1 files changed, 71 insertions, 0 deletions
diff --git a/source/blender/io/stl/importer/stl_import_mesh.hh b/source/blender/io/stl/importer/stl_import_mesh.hh
new file mode 100644
index 00000000000..f1c0d2126a9
--- /dev/null
+++ b/source/blender/io/stl/importer/stl_import_mesh.hh
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup stl
+ */
+
+#pragma once
+
+#include <cstdint>
+
+#include "BLI_math_vec_types.hh"
+#include "BLI_set.hh"
+#include "BLI_vector.hh"
+#include "BLI_vector_set.hh"
+
+#include "DNA_mesh_types.h"
+
+namespace blender::io::stl {
+class Triangle {
+ public:
+  int v1, v2, v3;
+  /* Based on an old version of Python's frozen-set hash
+   * https://web.archive.org/web/20220520211017/https://stackoverflow.com/questions/20832279/python-frozenset-hashing-algorithm-implementation
+   */
+  uint64_t hash() const
+  {
+    uint64_t res = 1927868237UL;
+    res *= 4;
+    res ^= (v1 ^ (v1 << 16) ^ 89869747UL) * 3644798167UL;
+    res ^= (v2 ^ (v2 << 16) ^ 89869747UL) * 3644798167UL;
+    res ^= (v3 ^ (v3 << 16) ^ 89869747UL) * 3644798167UL;
+    return res * 69069U + 907133923UL;
+  }
+  friend bool operator==(const Triangle &a, const Triangle &b)
+  {
+    bool i = (a.v1 == b.v1) && (a.v2 == b.v2) && (a.v3 == b.v3);
+    bool j = (a.v1 == b.v1) && (a.v3 == b.v2) && (a.v2 == b.v3);
+    bool k = (a.v2 == b.v1) && (a.v1 == b.v2) && (a.v3 == b.v3);
+
+    bool l = (a.v2 == b.v1) && (a.v3 == b.v2) && (a.v1 == b.v3);
+    bool m = (a.v3 == b.v1) && (a.v1 == b.v2) && (a.v2 == b.v3);
+    bool n = (a.v3 == b.v1) && (a.v2 == b.v2) && (a.v1 == b.v3);
+
+    return i || j || k || l || m || n;
+  }
+};
+
+class STLMeshHelper {
+ private:
+  VectorSet<float3> verts_;
+  VectorSet<Triangle> tris_;
+  Vector<float3> loop_normals_;
+  int degenerate_tris_num_;
+  int duplicate_tris_num_;
+  const bool use_custom_normals_;
+
+ public:
+  STLMeshHelper(int tris_num, bool use_custom_normals);
+
+  /* Creates a new triangle from specified vertex locations,
+   * duplicate vertices and triangles are merged.
+   */
+  bool add_triangle(const float3 &a, const float3 &b, const float3 &c);
+  void add_triangle(const float3 &a,
+                    const float3 &b,
+                    const float3 &c,
+                    const float3 &custom_normal);
+  Mesh *to_mesh(Main *bmain, char *mesh_name);
+};
+
+}  // namespace blender::io::stl