caryclark@google.com | 8dcf114 | 2012-07-02 20:27:02 +0000 | [diff] [blame^] | 1 | #include "DataTypes.h" |
| 2 | |
| 3 | void dxdy_at_t(const Quadratic& , double t, double& x, double& y); |
| 4 | |
caryclark@google.com | 639df89 | 2012-01-10 21:46:10 +0000 | [diff] [blame] | 5 | /* Parameterization form, given A*t*t + 2*B*t*(1-t) + C*(1-t)*(1-t) |
| 6 | * |
| 7 | * a = A - 2*B + C |
| 8 | * b = 2*B - 2*C |
| 9 | * c = C |
| 10 | */ |
caryclark@google.com | 27accef | 2012-01-25 18:57:23 +0000 | [diff] [blame] | 11 | inline void set_abc(const double* quad, double& a, double& b, double& c) { |
caryclark@google.com | 639df89 | 2012-01-10 21:46:10 +0000 | [diff] [blame] | 12 | a = quad[0]; // a = A |
| 13 | b = 2 * quad[2]; // b = 2*B |
| 14 | c = quad[4]; // c = C |
| 15 | b -= c; // b = 2*B - C |
| 16 | a -= b; // a = A - 2*B + C |
| 17 | b -= c; // b = 2*B - 2*C |
| 18 | } |
caryclark@google.com | 27accef | 2012-01-25 18:57:23 +0000 | [diff] [blame] | 19 | |
| 20 | int quadraticRoots(double A, double B, double C, double t[2]); |
caryclark@google.com | 8dcf114 | 2012-07-02 20:27:02 +0000 | [diff] [blame^] | 21 | |
| 22 | void xy_at_t(const Quadratic& , double t, double& x, double& y); |