From 21fddfef793c28c567be318a27362bbf080ad95d Mon Sep 17 00:00:00 2001
From: Fabio Pellacini <fabio.pellacini@gmail.com>
Date: Tue, 22 Dec 2020 07:40:19 +0100
Subject: [PATCH] Mesh loading of STL and triangles only

---
 apps/ymeshproc/ymeshproc.cpp |   8 +-
 apps/ymeshtest/ymeshtest.cpp |   2 +-
 libs/yocto/yocto_mesh.cpp    | 185 ++++++++++++++++++++++++++---------
 libs/yocto/yocto_mesh.h      |  16 ++-
 4 files changed, 156 insertions(+), 55 deletions(-)

diff --git a/apps/ymeshproc/ymeshproc.cpp b/apps/ymeshproc/ymeshproc.cpp
index 8a4c63c69..f54cfaa67 100644
--- a/apps/ymeshproc/ymeshproc.cpp
+++ b/apps/ymeshproc/ymeshproc.cpp
@@ -34,7 +34,7 @@ using namespace yocto;
 
 // Shape presets used ofr testing.
 bool make_mesh_preset(vector<vec3i>& triangles, vector<vec3f>& positions,
-    vector<vec3f>& normals, vector<vec2f>& texcoords, vector<vec3f>& colors,
+    vector<vec3f>& normals, vector<vec2f>& texcoords, vector<vec4f>& colors,
     const string& type, string& error) {
   auto set_quads = [&](quads_shape&& shape) {
     triangles = quads_to_triangles(shape.quads);
@@ -157,7 +157,7 @@ int main(int argc, const char* argv[]) {
   auto positions = vector<vec3f>{};
   auto normals   = vector<vec3f>{};
   auto texcoords = vector<vec2f>{};
-  auto colors    = vector<vec3f>{};
+  auto colors    = vector<vec4f>{};
   auto triangles = vector<vec3i>{};
   auto lines     = vector<vec2i>{};  // for line output
 
@@ -231,10 +231,10 @@ int main(int argc, const char* argv[]) {
         if (tags[i] == 1) triangles[i] = {-1, -1, -1};
       }
     } else {
-      colors = vector<vec3f>(positions.size());
+      colors = vector<vec4f>(positions.size());
       for (int i = 0; i < colors.size(); ++i) {
         auto c    = sinf(geodesic_scale * field[i]);
-        colors[i] = vec3f{c, c, c};
+        colors[i] = vec4f{c, c, c, 1};
       }
       // distance_to_color(shape.colors, field, geodesic_scale);
     }
diff --git a/apps/ymeshtest/ymeshtest.cpp b/apps/ymeshtest/ymeshtest.cpp
index f53e63f8c..d0b5946e6 100644
--- a/apps/ymeshtest/ymeshtest.cpp
+++ b/apps/ymeshtest/ymeshtest.cpp
@@ -600,7 +600,7 @@ int main(int argc, const char* argv[]) {
   auto positions = vector<vec3f>{};
   auto normals   = vector<vec3f>{};
   auto texcoords = vector<vec2f>{};
-  auto colors    = vector<vec3f>{};
+  auto colors    = vector<vec4f>{};
   auto triangles = vector<vec3i>{};
 
   // stats, progress
diff --git a/libs/yocto/yocto_mesh.cpp b/libs/yocto/yocto_mesh.cpp
index 4323d708c..859036bae 100644
--- a/libs/yocto/yocto_mesh.cpp
+++ b/libs/yocto/yocto_mesh.cpp
@@ -2633,10 +2633,21 @@ mesh_point eval_path_point(const geodesic_path& path,
 // -----------------------------------------------------------------------------
 namespace yocto {
 
+// Convert quads to triangles
+static vector<vec3i> quads_to_triangles(const vector<vec4i>& quads) {
+  auto triangles = vector<vec3i>{};
+  triangles.reserve(quads.size() * 2);
+  for (auto& q : quads) {
+    triangles.push_back({q.x, q.y, q.w});
+    if (q.z != q.w) triangles.push_back({q.z, q.w, q.y});
+  }
+  return triangles;
+}
+
 // Load ply mesh
 bool load_mesh(const string& filename, vector<vec3i>& triangles,
     vector<vec3f>& positions, vector<vec3f>& normals, vector<vec2f>& texcoords,
-    vector<vec3f>& colors, string& error, bool flip_texcoord) {
+    vector<vec4f>& colors, string& error, bool flip_texcoord) {
   auto format_error = [filename, &error]() {
     error = filename + ": unknown format";
     return false;
@@ -2658,16 +2669,13 @@ bool load_mesh(const string& filename, vector<vec3i>& triangles,
     auto ply_guard = std::make_unique<ply_model>();
     auto ply       = ply_guard.get();
     if (!load_ply(filename, ply, error)) return false;
-
     // gets vertex
     get_positions(ply, positions);
     get_normals(ply, normals);
     get_texcoords(ply, texcoords, flip_texcoord);
     get_colors(ply, colors);
-
     // get faces
     get_triangles(ply, triangles);
-
     if (positions.empty()) return shape_error();
     return true;
   } else if (ext == ".obj" || ext == ".OBJ") {
@@ -2675,24 +2683,16 @@ bool load_mesh(const string& filename, vector<vec3i>& triangles,
     auto obj_guard = std::make_unique<obj_scene>();
     auto obj       = obj_guard.get();
     if (!load_obj(filename, obj, error, true)) return false;
-
     // get shape
     if (obj->shapes.empty()) return shape_error();
     if (obj->shapes.size() > 1) return shape_error();
     auto shape = obj->shapes.front();
-    if (shape->points.empty() && shape->lines.empty() && shape->faces.empty())
-      return shape_error();
-
+    if (shape->faces.empty()) return shape_error();
     // decide what to do and get properties
     auto materials  = vector<string>{};
     auto ematerials = vector<int>{};
-    if (!shape->faces.empty()) {
-      get_triangles(shape, triangles, positions, normals, texcoords, materials,
-          ematerials, flip_texcoord);
-    } else {
-      return shape_error();
-    }
-
+    get_triangles(shape, triangles, positions, normals, texcoords, materials,
+        ematerials, flip_texcoord);
     if (positions.empty()) return shape_error();
     return true;
   } else {
@@ -2703,7 +2703,7 @@ bool load_mesh(const string& filename, vector<vec3i>& triangles,
 // Save ply mesh
 bool save_mesh(const string& filename, const vector<vec3i>& triangles,
     const vector<vec3f>& positions, const vector<vec3f>& normals,
-    const vector<vec2f>& texcoords, const vector<vec3f>& colors, string& error,
+    const vector<vec2f>& texcoords, const vector<vec4f>& colors, string& error,
     bool ascii, bool flip_texcoord) {
   auto format_error = [filename, &error]() {
     error = filename + ": unknown format";
@@ -2730,15 +2730,126 @@ bool save_mesh(const string& filename, const vector<vec3i>& triangles,
     auto obj_guard = std::make_unique<obj_scene>();
     auto obj       = obj_guard.get();
     auto oshape    = add_shape(obj);
-    if (!triangles.empty()) {
-      set_triangles(
-          oshape, triangles, positions, normals, texcoords, {}, flip_texcoord);
-    } else {
+    if (triangles.empty()) return shape_error();
+    set_triangles(
+        oshape, triangles, positions, normals, texcoords, {}, flip_texcoord);
+    if (!save_obj(filename, obj, error)) return false;
+    return true;
+  } else if (ext == ".stl" || ext == ".STL") {
+    auto stl_guard = std::make_unique<stl_model>();
+    auto stl       = stl_guard.get();
+    if (triangles.empty()) return shape_error();
+    add_triangles(stl, triangles, positions, {});
+    if (!save_stl(filename, stl, error)) return false;
+    return true;
+  } else {
+    return format_error();
+  }
+}
+
+// Load ply mesh
+bool load_mesh(const string& filename, vector<vec3i>& triangles,
+    vector<vec3f>& positions, string& error) {
+  auto format_error = [filename, &error]() {
+    error = filename + ": unknown format";
+    return false;
+  };
+  auto shape_error = [filename, &error]() {
+    error = filename + ": empty shape";
+    return false;
+  };
+
+  triangles = {};
+  positions = {};
+
+  auto ext = path_extension(filename);
+  if (ext == ".ply" || ext == ".PLY") {
+    // open ply
+    auto ply_guard = std::make_unique<ply_model>();
+    auto ply       = ply_guard.get();
+    if (!load_ply(filename, ply, error)) return false;
+    get_positions(ply, positions);
+    get_triangles(ply, triangles);
+    if (positions.empty()) return shape_error();
+    return true;
+  } else if (ext == ".obj" || ext == ".OBJ") {
+    // load obj
+    auto obj_guard = std::make_unique<obj_scene>();
+    auto obj       = obj_guard.get();
+    if (!load_obj(filename, obj, error, true)) return false;
+    // get shape
+    if (obj->shapes.empty()) return shape_error();
+    if (obj->shapes.size() > 1) return shape_error();
+    auto shape = obj->shapes.front();
+    if (shape->faces.empty()) return shape_error();
+    // decide what to do and get properties
+    auto materials     = vector<string>{};
+    auto ematerials    = vector<int>{};
+    auto quadspos      = vector<vec4i>{};
+    auto quadsnorm     = vector<vec4i>{};
+    auto quadstexcoord = vector<vec4i>{};
+    auto normals       = vector<vec3f>{};
+    auto texcoords     = vector<vec2f>{};
+    get_fvquads(shape, quadspos, quadsnorm, quadstexcoord, positions, normals,
+        texcoords, materials, ematerials);
+    triangles = quads_to_triangles(quadspos);
+    if (positions.empty()) return shape_error();
+    return true;
+  } else if (ext == ".stl" || ext == ".STL") {
+    // open ply
+    auto stl_guard = std::make_unique<stl_model>();
+    auto stl       = stl_guard.get();
+    if (!load_stl(filename, stl, error)) return false;
+    if (stl->shapes.empty()) return shape_error();
+    if (stl->shapes.size() > 1) return shape_error();
+    auto fnormals = vector<vec3f>{};
+    if (!get_triangles(stl, 0, triangles, positions, fnormals))
       return shape_error();
-    }
+    if (positions.empty()) return shape_error();
+    return true;
+  } else {
+    return format_error();
+  }
+}
+
+// Save ply mesh
+bool save_mesh(const string& filename, const vector<vec3i>& triangles,
+    const vector<vec3f>& positions, string& error, bool ascii) {
+  auto format_error = [filename, &error]() {
+    error = filename + ": unknown format";
+    return false;
+  };
+  auto shape_error = [filename, &error]() {
+    error = filename + ": empty shape";
+    return false;
+  };
+
+  auto ext = path_extension(filename);
+  if (ext == ".ply" || ext == ".PLY") {
+    // create ply
+    auto ply_guard = std::make_unique<ply_model>();
+    auto ply       = ply_guard.get();
+    if (triangles.empty()) return shape_error();
+    add_positions(ply, positions);
+    add_triangles(ply, triangles);
+    if (!save_ply(filename, ply, error)) return false;
+    return true;
+  } else if (ext == ".obj" || ext == ".OBJ") {
+    auto obj_guard = std::make_unique<obj_scene>();
+    auto obj       = obj_guard.get();
+    auto oshape    = add_shape(obj);
+    if (triangles.empty()) return shape_error();
+    set_triangles(oshape, triangles, positions, {}, {}, {});
     auto err = ""s;
     if (!save_obj(filename, obj, error)) return false;
     return true;
+  } else if (ext == ".stl" || ext == ".STL") {
+    auto stl_guard = std::make_unique<stl_model>();
+    auto stl       = stl_guard.get();
+    if (triangles.empty()) return shape_error();
+    add_triangles(stl, triangles, positions, {});
+    if (!save_stl(filename, stl, error)) return false;
+    return true;
   } else {
     return format_error();
   }
@@ -2747,7 +2858,7 @@ bool save_mesh(const string& filename, const vector<vec3i>& triangles,
 // Load ply mesh
 bool load_lines(const string& filename, vector<vec2i>& lines,
     vector<vec3f>& positions, vector<vec3f>& normals, vector<vec2f>& texcoords,
-    vector<vec3f>& colors, string& error, bool flip_texcoord) {
+    vector<vec4f>& colors, string& error, bool flip_texcoord) {
   auto format_error = [filename, &error]() {
     error = filename + ": unknown format";
     return false;
@@ -2769,16 +2880,13 @@ bool load_lines(const string& filename, vector<vec2i>& lines,
     auto ply_guard = std::make_unique<ply_model>();
     auto ply       = ply_guard.get();
     if (!load_ply(filename, ply, error)) return false;
-
     // gets vertex
     get_positions(ply, positions);
     get_normals(ply, normals);
     get_texcoords(ply, texcoords, flip_texcoord);
     get_colors(ply, colors);
-
     // get faces
     get_lines(ply, lines);
-
     if (positions.empty()) return shape_error();
     return true;
   } else if (ext == ".obj" || ext == ".OBJ") {
@@ -2786,24 +2894,16 @@ bool load_lines(const string& filename, vector<vec2i>& lines,
     auto obj_guard = std::make_unique<obj_scene>();
     auto obj       = obj_guard.get();
     if (!load_obj(filename, obj, error, true)) return false;
-
     // get shape
     if (obj->shapes.empty()) return shape_error();
     if (obj->shapes.size() > 1) return shape_error();
     auto shape = obj->shapes.front();
-    if (shape->points.empty() && shape->lines.empty() && shape->faces.empty())
-      return shape_error();
-
+    if (shape->lines.empty()) return shape_error();
     // decide what to do and get properties
     auto materials  = vector<string>{};
     auto ematerials = vector<int>{};
-    if (!shape->faces.empty()) {
-      get_lines(shape, lines, positions, normals, texcoords, materials,
-          ematerials, flip_texcoord);
-    } else {
-      return shape_error();
-    }
-
+    get_lines(shape, lines, positions, normals, texcoords, materials,
+        ematerials, flip_texcoord);
     if (positions.empty()) return shape_error();
     return true;
   } else {
@@ -2814,7 +2914,7 @@ bool load_lines(const string& filename, vector<vec2i>& lines,
 // Save ply mesh
 bool save_lines(const string& filename, const vector<vec2i>& lines,
     const vector<vec3f>& positions, const vector<vec3f>& normals,
-    const vector<vec2f>& texcoords, const vector<vec3f>& colors, string& error,
+    const vector<vec2f>& texcoords, const vector<vec4f>& colors, string& error,
     bool ascii, bool flip_texcoord) {
   auto format_error = [filename, &error]() {
     error = filename + ": unknown format";
@@ -2841,13 +2941,8 @@ bool save_lines(const string& filename, const vector<vec2i>& lines,
     auto obj_guard = std::make_unique<obj_scene>();
     auto obj       = obj_guard.get();
     auto oshape    = add_shape(obj);
-    if (!lines.empty()) {
-      set_lines(
-          oshape, lines, positions, normals, texcoords, {}, flip_texcoord);
-    } else {
-      return shape_error();
-    }
-    auto err = ""s;
+    if (lines.empty()) return shape_error();
+    set_lines(oshape, lines, positions, normals, texcoords, {}, flip_texcoord);
     if (!save_obj(filename, obj, error)) return false;
     return true;
   } else {
@@ -2864,7 +2959,7 @@ namespace yocto {
 
 vector<string> mesh_stats(const vector<vec3i>& triangles,
     const vector<vec3f>& positions, const vector<vec3f>& normals,
-    const vector<vec2f>& texcoords, const vector<vec3f>& colors, bool verbose) {
+    const vector<vec2f>& texcoords, const vector<vec4f>& colors, bool verbose) {
   auto format = [](auto num) {
     auto str = std::to_string(num);
     while (str.size() < 13) str = " " + str;
diff --git a/libs/yocto/yocto_mesh.h b/libs/yocto/yocto_mesh.h
index 0dd6f479b..d73433ad7 100644
--- a/libs/yocto/yocto_mesh.h
+++ b/libs/yocto/yocto_mesh.h
@@ -391,21 +391,27 @@ namespace yocto {
 // Load/save a shape as indexed meshes
 bool load_mesh(const string& filename, vector<vec3i>& triangles,
     vector<vec3f>& positions, vector<vec3f>& normals, vector<vec2f>& texcoords,
-    vector<vec3f>& colors, string& error, bool flip_texcoords = true);
+    vector<vec4f>& colors, string& error, bool flip_texcoords = true);
 bool save_mesh(const string& filename, const vector<vec3i>& triangles,
     const vector<vec3f>& positions, const vector<vec3f>& normals,
-    const vector<vec2f>& texcoords, const vector<vec3f>& colors, string& error,
+    const vector<vec2f>& texcoords, const vector<vec4f>& colors, string& error,
     bool ascii = false, bool flip_texcoords = true);
 
 // Load/save a set of lines
 bool load_lines(const string& filename, vector<vec2i>& lines,
     vector<vec3f>& positions, vector<vec3f>& normals, vector<vec2f>& texcoords,
-    vector<vec3f>& colors, string& error, bool flip_texcoords = true);
+    vector<vec4f>& colors, string& error, bool flip_texcoords = true);
 bool save_lines(const string& filename, const vector<vec2i>& lines,
     const vector<vec3f>& positions, const vector<vec3f>& normals,
-    const vector<vec2f>& texcoords, const vector<vec3f>& colors, string& error,
+    const vector<vec2f>& texcoords, const vector<vec4f>& colors, string& error,
     bool ascii = false, bool flip_texcoords = true);
 
+// Load/save a shape as indexed meshes
+bool load_mesh(const string& filename, vector<vec3i>& triangles,
+    vector<vec3f>& positions, string& error);
+bool save_mesh(const string& filename, const vector<vec3i>& triangles,
+    const vector<vec3f>& positions, string& error, bool ascii = false);
+
 }  // namespace yocto
 
 // -----------------------------------------------------------------------------
@@ -416,7 +422,7 @@ namespace yocto {
 // Get mesh statistics for printing
 vector<string> mesh_stats(const vector<vec3i>& triangles,
     const vector<vec3f>& positions, const vector<vec3f>& normals,
-    const vector<vec2f>& texcoords, const vector<vec3f>& colors,
+    const vector<vec2f>& texcoords, const vector<vec4f>& colors,
     bool verbose = false);
 
 }  // namespace yocto