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add alternative baking algorithm

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This commit is contained in:
ExPikaPaka
2026-09-09 08:42:37 +02:00
parent e245f5d069
commit 5c7cb6bed5
12 changed files with 503 additions and 69 deletions
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4
src/libslic3r/MeshBoolean.cpp
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@@ -261,7 +261,8 @@ indexed_triangle_set cgal_to_indexed_triangle_set(const CGALMesh &cgalmesh)
// /////////////////////////////////////////////////////////////////////////////
indexed_triangle_set remesh_isotropic(const indexed_triangle_set &mesh, double target_edge_length,
unsigned n_iterations, double sharp_angle_deg)
unsigned n_iterations, double sharp_angle_deg,
unsigned n_relaxation_steps)
{
if (mesh.indices.empty() || target_edge_length <= 0.0)
return mesh;
@@ -305,6 +306,7 @@ indexed_triangle_set remesh_isotropic(const indexed_triangle_set &mesh, double t
CGALProc::isotropic_remeshing(faces(cgal_mesh), target_edge_length, cgal_mesh,
CGALParams::number_of_iterations(n_iterations)
.number_of_relaxation_steps(n_relaxation_steps)
.edge_is_constrained_map(ecm)
.protect_constraints(true));
} catch (const std::exception &) {

7
src/libslic3r/MeshBoolean.hpp
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@@ -89,8 +89,13 @@ std::optional<std::vector<Vec2f>> parameterize_lscm(const indexed_triangle_set &
// Edges whose dihedral angle exceeds `sharp_angle_deg`, and any open border, are held fixed so hard
// features survive instead of being eroded by the relaxation pass; pass 0 to remesh everything.
// Returns the input unchanged if remeshing fails (e.g. a non-manifold or self-intersecting input).
// `n_relaxation_steps` is the number of tangential relaxation passes run inside each iteration. That
// relaxation is what actually evens out the triangle distribution - splitting and collapsing alone
// only bring edge *lengths* near the target, leaving the vertices wherever they happened to land. CGAL
// defaults it to 1, which on a few iterations is not enough to look uniform.
indexed_triangle_set remesh_isotropic(const indexed_triangle_set &mesh, double target_edge_length,
unsigned n_iterations = 3, double sharp_angle_deg = 40.0);
unsigned n_iterations = 3, double sharp_angle_deg = 40.0,
unsigned n_relaxation_steps = 1);
}
namespace mcut {

89
src/libslic3r/TextureBake/TextureBakeDecimate.cpp
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@@ -6,6 +6,11 @@
#include <limits>
#include <queue>
#include <boost/log/trivial.hpp>
#include <tbb/blocked_range.h>
#include <tbb/parallel_for.h>
namespace Slic3r {
namespace TextureBake {
@@ -74,13 +79,19 @@ Vec3d face_normal_unit(const std::vector<Vec3d> &pos, int a, int b, int c)
}
// Versions are captured at push time; a mismatch on pop means a later collapse invalidated the entry.
// Lazy deletion, far cheaper than removing entries eagerly.
// Lazy deletion, far cheaper than removing entries eagerly - but it means the heap accumulates stale
// duplicates, so it grows to several times the edge count and its size has to be reserved up front.
// Left to grow on its own it reallocates and copies the whole array repeatedly, which on a
// multi-million-entry heap costs more than every collapse put together.
//
// The collapse target is stored as float rather than double: it is a position on a mesh already held
// in float, and halving the entry cuts the memory the sift operations drag through cache.
struct HeapEntry
{
double cost;
int v1, v2;
uint32_t ver1, ver2;
Vec3d p;
Vec3f p;
bool operator>(const HeapEntry &o) const { return cost > o.cost; }
};
@@ -143,16 +154,29 @@ DecimateResult decimate(const TriSoup &geometry, size_t target_triangles, bool h
}
std::vector<Quadric> quadrics(vert_count);
for (size_t f = 0; f < face_count; ++f) {
const int a = faces[f * 3], b = faces[f * 3 + 1], c = faces[f * 3 + 2];
if (a < 0)
continue;
const Vec3d nrm = face_normal_unit(pos, a, b, c);
if (nrm.isZero())
continue;
const double d = -nrm.dot(pos[size_t(a)]);
for (const int v : { a, b, c })
quadrics[size_t(v)].add_plane(nrm.x(), nrm.y(), nrm.z(), d);
{
// The plane per face is independent; accumulating it into the three incident vertices is not,
// so only the first half is parallel.
std::vector<Vec4d> planes(face_count, Vec4d::Zero());
tbb::parallel_for(tbb::blocked_range<size_t>(0, face_count),
[&](const tbb::blocked_range<size_t> &range) {
for (size_t f = range.begin(); f < range.end(); ++f) {
const int a = faces[f * 3], b = faces[f * 3 + 1], c = faces[f * 3 + 2];
if (a < 0)
continue;
const Vec3d nrm = face_normal_unit(pos, a, b, c);
if (nrm.isZero())
continue;
planes[f] = Vec4d(nrm.x(), nrm.y(), nrm.z(), -nrm.dot(pos[size_t(a)]));
}
});
for (size_t f = 0; f < face_count; ++f) {
const Vec4d &pl = planes[f];
if (pl.head<3>().isZero())
continue;
for (int k = 0; k < 3; ++k)
quadrics[size_t(faces[f * 3 + size_t(k)])].add_plane(pl.x(), pl.y(), pl.z(), pl.w());
}
}
// Two penalty planes per endpoint on a sharp interior edge, each perpendicular to one adjacent
@@ -250,7 +274,22 @@ DecimateResult decimate(const TriSoup &geometry, size_t target_triangles, bool h
uint32_t epoch = 1, lk_epoch = 1;
size_t active_faces = face_count;
std::priority_queue<HeapEntry, std::vector<HeapEntry>, std::greater<HeapEntry>> heap;
// A plain vector driven by the heap algorithms, so the capacity can be reserved. Lazy deletion
// means roughly one entry per edge plus one per re-push after each collapse; the reserve below is
// sized from the edge count and simply grows if a mesh needs more.
std::vector<HeapEntry> heap;
heap.reserve(std::min<size_t>(face_count * 3, size_t(1) << 24));
const auto heap_push = [&](HeapEntry e) {
heap.push_back(e);
std::push_heap(heap.begin(), heap.end(), std::greater<HeapEntry>());
};
const auto heap_pop = [&]() {
std::pop_heap(heap.begin(), heap.end(), std::greater<HeapEntry>());
const HeapEntry e = heap.back();
heap.pop_back();
return e;
};
size_t pops = 0, stale_pops = 0;
const auto push_edge = [&](int v1, int v2) {
Vec3d p;
@@ -269,8 +308,8 @@ DecimateResult decimate(const TriSoup &geometry, size_t target_triangles, bool h
}
// Where quadric costs are all near zero, shorter edges first keeps triangle quality up.
const double len2 = (pos[size_t(v2)] - pos[size_t(v1)]).squaredNorm();
heap.push({ eval_sum(quadrics, v1, v2, p) + len2 * 1e-8, v1, v2, version[size_t(v1)],
version[size_t(v2)], p });
heap_push({ eval_sum(quadrics, v1, v2, p) + len2 * 1e-8, v1, v2, version[size_t(v1)],
version[size_t(v2)], p.cast<float>() });
};
{
@@ -384,27 +423,32 @@ DecimateResult decimate(const TriSoup &geometry, size_t target_triangles, bool h
reached_target = true;
}
const HeapEntry top = heap.top();
heap.pop();
const HeapEntry top = heap_pop();
++pops;
// The popped entry is the cheapest left, so exceeding the tolerance ends the run.
if (reached_target && top.cost > harvest_ceil)
break;
const int v1 = top.v1, v2 = top.v2;
if (!active[size_t(v1)] || !active[size_t(v2)])
if (!active[size_t(v1)] || !active[size_t(v2)]) {
++stale_pops;
continue;
if (version[size_t(v1)] != top.ver1 || version[size_t(v2)] != top.ver2)
}
if (version[size_t(v1)] != top.ver1 || version[size_t(v2)] != top.ver2) {
++stale_pops;
continue;
}
if (shared_face_count(v1, v2) < 2)
continue;
lk_epoch += 2; // +2 so ep and ep+1 cannot collide with the next call
if (has_link_violation(v1, v2, lk_epoch))
continue;
if (check_flipped(v1, v2, top.p) || check_flipped(v2, v1, top.p))
const Vec3d target = top.p.cast<double>();
if (check_flipped(v1, v2, target) || check_flipped(v2, v1, target))
continue;
// v1 survives at the new position, v2 goes.
pos[size_t(v1)] = top.p;
pos[size_t(v1)] = target;
quadrics[size_t(v1)] += quadrics[size_t(v2)];
++version[size_t(v1)];
@@ -459,6 +503,9 @@ DecimateResult decimate(const TriSoup &geometry, size_t target_triangles, bool h
}
}
BOOST_LOG_TRIVIAL(info) << "TextureBake decimate: pops=" << pops << " stale=" << stale_pops
<< " heap_peak=" << heap.capacity() << " faces=" << active_faces;
// Rebuild from the surviving faces, with per-face normals.
TriSoup &out = result.geometry;
for (size_t f = 0; f < face_count; ++f) {

54
src/libslic3r/TextureBake/TextureBakeDisplace.cpp
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@@ -4,6 +4,9 @@
#include <cmath>
#include <limits>
#include <tbb/blocked_range.h>
#include <tbb/parallel_for.h>
namespace Slic3r {
namespace TextureBake {
@@ -204,20 +207,30 @@ TriSoup apply_displacement(const TriSoup &geometry, const HeightSampleFn &sample
}
}
// Pass 2: one sample per unique position.
std::vector<double> grey(unique_count, 0.0);
std::vector<uint8_t> grey_set(unique_count, 0);
for (size_t i = 0; i < count; ++i) {
const size_t vid = size_t(vertex_id[i]);
if (grey_set[vid])
continue;
grey_set[vid] = 1;
grey[vid] = double(sample(geometry.pos[i], smooth_nrm[vid].cast<float>(),
blend_nrm[vid].cast<float>()));
}
// Pass 2: one sample per unique position. A representative corner is picked first so the sampling
// itself is a flat parallel loop - it is a texture fetch plus projection maths per layer, and by
// far the most expensive thing in this stage.
std::vector<double> grey(unique_count, 0.0);
std::vector<int> representative(unique_count, -1);
for (size_t i = 0; i < count; ++i)
if (representative[size_t(vertex_id[i])] < 0)
representative[size_t(vertex_id[i])] = int(i);
tbb::parallel_for(tbb::blocked_range<size_t>(0, unique_count),
[&](const tbb::blocked_range<size_t> &range) {
for (size_t vid = range.begin(); vid < range.end(); ++vid) {
const int rep = representative[vid];
if (rep < 0)
continue;
grey[vid] = double(sample(geometry.pos[size_t(rep)],
smooth_nrm[vid].cast<float>(),
blend_nrm[vid].cast<float>()));
}
});
// Pass 3: move every copy of a position by the identical vector.
for (size_t i = 0; i < count; ++i) {
// Pass 3: move every copy of a position by the identical vector. Each iteration writes only its
// own output slot, so the loop is independent per corner.
tbb::parallel_for(tbb::blocked_range<size_t>(0, count), [&](const tbb::blocked_range<size_t> &range) {
for (size_t i = range.begin(); i < range.end(); ++i) {
const Vec3f &p = geometry.pos[i];
const size_t vid = size_t(vertex_id[i]);
@@ -249,17 +262,18 @@ TriSoup apply_displacement(const TriSoup &geometry, const HeightSampleFn &sample
moved.z() = double(p.z());
out.pos[i] = moved.cast<float>();
if (on_progress && (i % 5000) == 0 && !on_progress(double(i) / double(count)))
return geometry; // cancelled: hand back the input untouched
}
});
// Per-face, not averaged across shared positions: averaging can flip an excluded face's normal
// when its neighbours moved outward.
for (size_t t = 0; t + 2 < count; t += 3) {
const Vec3f n = (out.pos[t + 1] - out.pos[t]).cross(out.pos[t + 2] - out.pos[t]).normalized();
out.nrm[t] = out.nrm[t + 1] = out.nrm[t + 2] = n;
}
tbb::parallel_for(tbb::blocked_range<size_t>(0, count / 3), [&](const tbb::blocked_range<size_t> &r) {
for (size_t f = r.begin(); f < r.end(); ++f) {
const size_t t = f * 3;
const Vec3f n = (out.pos[t + 1] - out.pos[t]).cross(out.pos[t + 2] - out.pos[t]).normalized();
out.nrm[t] = out.nrm[t + 1] = out.nrm[t + 2] = n;
}
});
out.exclude_weight = geometry.exclude_weight;
return out;
}

39
src/libslic3r/TextureBake/TextureBakePipeline.cpp
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@@ -1,8 +1,11 @@
#include "TextureBakePipeline.hpp"
#include <algorithm>
#include <chrono>
#include <cmath>
#include <boost/log/trivial.hpp>
namespace Slic3r {
namespace TextureBake {
@@ -111,6 +114,15 @@ PipelineResult run_pipeline(const TriSoup &input, const HeightSampleFn &sample,
const auto report = [&](const char *stage, double f) {
return !on_progress || on_progress(stage, f);
};
// Per-stage wall time. The stages differ in cost by orders of magnitude depending on the model, so
// without this it is guesswork which one to attack.
auto clock_now = [] { return std::chrono::steady_clock::now(); };
auto t_stage = clock_now();
const auto lap = [&](const char *stage, size_t tris) {
const double ms = std::chrono::duration<double, std::milli>(clock_now() - t_stage).count();
BOOST_LOG_TRIVIAL(info) << "TextureBake " << stage << ": " << ms << " ms, " << tris << " tris";
t_stage = clock_now();
};
if (input.empty() || !sample) {
result.geometry = input;
@@ -122,6 +134,7 @@ PipelineResult run_pipeline(const TriSoup &input, const HeightSampleFn &sample,
input, settings.refine_length, face_excluded, /* fast */ false, settings.safety_cap,
[&](double f, size_t, double) { return report("subdivide", f); });
result.safety_cap_hit = sub.safety_cap_hit;
lap("subdivide", sub.geometry.triangle_count());
if (!report("subdivide", 1.0)) {
result.canceled = true;
return result;
@@ -134,6 +147,7 @@ PipelineResult run_pipeline(const TriSoup &input, const HeightSampleFn &sample,
RegularizeResult reg = regularize_mesh(sub.geometry, sub.face_parent_id,
settings.refine_length, ropts);
result.collapse_count = reg.collapse_count;
lap("regularize", reg.geometry.triangle_count());
if (!report("regularize", 1.0)) {
result.canceled = true;
return result;
@@ -159,15 +173,31 @@ PipelineResult run_pipeline(const TriSoup &input, const HeightSampleFn &sample,
? reg.face_parent_id[size_t(mid)] : -1;
}
sub.face_parent_id = std::move(composed);
lap("re-subdivide", sub.geometry.triangle_count());
} else {
sub.geometry = std::move(reg.geometry);
sub.face_parent_id = std::move(reg.face_parent_id);
}
}
// 3. Displace.
// 3. Align the mesh to the height field's edges, then displace.
if (settings.relocate) {
std::vector<uint8_t> locked;
if (settings.preserve_untextured && !sub.geometry.exclude_weight.empty()) {
locked.assign(sub.geometry.triangle_count(), 0);
for (size_t t = 0; t < locked.size(); ++t)
locked[t] = sub.geometry.exclude_weight[t * 3] > 0.99f ? 1 : 0;
}
RelocateResult rel = relocate_to_contours(sub.geometry, sample, settings.relocate_opts, locked);
BOOST_LOG_TRIVIAL(info) << "TextureBake relocate: moved=" << rel.moved
<< " rejected=" << rel.rejected;
sub.geometry = std::move(rel.geometry);
lap("relocate", sub.geometry.triangle_count());
}
TriSoup displaced = apply_displacement(sub.geometry, sample, settings.displace, bounds,
[&](double f) { return report("displace", f); });
lap("displace", displaced.triangle_count());
if (!report("displace", 1.0)) {
result.canceled = true;
return result;
@@ -189,6 +219,7 @@ PipelineResult run_pipeline(const TriSoup &input, const HeightSampleFn &sample,
[&](double f) { return report("decimate", f); });
result.locked_over_budget = dec.locked_over_budget;
displaced = std::move(dec.geometry);
lap("decimate", displaced.triangle_count());
parent.clear(); // no longer meaningful
}
if (!report("decimate", 1.0)) {
@@ -198,14 +229,16 @@ PipelineResult run_pipeline(const TriSoup &input, const HeightSampleFn &sample,
}
// 5. Flatten the bed-contact surface.
if (settings.displace.bottom_angle_limit > 0.f)
if (settings.clamp_below_plate || settings.displace.bottom_angle_limit > 0.f)
clamp_below_bottom(displaced, bounds.min.z());
if (settings.bottom_snap_tol > 0.0)
snap_bottom_to_flat(displaced, bounds.min.z(), settings.bottom_snap_tol);
// 6. Close the T-junctions decimation left behind. Only meaningful when it ran.
if (mode == PipelineMode::Export && parent.empty())
if (mode == PipelineMode::Export && parent.empty()) {
displaced = resolve_t_junctions(displaced);
lap("repair", displaced.triangle_count());
}
result.geometry = std::move(displaced);
result.face_parent_id = std::move(parent);

12
src/libslic3r/TextureBake/TextureBakePipeline.hpp
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@@ -2,7 +2,7 @@
// The bake pipeline:
//
// subdivide -> [regularize -> re-subdivide] -> displace -> [decimate]
// subdivide -> [regularize -> re-subdivide] -> [relocate] -> displace -> [decimate]
// -> bottom clamp -> bottom snap -> [resolve T-junctions]
//
// Regularization sits between two subdivisions on purpose: it dissolves the slivers refinement
@@ -21,6 +21,7 @@
#include "TextureBakeDisplace.hpp"
#include "TextureBakeIndex.hpp"
#include "TextureBakeRegularize.hpp"
#include "TextureBakeRelocate.hpp"
#include "TextureBakeRepair.hpp"
#include "TextureBakeSubdivide.hpp"
@@ -47,6 +48,11 @@ struct PipelineSettings
// re-refining what it just merged.
double regularize_second_pass_mul = 1.1;
// Slide vertices onto the height map's own edges before displacing, so a step lands on a mesh
// edge instead of being quantised to wherever the grid fell.
bool relocate = false;
RelocateSettings relocate_opts;
DisplaceSettings displace;
// Export mode only.
@@ -56,6 +62,10 @@ struct PipelineSettings
// Lock the untextured region against both regularization and decimation.
bool preserve_untextured = true;
// Push anything that displaced below the plate back up to it. Downward movement is otherwise left
// alone, so relief on the underside is kept - only what would sink through the plate is stopped.
bool clamp_below_plate = false;
// Snap vertices within this of the bottom plane onto it. 0 disables.
double bottom_snap_tol = 0.1;

205
src/libslic3r/TextureBake/TextureBakeRelocate.cpp Normal file
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@@ -0,0 +1,205 @@
#include "TextureBakeRelocate.hpp"
#include <algorithm>
#include <cmath>
#include <limits>
#include <tbb/blocked_range.h>
#include <tbb/parallel_for.h>
namespace Slic3r {
namespace TextureBake {
namespace {
// Any two unit vectors orthogonal to n. Which two does not matter - the gradient is expressed in this
// basis and converted straight back, so the result is basis independent.
void tangent_basis(const Vec3f &n, Vec3f &t1, Vec3f &t2)
{
const Vec3f a = (std::abs(n.x()) < 0.9f) ? Vec3f(1.f, 0.f, 0.f) : Vec3f(0.f, 1.f, 0.f);
t1 = n.cross(a).normalized();
t2 = n.cross(t1).normalized();
}
} // namespace
RelocateResult relocate_to_contours(const TriSoup &geometry, const HeightSampleFn &sample,
const RelocateSettings &settings, const std::vector<uint8_t> &locked)
{
RelocateResult result;
result.geometry = geometry;
const size_t count = geometry.pos.size();
const size_t tri_ct = count / 3;
if (count == 0 || !sample || settings.iterations <= 0)
return result;
// Weld, so every copy of a position moves together and the mesh cannot come apart.
QuantizedPointMap weld(WELD_GRID_GEOMETRY, std::min(count, size_t(1) << 22));
std::vector<int> vid(count);
std::vector<Vec3f> pos;
for (size_t i = 0; i < count; ++i) {
vid[i] = weld.get_or_set(geometry.pos[i], int(pos.size()));
if (weld.inserted())
pos.push_back(geometry.pos[i]);
}
const size_t nv = pos.size();
// Incident corners per position, CSR style, plus the mean incident edge length that sets the scale
// for both the finite difference and the move limit.
std::vector<uint32_t> start(nv + 1, 0);
for (size_t i = 0; i < count; ++i)
++start[size_t(vid[i]) + 1];
for (size_t v = 0; v < nv; ++v)
start[v + 1] += start[v];
std::vector<uint32_t> inc(count), cursor(nv, 0);
for (size_t i = 0; i < count; ++i)
inc[start[size_t(vid[i])] + cursor[size_t(vid[i])]++] = uint32_t(i);
std::vector<uint8_t> frozen(nv, 0);
if (!locked.empty())
for (size_t t = 0; t < tri_ct && t < locked.size(); ++t)
if (locked[t])
for (int k = 0; k < 3; ++k)
frozen[size_t(vid[t * 3 + size_t(k)])] = 1;
std::vector<float> edge_len(nv, 0.f), normal_len(nv, 0.f);
std::vector<Vec3f> nrm(nv, Vec3f::Zero());
const auto rebuild_frames = [&]() {
std::fill(nrm.begin(), nrm.end(), Vec3f::Zero());
std::fill(edge_len.begin(), edge_len.end(), 0.f);
std::vector<uint32_t> deg(nv, 0);
for (size_t t = 0; t < tri_ct; ++t) {
const int a = vid[t * 3], b = vid[t * 3 + 1], c = vid[t * 3 + 2];
const Vec3f fn = (pos[size_t(b)] - pos[size_t(a)]).cross(pos[size_t(c)] - pos[size_t(a)]);
for (int k = 0; k < 3; ++k) {
const int u = vid[t * 3 + size_t(k)], w = vid[t * 3 + size_t((k + 1) % 3)];
nrm[size_t(u)] += fn;
edge_len[size_t(u)] += (pos[size_t(w)] - pos[size_t(u)]).norm();
++deg[size_t(u)];
}
}
for (size_t v = 0; v < nv; ++v) {
const float l = nrm[v].norm();
nrm[v] = (l > 0.f) ? Vec3f(nrm[v] / l) : Vec3f(0.f, 0.f, 1.f);
edge_len[v] = deg[v] > 0 ? edge_len[v] / float(deg[v]) : 0.f;
}
};
rebuild_frames();
// The level to snap onto, taken from the height actually present on this patch rather than assumed.
// A texture that never reaches full black or white would otherwise be measured against a range it
// does not occupy.
double h_lo = std::numeric_limits<double>::max(), h_hi = -h_lo;
{
std::vector<float> h0(nv, 0.f);
tbb::parallel_for(tbb::blocked_range<size_t>(0, nv), [&](const tbb::blocked_range<size_t> &r) {
for (size_t v = r.begin(); v < r.end(); ++v)
h0[v] = sample(pos[v], nrm[v], nrm[v]);
});
for (const float h : h0) {
h_lo = std::min(h_lo, double(h));
h_hi = std::max(h_hi, double(h));
}
}
const double h_range = h_hi - h_lo;
if (!(h_range > 0.0))
return result; // a flat height field has no contour to snap to
const double target = h_lo + h_range * settings.contour_level;
// A gradient is worth acting on when the height changes by this much across one edge length.
const double min_grad = h_range * settings.min_gradient_fraction;
std::vector<uint8_t> ever_moved(nv, 0);
for (int iter = 0; iter < settings.iterations; ++iter) {
std::vector<Vec3f> proposal(nv);
std::vector<uint8_t> want(nv, 0);
tbb::parallel_for(tbb::blocked_range<size_t>(0, nv), [&](const tbb::blocked_range<size_t> &r) {
for (size_t v = r.begin(); v < r.end(); ++v) {
if (frozen[v] || edge_len[v] <= 0.f)
continue;
const Vec3f n = nrm[v];
Vec3f t1, t2;
tangent_basis(n, t1, t2);
const float eps = edge_len[v] * float(settings.gradient_step_fraction);
if (eps <= 0.f)
continue;
// Central differences in the tangent plane. Sampling the field itself, not the mesh,
// so the gradient is the image's, at whatever resolution the mesh happens to have.
const double h = double(sample(pos[v], n, n));
const double gx = (double(sample(pos[v] + t1 * eps, n, n)) -
double(sample(pos[v] - t1 * eps, n, n))) / (2.0 * double(eps));
const double gy = (double(sample(pos[v] + t2 * eps, n, n)) -
double(sample(pos[v] - t2 * eps, n, n))) / (2.0 * double(eps));
const double g2 = gx * gx + gy * gy;
if (g2 <= 0.0)
continue;
// Scale-free test: how much the height changes across one edge, versus the patch range.
if (std::sqrt(g2) * double(edge_len[v]) < min_grad)
continue;
// Newton step onto the level set h = target, expressed back in 3D.
const double s = -(h - target) / g2;
Vec3f d = t1 * float(s * gx) + t2 * float(s * gy);
const float cap = edge_len[v] * float(settings.max_move_fraction);
const float len = d.norm();
if (len <= 0.f)
continue;
if (len > cap)
d *= cap / len;
proposal[v] = pos[v] + d;
want[v] = 1;
}
});
// Apply one at a time: a move is only valid against the neighbourhood as it stands, and two
// adjacent vertices moving together can invert a triangle neither would have on its own.
size_t applied = 0;
for (size_t v = 0; v < nv; ++v) {
if (!want[v])
continue;
const Vec3f old = pos[v];
pos[v] = proposal[v];
bool ok = true;
for (uint32_t k = start[v]; k < start[v + 1] && ok; ++k) {
const size_t t = size_t(inc[k]) / 3;
const Vec3f &a = pos[size_t(vid[t * 3])];
const Vec3f n2 = (pos[size_t(vid[t * 3 + 1])] - a).cross(pos[size_t(vid[t * 3 + 2])] - a);
// Compared against the frame this vertex carried before the move: a triangle that
// flips or collapses means the move crossed a neighbour.
if (n2.squaredNorm() <= 0.f || n2.normalized().dot(nrm[v]) < 0.f)
ok = false;
}
if (ok) {
++applied;
ever_moved[v] = 1;
} else {
pos[v] = old;
++result.rejected;
}
}
if (applied == 0)
break;
rebuild_frames();
}
for (size_t v = 0; v < nv; ++v)
if (ever_moved[v])
++result.moved;
// Write the relocated positions back to every copy, and rebuild the per-face normals.
for (size_t i = 0; i < count; ++i)
result.geometry.pos[i] = pos[size_t(vid[i])];
for (size_t t = 0; t < tri_ct; ++t) {
Vec3f n = (result.geometry.pos[t * 3 + 1] - result.geometry.pos[t * 3])
.cross(result.geometry.pos[t * 3 + 2] - result.geometry.pos[t * 3]);
const float len = n.norm();
n = (len > 0.f) ? Vec3f(n / len) : Vec3f(0.f, 0.f, 1.f);
result.geometry.nrm[t * 3] = result.geometry.nrm[t * 3 + 1] = result.geometry.nrm[t * 3 + 2] = n;
}
return result;
}
} // namespace TextureBake
} // namespace Slic3r

72
src/libslic3r/TextureBake/TextureBakeRelocate.hpp Normal file
View File

@@ -0,0 +1,72 @@
#pragma once
// Tangential relocation: slide vertices along the surface so triangle edges land on the height map's
// own edges, before any displacement happens.
//
// Displacement moves vertices along the normal only, so a step in the height map - the wall of a
// mortar groove, the rim of an embossed shape - is reproduced wherever the triangle grid happens to
// fall, as a staircase quantised to triangle boundaries. Refining further only makes the steps
// smaller; it never straightens them, because the edge in the image still does not coincide with any
// edge in the mesh.
//
// This pass fixes the cause rather than the symptom. For a vertex sitting near a step it takes a
// Newton step onto the contour: with h the sampled height and g its tangential gradient, the move
//
// d = -(h - target) * g / |g|^2
//
// lands on the level set h = target to first order. The ring of vertices nearest each step therefore
// snaps onto it, the triangle edges between them follow the step, and the displaced result has a
// straight wall instead of a sawtooth.
//
// Vertices in flat regions have no gradient to speak of and are left alone, so the pass costs nothing
// where there is nothing to align.
#include <cstdint>
#include <functional>
#include <vector>
#include "TextureBakeDisplace.hpp"
#include "TextureBakeIndex.hpp"
namespace Slic3r {
namespace TextureBake {
struct RelocateSettings
{
// Passes. Each is a Newton step, so a couple converge for vertices that start reasonably close;
// more mainly helps ones that begin further away.
int iterations = 3;
// How far a vertex may move in one pass, as a fraction of the mean length of its incident edges.
// Below a half it cannot pass a neighbour, which is what keeps the triangulation valid without
// needing a full topological check.
double max_move_fraction = 0.35;
// A vertex is only pulled when the height varies enough across its own footprint to mean
// something - as a fraction of the height range over the whole patch. Below this the gradient is
// noise, and chasing it would scramble flat regions.
double min_gradient_fraction = 0.05;
// The level to snap onto, as a position in the sampled height range: 0.5 is midway between the
// lowest and highest point of the relief, which is where the wall of a step is steepest.
double contour_level = 0.5;
// Sampling offset for the finite-difference gradient, as a fraction of the local edge length.
double gradient_step_fraction = 0.25;
};
struct RelocateResult
{
TriSoup geometry;
size_t moved = 0; // positions that were relocated at least once
size_t rejected = 0; // moves refused because a triangle would have inverted
};
// `locked`, when non-empty, has one entry per input triangle; a vertex touching a locked triangle is
// never moved, so an excluded region keeps its exact vertex positions.
RelocateResult relocate_to_contours(const TriSoup &geometry, const HeightSampleFn &sample,
const RelocateSettings &settings = {},
const std::vector<uint8_t> &locked = {});
} // namespace TextureBake
} // namespace Slic3r

47
src/libslic3r/TextureBake/TextureBakeSubdivide.cpp
View File

@@ -4,6 +4,10 @@
#include <cmath>
#include <unordered_map>
#include <tbb/blocked_range.h>
#include <tbb/parallel_for.h>
#include <tbb/parallel_reduce.h>
namespace Slic3r {
namespace TextureBake {
@@ -104,13 +108,18 @@ PassResult subdivide_pass(VertStore &verts, const std::vector<int> &indices, dou
return out; // changed stays false: nothing left to refine
}
// Step 1.5.
size_t predicted = 0;
for (size_t t = 0; t < tri_count; ++t) {
const int a = indices[t * 3], b = indices[t * 3 + 1], c = indices[t * 3 + 2];
const int n = int(is_marked(a, b)) + int(is_marked(b, c)) + int(is_marked(c, a));
predicted += (n == 0) ? 1 : size_t(n + 1);
}
// Step 1.5. Read-only against the finished mark set, so it reduces in parallel.
const size_t predicted = tbb::parallel_reduce(
tbb::blocked_range<size_t>(0, tri_count), size_t(0),
[&](const tbb::blocked_range<size_t> &range, size_t acc) {
for (size_t t = range.begin(); t < range.end(); ++t) {
const int a = indices[t * 3], b = indices[t * 3 + 1], c = indices[t * 3 + 2];
const int n = int(is_marked(a, b)) + int(is_marked(b, c)) + int(is_marked(c, a));
acc += (n == 0) ? 1 : size_t(n + 1);
}
return acc;
},
std::plus<size_t>());
if (predicted > size_t(safety_cap)) {
out.indices = indices;
out.face_excluded = face_excluded;
@@ -255,18 +264,20 @@ IndexedMesh to_indexed(const TriSoup &geometry)
// Per-face normals: unit for the angle test, raw for the area-weighted accumulation.
std::vector<Vec3d> face_unit(n), face_raw(n);
for (size_t t = 0; t + 2 < n; t += 3) {
const Vec3d a = geometry.pos[t].cast<double>();
const Vec3d b = geometry.pos[t + 1].cast<double>();
const Vec3d c = geometry.pos[t + 2].cast<double>();
const Vec3d r = (b - a).cross(c - a);
const double len = r.norm();
const Vec3d u = (len > 0.0) ? Vec3d(r / len) : Vec3d(0.0, 0.0, 1.0);
for (int v = 0; v < 3; ++v) {
face_unit[t + size_t(v)] = u;
face_raw[t + size_t(v)] = r;
tbb::parallel_for(tbb::blocked_range<size_t>(0, n / 3), [&](const tbb::blocked_range<size_t> &range) {
for (size_t f = range.begin(); f < range.end(); ++f) {
const size_t t = f * 3;
const Vec3d a = geometry.pos[t].cast<double>();
const Vec3d r = (geometry.pos[t + 1].cast<double>() - a).cross(
geometry.pos[t + 2].cast<double>() - a);
const double len = r.norm();
const Vec3d u = (len > 0.0) ? Vec3d(r / len) : Vec3d(0.0, 0.0, 1.0);
for (int v = 0; v < 3; ++v) {
face_unit[t + size_t(v)] = u;
face_raw[t + size_t(v)] = r;
}
}
}
});
out.indices.resize(n);
out.pos_canon_map = QuantizedPointMap(WELD_GRID_GEOMETRY, std::min(n, size_t(1) << 22));

5
src/libslic3r/TextureDisplacement.cpp
View File

@@ -1405,12 +1405,17 @@ indexed_triangle_set build_texture_displacement_v2(const indexed_triangle_set
settings.regularize = options.v2_regularize;
settings.max_triangles = size_t(std::max(0, options.v2_max_triangles_k)) * 1000;
settings.preserve_untextured = true;
settings.clamp_below_plate = options.v2_clamp_below_plate;
settings.relocate = options.v2_relocate;
// The sampler already returns millimetres, so the displacement stage must not scale it again.
settings.displace.amplitude = 1.f;
settings.displace.symmetric = false;
// The paint decides what moves here, so the angle limits stay off.
settings.displace.bottom_angle_limit = 0.f;
settings.displace.top_angle_limit = 0.f;
// The sampler above takes the smooth normal, never the smoothed blend normal, so computing the
// latter would build a full adjacency graph and run its iterations for a value nothing reads.
settings.displace.blend_normal_smoothing = 0;
TextureBake::DisplaceBounds bounds;
bounds.min = bounds.max = mesh.vertices.empty() ? Vec3f::Zero() : mesh.vertices.front();

11
src/libslic3r/TextureDisplacement.hpp
View File

@@ -373,6 +373,13 @@ struct TextureDisplacementOptions
float v2_refine_mm = 0.3f;
bool v2_regularize = false;
int v2_max_triangles_k = 750; // 0 skips simplification, which is worth comparing on its own
// Stop displacement pushing geometry through the build plate. Only what would end up below the
// model's own bottom is moved; downward relief above that is untouched.
bool v2_clamp_below_plate = false;
// Slide vertices onto the texture's own edges before displacing. Displacement moves vertices along
// the normal only, so without this a step in the image is reproduced wherever the triangle grid
// happens to fall, as a staircase rather than a straight wall.
bool v2_relocate = false;
// Colour, all of which belongs to the stack rather than to any one layer: it is about how the
// printer will realise the colours, not about which image they came from.
@@ -390,8 +397,8 @@ struct TextureDisplacementOptions
{
int mix_mode = int(color_mix_mode);
ar(displace_border, smooth_enabled, smooth_strength, smooth_iterations, smooth_skip_border,
pipeline_v2, v2_refine_mm, v2_regularize, v2_max_triangles_k, color_mix_enabled, mix_mode,
color_despeckle);
pipeline_v2, v2_refine_mm, v2_regularize, v2_max_triangles_k, v2_clamp_below_plate,
v2_relocate, color_mix_enabled, mix_mode, color_despeckle);
color_mix_mode = ColorMixMode(mix_mode);
}
};

27
src/slic3r/GUI/Gizmos/GLGizmoTextureDisplacement.cpp
View File

@@ -3828,8 +3828,13 @@ bool GLGizmoTextureDisplacement::plan_remesh(const indexed_triangle_set &src, fl
target_edge_mm = float(budget_edge);
}
indexed_triangle_set remeshed =
MeshBoolean::cgal::remesh_isotropic(src, double(target_edge_mm), 3, double(sharp_angle_deg));
// Five iterations with three relaxation passes each, rather than CGAL's three-and-one. Splitting
// and collapsing bring edge lengths near the target but leave the vertices where they fell, so it
// is the relaxation count that decides how even the result looks - and three passes in total was
// nowhere near enough. Fifteen costs proportionally more, but only on an explicit Remesh.
indexed_triangle_set remeshed = MeshBoolean::cgal::remesh_isotropic(
src, double(target_edge_mm), /* iterations */ 5, double(sharp_angle_deg),
/* relaxation steps */ 3);
// remesh_isotropic() signals failure by handing the input straight back, so compare against it
// structurally. Vertex count alone is not enough: a remesh that only redistributes triangles at
// roughly the current density legitimately lands on the same count, and treating that as failure
@@ -5405,6 +5410,24 @@ void GLGizmoTextureDisplacement::on_render_input_window(float x, float y, float
"simplification off, which is worth comparing on its own."),
m_imgui->scaled(20.f));
ImGui::PopItemWidth();
m_preview_params_dirty |= ImGui::Checkbox(_u8L("Keep above build plate").c_str(),
&opts.v2_clamp_below_plate);
if (ImGui::IsItemHovered())
m_imgui->tooltip(_u8L("Push anything the displacement drove below the build plate back up to it. "
"Only geometry that would end up under the model's own bottom is moved - "
"relief that goes downward but stays above the plate is left as it is."),
m_imgui->scaled(20.f));
m_preview_params_dirty |= ImGui::Checkbox(_u8L("Align mesh to texture edges").c_str(),
&opts.v2_relocate);
if (ImGui::IsItemHovered())
m_imgui->tooltip(_u8L("Slide vertices sideways onto the edges in the texture before displacing them. "
"Displacement can only move vertices up and down, so without this a sharp step "
"in the image lands wherever the triangles happen to be and comes out as a "
"staircase. Moving the vertices onto the step first gives a straight wall at the "
"same triangle count."),
m_imgui->scaled(20.f));
m_preview_params_dirty |= ImGui::Checkbox(_u8L("Clean up slivers").c_str(), &opts.v2_regularize);
if (ImGui::IsItemHovered())
m_imgui->tooltip(_u8L("Collapse the thin triangles refinement inherits from the model's own "