fix: take closest point

Author: oktomus

resources/models/plane.obj

@@ -0,0 +1,45 @@
+# Blender v2.79 (sub 0) OBJ File: 'boite.blend'
+# www.blender.org
+mtllib case.mtl
+o Cube
+v -1.000000 -1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v -1.000000 1.000000 0.999999
+v -0.999999 1.000000 -1.000001
+v 1.000000 1.000000 -1.000000
+v 1.000000 1.000000 1.000000
+vt 0.000000 0.000000
+vt 1.000000 0.000000
+vt 1.000000 1.000000
+vt 0.000000 1.000000
+vt 1.000000 0.000000
+vt 1.000000 1.000000
+vt 0.000000 1.000000
+vt 0.000000 0.000000
+vt 1.000000 1.000000
+vt 0.000000 1.000000
+vt 0.000000 1.000000
+vt 1.000000 0.000000
+vt 0.000000 0.000000
+vt 1.000000 -0.000000
+vt 0.000000 0.000000
+vt 1.000000 0.000000
+vt 1.000000 1.000000
+vt 0.000000 1.000000
+vn 0.0000 -1.0000 -0.0000
+vn 0.0000 1.0000 0.0000
+vn -1.0000 0.0000 -0.0000
+vn 0.0000 -0.0000 -1.0000
+vn 1.0000 -0.0000 0.0000
+vn -0.0000 0.0000 1.0000
+g Cube_Cube_Material
+usemtl Material
+s off
+# f 1/1/1 2/2/1 3/3/1 4/4/1
+f 5/5/2 8/6/2 7/7/2 6/8/2
+# f 1/9/3 5/10/3 6/8/3 2/2/3
+# f 2/11/4 6/8/4 7/12/4 3/3/4
+# f 3/3/5 7/7/5 8/13/5 4/14/5
+# f 5/15/6 1/16/6 4/17/6 8/18/6

src/core/closest_point_query.cpp

@@ -38,10 +38,7 @@ bool ClosestPointQuery::get_closest_point(
 {
     assert(max_distance > 0.0f);
 
-    static nanoflann::SearchParams search_params(
-        32,    // ignored param
-        0.0f,  // epsilon
-        true); // true means we want results to be sorted by squared dist
+    const float max_distance2 = max_distance * max_distance;
 
     // Take the 10 closest and keep the best out of them.
     const std::size_t expected_result_count = 200;
@@ -57,11 +54,11 @@ bool ClosestPointQuery::get_closest_point(
     bool found = false;
     float closest_distance2 = 0.0f;
 
-    for (std::size_t result_index = 0; result_index < num_results; ++result_index)
+    for (std::size_t i = 0; i < num_results; ++i)
     {
         // Ask the triangle to the point cloud.
         glm::vec3 v1, v2, v3;
-        m_mesh_point_cloud.get_triangle(ret_index[result_index], v1, v2, v3);
+        m_mesh_point_cloud.get_triangle(ret_index[i], v1, v2, v3);
 
         // Compute the point on the triangle.
         glm::vec3 p = closest_point_in_triangle(
@@ -73,11 +70,12 @@ bool ClosestPointQuery::get_closest_point(
         // Keep the best.
         const float distance2_to_triangle = distance2(p, query_point);
 
-        if (distance2_to_triangle < max_distance
+        if (distance2_to_triangle < max_distance2
             && (!found || distance2_to_triangle < closest_distance2))
         {
             found = true;
             result = p;
+            closest_distance2 = distance2_to_triangle;
         }
     }
 

src/core/mesh_point_cloud.cpp

@@ -7,24 +7,16 @@ MeshPointCloud::MeshPointCloud(const Mesh& mesh)
   : m_mesh(mesh)
 {
     // Add all mesh vertices in the point cloud.
-    // TODO: Uniform sample the mesh to generate a denser cloud.
     const std::vector<Mesh::Vertex>& vertices = m_mesh.get_vertices();
-    const std::size_t vertex_count = vertices.size();
     const std::vector<unsigned int>& triangles = m_mesh.get_triangles();
-    assert(triangles.size() % 3 == 0);
-    const std::size_t triangle_count = triangles.size() / 3;
+    const std::size_t index_count = triangles.size();
+    assert(index_count % 3 == 0);
 
-    m_points.reserve(triangle_count * 3);
+    m_points.reserve(index_count);
 
-    for (std::size_t triangle_index = 0; triangle_index < triangle_count; ++triangle_index)
+    for (std::size_t i = 0; i < index_count; ++i)
     {
-        const std::size_t v1_index = triangles[triangle_index * 3];
-        const std::size_t v2_index = triangles[triangle_index * 3 + 1];
-        const std::size_t v3_index = triangles[triangle_index * 3 + 2];
-
-        m_points.push_back(vertices[v1_index].pos);
-        m_points.push_back(vertices[v2_index].pos);
-        m_points.push_back(vertices[v3_index].pos);
+        m_points.push_back(vertices[triangles[i]].pos);
     }
 }
 

src/core/mesh_point_cloud.h

@@ -57,6 +57,11 @@ class MeshPointCloud
         }
     }
 
+    inline std::size_t get_triangle_count() const
+    {
+        return m_points.size() / 3;
+    }
+
     // nanoflann compatibility implementaiton.
     inline std::size_t kdtree_get_point_count() const
     {

src/core/scene.cpp

@@ -10,7 +10,7 @@ namespace core
 
 Scene::Scene(const std::vector<Mesh>& meshes)
   : m_meshes(meshes)
-{ 
+{
     // Prepare to render meshes.
     m_drawing_meshes.reserve(m_meshes.size());
 
@@ -22,6 +22,11 @@ Scene::Scene(const std::vector<Mesh>& meshes)
     }
 }
 
+std::size_t Scene::get_mesh_count() const
+{
+    return m_meshes.size();
+}
+
 const Mesh& Scene::get_mesh() const
 {
     assert(m_meshes.size() > 0);
@@ -36,4 +41,4 @@ void Scene::render() const
     }
 }
 
-} // namespace core
+} // namespace core

src/core/scene.h

@@ -16,6 +16,8 @@ class Scene
   public:
     Scene(const std::vector<Mesh>& meshes);
 
+    std::size_t get_mesh_count() const;
+
     // FIXME: Multiple mesh usage is not supported.
     const Mesh& get_mesh() const;
 
@@ -26,4 +28,4 @@ class Scene
     std::vector<RasterizedMesh> m_drawing_meshes;
 };
 
-} // namespace core
+} // namespace core

src/gui/mainwindow.cpp

@@ -159,6 +159,14 @@ void MainWindow::load_scene(const std::string& path)
     // Load the scene.
     m_scene.reset(core::load_scene_from_file(path));
 
+    if (m_scene->get_mesh_count() == 0)
+    {
+        std::cerr << "No mesh in the scene.\n";
+        m_mesh_point_cloud.reset(nullptr);
+        m_closest_point_query.reset(nullptr);
+        return;
+    }
+
     // Build a point cloud of the mesh.
     m_mesh_point_cloud.reset(new core::MeshPointCloud(m_scene->get_mesh()));
 
@@ -359,11 +367,10 @@ void MainWindow::animate_query_point()
     const glm::vec3 towards_model = m_closest_point_pos - m_query_point_pos;
     const glm::vec3 fake_tangent = glm::cross(towards_model, glm::vec3(0.0f, 1.0f, 0.0f));
 
-    const float wiggle = std::sin(m_time_since_startup * 0.5f) * 0.5f;
+    const float wiggle = std::sin(m_time_since_startup) * 0.5f;
 
-    m_query_point_pos += towards_model * wiggle * m_frame_delta_time;
-    m_query_point_pos += fake_tangent * m_frame_delta_time;
-    m_query_point_pos -= glm::cross(fake_tangent, towards_model) * wiggle * m_frame_delta_time;
+    m_query_point_pos += fake_tangent * wiggle * m_frame_delta_time;
+    m_query_point_pos += glm::cross(fake_tangent, towards_model) * wiggle * m_frame_delta_time;
 }
 
 // GLFW Window callbacks.