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blender-archive/source/blender/blenkernel/intern/geometry_component_pointcloud.cc
Jacques Lucke 5cf6f570c6 Geometry Nodes: use virtual arrays in internal attribute api
A virtual array is a data structure that is similar to a normal array
in that its elements can be accessed by an index. However, a virtual
array does not have to be a contiguous array internally. Instead, its
elements can be layed out arbitrarily while element access happens
through a virtual function call. However, the virtual array data
structures are designed so that the virtual function call can be avoided
in cases where it could become a bottleneck.

Most commonly, a virtual array is backed by an actual array/span or
is a single value internally, that is the same for every index.
Besides those, there are many more specialized virtual arrays like the
ones that provides vertex positions based on the `MVert` struct or
vertex group weights.

Not all attributes used by geometry nodes are stored in simple contiguous
arrays. To provide uniform access to all kinds of attributes, the attribute
API has to provide virtual array functionality that hides the implementation
details of attributes.

Before this refactor, the attribute API provided its own virtual array
implementation as part of the `ReadAttribute` and `WriteAttribute` types.
That resulted in unnecessary code duplication with the virtual array system.
Even worse, it bound many algorithms used by geometry nodes to the specifics
of the attribute API, even though they could also use different data sources
(such as data from sockets, default values, later results of expressions, ...).

This refactor removes the `ReadAttribute` and `WriteAttribute` types and
replaces them with `GVArray` and `GVMutableArray` respectively. The `GV`
stands for "generic virtual". The "generic" means that the data type contained
in those virtual arrays is only known at run-time. There are the corresponding
statically typed types `VArray<T>` and `VMutableArray<T>` as well.

No regressions are expected from this refactor. It does come with one
improvement for users. The attribute API can convert the data type
on write now. This is especially useful when writing to builtin attributes
like `material_index` with e.g. the Attribute Math node (which usually
just writes to float attributes, while `material_index` is an integer attribute).

Differential Revision: https://developer.blender.org/D10994
2021-04-17 16:41:39 +02:00

220 lines
7.7 KiB
C++

/*
* 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 "DNA_pointcloud_types.h"
#include "BKE_attribute_access.hh"
#include "BKE_geometry_set.hh"
#include "BKE_lib_id.h"
#include "BKE_pointcloud.h"
#include "attribute_access_intern.hh"
/* -------------------------------------------------------------------- */
/** \name Geometry Component Implementation
* \{ */
PointCloudComponent::PointCloudComponent() : GeometryComponent(GEO_COMPONENT_TYPE_POINT_CLOUD)
{
}
PointCloudComponent::~PointCloudComponent()
{
this->clear();
}
GeometryComponent *PointCloudComponent::copy() const
{
PointCloudComponent *new_component = new PointCloudComponent();
if (pointcloud_ != nullptr) {
new_component->pointcloud_ = BKE_pointcloud_copy_for_eval(pointcloud_, false);
new_component->ownership_ = GeometryOwnershipType::Owned;
}
return new_component;
}
void PointCloudComponent::clear()
{
BLI_assert(this->is_mutable());
if (pointcloud_ != nullptr) {
if (ownership_ == GeometryOwnershipType::Owned) {
BKE_id_free(nullptr, pointcloud_);
}
pointcloud_ = nullptr;
}
}
bool PointCloudComponent::has_pointcloud() const
{
return pointcloud_ != nullptr;
}
/* Clear the component and replace it with the new point cloud. */
void PointCloudComponent::replace(PointCloud *pointcloud, GeometryOwnershipType ownership)
{
BLI_assert(this->is_mutable());
this->clear();
pointcloud_ = pointcloud;
ownership_ = ownership;
}
/* Return the point cloud and clear the component. The caller takes over responsibility for freeing
* the point cloud (if the component was responsible before). */
PointCloud *PointCloudComponent::release()
{
BLI_assert(this->is_mutable());
PointCloud *pointcloud = pointcloud_;
pointcloud_ = nullptr;
return pointcloud;
}
/* Get the point cloud from this component. This method can be used by multiple threads at the same
* time. Therefore, the returned point cloud should not be modified. No ownership is transferred.
*/
const PointCloud *PointCloudComponent::get_for_read() const
{
return pointcloud_;
}
/* Get the point cloud from this component. This method can only be used when the component is
* mutable, i.e. it is not shared. The returned point cloud can be modified. No ownership is
* transferred. */
PointCloud *PointCloudComponent::get_for_write()
{
BLI_assert(this->is_mutable());
if (ownership_ == GeometryOwnershipType::ReadOnly) {
pointcloud_ = BKE_pointcloud_copy_for_eval(pointcloud_, false);
ownership_ = GeometryOwnershipType::Owned;
}
return pointcloud_;
}
bool PointCloudComponent::is_empty() const
{
return pointcloud_ == nullptr;
}
bool PointCloudComponent::owns_direct_data() const
{
return ownership_ == GeometryOwnershipType::Owned;
}
void PointCloudComponent::ensure_owns_direct_data()
{
BLI_assert(this->is_mutable());
if (ownership_ != GeometryOwnershipType::Owned) {
pointcloud_ = BKE_pointcloud_copy_for_eval(pointcloud_, false);
ownership_ = GeometryOwnershipType::Owned;
}
}
/** \} */
/* -------------------------------------------------------------------- */
/** \name Attribute Access
* \{ */
int PointCloudComponent::attribute_domain_size(const AttributeDomain domain) const
{
if (pointcloud_ == nullptr) {
return 0;
}
if (domain != ATTR_DOMAIN_POINT) {
return 0;
}
return pointcloud_->totpoint;
}
namespace blender::bke {
template<typename T>
static GVArrayPtr make_array_read_attribute(const void *data, const int domain_size)
{
return std::make_unique<fn::GVArray_For_Span<T>>(Span<T>((const T *)data, domain_size));
}
template<typename T>
static GVMutableArrayPtr make_array_write_attribute(void *data, const int domain_size)
{
return std::make_unique<fn::GVMutableArray_For_MutableSpan<T>>(
MutableSpan<T>((T *)data, domain_size));
}
/**
* In this function all the attribute providers for a point cloud component are created. Most data
* in this function is statically allocated, because it does not change over time.
*/
static ComponentAttributeProviders create_attribute_providers_for_point_cloud()
{
static auto update_custom_data_pointers = [](GeometryComponent &component) {
PointCloudComponent &pointcloud_component = static_cast<PointCloudComponent &>(component);
PointCloud *pointcloud = pointcloud_component.get_for_write();
if (pointcloud != nullptr) {
BKE_pointcloud_update_customdata_pointers(pointcloud);
}
};
static CustomDataAccessInfo point_access = {
[](GeometryComponent &component) -> CustomData * {
PointCloudComponent &pointcloud_component = static_cast<PointCloudComponent &>(component);
PointCloud *pointcloud = pointcloud_component.get_for_write();
return pointcloud ? &pointcloud->pdata : nullptr;
},
[](const GeometryComponent &component) -> const CustomData * {
const PointCloudComponent &pointcloud_component = static_cast<const PointCloudComponent &>(
component);
const PointCloud *pointcloud = pointcloud_component.get_for_read();
return pointcloud ? &pointcloud->pdata : nullptr;
},
update_custom_data_pointers};
static BuiltinCustomDataLayerProvider position("position",
ATTR_DOMAIN_POINT,
CD_PROP_FLOAT3,
CD_PROP_FLOAT3,
BuiltinAttributeProvider::NonCreatable,
BuiltinAttributeProvider::Writable,
BuiltinAttributeProvider::NonDeletable,
point_access,
make_array_read_attribute<float3>,
make_array_write_attribute<float3>,
nullptr);
static BuiltinCustomDataLayerProvider radius("radius",
ATTR_DOMAIN_POINT,
CD_PROP_FLOAT,
CD_PROP_FLOAT,
BuiltinAttributeProvider::Creatable,
BuiltinAttributeProvider::Writable,
BuiltinAttributeProvider::Deletable,
point_access,
make_array_read_attribute<float>,
make_array_write_attribute<float>,
nullptr);
static CustomDataAttributeProvider point_custom_data(ATTR_DOMAIN_POINT, point_access);
return ComponentAttributeProviders({&position, &radius}, {&point_custom_data});
}
} // namespace blender::bke
const blender::bke::ComponentAttributeProviders *PointCloudComponent::get_attribute_providers()
const
{
static blender::bke::ComponentAttributeProviders providers =
blender::bke::create_attribute_providers_for_point_cloud();
return &providers;
}
/** \} */