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#include "config.h"
#include "point.h"
#include "vector.h"
flt dotproduct(struct vector * a, struct vector * b)
{
return a->dx * b->dx + a->dy * b->dy + a->dz * b->dz;
}
void between(struct point * p, struct point * q,
/*out*/ struct vector * v)
{
v->dx = q->x - p->x;
v->dy = q->y - p->y;
v->dz = q->z - p->z;
}
void opposite(struct vector * v,
/*out*/ struct vector * w)
{
w->dx = - v->dx;
w->dy = - v->dy;
w->dz = - v->dz;
}
void point_along(struct point * p, struct vector * v,
flt ac,
/*out*/ struct point * q)
{
q->x = p->x + v->dx * ac;
q->y = p->y + v->dy * ac;
q->z = p->z + v->dz * ac;
}
void product(struct vector * a, struct vector * b,
/*out*/ struct vector * v)
{
v->dx = a->dy * b->dz - a->dz * b->dy;
v->dy = a->dz * b->dx - a->dx * b->dz;
v->dz = a->dx * b->dy - a->dy * b->dx;
}
flt vlength2(struct vector * a)
{
return a->dx * a->dx + a->dy * a->dy + a->dz * a->dz;
}
flt vlength(struct vector * a)
{
return sqrt(vlength2(a));
}
void vscale(struct vector * a, flt s,
/*out*/ struct vector * v)
{
v->dx = a->dx * s;
v->dy = a->dy * s;
v->dz = a->dz * s;
}
void vnormalize(struct vector * a, /*out*/ struct vector * v)
{
vscale(a, 1 / vlength(a), v);
}
void vsub(struct vector * a, struct vector * b,
/*out*/ struct vector * v)
{
v->dx = a->dx - b->dx;
v->dy = a->dy - b->dy;
v->dz = a->dz - b->dz;
}
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