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blender-archive/source/blender/blenkernel/intern/mesh_sample.cc

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/* SPDX-License-Identifier: GPL-2.0-or-later */
#include "BKE_attribute_math.hh"
#include "BKE_bvhutils.h"
#include "BKE_mesh_runtime.h"
#include "BKE_mesh_sample.hh"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "BLI_rand.hh"
namespace blender::bke::mesh_surface_sample {
template<typename T>
BLI_NOINLINE static void sample_point_attribute(const Mesh &mesh,
const Span<int> looptri_indices,
const Span<float3> bary_coords,
const VArray<T> &src,
const IndexMask mask,
const MutableSpan<T> dst)
{
const Span<MLoopTri> looptris{BKE_mesh_runtime_looptri_ensure(&mesh),
BKE_mesh_runtime_looptri_len(&mesh)};
for (const int i : mask) {
const int looptri_index = looptri_indices[i];
const MLoopTri &looptri = looptris[looptri_index];
const float3 &bary_coord = bary_coords[i];
const int v0_index = mesh.mloop[looptri.tri[0]].v;
const int v1_index = mesh.mloop[looptri.tri[1]].v;
const int v2_index = mesh.mloop[looptri.tri[2]].v;
const T v0 = src[v0_index];
const T v1 = src[v1_index];
const T v2 = src[v2_index];
const T interpolated_value = attribute_math::mix3(bary_coord, v0, v1, v2);
dst[i] = interpolated_value;
}
}
void sample_point_attribute(const Mesh &mesh,
const Span<int> looptri_indices,
const Span<float3> bary_coords,
const GVArray &src,
const IndexMask mask,
const GMutableSpan dst)
{
BLI_assert(src.size() == mesh.totvert);
BLI_assert(src.type() == dst.type());
const CPPType &type = src.type();
attribute_math::convert_to_static_type(type, [&](auto dummy) {
using T = decltype(dummy);
sample_point_attribute<T>(
mesh, looptri_indices, bary_coords, src.typed<T>(), mask, dst.typed<T>());
});
}
template<typename T>
BLI_NOINLINE static void sample_corner_attribute(const Mesh &mesh,
const Span<int> looptri_indices,
const Span<float3> bary_coords,
const VArray<T> &src,
const IndexMask mask,
const MutableSpan<T> dst)
{
const Span<MLoopTri> looptris{BKE_mesh_runtime_looptri_ensure(&mesh),
BKE_mesh_runtime_looptri_len(&mesh)};
for (const int i : mask) {
const int looptri_index = looptri_indices[i];
const MLoopTri &looptri = looptris[looptri_index];
const float3 &bary_coord = bary_coords[i];
const int loop_index_0 = looptri.tri[0];
const int loop_index_1 = looptri.tri[1];
const int loop_index_2 = looptri.tri[2];
const T v0 = src[loop_index_0];
const T v1 = src[loop_index_1];
const T v2 = src[loop_index_2];
const T interpolated_value = attribute_math::mix3(bary_coord, v0, v1, v2);
dst[i] = interpolated_value;
}
}
void sample_corner_attribute(const Mesh &mesh,
const Span<int> looptri_indices,
const Span<float3> bary_coords,
const GVArray &src,
const IndexMask mask,
const GMutableSpan dst)
{
BLI_assert(src.size() == mesh.totloop);
BLI_assert(src.type() == dst.type());
const CPPType &type = src.type();
attribute_math::convert_to_static_type(type, [&](auto dummy) {
using T = decltype(dummy);
sample_corner_attribute<T>(
mesh, looptri_indices, bary_coords, src.typed<T>(), mask, dst.typed<T>());
});
}
template<typename T>
void sample_face_attribute(const Mesh &mesh,
const Span<int> looptri_indices,
const VArray<T> &src,
const IndexMask mask,
const MutableSpan<T> dst)
{
const Span<MLoopTri> looptris{BKE_mesh_runtime_looptri_ensure(&mesh),
BKE_mesh_runtime_looptri_len(&mesh)};
for (const int i : mask) {
const int looptri_index = looptri_indices[i];
const MLoopTri &looptri = looptris[looptri_index];
const int poly_index = looptri.poly;
dst[i] = src[poly_index];
}
}
void sample_face_attribute(const Mesh &mesh,
const Span<int> looptri_indices,
const GVArray &src,
const IndexMask mask,
const GMutableSpan dst)
{
BLI_assert(src.size() == mesh.totpoly);
BLI_assert(src.type() == dst.type());
const CPPType &type = src.type();
attribute_math::convert_to_static_type(type, [&](auto dummy) {
using T = decltype(dummy);
sample_face_attribute<T>(mesh, looptri_indices, src.typed<T>(), mask, dst.typed<T>());
});
}
MeshAttributeInterpolator::MeshAttributeInterpolator(const Mesh *mesh,
const IndexMask mask,
const Span<float3> positions,
const Span<int> looptri_indices)
: mesh_(mesh), mask_(mask), positions_(positions), looptri_indices_(looptri_indices)
{
BLI_assert(positions.size() == looptri_indices.size());
}
Span<float3> MeshAttributeInterpolator::ensure_barycentric_coords()
{
if (!bary_coords_.is_empty()) {
BLI_assert(bary_coords_.size() >= mask_.min_array_size());
return bary_coords_;
}
bary_coords_.reinitialize(mask_.min_array_size());
const Span<MLoopTri> looptris{BKE_mesh_runtime_looptri_ensure(mesh_),
BKE_mesh_runtime_looptri_len(mesh_)};
for (const int i : mask_) {
const int looptri_index = looptri_indices_[i];
const MLoopTri &looptri = looptris[looptri_index];
const int v0_index = mesh_->mloop[looptri.tri[0]].v;
const int v1_index = mesh_->mloop[looptri.tri[1]].v;
const int v2_index = mesh_->mloop[looptri.tri[2]].v;
interp_weights_tri_v3(bary_coords_[i],
mesh_->mvert[v0_index].co,
mesh_->mvert[v1_index].co,
mesh_->mvert[v2_index].co,
positions_[i]);
}
return bary_coords_;
}
Span<float3> MeshAttributeInterpolator::ensure_nearest_weights()
{
if (!nearest_weights_.is_empty()) {
BLI_assert(nearest_weights_.size() >= mask_.min_array_size());
return nearest_weights_;
}
nearest_weights_.reinitialize(mask_.min_array_size());
const Span<MLoopTri> looptris{BKE_mesh_runtime_looptri_ensure(mesh_),
BKE_mesh_runtime_looptri_len(mesh_)};
for (const int i : mask_) {
const int looptri_index = looptri_indices_[i];
const MLoopTri &looptri = looptris[looptri_index];
const int v0_index = mesh_->mloop[looptri.tri[0]].v;
const int v1_index = mesh_->mloop[looptri.tri[1]].v;
const int v2_index = mesh_->mloop[looptri.tri[2]].v;
const float d0 = len_squared_v3v3(positions_[i], mesh_->mvert[v0_index].co);
const float d1 = len_squared_v3v3(positions_[i], mesh_->mvert[v1_index].co);
const float d2 = len_squared_v3v3(positions_[i], mesh_->mvert[v2_index].co);
nearest_weights_[i] = MIN3_PAIR(d0, d1, d2, float3(1, 0, 0), float3(0, 1, 0), float3(0, 0, 1));
}
return nearest_weights_;
}
void MeshAttributeInterpolator::sample_data(const GVArray &src,
const eAttrDomain domain,
const eAttributeMapMode mode,
const GMutableSpan dst)
{
if (src.is_empty() || dst.is_empty()) {
return;
}
/* Compute barycentric coordinates only when they are needed. */
Span<float3> weights;
if (ELEM(domain, ATTR_DOMAIN_POINT, ATTR_DOMAIN_CORNER)) {
switch (mode) {
case eAttributeMapMode::INTERPOLATED:
weights = this->ensure_barycentric_coords();
break;
case eAttributeMapMode::NEAREST:
weights = this->ensure_nearest_weights();
break;
}
}
/* Interpolate the source attributes on the surface. */
switch (domain) {
case ATTR_DOMAIN_POINT:
sample_point_attribute(*mesh_, looptri_indices_, weights, src, mask_, dst);
break;
case ATTR_DOMAIN_FACE:
sample_face_attribute(*mesh_, looptri_indices_, src, mask_, dst);
break;
case ATTR_DOMAIN_CORNER:
sample_corner_attribute(*mesh_, looptri_indices_, weights, src, mask_, dst);
break;
case ATTR_DOMAIN_EDGE:
/* Not yet supported. */
break;
default:
BLI_assert_unreachable();
break;
}
}
int sample_surface_points_spherical(RandomNumberGenerator &rng,
const Mesh &mesh,
const Span<int> looptri_indices_to_sample,
const float3 &sample_pos,
const float sample_radius,
const float approximate_density,
Vector<float3> &r_bary_coords,
Vector<int> &r_looptri_indices,
Vector<float3> &r_positions)
{
const Span<MLoopTri> looptris{BKE_mesh_runtime_looptri_ensure(&mesh),
BKE_mesh_runtime_looptri_len(&mesh)};
const float sample_radius_sq = pow2f(sample_radius);
const float sample_plane_area = M_PI * sample_radius_sq;
/* Used for switching between two triangle sampling strategies. */
const float area_threshold = sample_plane_area;
const int old_num = r_bary_coords.size();
for (const int looptri_index : looptri_indices_to_sample) {
const MLoopTri &looptri = looptris[looptri_index];
const float3 &v0 = mesh.mvert[mesh.mloop[looptri.tri[0]].v].co;
const float3 &v1 = mesh.mvert[mesh.mloop[looptri.tri[1]].v].co;
const float3 &v2 = mesh.mvert[mesh.mloop[looptri.tri[2]].v].co;
const float looptri_area = area_tri_v3(v0, v1, v2);
if (looptri_area < area_threshold) {
/* The triangle is small compared to the sample radius. Sample by generating random
* barycentric coordinates. */
const int amount = rng.round_probabilistic(approximate_density * looptri_area);
for ([[maybe_unused]] const int i : IndexRange(amount)) {
const float3 bary_coord = rng.get_barycentric_coordinates();
const float3 point_pos = attribute_math::mix3(bary_coord, v0, v1, v2);
const float dist_to_sample_sq = math::distance_squared(point_pos, sample_pos);
if (dist_to_sample_sq > sample_radius_sq) {
continue;
}
r_bary_coords.append(bary_coord);
r_looptri_indices.append(looptri_index);
r_positions.append(point_pos);
}
}
else {
/* The triangle is large compared to the sample radius. Sample by generating random points
* on the triangle plane within the sample radius. */
float3 normal;
normal_tri_v3(normal, v0, v1, v2);
float3 sample_pos_proj = sample_pos;
project_v3_plane(sample_pos_proj, normal, v0);
const float proj_distance_sq = math::distance_squared(sample_pos_proj, sample_pos);
const float sample_radius_factor_sq = 1.0f -
std::min(1.0f, proj_distance_sq / sample_radius_sq);
const float radius_proj_sq = sample_radius_sq * sample_radius_factor_sq;
const float radius_proj = std::sqrt(radius_proj_sq);
const float circle_area = M_PI * radius_proj_sq;
const int amount = rng.round_probabilistic(approximate_density * circle_area);
const float3 axis_1 = math::normalize(v1 - v0) * radius_proj;
const float3 axis_2 = math::normalize(math::cross(axis_1, math::cross(axis_1, v2 - v0))) *
radius_proj;
for ([[maybe_unused]] const int i : IndexRange(amount)) {
const float r = std::sqrt(rng.get_float());
const float angle = rng.get_float() * 2.0f * M_PI;
const float x = r * std::cos(angle);
const float y = r * std::sin(angle);
const float3 point_pos = sample_pos_proj + axis_1 * x + axis_2 * y;
if (!isect_point_tri_prism_v3(point_pos, v0, v1, v2)) {
/* Sampled point is not in the triangle. */
continue;
}
float3 bary_coord;
interp_weights_tri_v3(bary_coord, v0, v1, v2, point_pos);
r_bary_coords.append(bary_coord);
r_looptri_indices.append(looptri_index);
r_positions.append(point_pos);
}
}
}
return r_bary_coords.size() - old_num;
}
int sample_surface_points_projected(
RandomNumberGenerator &rng,
const Mesh &mesh,
BVHTreeFromMesh &mesh_bvhtree,
const float2 &sample_pos_re,
const float sample_radius_re,
const FunctionRef<void(const float2 &pos_re, float3 &r_start, float3 &r_end)>
region_position_to_ray,
const bool front_face_only,
const int tries_num,
const int max_points,
Vector<float3> &r_bary_coords,
Vector<int> &r_looptri_indices,
Vector<float3> &r_positions)
{
const Span<MLoopTri> looptris{BKE_mesh_runtime_looptri_ensure(&mesh),
BKE_mesh_runtime_looptri_len(&mesh)};
int point_count = 0;
for ([[maybe_unused]] const int _ : IndexRange(tries_num)) {
if (point_count == max_points) {
break;
}
const float r = sample_radius_re * std::sqrt(rng.get_float());
const float angle = rng.get_float() * 2.0f * M_PI;
float3 ray_start, ray_end;
const float2 pos_re = sample_pos_re + r * float2(std::cos(angle), std::sin(angle));
region_position_to_ray(pos_re, ray_start, ray_end);
const float3 ray_direction = math::normalize(ray_end - ray_start);
BVHTreeRayHit ray_hit;
ray_hit.dist = FLT_MAX;
ray_hit.index = -1;
BLI_bvhtree_ray_cast(mesh_bvhtree.tree,
ray_start,
ray_direction,
0.0f,
&ray_hit,
mesh_bvhtree.raycast_callback,
&mesh_bvhtree);
if (ray_hit.index == -1) {
continue;
}
if (front_face_only) {
const float3 normal = ray_hit.no;
if (math::dot(ray_direction, normal) >= 0.0f) {
continue;
}
}
const int looptri_index = ray_hit.index;
const float3 pos = ray_hit.co;
const float3 bary_coords = compute_bary_coord_in_triangle(mesh, looptris[looptri_index], pos);
r_positions.append(pos);
r_bary_coords.append(bary_coords);
r_looptri_indices.append(looptri_index);
point_count++;
}
return point_count;
}
float3 compute_bary_coord_in_triangle(const Mesh &mesh,
const MLoopTri &looptri,
const float3 &position)
{
const float3 &v0 = mesh.mvert[mesh.mloop[looptri.tri[0]].v].co;
const float3 &v1 = mesh.mvert[mesh.mloop[looptri.tri[1]].v].co;
const float3 &v2 = mesh.mvert[mesh.mloop[looptri.tri[2]].v].co;
float3 bary_coords;
interp_weights_tri_v3(bary_coords, v0, v1, v2, position);
return bary_coords;
}
} // namespace blender::bke::mesh_surface_sample