From 16abe9343a5e01426e85e4bb9d0e95c3217e35ea Mon Sep 17 00:00:00 2001 From: Jacques Lucke Date: Fri, 5 Feb 2021 16:20:14 +0100 Subject: Geometry Nodes: add Volume to Mesh node This node takes a volume and generates a mesh on it's "surface". The surface is defined by a threshold value. Currently, the node only works on volumes generated by the Points to Volume node. This limitation will be resolved soonish. Ref T84605. Differential Revision: https://developer.blender.org/D10243 --- source/blender/blenkernel/intern/node.cc | 1 + source/blender/blenkernel/intern/volume_to_mesh.cc | 183 +++++++++++++++++++++ 2 files changed, 184 insertions(+) create mode 100644 source/blender/blenkernel/intern/volume_to_mesh.cc (limited to 'source/blender/blenkernel/intern') diff --git a/source/blender/blenkernel/intern/node.cc b/source/blender/blenkernel/intern/node.cc index 44efbe64202..434875820c3 100644 --- a/source/blender/blenkernel/intern/node.cc +++ b/source/blender/blenkernel/intern/node.cc @@ -4777,6 +4777,7 @@ static void registerGeometryNodes() register_node_type_geo_points_to_volume(); register_node_type_geo_collection_info(); register_node_type_geo_is_viewport(); + register_node_type_geo_volume_to_mesh(); } static void registerFunctionNodes() diff --git a/source/blender/blenkernel/intern/volume_to_mesh.cc b/source/blender/blenkernel/intern/volume_to_mesh.cc new file mode 100644 index 00000000000..7ab67516242 --- /dev/null +++ b/source/blender/blenkernel/intern/volume_to_mesh.cc @@ -0,0 +1,183 @@ +/* + * 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 + +#include "BLI_float3.hh" +#include "BLI_span.hh" +#include "BLI_utildefines.h" + +#include "DNA_mesh_types.h" +#include "DNA_meshdata_types.h" +#include "DNA_volume_types.h" + +#include "BKE_mesh.h" +#include "BKE_volume.h" + +#ifdef WITH_OPENVDB +# include +# include +#endif + +#include "BKE_volume_to_mesh.hh" + +namespace blender::bke { + +#ifdef WITH_OPENVDB + +struct VolumeToMeshOp { + const openvdb::GridBase &base_grid; + const VolumeToMeshResolution resolution; + const float threshold; + const float adaptivity; + std::vector verts; + std::vector tris; + std::vector quads; + + template bool operator()() + { + if constexpr (std::is_scalar_v) { + this->generate_mesh_data(); + return true; + } + return false; + } + + template void generate_mesh_data() + { + const GridType &grid = static_cast(base_grid); + + if (this->resolution.mode == VOLUME_TO_MESH_RESOLUTION_MODE_GRID) { + this->grid_to_mesh(grid); + return; + } + + const float resolution_factor = this->compute_resolution_factor(base_grid); + typename GridType::Ptr temp_grid = this->create_grid_with_changed_resolution( + grid, resolution_factor); + this->grid_to_mesh(*temp_grid); + } + + template + typename GridType::Ptr create_grid_with_changed_resolution(const GridType &old_grid, + const float resolution_factor) + { + BLI_assert(resolution_factor > 0.0f); + + openvdb::Mat4R xform; + xform.setToScale(openvdb::Vec3d(resolution_factor)); + openvdb::tools::GridTransformer transformer{xform}; + + typename GridType::Ptr new_grid = GridType::create(); + transformer.transformGrid(old_grid, *new_grid); + new_grid->transform() = old_grid.transform(); + new_grid->transform().preScale(1.0f / resolution_factor); + return new_grid; + } + + float compute_resolution_factor(const openvdb::GridBase &grid) const + { + const openvdb::Vec3s voxel_size{grid.voxelSize()}; + const float current_voxel_size = std::max({voxel_size[0], voxel_size[1], voxel_size[2]}); + const float desired_voxel_size = this->compute_desired_voxel_size(grid); + return current_voxel_size / desired_voxel_size; + } + + float compute_desired_voxel_size(const openvdb::GridBase &grid) const + { + if (this->resolution.mode == VOLUME_TO_MESH_RESOLUTION_MODE_VOXEL_SIZE) { + return this->resolution.settings.voxel_size; + } + const openvdb::CoordBBox coord_bbox = base_grid.evalActiveVoxelBoundingBox(); + const openvdb::BBoxd bbox = grid.transform().indexToWorld(coord_bbox); + const float max_extent = bbox.extents()[bbox.maxExtent()]; + const float voxel_size = max_extent / this->resolution.settings.voxel_amount; + return voxel_size; + } + + template void grid_to_mesh(const GridType &grid) + { + openvdb::tools::volumeToMesh( + grid, this->verts, this->tris, this->quads, this->threshold, this->adaptivity); + + /* Better align generated mesh with volume (see T85312). */ + openvdb::Vec3s offset = grid.voxelSize() / 2.0f; + for (openvdb::Vec3s &position : this->verts) { + position += offset; + } + } +}; + +static Mesh *new_mesh_from_openvdb_data(Span verts, + Span tris, + Span quads) +{ + const int tot_loops = 3 * tris.size() + 4 * quads.size(); + const int tot_polys = tris.size() + quads.size(); + + Mesh *mesh = BKE_mesh_new_nomain(verts.size(), 0, 0, tot_loops, tot_polys); + + /* Write vertices. */ + for (const int i : verts.index_range()) { + const blender::float3 co = blender::float3(verts[i].asV()); + copy_v3_v3(mesh->mvert[i].co, co); + } + + /* Write triangles. */ + for (const int i : tris.index_range()) { + mesh->mpoly[i].loopstart = 3 * i; + mesh->mpoly[i].totloop = 3; + for (int j = 0; j < 3; j++) { + /* Reverse vertex order to get correct normals. */ + mesh->mloop[3 * i + j].v = tris[i][2 - j]; + } + } + + /* Write quads. */ + const int poly_offset = tris.size(); + const int loop_offset = tris.size() * 3; + for (const int i : quads.index_range()) { + mesh->mpoly[poly_offset + i].loopstart = loop_offset + 4 * i; + mesh->mpoly[poly_offset + i].totloop = 4; + for (int j = 0; j < 4; j++) { + /* Reverse vertex order to get correct normals. */ + mesh->mloop[loop_offset + 4 * i + j].v = quads[i][3 - j]; + } + } + + BKE_mesh_calc_edges(mesh, false, false); + BKE_mesh_calc_normals(mesh); + return mesh; +} + +Mesh *volume_to_mesh(const openvdb::GridBase &grid, + const VolumeToMeshResolution &resolution, + const float threshold, + const float adaptivity) +{ + const VolumeGridType grid_type = BKE_volume_grid_type_openvdb(grid); + + VolumeToMeshOp to_mesh_op{grid, resolution, threshold, adaptivity}; + if (!BKE_volume_grid_type_operation(grid_type, to_mesh_op)) { + return nullptr; + } + + return new_mesh_from_openvdb_data(to_mesh_op.verts, to_mesh_op.tris, to_mesh_op.quads); +} + +#endif /* WITH_OPENVDB */ + +} // namespace blender::bke -- cgit v1.2.3