Refactors alignment geometry

src/ifcgeom/function_item_evaluator.h

@@ -0,0 +1,70 @@
+#ifndef ITERATOR_PWF_EVALUATOR_H
+#define ITERATOR_PWF_EVALUATOR_H
+
+#include "../ifcgeom/taxonomy.h"
+
+#include <boost/function.hpp>
+
+namespace ifcopenshell { namespace geometry {
+
+/// @brief Abstract class for evaluating a function_item. This class is specialized for each of the function_item types.
+struct fn_evaluator {
+    fn_evaluator(const ifcopenshell::geometry::Settings& settings) : settings_(settings) {
+    }
+    fn_evaluator(const fn_evaluator& other) = default;
+    virtual ~fn_evaluator() = default;
+
+    virtual fn_evaluator* clone() const = 0;
+
+    virtual Eigen::Matrix4d evaluate(double u) const = 0;
+    virtual double start() const = 0;
+    virtual double end() const = 0;
+    double length() const { return end() - start(); }
+
+    ifcopenshell::geometry::Settings settings_;
+};
+
+/// @brief utility class to evaluate function_item objects.
+class function_item_evaluator {
+  public:
+    function_item_evaluator(const ifcopenshell::geometry::Settings& settings, taxonomy::function_item::const_ptr fn);
+    function_item_evaluator(const function_item_evaluator& other);
+    ~function_item_evaluator();
+
+    /// @brief returns a vector of "distance along" points where the evaluate function computes loop points
+    std::vector<double> evaluation_points() const;
+
+    /// @brief returns a vector of "distance along" points between ustart and uend
+    /// @param ustart starting location
+    /// @param uend ending location
+    /// @param nsteps number of steps to evaluate
+    std::vector<double> evaluation_points(double ustart, double uend, unsigned nsteps) const;
+
+    /// @brief evaluates the function between start and end
+    /// evaluation point step size is taken from the settings object
+    taxonomy::item::ptr evaluate() const;
+
+    /// @brief evaluates the function between ustart and uend
+    /// if ustart and uend are out of range, the range of values evaluated
+    /// are constrained to start_ and start_+length_
+    /// @param ustart starting location
+    /// @param uend ending location
+    /// @param nsteps number of steps to evaluate
+    /// @return taxonomy::loop::ptr
+    taxonomy::item::ptr evaluate(double ustart, double uend, unsigned nsteps) const;
+
+    /// @brief evaluates the function at u
+    /// @param u u is constrained to be between start_ and start_+length
+    /// @return 4x4 placement matrix
+    Eigen::Matrix4d evaluate(double u) const;
+
+  private:
+    taxonomy::item::ptr evaluate(const std::vector<double>& dist) const;
+    fn_evaluator* fn_evaluator_ = nullptr;
+
+    mutable boost::optional<std::vector<double>> eval_points_; // cache evaluation points
+};
+
+}}
+
+#endif