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/*
* 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_task.hh"
#include "BKE_spline.hh"
#include "node_geometry_util.hh"
namespace blender::nodes {
static void geo_node_input_tangent_declare(NodeDeclarationBuilder &b)
{
b.add_output<decl::Vector>("Tangent").field_source();
}
static void calculate_bezier_tangents(const BezierSpline &spline, MutableSpan<float3> tangents)
{
Span<int> offsets = spline.control_point_offsets();
Span<float3> evaluated_tangents = spline.evaluated_tangents();
for (const int i : IndexRange(spline.size())) {
tangents[i] = evaluated_tangents[offsets[i]];
}
}
static void calculate_poly_tangents(const PolySpline &spline, MutableSpan<float3> tangents)
{
tangents.copy_from(spline.evaluated_tangents());
}
/**
* Because NURBS control points are not necessarily on the path, the tangent at the control points
* is not well defined, so create a temporary poly spline to find the tangents. This requires extra
* copying currently, but may be more efficient in the future if attributes have some form of CoW.
*/
static void calculate_nurbs_tangents(const NURBSpline &spline, MutableSpan<float3> tangents)
{
PolySpline poly_spline;
poly_spline.resize(spline.size());
poly_spline.positions().copy_from(spline.positions());
tangents.copy_from(poly_spline.evaluated_tangents());
}
static Array<float3> curve_tangent_point_domain(const CurveEval &curve)
{
Span<SplinePtr> splines = curve.splines();
Array<int> offsets = curve.control_point_offsets();
const int total_size = offsets.last();
Array<float3> tangents(total_size);
threading::parallel_for(splines.index_range(), 128, [&](IndexRange range) {
for (const int i : range) {
const Spline &spline = *splines[i];
MutableSpan spline_tangents{tangents.as_mutable_span().slice(offsets[i], spline.size())};
switch (splines[i]->type()) {
case Spline::Type::Bezier: {
calculate_bezier_tangents(static_cast<const BezierSpline &>(spline), spline_tangents);
break;
}
case Spline::Type::Poly: {
calculate_poly_tangents(static_cast<const PolySpline &>(spline), spline_tangents);
break;
}
case Spline::Type::NURBS: {
calculate_nurbs_tangents(static_cast<const NURBSpline &>(spline), spline_tangents);
break;
}
}
}
});
return tangents;
}
static const GVArray *construct_curve_tangent_gvarray(const CurveComponent &component,
const AttributeDomain domain,
ResourceScope &scope)
{
const CurveEval *curve = component.get_for_read();
if (curve == nullptr) {
return nullptr;
}
if (domain == ATTR_DOMAIN_POINT) {
const Span<SplinePtr> splines = curve->splines();
/* Use a reference to evaluated tangents if possible to avoid an allocation and a copy.
* This is only possible when there is only one poly spline. */
if (splines.size() == 1 && splines.first()->type() == Spline::Type::Poly) {
const PolySpline &spline = static_cast<PolySpline &>(*splines.first());
return &scope.construct<fn::GVArray_For_Span<float3>>(spline.evaluated_tangents());
}
Array<float3> tangents = curve_tangent_point_domain(*curve);
return &scope.construct<fn::GVArray_For_ArrayContainer<Array<float3>>>(std::move(tangents));
}
if (domain == ATTR_DOMAIN_CURVE) {
Array<float3> point_tangents = curve_tangent_point_domain(*curve);
GVArrayPtr gvarray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<float3>>>(
std::move(point_tangents));
GVArrayPtr spline_tangents = component.attribute_try_adapt_domain(
std::move(gvarray), ATTR_DOMAIN_POINT, ATTR_DOMAIN_CURVE);
return scope.add_value(std::move(spline_tangents)).get();
}
return nullptr;
}
class TangentFieldInput final : public fn::FieldInput {
public:
TangentFieldInput() : fn::FieldInput(CPPType::get<float3>(), "Tangent")
{
}
const GVArray *get_varray_for_context(const fn::FieldContext &context,
IndexMask UNUSED(mask),
ResourceScope &scope) const final
{
if (const GeometryComponentFieldContext *geometry_context =
dynamic_cast<const GeometryComponentFieldContext *>(&context)) {
const GeometryComponent &component = geometry_context->geometry_component();
const AttributeDomain domain = geometry_context->domain();
if (component.type() == GEO_COMPONENT_TYPE_CURVE) {
const CurveComponent &curve_component = static_cast<const CurveComponent &>(component);
return construct_curve_tangent_gvarray(curve_component, domain, scope);
}
}
return nullptr;
}
uint64_t hash() const override
{
/* Some random constant hash. */
return 91827364589;
}
bool is_equal_to(const fn::FieldNode &other) const override
{
return dynamic_cast<const TangentFieldInput *>(&other) != nullptr;
}
};
static void geo_node_input_tangent_exec(GeoNodeExecParams params)
{
Field<float3> tangent_field{std::make_shared<TangentFieldInput>()};
params.set_output("Tangent", std::move(tangent_field));
}
} // namespace blender::nodes
void register_node_type_geo_input_tangent()
{
static bNodeType ntype;
geo_node_type_base(&ntype, GEO_NODE_INPUT_TANGENT, "Curve Tangent", NODE_CLASS_INPUT, 0);
ntype.geometry_node_execute = blender::nodes::geo_node_input_tangent_exec;
ntype.declare = blender::nodes::geo_node_input_tangent_declare;
nodeRegisterType(&ntype);
}
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