_single(resolution + 1, CURVE_TYPE_POLY);
  bke::CurvesGeometry &curves = curves_id->geometry.wrap();
 
  MutableSpan<float3> positions = curves.positions_for_write();
 
  const float step = 1.0f / resolution;
  for (const int i : IndexRange(resolution + 1)) {
    const float factor = step * i;
    const float3 q1 = math::interpolate(p1, p2, factor);
    const float3 q2 = math::interpolate(p2, p3, factor);
    positions[i] = math::interpolate(q1, q2, factor);
  }
 
  return curves_id;
}
 
static void node_geo_exec(GeoNodeExecParams params)
{
  Curves *curves = create_quadratic_bezier_curve(
      params.extract_input<float3>("Start"),
      params.extract_input<float3>("Middle"),
      params.extract_input<float3>("End"),
      std::max(params.extract_input<int>("Resolution"), 3));
  params.set_output("Curve", GeometrySet::from_curves(curves));
}
 
static void node_register()
{
  static blender::bke::bNodeType ntype;
  geo_node_type_base(
      &ntype, "GeometryNodeCurveQuadraticBezier", GEO_NODE_CURVE_PRIMITIVE_QUADRATIC_BEZIER);
  ntype.ui_name = "Quadratic Bézier";
  ntype.ui_description =
      "Generate a poly spline in a parabola shape with control points positions";
  ntype.enum_name_legacy = "CURVE_PRIMITIVE_QUADRATIC_BEZIER";
  ntype.nclass = NODE_CLASS_GEOMETRY;
  ntype.declare = node_declare;
  ntype.geometry_node_execute = node_geo_exec;
  blender::bke::node_register_type(ntype);
}
NOD_REGISTER_NODE(node_register)
 
}  // namespace blender::nodes::node_geo_curve_primitive_quadratic_bezier_cc