[SpatialPartitioning] Add KdTreeTraits and refactor KnnGraph (WIP)

Ponca/src/SpatialPartitioning/KnnGraph/KnnGraph.h

@@ -6,32 +6,64 @@
 
 #pragma once
 
+#include "./knnGraphTraits.h"
+
 #include "Query/knnGraphQuery.h"
 #include "Query/knnGraphRangeQuery.h"
 
 #include <memory>
 
 namespace Ponca {
 
-class KdTree;
+template <typename Traits> class KnnGraphBase;
+
+/*!
+ * \brief Public interface for KnnGraph datastructure.
+ *
+ * Provides default implementation of the KnnGraph
+ *
+ * \see KnnGraphDefaultTraits for the default trait interface documentation.
+ * \see KnnGraphBase for complete API
+ */
+template <typename DataPoint>
+using KnnGraph = KnnGraphBase<KnnGraphDefaultTraits<DataPoint>>;
 
-class KnnGraph
+class KdTree;
+/*!
+ * \brief Customizable base class for KnnGraph datastructure
+ *
+ * \see Ponca::KnGraph
+ *
+ * \tparam Traits Traits type providing the types and constants used by the KnnGraph. Must have the
+ * same interface as the default traits type.
+ *
+ * \see KnnGraphDefaultTraits for the trait interface documentation.
+ *
+ */
+template <typename Traits> class KnnGraphBase
 {
-    // Types -------------------------------------------------------------------
 public:
+    using DataPoint  = typename Traits::DataPoint; ///< DataPoint given by user via Traits
+    using Scalar     = typename DataPoint::Scalar; ///< Scalar given by user via DataPoint
+    using VectorType = typename DataPoint::VectorType; ///< VectorType given by user via DataPoint
+
+    using IndexType      = typename Traits::IndexType;
+    using PointContainer = typename Traits::PointContainer; ///< Container for DataPoint used inside the KdTree
+    using IndexContainer = typename Traits::IndexContainer; ///< Container for indices used inside the KdTree
+
     using KNearestIndexQuery = KnnGraphQuery;
     using RangeIndexQuery    = KnnGraphRangeQuery;
 
     // knnGraph ----------------------------------------------------------------
 public:
-    KnnGraph();
-    KnnGraph(int k);
+    KnnGraphBase();
+    KnnGraphBase(int k);
 
     void clear();
     void build(const KdTree& kdtree);
     void build(const KdTree& kdtree, int k);
-    void build(const KdTree& kdtree, const std::vector<int>& indices);
-    void build(const KdTree& kdtree, int k, const std::vector<int>& indices);
+    void build(const KdTree& kdtree, const IndexContainer& indices);
+    void build(const KdTree& kdtree, int k, const IndexContainer& indices);
 
 
     // Query -------------------------------------------------------------------
@@ -50,19 +82,19 @@ class KnnGraph
     int k() const;
     int size() const;
 
-    const Vector3Array& point_data() const;
-          Vector3Array& point_data();
+    const PointContainer& point_data() const;
+          PointContainer& point_data();
 
-    const std::vector<int>& index_data() const;
-          std::vector<int>& index_data();
+    const IndexContainer& index_data() const;
+          IndexContainer& index_data();
 
     void set_verbose(bool verbose = true);
 
     // Data --------------------------------------------------------------------
 protected:
     int m_k;
-    std::shared_ptr<Vector3Array>     m_points;
-    std::shared_ptr<std::vector<int>> m_indices;
+    std::shared_ptr<PointContainer>   m_points;
+    std::shared_ptr<IndexContainer> m_indices;
 
     bool m_verbose;
 };

Ponca/src/SpatialPartitioning/KnnGraph/knnGraphTraits.h

@@ -0,0 +1,48 @@
+/*
+ This Source Code Form is subject to the terms of the Mozilla Public
+ License, v. 2.0. If a copy of the MPL was not distributed with this
+ file, You can obtain one at http://mozilla.org/MPL/2.0/.
+*/
+
+
+#pragma once
+
+#include <Eigen/Geometry>
+
+namespace Ponca {
+
+/*!
+ * \brief The default traits type used by the kd-tree.
+ */
+template <typename _DataPoint>
+struct KnnGraphDefaultTraits
+{
+    /*!
+     * \brief The type used to store point data.
+     *
+     * Must provide `Scalar` and `VectorType` typedefs.
+     *
+     * `VectorType` must provide a `squaredNorm()` function returning a `Scalar`, as well as a
+     * `maxCoeff(int*)` function returning the dimension index of its largest scalar in its output
+     * parameter (e.g. 0 for *x*, 1 for *y*, etc.).
+     */
+    using DataPoint = _DataPoint;
+
+private:
+    using Scalar     = typename DataPoint::Scalar;
+    using VectorType = typename DataPoint::VectorType;
+
+public:
+    /*!
+     * \brief The type used to calculate node bounding boxes.
+     *
+     * Must provide `min()`, `max()`, and `center()` functions, all returning a `VectorType`.
+     */
+    using AabbType = Eigen::AlignedBox<Scalar, DataPoint::Dim>;
+
+    // Containers
+    using IndexType      = int;
+    using PointContainer = std::vector<DataPoint>;
+    using IndexContainer = std::vector<IndexType>;
+};
+} // namespace Ponca