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#pragma once
#include <vector>
#include <glm/vec3.hpp>
namespace pymol
{
enum class BezierControlPointMode {
ALIGNED, // linear with other handle (smooth)
VECTOR, // linear with previous/next control point (sharp)
FREE // Independent of handles/control point
};
struct BezierSplinePoint {
glm::vec3 control;
glm::vec3 leftHandle;
glm::vec3 rightHandle;
BezierControlPointMode mode = BezierControlPointMode::ALIGNED;
};
class BezierSpline
{
public:
/**
* Retrives points along bezier spline
* @param globalT
* @return point at t distance along spline
*/
glm::vec3 getBezierPoint(float globalT) const;
/**
* Retrives first derivative along bezier spline
* @param globalT t along entire spline
* @return derivative at t distance along spline
* @note this is unnormalized
*/
glm::vec3 getFirstDerivative(float globalT) const;
/**
* @return number of curves in spline
*/
std::uint32_t curveCount() const;
/**
* Adds a bezier point to spline
* @param pt new point to add
*/
void addBezierPoint(const BezierSplinePoint& pt);
/**
* Automatically adds a bezier point to spline
*/
void addBezierPoint();
/**
* @return the last point (t == 1) along spline
*/
BezierSplinePoint* getLastBezierPoint();
/**
* @return list of Bezier points that construct spline
*/
std::vector<BezierSplinePoint>& getBezierPoints() noexcept
{
return bezierPoints;
}
/**
* @return list of Bezier points that construct spline
*/
const std::vector<BezierSplinePoint>& getBezierPoints() const noexcept
{
return bezierPoints;
}
private:
std::vector<BezierSplinePoint> bezierPoints;
/**
* Retrives the index (immediately preceding global T) and the t parameter
* between index and index + t
* @param globalT t along entire spline
*/
std::pair<int, float> getIndexAndLocalT(float globalT) const;
/**
* Interpolated calculation of a point along a cubic bezier curve
* @param a Bezier Point A
* @param b Bezier Point B
* @param t Parameter t along cubic bezier curve
* @return point at t distance along curve
*/
static glm::vec3 GetBezierPoint(
const BezierSplinePoint& a, const BezierSplinePoint& b, float t);
/**
* Generalized interpolated calculation of a point along a cubic bezier curve
* @param p0 Bezier start control point
* @param p1 Bezier start handle point
* @param p2 Bezier end handle point
* @param p3 Bezier end control point
* @param t Parameter t along cubic bezier curve
* @return point at t distance along curve
*/
static glm::vec3 GetBezierPoint(const glm::vec3& p0, const glm::vec3& p1,
const glm::vec3& p2, const glm::vec3& p3, float t);
/**
* Interpolated calculation of the first derivative along a cubic beziercurve
* @param a Bezier Point A
* @param b Bezier Point B
* @param t Parameter t along cubic bezier curve
* @return first derivative at t distance along curve
*/
static glm::vec3 GetBezierFirstDerivative(
const BezierSplinePoint& a, const BezierSplinePoint& b, float t);
/**
* Generalized interpolated calculation of the first derivative along a cubic
* beziercurve
* @param a Bezier Point A
* @param b Bezier Point B
* @param t Parameter t along cubic bezier curve
* @return first derivative at t distance along curve
*/
static glm::vec3 GetBezierFirstDerivative(const glm::vec3& p0,
const glm::vec3& p1, const glm::vec3& p2, const glm::vec3& p3, float t);
};
} // namespace pymol
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