comparison: src/bezier_curve.cpp
src/bezier_curve.cpp
- changeset 373
- e34d6a30b96d
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| 372:b2914aaeec1a | 373:e34d6a30b96d |
|---|---|
| 1 #include "bezier_curve.h" | |
| 2 | |
| 3 /** | |
| 4 * @brief computes the point on a Bezier curve | |
| 5 * @param curve | |
| 6 * @param t scalar between 0 and 1, with t=0 being P0 and t=1 being P3 | |
| 7 * @return point on curve | |
| 8 */ | |
| 9 glm::vec3 point_on_bezier_curve(const struct bezier_curve &curve, float t) | |
| 10 { | |
| 11 // clamp t as rounding errors might make it slightly out of bounds | |
| 12 t = std::clamp(t, 0.0f, 1.0f); | |
| 13 const float t_squared = t * t; | |
| 14 const float t_cubed = t * t * t; | |
| 15 const float coefficients[3] = { | |
| 16 -1*t_cubed +3*t_squared -3*t +1, | |
| 17 +3*t_cubed -6*t_squared +3*t, | |
| 18 -3*t_cubed +3*t_squared, | |
| 19 }; | |
| 20 return coefficients[0] * curve.points[0] | |
| 21 + coefficients[1] * curve.points[1] | |
| 22 + coefficients[2] * curve.points[2] | |
| 23 + t_cubed * curve.points[3]; | |
| 24 } | |
| 25 | |
| 26 /** | |
| 27 * @brief computes the derivative of a point on a Bezier curve | |
| 28 * @param curve | |
| 29 * @param t scalar between 0 and 1, with t=0 being P0 and t=1 being P3 | |
| 30 * @return point on curve | |
| 31 */ | |
| 32 glm::vec3 derivate_on_bezier_curve(const struct bezier_curve &curve, float t) | |
| 33 { | |
| 34 // clamp t as rounding errors might make it slightly out of bounds | |
| 35 t = std::clamp(t, 0.0f, 1.0f); | |
| 36 const float t_cubed = t * t; | |
| 37 const float coefficients[4] = { | |
| 38 -3*t_cubed + 6*t -3, | |
| 39 +9*t_cubed -12*t +3, | |
| 40 -9*t_cubed + 6*t, | |
| 41 +3*t_cubed | |
| 42 }; | |
| 43 return coefficients[0] * curve.points[0] | |
| 44 + coefficients[1] * curve.points[1] | |
| 45 + coefficients[2] * curve.points[2] | |
| 46 + coefficients[3] * curve.points[3]; | |
| 47 } |
