rotate a vector 90 degrees */
| 1676 | |
| 1677 | /* rotate a vector 90 degrees */ |
| 1678 | static pointObj point_rotz90(const pointObj a) { |
| 1679 | double nx=-1.0*a.y, ny=a.x; |
| 1680 | pointObj retv=a; |
| 1681 | retv.x=nx; retv.y=ny; |
| 1682 | return retv; |
| 1683 | } |
| 1684 | |
| 1685 | /* vector cross product (warning: z and m dimensions are ignored!) */ |
| 1686 | static double point_cross(const pointObj a, const pointObj b) { |