Add alternative backe pipeline

src/libslic3r/TextureBake/TextureBakeMesh.cpp

@@ -0,0 +1,62 @@
+#include "TextureBakeMesh.hpp"
+
+#include <algorithm>
+
+namespace Slic3r {
+namespace TextureBake {
+
+TriSoup to_soup(const indexed_triangle_set &its, const std::vector<uint8_t> &face_excluded)
+{
+    TriSoup      out;
+    const size_t n = its.indices.size();
+    out.pos.resize(n * 3);
+    out.nrm.resize(n * 3);
+    const bool have_excl = face_excluded.size() == n;
+    if (have_excl)
+        out.exclude_weight.resize(n * 3);
+
+    for (size_t t = 0; t < n; ++t) {
+        const stl_triangle_vertex_indices &tri = its.indices[t];
+        const Vec3f a = its.vertices[size_t(tri[0])];
+        const Vec3f b = its.vertices[size_t(tri[1])];
+        const Vec3f c = its.vertices[size_t(tri[2])];
+        Vec3f       nrm = (b - a).cross(c - a);
+        const float len = nrm.norm();
+        nrm = (len > 0.f) ? Vec3f(nrm / len) : Vec3f(0.f, 0.f, 1.f);
+        out.pos[t * 3]     = a;
+        out.pos[t * 3 + 1] = b;
+        out.pos[t * 3 + 2] = c;
+        // Per-face on purpose: the accurate indexer derives smooth normals and splits at sharp edges
+        // itself, so averaged ones would pre-empt that.
+        out.nrm[t * 3] = out.nrm[t * 3 + 1] = out.nrm[t * 3 + 2] = nrm;
+        if (have_excl) {
+            const float w = face_excluded[t] ? 1.f : 0.f;
+            out.exclude_weight[t * 3] = out.exclude_weight[t * 3 + 1] = out.exclude_weight[t * 3 + 2] = w;
+        }
+    }
+    return out;
+}
+
+indexed_triangle_set to_indexed_triangle_set(const TriSoup &soup)
+{
+    indexed_triangle_set out;
+    const size_t         n = soup.pos.size();
+    out.indices.reserve(n / 3);
+    QuantizedPointMap map(WELD_GRID_GEOMETRY, std::min(n, size_t(1) << 22));
+    std::vector<int>  id(n);
+    for (size_t i = 0; i < n; ++i) {
+        id[i] = map.get_or_set(soup.pos[i], int(out.vertices.size()));
+        if (map.inserted())
+            out.vertices.push_back(soup.pos[i]);
+    }
+    for (size_t t = 0; t + 2 < n; t += 3) {
+        // Welded-together corners carry no area.
+        if (id[t] == id[t + 1] || id[t + 1] == id[t + 2] || id[t] == id[t + 2])
+            continue;
+        out.indices.emplace_back(id[t], id[t + 1], id[t + 2]);
+    }
+    return out;
+}
+
+} // namespace TextureBake
+} // namespace Slic3r