tornavis/source/blender/blenkernel/intern/mesh_tessellate.cc

343 lines
13 KiB
C++

/* SPDX-FileCopyrightText: 2001-2002 NaN Holding BV. All rights reserved.
*
* SPDX-License-Identifier: GPL-2.0-or-later */
/** \file
* \ingroup bke
*
* This file contains code for face tessellation
* (creating triangles from polygons).
*
* \see `bmesh_mesh_tessellate.cc` for the #BMesh equivalent of this file.
*/
#include "BLI_enumerable_thread_specific.hh"
#include "BLI_math_geom.h"
#include "BLI_math_matrix.h"
#include "BLI_math_vector.h"
#include "BLI_memarena.h"
#include "BLI_polyfill_2d.h"
#include "BLI_task.h"
#include "BLI_task.hh"
#include "BKE_mesh.hh"
#include "BLI_strict_flags.h"
namespace blender::bke::mesh {
/** Compared against total loops. */
#define MESH_FACE_TESSELLATE_THREADED_LIMIT 4096
/* -------------------------------------------------------------------- */
/** \name Loop Tessellation
*
* Fill in #MLoopTri data-structure.
* \{ */
/**
* \param face_normal: This will be optimized out as a constant.
*/
BLI_INLINE void mesh_calc_tessellation_for_face_impl(const Span<int> corner_verts,
const blender::OffsetIndices<int> faces,
const Span<float3> positions,
uint face_index,
MLoopTri *mlt,
MemArena **pf_arena_p,
const bool face_normal,
const float normal_precalc[3])
{
const uint mp_loopstart = uint(faces[face_index].start());
const uint mp_totloop = uint(faces[face_index].size());
auto create_tri = [&](uint i1, uint i2, uint i3) {
mlt->tri[0] = mp_loopstart + i1;
mlt->tri[1] = mp_loopstart + i2;
mlt->tri[2] = mp_loopstart + i3;
};
switch (mp_totloop) {
case 3: {
create_tri(0, 1, 2);
break;
}
case 4: {
create_tri(0, 1, 2);
MLoopTri *mlt_a = mlt++;
create_tri(0, 2, 3);
MLoopTri *mlt_b = mlt;
if (UNLIKELY(is_quad_flip_v3_first_third_fast(positions[corner_verts[mlt_a->tri[0]]],
positions[corner_verts[mlt_a->tri[1]]],
positions[corner_verts[mlt_a->tri[2]]],
positions[corner_verts[mlt_b->tri[2]]])))
{
/* Flip out of degenerate 0-2 state. */
mlt_a->tri[2] = mlt_b->tri[2];
mlt_b->tri[0] = mlt_a->tri[1];
}
break;
}
default: {
float axis_mat[3][3];
/* Calculate `axis_mat` to project verts to 2D. */
if (face_normal == false) {
float normal[3];
const float *co_curr, *co_prev;
zero_v3(normal);
/* Calc normal, flipped: to get a positive 2D cross product. */
co_prev = positions[corner_verts[mp_loopstart + mp_totloop - 1]];
for (uint j = 0; j < mp_totloop; j++) {
co_curr = positions[corner_verts[mp_loopstart + j]];
add_newell_cross_v3_v3v3(normal, co_prev, co_curr);
co_prev = co_curr;
}
if (UNLIKELY(normalize_v3(normal) == 0.0f)) {
normal[2] = 1.0f;
}
axis_dominant_v3_to_m3_negate(axis_mat, normal);
}
else {
axis_dominant_v3_to_m3_negate(axis_mat, normal_precalc);
}
const uint totfilltri = mp_totloop - 2;
MemArena *pf_arena = *pf_arena_p;
if (UNLIKELY(pf_arena == nullptr)) {
pf_arena = *pf_arena_p = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__);
}
uint(*tris)[3] = static_cast<uint(*)[3]>(
BLI_memarena_alloc(pf_arena, sizeof(*tris) * size_t(totfilltri)));
float(*projverts)[2] = static_cast<float(*)[2]>(
BLI_memarena_alloc(pf_arena, sizeof(*projverts) * size_t(mp_totloop)));
for (uint j = 0; j < mp_totloop; j++) {
mul_v2_m3v3(projverts[j], axis_mat, positions[corner_verts[mp_loopstart + j]]);
}
BLI_polyfill_calc_arena(projverts, mp_totloop, 1, tris, pf_arena);
/* Apply fill. */
for (uint j = 0; j < totfilltri; j++, mlt++) {
const uint *tri = tris[j];
create_tri(tri[0], tri[1], tri[2]);
}
BLI_memarena_clear(pf_arena);
break;
}
}
#undef ML_TO_MLT
}
static void mesh_calc_tessellation_for_face(const Span<int> corner_verts,
const blender::OffsetIndices<int> faces,
const Span<float3> positions,
uint face_index,
MLoopTri *mlt,
MemArena **pf_arena_p)
{
mesh_calc_tessellation_for_face_impl(
corner_verts, faces, positions, face_index, mlt, pf_arena_p, false, nullptr);
}
static void mesh_calc_tessellation_for_face_with_normal(const Span<int> corner_verts,
const blender::OffsetIndices<int> faces,
const Span<float3> positions,
uint face_index,
MLoopTri *mlt,
MemArena **pf_arena_p,
const float normal_precalc[3])
{
mesh_calc_tessellation_for_face_impl(
corner_verts, faces, positions, face_index, mlt, pf_arena_p, true, normal_precalc);
}
static void mesh_recalc_looptri__single_threaded(const Span<int> corner_verts,
const blender::OffsetIndices<int> faces,
const Span<float3> positions,
MLoopTri *mlooptri,
const float (*face_normals)[3])
{
MemArena *pf_arena = nullptr;
uint looptri_i = 0;
if (face_normals != nullptr) {
for (const int64_t i : faces.index_range()) {
mesh_calc_tessellation_for_face_with_normal(corner_verts,
faces,
positions,
uint(i),
&mlooptri[looptri_i],
&pf_arena,
face_normals[i]);
looptri_i += uint(faces[i].size() - 2);
}
}
else {
for (const int64_t i : faces.index_range()) {
mesh_calc_tessellation_for_face(
corner_verts, faces, positions, uint(i), &mlooptri[looptri_i], &pf_arena);
looptri_i += uint(faces[i].size() - 2);
}
}
if (pf_arena) {
BLI_memarena_free(pf_arena);
pf_arena = nullptr;
}
BLI_assert(looptri_i == uint(poly_to_tri_count(int(faces.size()), int(corner_verts.size()))));
}
struct TessellationUserData {
Span<int> corner_verts;
blender::OffsetIndices<int> faces;
Span<float3> positions;
/** Output array. */
MutableSpan<MLoopTri> mlooptri;
/** Optional pre-calculated face normals array. */
const float (*face_normals)[3];
};
struct TessellationUserTLS {
MemArena *pf_arena;
};
static void mesh_calc_tessellation_for_face_fn(void *__restrict userdata,
const int index,
const TaskParallelTLS *__restrict tls)
{
const TessellationUserData *data = static_cast<const TessellationUserData *>(userdata);
TessellationUserTLS *tls_data = static_cast<TessellationUserTLS *>(tls->userdata_chunk);
const int looptri_i = poly_to_tri_count(index, int(data->faces[index].start()));
mesh_calc_tessellation_for_face_impl(data->corner_verts,
data->faces,
data->positions,
uint(index),
&data->mlooptri[looptri_i],
&tls_data->pf_arena,
false,
nullptr);
}
static void mesh_calc_tessellation_for_face_with_normal_fn(void *__restrict userdata,
const int index,
const TaskParallelTLS *__restrict tls)
{
const TessellationUserData *data = static_cast<const TessellationUserData *>(userdata);
TessellationUserTLS *tls_data = static_cast<TessellationUserTLS *>(tls->userdata_chunk);
const int looptri_i = poly_to_tri_count(index, int(data->faces[index].start()));
mesh_calc_tessellation_for_face_impl(data->corner_verts,
data->faces,
data->positions,
uint(index),
&data->mlooptri[looptri_i],
&tls_data->pf_arena,
true,
data->face_normals[index]);
}
static void mesh_calc_tessellation_for_face_free_fn(const void *__restrict /*userdata*/,
void *__restrict tls_v)
{
TessellationUserTLS *tls_data = static_cast<TessellationUserTLS *>(tls_v);
if (tls_data->pf_arena) {
BLI_memarena_free(tls_data->pf_arena);
}
}
static void looptris_calc_all(const Span<float3> positions,
const blender::OffsetIndices<int> faces,
const Span<int> corner_verts,
const Span<float3> face_normals,
MutableSpan<MLoopTri> looptris)
{
if (corner_verts.size() < MESH_FACE_TESSELLATE_THREADED_LIMIT) {
mesh_recalc_looptri__single_threaded(corner_verts,
faces,
positions,
looptris.data(),
reinterpret_cast<const float(*)[3]>(face_normals.data()));
return;
}
TessellationUserTLS tls_data_dummy = {nullptr};
TessellationUserData data{};
data.corner_verts = corner_verts;
data.faces = faces;
data.positions = positions;
data.mlooptri = looptris;
data.face_normals = reinterpret_cast<const float(*)[3]>(face_normals.data());
TaskParallelSettings settings;
BLI_parallel_range_settings_defaults(&settings);
settings.userdata_chunk = &tls_data_dummy;
settings.userdata_chunk_size = sizeof(tls_data_dummy);
settings.func_free = mesh_calc_tessellation_for_face_free_fn;
BLI_task_parallel_range(0,
int(faces.size()),
&data,
data.face_normals ? mesh_calc_tessellation_for_face_with_normal_fn :
mesh_calc_tessellation_for_face_fn,
&settings);
}
void looptris_calc(const Span<float3> vert_positions,
const OffsetIndices<int> faces,
const Span<int> corner_verts,
MutableSpan<MLoopTri> looptris)
{
looptris_calc_all(vert_positions, faces, corner_verts, {}, looptris);
}
void looptris_calc_face_indices(const OffsetIndices<int> faces, MutableSpan<int> looptri_faces)
{
threading::parallel_for(faces.index_range(), 1024, [&](const IndexRange range) {
for (const int64_t i : range) {
const IndexRange face = faces[i];
const int start = poly_to_tri_count(int(i), int(face.start()));
const int num = face_triangles_num(int(face.size()));
looptri_faces.slice(start, num).fill(int(i));
}
});
}
void looptris_calc_with_normals(const Span<float3> vert_positions,
const OffsetIndices<int> faces,
const Span<int> corner_verts,
const Span<float3> face_normals,
MutableSpan<MLoopTri> looptris)
{
BLI_assert(!face_normals.is_empty() || faces.size() == 0);
looptris_calc_all(vert_positions, faces, corner_verts, face_normals, looptris);
}
/** \} */
} // namespace blender::bke::mesh
void BKE_mesh_recalc_looptri(const int *corner_verts,
const int *face_offsets,
const float (*vert_positions)[3],
int totvert,
int totloop,
int faces_num,
MLoopTri *mlooptri)
{
blender::bke::mesh::looptris_calc(
{reinterpret_cast<const blender::float3 *>(vert_positions), totvert},
blender::Span(face_offsets, faces_num + 1),
{corner_verts, totloop},
{mlooptri, poly_to_tri_count(faces_num, totloop)});
}