76 lines
2.8 KiB
C++
76 lines
2.8 KiB
C++
//
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// This source code is property of the Computer Graphics and Visualization
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// chair of the TU Dresden. Do not distribute in modified or unmodified form!
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// Copyright (C) 2016 CGV TU Dresden - All Rights Reserved
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//
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/*************************************************************************
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Abstract curve.
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This class provides a basic interface for all curve types. It is
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constructed by passing a reference of a list of control points.
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It corresponds to the mathematical formulation of a curve c(t) via the
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"evaluate" method that returns a certain point as a function of the
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domain parameter "t". The range of "t" can be obtained with the methods
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"get_min_t" and "get_max_t".
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Since every point on a curve is generally the sum of the control
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points weightened with basis functions for every control point
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the interface declares the method "evaluate_basis" as a function
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of the parameter "t" and a control point. Specific curves have to
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implement that method accordingly.
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Because the control points are updated outside of an inherited instance
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of this class the method "control_points_updated" is called after
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every change, addition or removal of a control point.
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The rendering of the curve is not part of this interface but provided
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in another class called "curve_renderer".
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For debugging purpose an additional method called "set_text" is
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provided. Text put into the stream which is passed as a parameter to
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this function will be displayed in the main window.
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**************************************************************************/
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#pragma once
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// needed for arbitrary long lists
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#include <vector>
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// needed for the set_text method
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#include <sstream>
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// needed for the data type "point2d"
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#include "tiny_vec.h"
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class abstract_curve
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{
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public:
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// Initialize the curve and store a reference of the control points
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abstract_curve(std::vector<point2d> &control_points);
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virtual ~abstract_curve();
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// Get the minimum value of the domain
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double get_min_t();
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// Get the maximum value of the domain
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double get_max_t();
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// Evaluate a curve point as a function of the parameter "t". The
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// range of that function is given by "get_min_t" and "get_max_t"
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virtual point2d evaluate(double t);
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// Evaluate a basis as a function of a control point and
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// the parameter "t"
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virtual double evaluate_basis(int point_num, double t) = 0;
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// Shall be called whenever the control point set changes
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virtual void control_points_updated();
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// Get a constant list of control points
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const std::vector<point2d>& get_control_points() const;
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// Put a text into the stream "stream" which will be displayed
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// in the main window
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virtual void set_text(std::stringstream &stream);
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protected:
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// Range of the domain
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double t_min, t_max;
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// The reference of the control points
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std::vector<point2d> &control_points;
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}; |