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Diffstat (limited to 'source/blender/blenkernel/BKE_instances.hh')
| -rw-r--r-- | source/blender/blenkernel/BKE_instances.hh | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/source/blender/blenkernel/BKE_instances.hh b/source/blender/blenkernel/BKE_instances.hh new file mode 100644 index 00000000000..f17ebba0dfa --- /dev/null +++ b/source/blender/blenkernel/BKE_instances.hh @@ -0,0 +1,270 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#pragma once + +/** \file + * \ingroup bke + * + * #Instances is a container for geometry instances. It fulfills some key requirements: + * - Support nested instances. + * - Support instance attributes. + * - Support referencing different kinds of instances (objects, collections, geometry sets). + * - Support efficiently iterating over the instanced geometries, i.e. without have to iterate over + * all instances. + * + * #Instances has an ordered set of #InstanceReference. An #InstanceReference contains information + * about a particular instanced geometry. Each #InstanceReference has a handle (integer index) + * which is then stored per instance. Many instances can use the same #InstanceReference. + */ + +#include <mutex> + +#include "BLI_float4x4.hh" +#include "BLI_vector.hh" +#include "BLI_vector_set.hh" + +#include "BKE_attribute.hh" + +struct GeometrySet; +struct Object; +struct Collection; + +namespace blender::bke { + +/** + * Holds a reference to conceptually unique geometry or a pointer to object/collection data + * that is instanced with a transform in #Instances. + */ +class InstanceReference { + public: + enum class Type { + /** + * An empty instance. This allows an `InstanceReference` to be default constructed without + * being in an invalid state. There might also be other use cases that we haven't explored + * much yet (such as changing the instance later on, and "disabling" some instances). + */ + None, + Object, + Collection, + GeometrySet, + }; + + private: + Type type_ = Type::None; + /** Depending on the type this is either null, an Object or Collection pointer. */ + void *data_ = nullptr; + std::unique_ptr<GeometrySet> geometry_set_; + + public: + InstanceReference() = default; + InstanceReference(Object &object); + InstanceReference(Collection &collection); + InstanceReference(GeometrySet geometry_set); + + InstanceReference(const InstanceReference &other); + InstanceReference(InstanceReference &&other); + + InstanceReference &operator=(const InstanceReference &other); + InstanceReference &operator=(InstanceReference &&other); + + Type type() const; + Object &object() const; + Collection &collection() const; + const GeometrySet &geometry_set() const; + + bool owns_direct_data() const; + void ensure_owns_direct_data(); + + uint64_t hash() const; + friend bool operator==(const InstanceReference &a, const InstanceReference &b); +}; + +class Instances { + private: + /** + * Indexed set containing information about the data that is instanced. + * Actual instances store an index ("handle") into this set. + */ + blender::VectorSet<InstanceReference> references_; + + /** Indices into `references_`. Determines what data is instanced. */ + blender::Vector<int> reference_handles_; + /** Transformation of the instances. */ + blender::Vector<blender::float4x4> transforms_; + + /* These almost unique ids are generated based on the `id` attribute, which might not contain + * unique ids at all. They are *almost* unique, because under certain very unlikely + * circumstances, they are not unique. Code using these ids should not crash when they are not + * unique but can generally expect them to be unique. */ + mutable std::mutex almost_unique_ids_mutex_; + mutable blender::Array<int> almost_unique_ids_; + + CustomDataAttributes attributes_; + + public: + Instances() = default; + Instances(const Instances &other); + + void reserve(int min_capacity); + /** + * Resize the transform, handles, and attributes to the specified capacity. + * + * \note This function should be used carefully, only when it's guaranteed + * that the data will be filled. + */ + void resize(int capacity); + + /** + * Returns a handle for the given reference. + * If the reference exists already, the handle of the existing reference is returned. + * Otherwise a new handle is added. + */ + int add_reference(const InstanceReference &reference); + /** + * Add a reference to the instance reference with an index specified by the #instance_handle + * argument. For adding many instances, using #resize and accessing the transform array + * directly is preferred. + */ + void add_instance(int instance_handle, const blender::float4x4 &transform); + + blender::Span<InstanceReference> references() const; + void remove_unused_references(); + + /** + * If references have a collection or object type, convert them into geometry instances + * recursively. After that, the geometry sets can be edited. There may still be instances of + * other types of they can't be converted to geometry sets. + */ + void ensure_geometry_instances(); + /** + * With write access to the instances component, the data in the instanced geometry sets can be + * changed. This is a function on the component rather than each reference to ensure `const` + * correctness for that reason. + */ + GeometrySet &geometry_set_from_reference(int reference_index); + + blender::Span<int> reference_handles() const; + blender::MutableSpan<int> reference_handles(); + blender::MutableSpan<blender::float4x4> transforms(); + blender::Span<blender::float4x4> transforms() const; + + int instances_num() const; + int references_num() const; + + /** + * Remove the indices that are not contained in the mask input, and remove unused instance + * references afterwards. + */ + void remove(const blender::IndexMask mask); + /** + * Get an id for every instance. These can be used for e.g. motion blur. + */ + blender::Span<int> almost_unique_ids() const; + + blender::bke::AttributeAccessor attributes() const; + blender::bke::MutableAttributeAccessor attributes_for_write(); + + CustomDataAttributes &custom_data_attributes(); + const CustomDataAttributes &custom_data_attributes() const; + + void foreach_referenced_geometry( + blender::FunctionRef<void(const GeometrySet &geometry_set)> callback) const; + + bool owns_direct_data() const; + void ensure_owns_direct_data(); +}; + +/* -------------------------------------------------------------------- */ +/** \name #InstanceReference Inline Methods + * \{ */ + +inline InstanceReference::InstanceReference(Object &object) : type_(Type::Object), data_(&object) +{ +} + +inline InstanceReference::InstanceReference(Collection &collection) + : type_(Type::Collection), data_(&collection) +{ +} + +inline InstanceReference::InstanceReference(const InstanceReference &other) + : type_(other.type_), data_(other.data_) +{ + if (other.geometry_set_) { + geometry_set_ = std::make_unique<GeometrySet>(*other.geometry_set_); + } +} + +inline InstanceReference::InstanceReference(InstanceReference &&other) + : type_(other.type_), data_(other.data_), geometry_set_(std::move(other.geometry_set_)) +{ + other.type_ = Type::None; + other.data_ = nullptr; +} + +inline InstanceReference &InstanceReference::operator=(const InstanceReference &other) +{ + if (this == &other) { + return *this; + } + this->~InstanceReference(); + new (this) InstanceReference(other); + return *this; +} + +inline InstanceReference &InstanceReference::operator=(InstanceReference &&other) +{ + if (this == &other) { + return *this; + } + this->~InstanceReference(); + new (this) InstanceReference(std::move(other)); + return *this; +} + +inline InstanceReference::Type InstanceReference::type() const +{ + return type_; +} + +inline Object &InstanceReference::object() const +{ + BLI_assert(type_ == Type::Object); + return *(Object *)data_; +} + +inline Collection &InstanceReference::collection() const +{ + BLI_assert(type_ == Type::Collection); + return *(Collection *)data_; +} + +inline const GeometrySet &InstanceReference::geometry_set() const +{ + BLI_assert(type_ == Type::GeometrySet); + return *geometry_set_; +} + +inline CustomDataAttributes &Instances::custom_data_attributes() +{ + return attributes_; +} + +inline const CustomDataAttributes &Instances::custom_data_attributes() const +{ + return attributes_; +} + +inline uint64_t InstanceReference::hash() const +{ + return blender::get_default_hash_2(data_, geometry_set_.get()); +} + +inline bool operator==(const InstanceReference &a, const InstanceReference &b) +{ + return a.data_ == b.data_ && a.geometry_set_.get() == b.geometry_set_.get(); +} + +/** \} */ + +} // namespace blender::bke |