Erik Abrahamsson
4b30b5c57f
Geometry Nodes: SDF Volume nodes milestone 1 Adds initial support for SDF volume creation and manipulation. `SDF volume` is Blender's name of an OpenVDB grid of type Level Set. See the discussion about naming in #91668. The new nodes are: - Mesh to SDF Volume: Converts a mesh to an SDF Volume - Points to SDF Volume: Converts points to an SDF Volume - Mean Filter SDF Volume: Applies a Mean Filter to an SDF - Offset SDF Volume: Applies an offset to an SDF - SDF Volume Sphere: Creates an SDF Volume in the shape of a sphere For now an experimental option `New Volume Nodes` needs to be enabled in Blender preferences for the nodes to be visible. See the current work plan for Volume Nodes in #103248. Pull Request: blender/blender#105090
97 lines
3.2 KiB
C++
97 lines
3.2 KiB
C++
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#include "BLI_math_matrix.hh"
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#include "BKE_volume.h"
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#include "GEO_points_to_volume.hh"
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#ifdef WITH_OPENVDB
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# include <openvdb/openvdb.h>
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# include <openvdb/tools/LevelSetUtil.h>
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# include <openvdb/tools/ParticlesToLevelSet.h>
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namespace blender::geometry {
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/* Implements the interface required by #openvdb::tools::ParticlesToLevelSet. */
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struct OpenVDBParticleList {
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using PosType = openvdb::Vec3R;
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Span<float3> positions;
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Span<float> radii;
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size_t size() const
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{
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return size_t(positions.size());
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}
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void getPos(size_t n, openvdb::Vec3R &xyz) const
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{
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xyz = &positions[n].x;
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}
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void getPosRad(size_t n, openvdb::Vec3R &xyz, openvdb::Real &radius) const
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{
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xyz = &positions[n].x;
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radius = radii[n];
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}
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};
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static openvdb::FloatGrid::Ptr points_to_sdf_grid(const Span<float3> positions,
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const Span<float> radii)
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{
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/* Create a new grid that will be filled. #ParticlesToLevelSet requires
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* the background value to be positive */
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openvdb::FloatGrid::Ptr new_grid = openvdb::FloatGrid::create(1.0f);
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/* Create a narrow-band level set grid based on the positions and radii. */
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openvdb::tools::ParticlesToLevelSet op{*new_grid};
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/* Don't ignore particles based on their radius. */
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op.setRmin(0.0f);
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op.setRmax(FLT_MAX);
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OpenVDBParticleList particles{positions, radii};
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op.rasterizeSpheres(particles);
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op.finalize();
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return new_grid;
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}
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VolumeGrid *fog_volume_grid_add_from_points(Volume *volume,
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const StringRefNull name,
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const Span<float3> positions,
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const Span<float> radii,
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const float voxel_size,
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const float density)
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{
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openvdb::FloatGrid::Ptr new_grid = points_to_sdf_grid(positions, radii);
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new_grid->transform().postScale(voxel_size);
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new_grid->setGridClass(openvdb::GRID_FOG_VOLUME);
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/* Convert the level set to a fog volume. This also sets the background value to zero. Inside the
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* fog there will be a density of 1. */
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openvdb::tools::sdfToFogVolume(*new_grid);
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/* Take the desired density into account. */
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openvdb::tools::foreach (new_grid->beginValueOn(),
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[&](const openvdb::FloatGrid::ValueOnIter &iter) {
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iter.modifyValue([&](float &value) { value *= density; });
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});
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return BKE_volume_grid_add_vdb(*volume, name, std::move(new_grid));
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}
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VolumeGrid *sdf_volume_grid_add_from_points(Volume *volume,
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const StringRefNull name,
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const Span<float3> positions,
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const Span<float> radii,
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const float voxel_size)
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{
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openvdb::FloatGrid::Ptr new_grid = points_to_sdf_grid(positions, radii);
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new_grid->transform().postScale(voxel_size);
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new_grid->setGridClass(openvdb::GRID_LEVEL_SET);
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return BKE_volume_grid_add_vdb(*volume, name, std::move(new_grid));
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}
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} // namespace blender::geometry
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#endif
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