easy3d::curve Namespace Reference

Algorithms for evaluating curves. More...

Functions
template<typename Point_t >
void	quadratic (const Point_t &A, const Point_t &B, const Point_t &C, std::vector< Point_t > &curve, unsigned int bezier_steps=4, bool include_end=false)
	De Casteljau algorithm evaluating a quadratic or conic (second degree) curve from the given control points A, B, and C. Works for both 2D and 3D. More...
template<typename Point_t >
void	cubic (const Point_t &A, const Point_t &B, const Point_t &C, const Point_t &D, std::vector< Point_t > &curve, unsigned int bezier_steps=4, bool include_end=false)
	De Casteljau algorithm evaluating a cubic (third degree) curve from the given control points A, B, and C. Works for both 2D and 3D. More...

Detailed Description

Algorithms for evaluating curves.

Function Documentation

cubic()

void easy3d::curve::cubic ( const Point_t &  A, const Point_t &  B, const Point_t &  C, const Point_t &  D, std::vector< Point_t > &  curve, unsigned int  bezier_steps = 4, bool  include_end = false  )

inline

De Casteljau algorithm evaluating a cubic (third degree) curve from the given control points A, B, and C. Works for both 2D and 3D.

Parameters

curve	Returns the sequence of points on the curve.
bezier_steps	Controls the smoothness of the curved corners. A greater value results in a smoother transitions but more vertices. Suggested value is 4.
include_end	Ture to extend the curve to the end point.

The following code shows how to visualize a quadratic curve (as a polyline):

{
    vec3 a(0, 0, 0);
    vec3 b(400, 0, 0);
    vec3 c(400, 800, 0);
    vec3 d(800, 800, 0);
    unsigned int steps = 20;
 
    std::vector<vec3> points;
    curve::cubic(a, b, c, d, steps, points);
    std::cout << "first point: " << points.front() << ", last point: " << points.back() << std::endl;
 
    std::vector<unsigned int> indices;
    for (unsigned int i = 0; i < points.size() - 1; ++i) {
        indices.push_back(i);
        indices.push_back(i + 1);
    }
    LinesDrawable *curve = new LinesDrawable;
    curve->update_vertex_buffer(points);
    curve->update_element_buffer(indices);
    curve->set_impostor_type(easy3d::LinesDrawable::CYLINDER);
    curve->set_line_width(5);
    curve->set_uniform_coloring(vec3(0, 1, 0, 1));
    viewer.add_drawable(curve);
}

quadratic()

void easy3d::curve::quadratic ( const Point_t &  A, const Point_t &  B, const Point_t &  C, std::vector< Point_t > &  curve, unsigned int  bezier_steps = 4, bool  include_end = false  )

inline

De Casteljau algorithm evaluating a quadratic or conic (second degree) curve from the given control points A, B, and C. Works for both 2D and 3D.

Parameters

curve	Returns the sequence of points on the curve.
bezier_steps	Controls the smoothness of the curved corners. A greater value results in a smoother transitions but more vertices. Suggested value is 4.
include_end	Ture to extend the curve to the end point.

The following code shows how to visualize a quadratic curve (as a polyline):

{
    vec3 a(0, 0, 0);
    vec3 b(800, 0, 0);
    vec3 c(800, 800, 0);
    unsigned int steps = 20;
 
    std::vector<vec3> points;
    curve::quadratic(a, b, c, steps, points);
    std::cout << "first point: " << points.front() << ", last point: " << points.back() << std::endl;
 
    std::vector<unsigned int> indices;
    for (unsigned int i=0; i<points.size() - 1; ++i) {
        indices.push_back(i);
        indices.push_back(i+1);
    }
    LinesDrawable *curve = new LinesDrawable;
    curve->update_vertex_buffer(points);
    curve->update_element_buffer(indices);
    curve->set_impostor_type(easy3d::LinesDrawable::CYLINDER);
    curve->set_line_width(5);
    curve->set_uniform_coloring(vec3(0, 0, 1, 1));
    viewer.add_drawable(curve);
}