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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.
*/
#pragma once
#include <mutex>
#include "FN_cpp_type.hh"
#include "FN_generic_span.hh"
#include "FN_generic_virtual_array.hh"
#include "BKE_anonymous_attribute.hh"
#include "BKE_attribute.h"
#include "BLI_color.hh"
#include "BLI_float2.hh"
#include "BLI_float3.hh"
#include "BLI_function_ref.hh"
/**
* This file defines classes that help to provide access to attribute data on a #GeometryComponent.
* The API for retrieving attributes is defined in `BKE_geometry_set.hh`, but this comment has some
* general comments about the system.
*
* Attributes are stored in geometry data, though they can also be stored in instances. Their
* storage is often tied to `CustomData`, which is a system to store "layers" of data with specific
* types and names. However, since `CustomData` was added to Blender before attributes were
* conceptualized, it combines the "legacy" style of task-specific attribute types with generic
* types like "Float". The attribute API here only provides access to generic types.
*
* Attributes are retrieved from geometry components by providing an "id" (#AttributeIDRef). This
* is most commonly just an attribute name. The attribute API on geometry components has some more
* advanced capabilities:
* 1. Read-only access: With a `const` geometry component, an attribute on the geometry cannot be
* modified, so the `for_write` and `for_output` versions of the API are not available. This is
* extremely important for writing coherent bug-free code. When an attribute is retrieved with
* write access, via #WriteAttributeLookup or #OutputAttribute, the geometry component must be
* tagged to clear caches that depend on the changed data.
* 2. Domain interpolation: When retrieving an attribute, a domain (#AttributeDomain) can be
* provided. If the attribute is stored on a different domain and conversion is possible, a
* version of the data interpolated to the requested domain will be provided. These conversions
* are implemented in each #GeometryComponent by `attribute_try_adapt_domain_impl`.
* 3. Implicit type conversion: In addition to interpolating domains, attribute types can be
* converted, using the conversions in `BKE_type_conversions.hh`. The #VArray / #GVArray system
* makes it possible to only convert necessary indices on-demand.
* 4. Anonymous attributes: The "id" used to look up an attribute can also be an anonymous
* attribute reference. Currently anonymous attributes are only used in geometry nodes.
* 5. Abstracted storage: Since the data returned from the API is usually a virtual array,
* it doesn't have to be stored contiguously (even though that is generally preferred). This
* allows accessing "legacy" attributes like `material_index`, which is stored in `MPoly`.
*/
namespace blender::bke {
/**
* Identifies an attribute that is either named or anonymous.
* It does not own the identifier, so it is just a reference.
*/
class AttributeIDRef {
private:
StringRef name_;
const AnonymousAttributeID *anonymous_id_ = nullptr;
public:
AttributeIDRef();
AttributeIDRef(StringRef name);
AttributeIDRef(StringRefNull name);
AttributeIDRef(const char *name);
AttributeIDRef(const std::string &name);
AttributeIDRef(const AnonymousAttributeID *anonymous_id);
operator bool() const;
uint64_t hash() const;
bool is_named() const;
bool is_anonymous() const;
StringRef name() const;
const AnonymousAttributeID &anonymous_id() const;
bool should_be_kept() const;
friend bool operator==(const AttributeIDRef &a, const AttributeIDRef &b);
friend std::ostream &operator<<(std::ostream &stream, const AttributeIDRef &attribute_id);
};
} // namespace blender::bke
/**
* Contains information about an attribute in a geometry component.
* More information can be added in the future. E.g. whether the attribute is builtin and how it is
* stored (uv map, vertex group, ...).
*/
struct AttributeMetaData {
AttributeDomain domain;
CustomDataType data_type;
constexpr friend bool operator==(AttributeMetaData a, AttributeMetaData b)
{
return (a.domain == b.domain) && (a.data_type == b.data_type);
}
};
struct AttributeKind {
AttributeDomain domain;
CustomDataType data_type;
};
/**
* Base class for the attribute initializer types described below.
*/
struct AttributeInit {
enum class Type {
Default,
VArray,
MoveArray,
};
Type type;
AttributeInit(const Type type) : type(type)
{
}
};
/**
* Create an attribute using the default value for the data type.
* The default values may depend on the attribute provider implementation.
*/
struct AttributeInitDefault : public AttributeInit {
AttributeInitDefault() : AttributeInit(Type::Default)
{
}
};
/**
* Create an attribute by copying data from an existing virtual array. The virtual array
* must have the same type as the newly created attribute.
*
* Note that this can be used to fill the new attribute with the default
*/
struct AttributeInitVArray : public AttributeInit {
blender::fn::GVArray varray;
AttributeInitVArray(blender::fn::GVArray varray)
: AttributeInit(Type::VArray), varray(std::move(varray))
{
}
};
/**
* Create an attribute with a by passing ownership of a pre-allocated contiguous array of data.
* Sometimes data is created before a geometry component is available. In that case, it's
* preferable to move data directly to the created attribute to avoid a new allocation and a copy.
*
* Note that this will only have a benefit for attributes that are stored directly as contiguous
* arrays, so not for some built-in attributes.
*
* The array must be allocated with MEM_*, since `attribute_try_create` will free the array if it
* can't be used directly, and that is generally how Blender expects custom data to be allocated.
*/
struct AttributeInitMove : public AttributeInit {
void *data = nullptr;
AttributeInitMove(void *data) : AttributeInit(Type::MoveArray), data(data)
{
}
};
/* Returns false when the iteration should be stopped. */
using AttributeForeachCallback = blender::FunctionRef<bool(
const blender::bke::AttributeIDRef &attribute_id, const AttributeMetaData &meta_data)>;
namespace blender::bke {
using fn::CPPType;
using fn::GVArray;
using fn::GVMutableArray;
const CPPType *custom_data_type_to_cpp_type(const CustomDataType type);
CustomDataType cpp_type_to_custom_data_type(const CPPType &type);
CustomDataType attribute_data_type_highest_complexity(Span<CustomDataType> data_types);
/**
* Domains with a higher "information density" have a higher priority,
* in order to choose a domain that will not lose data through domain conversion.
*/
AttributeDomain attribute_domain_highest_priority(Span<AttributeDomain> domains);
/**
* Used when looking up a "plain attribute" based on a name for reading from it.
*/
struct ReadAttributeLookup {
/* The virtual array that is used to read from this attribute. */
GVArray varray;
/* Domain the attribute lives on in the geometry. */
AttributeDomain domain;
/* Convenience function to check if the attribute has been found. */
operator bool() const
{
return this->varray;
}
};
/**
* Used when looking up a "plain attribute" based on a name for reading from it and writing to it.
*/
struct WriteAttributeLookup {
/** The virtual array that is used to read from and write to the attribute. */
GVMutableArray varray;
/** Domain the attributes lives on in the geometry component. */
AttributeDomain domain;
/**
* Call this after changing the attribute to invalidate caches that depend on this attribute.
* \note Do not call this after the component the attribute is from has been destructed.
*/
std::function<void()> tag_modified_fn;
/* Convenience function to check if the attribute has been found. */
operator bool() const
{
return this->varray;
}
};
/**
* An output attribute allows writing to an attribute (and optionally reading as well). It adds
* some convenience features on top of `GVMutableArray` that are very commonly used.
*
* Supported convenience features:
* - Implicit type conversion when writing to builtin attributes.
* - Supports simple access to a span containing the attribute values (that avoids the use of
* VMutableArray_Span in many cases).
* - An output attribute can live side by side with an existing attribute with a different domain
* or data type. The old attribute will only be overwritten when the #save function is called.
*
* \note The lifetime of an output attribute should not be longer than the the lifetime of the
* geometry component it comes from, since it can keep a reference to the component for use in
* the #save method.
*/
class OutputAttribute {
public:
using SaveFn = std::function<void(OutputAttribute &)>;
private:
GVMutableArray varray_;
AttributeDomain domain_ = ATTR_DOMAIN_AUTO;
SaveFn save_;
std::unique_ptr<fn::GVMutableArray_GSpan> optional_span_varray_;
bool ignore_old_values_ = false;
bool save_has_been_called_ = false;
public:
OutputAttribute();
OutputAttribute(OutputAttribute &&other);
OutputAttribute(GVMutableArray varray,
AttributeDomain domain,
SaveFn save,
const bool ignore_old_values);
~OutputAttribute();
operator bool() const;
GVMutableArray &operator*();
fn::GVMutableArray *operator->();
GVMutableArray &varray();
AttributeDomain domain() const;
const CPPType &cpp_type() const;
CustomDataType custom_data_type() const;
fn::GMutableSpan as_span();
template<typename T> MutableSpan<T> as_span();
void save();
};
/**
* Same as OutputAttribute, but should be used when the data type is known at compile time.
*/
template<typename T> class OutputAttribute_Typed {
private:
OutputAttribute attribute_;
VMutableArray<T> varray_;
public:
OutputAttribute_Typed();
OutputAttribute_Typed(OutputAttribute attribute) : attribute_(std::move(attribute))
{
if (attribute_) {
varray_ = attribute_.varray().template typed<T>();
}
}
OutputAttribute_Typed(OutputAttribute_Typed &&other);
~OutputAttribute_Typed();
OutputAttribute_Typed &operator=(OutputAttribute_Typed &&other)
{
if (this == &other) {
return *this;
}
this->~OutputAttribute_Typed();
new (this) OutputAttribute_Typed(std::move(other));
return *this;
}
operator bool() const
{
return varray_;
}
VMutableArray<T> &operator*()
{
return varray_;
}
VMutableArray<T> *operator->()
{
return &varray_;
}
VMutableArray<T> &varray()
{
return varray_;
}
AttributeDomain domain() const
{
return attribute_.domain();
}
const CPPType &cpp_type() const
{
return CPPType::get<T>();
}
CustomDataType custom_data_type() const
{
return cpp_type_to_custom_data_type(this->cpp_type());
}
MutableSpan<T> as_span()
{
return attribute_.as_span<T>();
}
void save()
{
attribute_.save();
}
};
/* These are not defined in the class directly, because when defining them there, the external
* template instantiation does not work, resulting in longer compile times. */
template<typename T> inline OutputAttribute_Typed<T>::OutputAttribute_Typed() = default;
template<typename T>
inline OutputAttribute_Typed<T>::OutputAttribute_Typed(OutputAttribute_Typed &&other) = default;
template<typename T> inline OutputAttribute_Typed<T>::~OutputAttribute_Typed() = default;
/**
* A basic container around DNA CustomData so that its users
* don't have to implement special copy and move constructors.
*/
class CustomDataAttributes {
/**
* #CustomData needs a size to be freed, and unfortunately it isn't stored in the struct
* itself, so keep track of the size here so this class can implement its own destructor.
* If the implementation of the attribute storage changes, this could be removed.
*/
int size_;
public:
CustomData data;
CustomDataAttributes();
~CustomDataAttributes();
CustomDataAttributes(const CustomDataAttributes &other);
CustomDataAttributes(CustomDataAttributes &&other);
CustomDataAttributes &operator=(const CustomDataAttributes &other);
void reallocate(const int size);
void clear();
std::optional<blender::fn::GSpan> get_for_read(const AttributeIDRef &attribute_id) const;
/**
* Return a virtual array for a stored attribute, or a single value virtual array with the
* default value if the attribute doesn't exist. If no default value is provided, the default
* value for the type will be used.
*/
blender::fn::GVArray get_for_read(const AttributeIDRef &attribute_id,
const CustomDataType data_type,
const void *default_value) const;
template<typename T>
blender::VArray<T> get_for_read(const AttributeIDRef &attribute_id, const T &default_value) const
{
const blender::fn::CPPType &cpp_type = blender::fn::CPPType::get<T>();
const CustomDataType type = blender::bke::cpp_type_to_custom_data_type(cpp_type);
GVArray varray = this->get_for_read(attribute_id, type, &default_value);
return varray.typed<T>();
}
std::optional<blender::fn::GMutableSpan> get_for_write(const AttributeIDRef &attribute_id);
bool create(const AttributeIDRef &attribute_id, const CustomDataType data_type);
bool create_by_move(const AttributeIDRef &attribute_id,
const CustomDataType data_type,
void *buffer);
bool remove(const AttributeIDRef &attribute_id);
/**
* Change the order of the attributes to match the order of IDs in the argument.
*/
void reorder(Span<AttributeIDRef> new_order);
bool foreach_attribute(const AttributeForeachCallback callback,
const AttributeDomain domain) const;
};
/* -------------------------------------------------------------------- */
/** \name #AttributeIDRef Inline Methods
* \{ */
inline AttributeIDRef::AttributeIDRef() = default;
inline AttributeIDRef::AttributeIDRef(StringRef name) : name_(name)
{
}
inline AttributeIDRef::AttributeIDRef(StringRefNull name) : name_(name)
{
}
inline AttributeIDRef::AttributeIDRef(const char *name) : name_(name)
{
}
inline AttributeIDRef::AttributeIDRef(const std::string &name) : name_(name)
{
}
/* The anonymous id is only borrowed, the caller has to keep a reference to it. */
inline AttributeIDRef::AttributeIDRef(const AnonymousAttributeID *anonymous_id)
: anonymous_id_(anonymous_id)
{
}
inline bool operator==(const AttributeIDRef &a, const AttributeIDRef &b)
{
return a.anonymous_id_ == b.anonymous_id_ && a.name_ == b.name_;
}
inline AttributeIDRef::operator bool() const
{
return this->is_named() || this->is_anonymous();
}
inline uint64_t AttributeIDRef::hash() const
{
return get_default_hash_2(name_, anonymous_id_);
}
inline bool AttributeIDRef::is_named() const
{
return !name_.is_empty();
}
inline bool AttributeIDRef::is_anonymous() const
{
return anonymous_id_ != nullptr;
}
inline StringRef AttributeIDRef::name() const
{
BLI_assert(this->is_named());
return name_;
}
inline const AnonymousAttributeID &AttributeIDRef::anonymous_id() const
{
BLI_assert(this->is_anonymous());
return *anonymous_id_;
}
/**
* \return True if the attribute should not be removed automatically as an optimization during
* processing or copying. Anonymous attributes can be removed when they no longer have any
* references.
*/
inline bool AttributeIDRef::should_be_kept() const
{
return this->is_named() || BKE_anonymous_attribute_id_has_strong_references(anonymous_id_);
}
/** \} */
/* -------------------------------------------------------------------- */
/** \name #OutputAttribute Inline Methods
* \{ */
inline OutputAttribute::OutputAttribute() = default;
inline OutputAttribute::OutputAttribute(OutputAttribute &&other) = default;
inline OutputAttribute::OutputAttribute(GVMutableArray varray,
AttributeDomain domain,
SaveFn save,
const bool ignore_old_values)
: varray_(std::move(varray)),
domain_(domain),
save_(std::move(save)),
ignore_old_values_(ignore_old_values)
{
}
inline OutputAttribute::operator bool() const
{
return varray_;
}
inline GVMutableArray &OutputAttribute::operator*()
{
return varray_;
}
inline fn::GVMutableArray *OutputAttribute::operator->()
{
return &varray_;
}
inline GVMutableArray &OutputAttribute::varray()
{
return varray_;
}
inline AttributeDomain OutputAttribute::domain() const
{
return domain_;
}
inline const CPPType &OutputAttribute::cpp_type() const
{
return varray_.type();
}
inline CustomDataType OutputAttribute::custom_data_type() const
{
return cpp_type_to_custom_data_type(this->cpp_type());
}
template<typename T> inline MutableSpan<T> OutputAttribute::as_span()
{
return this->as_span().typed<T>();
}
/** \} */
} // namespace blender::bke
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