blender::bke::curves::nurbs Namespace Reference

Classes
struct	BasisCache

Functions
bool	check_valid_num_and_order (int points_num, int8_t order, bool cyclic, KnotsMode knots_mode)
int	calculate_evaluated_num (int points_num, int8_t order, bool cyclic, int resolution, KnotsMode knots_mode)
int	knots_num (int points_num, int8_t order, bool cyclic)
void	load_curve_knots (KnotsMode mode, int points_num, int8_t order, bool cyclic, IndexRange curve_knots, Span< float > custom_knots, MutableSpan< float > knots)
void	calculate_knots (int points_num, KnotsMode mode, int8_t order, bool cyclic, MutableSpan< float > knots)
Vector< int >	calculate_multiplicity_sequence (Span< float > knots)
void	calculate_basis_cache (int points_num, int evaluated_num, int8_t order, bool cyclic, Span< float > knots, BasisCache &basis_cache)
void	interpolate_to_evaluated (const BasisCache &basis_cache, int8_t order, Span< float > control_weights, GSpan src, GMutableSpan dst)
void	gather_custom_knots (const bke::CurvesGeometry &src, const IndexMask &src_curves, int dst_curve_offset, bke::CurvesGeometry &dst)
void	update_custom_knot_modes (const IndexMask &mask, const KnotsMode mode_for_regular, const KnotsMode mode_for_cyclic, bke::CurvesGeometry &curves)
void	copy_custom_knots (const bke::CurvesGeometry &src_curves, const IndexMask &exclude_curves, bke::CurvesGeometry &dst_curves)
static void	copy_custom_knots (const int8_t order, const bool cyclic, const Span< float > custom_knots, MutableSpan< float > knots)
static void	calculate_basis_for_point (const float parameter, const int points_num, const int degree, const Span< float > knots, MutableSpan< float > r_weights, int &r_start_index)
template<typename T>
static void	interpolate_to_evaluated (const BasisCache &basis_cache, const int8_t order, const Span< T > src, MutableSpan< T > dst)
template<typename T>
static void	interpolate_to_evaluated_rational (const BasisCache &basis_cache, const int8_t order, const Span< float > control_weights, const Span< T > src, MutableSpan< T > dst)

Function Documentation

calculate_basis_cache()

void blender::bke::curves::nurbs::calculate_basis_cache	(	int	points_num,
		int	evaluated_num,
		int8_t	order,
		bool	cyclic,
		Span< float >	knots,
		BasisCache &	basis_cache )

Based on the knots, the order, and other properties of a NURBS curve, calculate a cache that can be used to more simply interpolate attributes to the evaluated points later. The cache includes two pieces of information for every evaluated point: the first control point that influences it, and a weight for each control point.

Definition at line 206 of file curve_nurbs.cc.

References BLI_assert, calculate_basis_for_point(), i, blender::Vector< T, InlineBufferCapacity, Allocator >::resize(), Vector< T, InlineBufferCapacity, Allocator >::resize(), blender::bke::curves::segments_num(), blender::MutableSpan< T >::slice(), blender::bke::curves::nurbs::BasisCache::start_indices, step, and blender::bke::curves::nurbs::BasisCache::weights.

calculate_basis_for_point()

void blender::bke::curves::nurbs::calculate_basis_for_point ( const float parameter, const int points_num, const int degree, const Span< float > knots, MutableSpan< float > r_weights, int & r_start_index )

static

Definition at line 153 of file curve_nurbs.cc.

References blender::Array< T, InlineBufferCapacity, Allocator >::as_mutable_span(), blender::Array< T, InlineBufferCapacity, Allocator >::as_span(), blender::MutableSpan< T >::copy_from(), i, and blender::Span< T >::size().

Referenced by calculate_basis_cache().

calculate_evaluated_num()

int blender::bke::curves::nurbs::calculate_evaluated_num	(	int	points_num,
		int8_t	order,
		bool	cyclic,
		int	resolution,
		KnotsMode	knots_mode )

Calculate the standard evaluated size for a NURBS curve, using the standard that the resolution is multiplied by the number of segments between the control points.

Note

Though the number of evaluated points is rather arbitrary, it's useful to have a standard for predictability and so that cached basis weights of NURBS curves with these properties can be shared.

Definition at line 35 of file curve_nurbs.cc.

References check_valid_num_and_order(), and blender::bke::curves::segments_num().

Referenced by blender::bke::calculate_evaluated_offsets().

calculate_knots()

void blender::bke::curves::nurbs::calculate_knots	(	int	points_num,
		KnotsMode	mode,
		int8_t	order,
		bool	cyclic,
		MutableSpan< float >	knots )

Calculate the knots for a curve given its properties, based on built-in standards defined by KnotsMode.

Note

Theoretically any sorted values can be used for NURBS knots, but calculating based on standard modes allows useful presets, automatic recalculation when the number of points changes, and is generally more intuitive than defining the knot vector manually.

Definition at line 71 of file curve_nurbs.cc.

References BLI_assert, ELEM, i, knots_num(), min_ii(), NURBS_KNOT_MODE_BEZIER, NURBS_KNOT_MODE_ENDPOINT, NURBS_KNOT_MODE_ENDPOINT_BEZIER, blender::MutableSpan< T >::size(), and UNUSED_VARS_NDEBUG.

Referenced by blender::io::obj::OBJCurve::get_knots_u(), load_curve_knots(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), and blender::bke::tests::TEST().

calculate_multiplicity_sequence()

Vector< int > blender::bke::curves::nurbs::calculate_multiplicity_sequence

(

Span< float >

knots

)

Compute the number of occurrences of each unique knot value (so knot multiplicity), forming a sequence for which: sum(multiplicity) == knots.size().

Example: Knots: [0, 0, 0, 0.1, 0.3, 0.4, 0.4, 0.4] Result: [3, 1, 1, 3]

Definition at line 133 of file curve_nurbs.cc.

References blender::Vector< T, InlineBufferCapacity, Allocator >::append(), blender::IndexRange::drop_front(), i, blender::Span< T >::index_range(), blender::Vector< T, InlineBufferCapacity, Allocator >::reserve(), and blender::Span< T >::size().

Referenced by blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), and blender::bke::tests::TEST().

check_valid_num_and_order()

bool blender::bke::curves::nurbs::check_valid_num_and_order	(	int	points_num,
		int8_t	order,
		bool	cyclic,
		KnotsMode	knots_mode )

Checks the conditions that a NURBS curve needs to evaluate.

Definition at line 16 of file curve_nurbs.cc.

References ELEM, NURBS_KNOT_MODE_BEZIER, and NURBS_KNOT_MODE_ENDPOINT_BEZIER.

Referenced by calculate_evaluated_num().

copy_custom_knots() [1/2]

void blender::bke::curves::nurbs::copy_custom_knots	(	const bke::CurvesGeometry &	src_curves,
		const IndexMask &	exclude_curves,
		bke::CurvesGeometry &	dst_curves )

Copies NURBS custom knots from one CurvesGeometry instance to another excluding exclude_curves. For excluded curves with NURBS_KNOT_MODE_CUSTOM knot mode is overwritten to NURBS_KNOT_MODE_NORMAL.

Definition at line 255 of file curves_utils.cc.

References BLI_assert, blender::bke::CurvesGeometry::curves_num(), blender::IndexMask::from_difference(), gather_custom_knots(), blender::bke::CurvesGeometry::nurbs_custom_knot_curves(), blender::bke::CurvesGeometry::nurbs_has_custom_knots(), NURBS_KNOT_MODE_NORMAL, and update_custom_knot_modes().

Referenced by blender::geometry::convert_curves_to_bezier(), blender::geometry::convert_curves_to_catmull_rom_or_poly(), blender::geometry::convert_curves_to_nurbs(), load_curve_knots(), blender::geometry::resample_to_count(), blender::geometry::resample_to_evaluated(), blender::geometry::resample_to_length(), blender::geometry::resample_to_uniform(), and blender::geometry::subdivide_curves().

copy_custom_knots() [2/2]

void blender::bke::curves::nurbs::copy_custom_knots ( const int8_t order, const bool cyclic, const Span< float > custom_knots, MutableSpan< float > knots )

static

Definition at line 55 of file curve_nurbs.cc.

References blender::MutableSpan< T >::copy_from(), blender::MutableSpan< T >::index_range(), blender::Span< T >::last(), blender::Span< T >::size(), blender::MutableSpan< T >::slice(), and blender::MutableSpan< T >::take_back().

gather_custom_knots()

void blender::bke::curves::nurbs::gather_custom_knots	(	const bke::CurvesGeometry &	src,
		const IndexMask &	src_curves,
		int	dst_curve_offset,
		bke::CurvesGeometry &	dst )

Gathers NURBS custom knots of selected curves from one CurvesGeometry instance to another. Should be used to implement operator's custom knot copying logic. dst_curve_offset can be used to append knots to already existing ones in the CurvesGeometry.

Definition at line 220 of file curves_utils.cc.

References blender::Array< T, InlineBufferCapacity, Allocator >::as_span(), blender::array_utils::gather_group_to_group(), blender::offset_indices::gather_selected_offsets(), blender::bke::CurvesGeometry::nurbs_custom_knots(), blender::bke::CurvesGeometry::nurbs_custom_knots_by_curve(), blender::bke::CurvesGeometry::nurbs_custom_knots_for_write(), and blender::index_mask::IndexMask::size().

Referenced by blender::ed::curves::append_curve_knots(), blender::geometry::copy_and_reorder_curves(), copy_custom_knots(), and blender::ed::greasepencil::extrude_grease_pencil_curves().

interpolate_to_evaluated() [1/2]

template<typename T>

void blender::bke::curves::nurbs::interpolate_to_evaluated ( const BasisCache & basis_cache, const int8_t order, const Span< T > src, MutableSpan< T > dst )

static

Definition at line 245 of file curve_nurbs.cc.

References blender::MutableSpan< T >::index_range(), and blender::threading::parallel_for().

interpolate_to_evaluated() [2/2]

void blender::bke::curves::nurbs::interpolate_to_evaluated	(	const BasisCache &	basis_cache,
		int8_t	order,
		Span< float >	control_weights,
		GSpan	src,
		GMutableSpan	dst )

Using a "basis cache" generated by BasisCache, interpolate attribute values to the evaluated points. The number of evaluated points is determined by the #basis_cache argument.

Parameters

control_weights

An optional span of control point weights, which must have the same size as the number of control points in the curve if provided. Using this argument gives a NURBS curve the "Rational" behavior that's part of its acronym; otherwise it is a NUBS.

Definition at line 287 of file curve_nurbs.cc.

References BLI_assert, blender::bke::attribute_math::convert_to_static_type(), blender::GMutableSpan::copy_from(), interpolate_to_evaluated(), blender::bke::curves::nurbs::BasisCache::invalid, blender::GMutableSpan::size(), blender::Vector< T, InlineBufferCapacity, Allocator >::size(), blender::bke::curves::nurbs::BasisCache::start_indices, and blender::GSpan::type().

Referenced by blender::bke::evaluate_generic_data_for_curve(), blender::bke::CurvesGeometry::evaluated_positions(), and interpolate_to_evaluated().

interpolate_to_evaluated_rational()

template<typename T>

void blender::bke::curves::nurbs::interpolate_to_evaluated_rational ( const BasisCache & basis_cache, const int8_t order, const Span< float > control_weights, const Span< T > src, MutableSpan< T > dst )

static

Definition at line 265 of file curve_nurbs.cc.

References blender::MutableSpan< T >::index_range(), interpolate_to_evaluated_rational(), and blender::threading::parallel_for().

Referenced by interpolate_to_evaluated_rational().

knots_num()

int blender::bke::curves::nurbs::knots_num	(	int	points_num,
		int8_t	order,
		bool	cyclic )

Calculate the length of the knot vector for a NURBS curve with the given properties. The knots must be longer for a cyclic curve, for example, in order to provide weights for the last evaluated points that are also influenced by the first control points.

Definition at line 47 of file curve_nurbs.cc.

Referenced by calculate_knots(), blender::bke::copy_point_selection_custom_knots(), blender::io::obj::OBJCurve::get_knots_u(), blender::io::usd::populate_curve_props_for_nurbs(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), blender::bke::tests::TEST(), and blender::bke::tests::TEST().

load_curve_knots()

void blender::bke::curves::nurbs::load_curve_knots	(	KnotsMode	mode,
		int	points_num,
		int8_t	order,
		bool	cyclic,
		IndexRange	curve_knots,
		Span< float >	custom_knots,
		MutableSpan< float >	knots )

Depending on KnotsMode calculates knots or copies custom knots into given MutableSpan. Adds order - 1 length tail for cyclic curves.

Definition at line 115 of file curve_nurbs.cc.

References BLI_assert, calculate_knots(), copy_custom_knots(), blender::IndexRange::is_empty(), blender::Span< T >::is_empty(), NURBS_KNOT_MODE_CUSTOM, and blender::Span< T >::slice().

Referenced by blender::io::usd::populate_curve_props_for_nurbs().

update_custom_knot_modes()

void blender::bke::curves::nurbs::update_custom_knot_modes	(	const IndexMask &	mask,
		const KnotsMode	mode_for_regular,
		const KnotsMode	mode_for_cyclic,
		bke::CurvesGeometry &	curves )

Overwrites NURBS_KNOT_MODE_CUSTOM to given ones for regular and cyclic curves. The purpose is to update knot modes for curves when knot copying or calculation is not possible or too complex. Curve operators not supporting NURBS custom knots should call this function with IndexMask CurvesGeometry.curves_range(), if resulting curves are created by copying all attributes. This way NURBS_KNOT_MODE_CUSTOM values might be copied though custom knots not.

Definition at line 239 of file curves_utils.cc.

References mask(), and NURBS_KNOT_MODE_CUSTOM.

Referenced by copy_custom_knots(), blender::geometry::curves_merge_endpoints(), blender::ed::greasepencil::extrude_grease_pencil_curves(), blender::geometry::fillet_curves(), blender::geometry::remove_points_and_split(), blender::ed::curves::resize_curves(), and blender::geometry::trim_curves().