tornavis/source/blender/blenkernel/BKE_spline.hh

689 lines
26 KiB
C++

/* SPDX-License-Identifier: GPL-2.0-or-later */
#pragma once
/** \file
* \ingroup bke
*/
#include <mutex>
#include "DNA_curves_types.h"
#include "BLI_float4x4.hh"
#include "BLI_generic_virtual_array.hh"
#include "BLI_math_vec_types.hh"
#include "BLI_vector.hh"
#include "BKE_attribute.hh"
#include "BKE_attribute_math.hh"
struct Curve;
struct Curves;
struct ListBase;
class Spline;
using SplinePtr = std::unique_ptr<Spline>;
/**
* A spline is an abstraction of a single branch-less curve section, its evaluation methods,
* and data. The spline data itself is just control points and a set of attributes by the set
* of "evaluated" data is often used instead. Conceptually, the derived vs. original data is
* an essential distinction. Derived data is usually calculated lazily and cached on the spline.
*
* Any derived class of Spline has to manage two things:
* 1. Interpolating arbitrary attribute data from the control points to evaluated points.
* 2. Evaluating the positions based on the stored control point data.
*
* Beyond that, everything is the base class's responsibility, with minor exceptions. Further
* evaluation happens in a layer on top of the evaluated points generated by the derived types.
*
* There are a few methods to evaluate a spline:
* 1. #evaluated_positions and #interpolate_to_evaluated give data for the initial
* evaluated points, depending on the resolution.
* 2. #lookup_evaluated_factor and #lookup_evaluated_factor are meant for one-off lookups
* along the length of a curve.
* 3. #sample_uniform_index_factors returns an array that stores uniform-length samples
* along the spline which can be used to interpolate data from method 1.
*
* Commonly used evaluated data is stored in caches on the spline itself so that operations on
* splines don't need to worry about taking ownership of evaluated data when they don't need to.
*/
class Spline {
public:
NormalMode normal_mode = NORMAL_MODE_MINIMUM_TWIST;
blender::bke::CustomDataAttributes attributes;
protected:
CurveType type_;
bool is_cyclic_ = false;
/** Direction of the spline at each evaluated point. */
mutable blender::Vector<blender::float3> evaluated_tangents_cache_;
mutable std::mutex tangent_cache_mutex_;
mutable bool tangent_cache_dirty_ = true;
/** Normal direction vectors for each evaluated point. */
mutable blender::Vector<blender::float3> evaluated_normals_cache_;
mutable std::mutex normal_cache_mutex_;
mutable bool normal_cache_dirty_ = true;
/** Accumulated lengths along the evaluated points. */
mutable blender::Vector<float> evaluated_lengths_cache_;
mutable std::mutex length_cache_mutex_;
mutable bool length_cache_dirty_ = true;
public:
virtual ~Spline() = default;
Spline(const CurveType type) : type_(type)
{
}
Spline(Spline &other) : attributes(other.attributes), type_(other.type_)
{
copy_base_settings(other, *this);
}
/**
* Return a new spline with the same data, settings, and attributes.
*/
SplinePtr copy() const;
/**
* Return a new spline with the same type and settings like "cyclic", but without any data.
*/
SplinePtr copy_only_settings() const;
/**
* The same as #copy, but skips copying dynamic attributes to the new spline.
*/
SplinePtr copy_without_attributes() const;
static void copy_base_settings(const Spline &src, Spline &dst);
CurveType type() const;
/** Return the number of control points. */
virtual int size() const = 0;
int segments_num() const;
bool is_cyclic() const;
void set_cyclic(bool value);
virtual void resize(int size) = 0;
virtual blender::MutableSpan<blender::float3> positions() = 0;
virtual blender::Span<blender::float3> positions() const = 0;
virtual blender::MutableSpan<float> radii() = 0;
virtual blender::Span<float> radii() const = 0;
virtual blender::MutableSpan<float> tilts() = 0;
virtual blender::Span<float> tilts() const = 0;
virtual void translate(const blender::float3 &translation);
virtual void transform(const blender::float4x4 &matrix);
/**
* Change the direction of the spline (switch the start and end) without changing its shape.
*/
void reverse();
/**
* Mark all caches for re-computation. This must be called after any operation that would
* change the generated positions, tangents, normals, mapping, etc. of the evaluated points.
*/
virtual void mark_cache_invalid() = 0;
virtual int evaluated_points_num() const = 0;
int evaluated_edges_num() const;
float length() const;
virtual blender::Span<blender::float3> evaluated_positions() const = 0;
/**
* Return non-owning access to the cache of accumulated lengths along the spline. Each item is
* the length of the subsequent segment, i.e. the first value is the length of the first segment
* rather than 0. This calculation is rather trivial, and only depends on the evaluated
* positions. However, the results are used often, and it is necessarily single threaded, so it
* is cached.
*/
blender::Span<float> evaluated_lengths() const;
/**
* Return non-owning access to the direction of the curve at each evaluated point.
*/
blender::Span<blender::float3> evaluated_tangents() const;
/**
* Return non-owning access to the direction vectors perpendicular to the tangents at every
* evaluated point. The method used to generate the normal vectors depends on Spline.normal_mode.
*/
blender::Span<blender::float3> evaluated_normals() const;
void bounds_min_max(blender::float3 &min, blender::float3 &max, bool use_evaluated) const;
struct LookupResult {
/**
* The index of the evaluated point before the result location. In other words, the index of
* the edge that the result lies on. If the sampled factor/length is the very end of the
* spline, this will be the second to last index, if it's the very beginning, this will be 0.
*/
int evaluated_index;
/**
* The index of the evaluated point after the result location, accounting for wrapping when
* the spline is cyclic. If the sampled factor/length is the very end of the spline, this will
* be the last index (#evaluated_points_num - 1).
*/
int next_evaluated_index;
/**
* The portion of the way from the evaluated point at #evaluated_index to the next point.
* If the sampled factor/length is the very end of the spline, this will be the 1.0f
*/
float factor;
};
/**
* Find the position on the evaluated spline at the given portion of the total length.
* The return value is the indices of the two neighboring points at that location and the
* factor between them, which can be used to look up any attribute on the evaluated points.
* \note This does not support extrapolation.
*/
LookupResult lookup_evaluated_factor(float factor) const;
/**
* The same as #lookup_evaluated_factor, but looks up a length directly instead of
* a portion of the total.
*/
LookupResult lookup_evaluated_length(float length) const;
/**
* Return an array of evenly spaced samples along the length of the spline. The samples are
* indices and factors to the next index encoded in floats. The logic for converting from the
* float values to interpolation data is in #lookup_data_from_index_factor.
*/
blender::Array<float> sample_uniform_index_factors(int samples_num) const;
LookupResult lookup_data_from_index_factor(float index_factor) const;
/**
* Sample any input data with a value for each evaluated point (already interpolated to evaluated
* points) to arbitrary parameters in between the evaluated points. The interpolation is quite
* simple, but this handles the cyclic and end point special cases.
*/
void sample_with_index_factors(const blender::GVArray &src,
blender::Span<float> index_factors,
blender::GMutableSpan dst) const;
template<typename T>
void sample_with_index_factors(const blender::VArray<T> &src,
blender::Span<float> index_factors,
blender::MutableSpan<T> dst) const
{
this->sample_with_index_factors(
blender::GVArray(src), index_factors, blender::GMutableSpan(dst));
}
template<typename T>
void sample_with_index_factors(blender::Span<T> src,
blender::Span<float> index_factors,
blender::MutableSpan<T> dst) const
{
this->sample_with_index_factors(blender::VArray<T>::ForSpan(src), index_factors, dst);
}
/**
* Interpolate a virtual array of data with the size of the number of control points to the
* evaluated points. For poly splines, the lifetime of the returned virtual array must not
* exceed the lifetime of the input data.
*/
virtual blender::GVArray interpolate_to_evaluated(const blender::GVArray &src) const = 0;
blender::GVArray interpolate_to_evaluated(blender::GSpan data) const;
template<typename T> blender::VArray<T> interpolate_to_evaluated(blender::Span<T> data) const
{
return this->interpolate_to_evaluated(blender::GSpan(data)).typed<T>();
}
protected:
virtual void correct_end_tangents() const = 0;
virtual void copy_settings(Spline &dst) const = 0;
virtual void copy_data(Spline &dst) const = 0;
virtual void reverse_impl() = 0;
};
/**
* A Bezier spline is made up of a many curve segments, possibly achieving continuity of curvature
* by constraining the alignment of curve handles. Evaluation stores the positions and a map of
* factors and indices in a list of floats, which is then used to interpolate any other data.
*/
class BezierSpline final : public Spline {
blender::Vector<blender::float3> positions_;
blender::Vector<float> radii_;
blender::Vector<float> tilts_;
int resolution_;
blender::Vector<int8_t> handle_types_left_;
blender::Vector<int8_t> handle_types_right_;
/* These are mutable to allow lazy recalculation of #Auto and #Vector handle positions. */
mutable blender::Vector<blender::float3> handle_positions_left_;
mutable blender::Vector<blender::float3> handle_positions_right_;
mutable std::mutex auto_handle_mutex_;
mutable bool auto_handles_dirty_ = true;
/** Start index in evaluated points array for every control point. */
mutable blender::Vector<int> offset_cache_;
mutable std::mutex offset_cache_mutex_;
mutable bool offset_cache_dirty_ = true;
/** Cache of evaluated positions. */
mutable blender::Vector<blender::float3> evaluated_position_cache_;
mutable std::mutex position_cache_mutex_;
mutable bool position_cache_dirty_ = true;
/** Cache of "index factors" based calculated from the evaluated positions. */
mutable blender::Vector<float> evaluated_mapping_cache_;
mutable std::mutex mapping_cache_mutex_;
mutable bool mapping_cache_dirty_ = true;
public:
BezierSpline() : Spline(CURVE_TYPE_BEZIER)
{
}
BezierSpline(const BezierSpline &other)
: Spline((Spline &)other),
positions_(other.positions_),
radii_(other.radii_),
tilts_(other.tilts_),
resolution_(other.resolution_),
handle_types_left_(other.handle_types_left_),
handle_types_right_(other.handle_types_right_),
handle_positions_left_(other.handle_positions_left_),
handle_positions_right_(other.handle_positions_right_)
{
}
int size() const final;
int resolution() const;
void set_resolution(int value);
void resize(int size) final;
blender::MutableSpan<blender::float3> positions() final;
blender::Span<blender::float3> positions() const final;
blender::MutableSpan<float> radii() final;
blender::Span<float> radii() const final;
blender::MutableSpan<float> tilts() final;
blender::Span<float> tilts() const final;
blender::Span<int8_t> handle_types_left() const;
blender::MutableSpan<int8_t> handle_types_left();
blender::Span<blender::float3> handle_positions_left() const;
/**
* Get writable access to the handle position.
*
* \param write_only: pass true for an uninitialized spline, this prevents accessing
* uninitialized memory while auto-generating handles.
*/
blender::MutableSpan<blender::float3> handle_positions_left(bool write_only = false);
blender::Span<int8_t> handle_types_right() const;
blender::MutableSpan<int8_t> handle_types_right();
blender::Span<blender::float3> handle_positions_right() const;
/**
* Get writable access to the handle position.
*
* \param write_only: pass true for an uninitialized spline, this prevents accessing
* uninitialized memory while auto-generating handles.
*/
blender::MutableSpan<blender::float3> handle_positions_right(bool write_only = false);
/**
* Recalculate all #Auto and #Vector handles with positions automatically
* derived from the neighboring control points.
*/
void ensure_auto_handles() const;
void translate(const blender::float3 &translation) override;
void transform(const blender::float4x4 &matrix) override;
/**
* Set positions for the right handle of the control point, ensuring that
* aligned handles stay aligned. Has no effect for auto and vector type handles.
*/
void set_handle_position_right(int index, const blender::float3 &value);
/**
* Set positions for the left handle of the control point, ensuring that
* aligned handles stay aligned. Has no effect for auto and vector type handles.
*/
void set_handle_position_left(int index, const blender::float3 &value);
bool point_is_sharp(int index) const;
void mark_cache_invalid() final;
int evaluated_points_num() const final;
/**
* Returns access to a cache of offsets into the evaluated point array for each control point.
* While most control point edges generate the number of edges specified by the resolution,
* vector segments only generate one edge.
*
* \note The length of the result is one greater than the number of points, so that the last item
* is the total number of evaluated points. This is useful to avoid recalculating the size of the
* last segment everywhere.
*/
blender::Span<int> control_point_offsets() const;
/**
* Returns non-owning access to an array of values containing the information necessary to
* interpolate values from the original control points to evaluated points. The control point
* index is the integer part of each value, and the factor used for interpolating to the next
* control point is the remaining factional part.
*/
blender::Span<float> evaluated_mappings() const;
blender::Span<blender::float3> evaluated_positions() const final;
struct InterpolationData {
int control_point_index;
int next_control_point_index;
/**
* Linear interpolation weight between the two indices, from 0 to 1.
* Higher means closer to next control point.
*/
float factor;
};
/**
* Convert the data encoded in #evaulated_mappings into its parts-- the information necessary
* to interpolate data from control points to evaluated points between them. The next control
* point index result will not overflow the size of the control point vectors.
*/
InterpolationData interpolation_data_from_index_factor(float index_factor) const;
virtual blender::GVArray interpolate_to_evaluated(const blender::GVArray &src) const override;
void evaluate_segment(int index,
int next_index,
blender::MutableSpan<blender::float3> positions) const;
/**
* \warning This functional assumes that the spline has more than one point.
*/
bool segment_is_vector(int start_index) const;
/** See comment and diagram for #calculate_segment_insertion. */
struct InsertResult {
blender::float3 handle_prev;
blender::float3 left_handle;
blender::float3 position;
blender::float3 right_handle;
blender::float3 handle_next;
};
/**
* De Casteljau Bezier subdivision.
* \param index: The index of the segment's start control point.
* \param next_index: The index of the control point at the end of the segment. Could be 0,
* if the spline is cyclic.
* \param parameter: The factor along the segment, between 0 and 1. Note that this is used
* directly by the calculation, it doesn't correspond to a portion of the evaluated length.
*
* <pre>
* handle_prev handle_next
* x----------------x
* / \
* / x---O---x \
* / result \
* / \
* O O
* point_prev point_next
* </pre>
*/
InsertResult calculate_segment_insertion(int index, int next_index, float parameter);
private:
/**
* If the spline is not cyclic, the direction for the first and last points is just the
* direction formed by the corresponding handles and control points. In the unlikely situation
* that the handles define a zero direction, fallback to using the direction defined by the
* first and last evaluated segments already calculated in #Spline::evaluated_tangents().
*/
void correct_end_tangents() const final;
void copy_settings(Spline &dst) const final;
void copy_data(Spline &dst) const final;
protected:
void reverse_impl() override;
};
/**
* Data for Non-Uniform Rational B-Splines. The mapping from control points to evaluated points is
* influenced by a vector of knots, weights for each point, and the order of the spline. Every
* mapping of data to evaluated points is handled the same way, but the positions are cached in
* the spline.
*/
class NURBSpline final : public Spline {
public:
/** Method used to recalculate the knots vector when points are added or removed. */
KnotsMode knots_mode;
struct BasisCache {
/**
* For each evaluated point, the weight for all control points that influences it.
* The vector's size is the evaluated point count multiplied by the spline's order.
*/
blender::Vector<float> weights;
/**
* An offset for the start of #weights: the first control point index with a non-zero weight.
*/
blender::Vector<int> start_indices;
};
private:
blender::Vector<blender::float3> positions_;
blender::Vector<float> radii_;
blender::Vector<float> tilts_;
blender::Vector<float> weights_;
int resolution_;
/**
* Defines the number of nearby control points that influence a given evaluated point. Higher
* orders give smoother results. The number of control points must be greater than or equal to
* this value.
*/
uint8_t order_;
/**
* Determines where and how the control points affect the evaluated points. The length should
* always be the value returned by #knots_num(), and each value should be greater than or equal
* to the previous. Only invalidated when a point is added or removed.
*/
mutable blender::Vector<float> knots_;
mutable std::mutex knots_mutex_;
mutable bool knots_dirty_ = true;
/** Cache of control point influences on each evaluated point. */
mutable BasisCache basis_cache_;
mutable std::mutex basis_cache_mutex_;
mutable bool basis_cache_dirty_ = true;
/**
* Cache of position data calculated from the basis cache. Though it is interpolated
* in the same way as any other attribute, it is stored to save unnecessary recalculation.
*/
mutable blender::Vector<blender::float3> evaluated_position_cache_;
mutable std::mutex position_cache_mutex_;
mutable bool position_cache_dirty_ = true;
public:
NURBSpline() : Spline(CURVE_TYPE_NURBS)
{
}
NURBSpline(const NURBSpline &other)
: Spline((Spline &)other),
knots_mode(other.knots_mode),
positions_(other.positions_),
radii_(other.radii_),
tilts_(other.tilts_),
weights_(other.weights_),
resolution_(other.resolution_),
order_(other.order_)
{
}
int size() const final;
int resolution() const;
void set_resolution(int value);
uint8_t order() const;
void set_order(uint8_t value);
bool check_valid_num_and_order() const;
int knots_num() const;
void resize(int size) final;
blender::MutableSpan<blender::float3> positions() final;
blender::Span<blender::float3> positions() const final;
blender::MutableSpan<float> radii() final;
blender::Span<float> radii() const final;
blender::MutableSpan<float> tilts() final;
blender::Span<float> tilts() const final;
blender::Span<float> knots() const;
blender::MutableSpan<float> weights();
blender::Span<float> weights() const;
void mark_cache_invalid() final;
int evaluated_points_num() const final;
blender::Span<blender::float3> evaluated_positions() const final;
blender::GVArray interpolate_to_evaluated(const blender::GVArray &src) const final;
protected:
void correct_end_tangents() const final;
void copy_settings(Spline &dst) const final;
void copy_data(Spline &dst) const final;
void reverse_impl() override;
void calculate_knots() const;
const BasisCache &calculate_basis_cache() const;
};
/**
* A Poly spline is like a Bezier spline with a resolution of one. The main reason to distinguish
* the two is for reduced complexity and increased performance, since interpolating data to control
* points does not change it.
*
* Poly spline code is very simple, since it doesn't do anything that the base #Spline doesn't
* handle. Mostly it just worries about storing the data used by the base class.
*/
class PolySpline final : public Spline {
blender::Vector<blender::float3> positions_;
blender::Vector<float> radii_;
blender::Vector<float> tilts_;
public:
PolySpline() : Spline(CURVE_TYPE_POLY)
{
}
PolySpline(const PolySpline &other)
: Spline((Spline &)other),
positions_(other.positions_),
radii_(other.radii_),
tilts_(other.tilts_)
{
}
int size() const final;
void resize(int size) final;
blender::MutableSpan<blender::float3> positions() final;
blender::Span<blender::float3> positions() const final;
blender::MutableSpan<float> radii() final;
blender::Span<float> radii() const final;
blender::MutableSpan<float> tilts() final;
blender::Span<float> tilts() const final;
void mark_cache_invalid() final;
int evaluated_points_num() const final;
blender::Span<blender::float3> evaluated_positions() const final;
/**
* Poly spline interpolation from control points to evaluated points is a special case, since
* the result data is the same as the input data. This function returns a #GVArray that points to
* the original data. Therefore the lifetime of the returned virtual array must not be longer
* than the source data.
*/
blender::GVArray interpolate_to_evaluated(const blender::GVArray &src) const final;
protected:
void correct_end_tangents() const final;
void copy_settings(Spline &dst) const final;
void copy_data(Spline &dst) const final;
void reverse_impl() override;
};
/**
* A collection of #Spline objects with the same attribute types and names. Most data and
* functionality is in splines, but this contains some helpers for working with them as a group.
*
* \note A #CurveEval corresponds to the #Curve object data. The name is different for clarity,
* since more of the data is stored in the splines, but also just to be different than the name in
* DNA.
*/
struct CurveEval {
private:
blender::Vector<SplinePtr> splines_;
public:
blender::bke::CustomDataAttributes attributes;
CurveEval() = default;
CurveEval(const CurveEval &other) : attributes(other.attributes)
{
for (const SplinePtr &spline : other.splines()) {
this->add_spline(spline->copy());
}
}
blender::Span<SplinePtr> splines() const;
blender::MutableSpan<SplinePtr> splines();
/**
* \return True if the curve contains a spline with the given type.
*
* \note If you are looping over all of the splines in the same scope anyway,
* it's better to avoid calling this function, in case there are many splines.
*/
bool has_spline_with_type(const CurveType type) const;
void resize(int size);
/**
* \warning Call #reallocate on the spline's attributes after adding all splines.
*/
void add_spline(SplinePtr spline);
void add_splines(blender::MutableSpan<SplinePtr> splines);
void remove_splines(blender::IndexMask mask);
void translate(const blender::float3 &translation);
void transform(const blender::float4x4 &matrix);
bool bounds_min_max(blender::float3 &min, blender::float3 &max, bool use_evaluated) const;
blender::bke::MutableAttributeAccessor attributes_for_write();
/**
* Return the start indices for each of the curve spline's control points, if they were part
* of a flattened array. This can be used to facilitate parallelism by avoiding the need to
* accumulate an offset while doing more complex calculations.
*
* \note The result is one longer than the spline count; the last element is the total size.
*/
blender::Array<int> control_point_offsets() const;
/**
* Exactly like #control_point_offsets, but uses the number of evaluated points instead.
*/
blender::Array<int> evaluated_point_offsets() const;
/**
* Return the accumulated length at the start of every spline in the curve.
* \note The result is one longer than the spline count; the last element is the total length.
*/
blender::Array<float> accumulated_spline_lengths() const;
float total_length() const;
int total_control_point_num() const;
void mark_cache_invalid();
/**
* Check the invariants that curve control point attributes should always uphold, necessary
* because attributes are stored on splines rather than in a flat array on the curve:
* - The same set of attributes exists on every spline.
* - Attributes with the same name have the same type on every spline.
* - Attributes are in the same order on every spline.
*/
void assert_valid_point_attributes() const;
};
std::unique_ptr<CurveEval> curve_eval_from_dna_curve(const Curve &curve,
const ListBase &nurbs_list);
std::unique_ptr<CurveEval> curve_eval_from_dna_curve(const Curve &dna_curve);
std::unique_ptr<CurveEval> curves_to_curve_eval(const Curves &curves);
Curves *curve_eval_to_curves(const CurveEval &curve_eval);