vec2.c

/*
 * See Licensing and Copyright notice in naev.h
 */
#include <stdio.h>
#include <stdlib.h>
 
#include "naev.h"
#include "vec2.h"
 
void vec2_cset( vec2* v, double x, double y )
{
   v->x     = x;
   v->y     = y;
   v->mod   = MOD(x,y);
   v->angle = ANGLE(x,y);
}
 
void vec2_csetmin( vec2* v, double x, double y )
{
   v->x = x;
   v->y = y;
}
 
void vec2_pset( vec2* v, double mod, double angle )
{
   v->mod   = mod;
   v->angle = angle;
   v->x     = v->mod*cos(v->angle);
   v->y     = v->mod*sin(v->angle);
}
 
void vectnull( vec2* v )
{
   v->x     = 0.;
   v->y     = 0.;
   v->mod   = 0.;
   v->angle = 0.;
}
 
double vec2_angle( const vec2* ref, const vec2* v )
{
   double x = v->x - ref->x;
   double y = v->y - ref->y;
   return ANGLE( x, y );
}
 
void vec2_cadd( vec2* v, double x, double y )
{
   v->x    += x;
   v->y    += y;
   v->mod   = MOD(v->x,v->y);
   v->angle = ANGLE(v->x,v->y);
}
 
void vec2_padd( vec2* v, double m, double a )
{
   v->x    += m*cos(a);
   v->y    += m*sin(a);
   v->mod   = MOD(v->x,v->y);
   v->angle = ANGLE(v->x,v->y);
}
 
void vec2_reflect( vec2* r, const vec2* v, const vec2* n )
{
   double dot = vec2_dot( v, n );
   r->x     = v->x - ((2. * dot) * n->x);
   r->y     = v->y - ((2. * dot) * n->y);
   r->mod   = MOD(r->x,r->y);
   r->angle = ANGLE(r->x,r->y);
}
 
double vec2_dot( const vec2* a, const vec2* b )
{
   return a->x * b->x + a->y * b->y;
}
 
void vec2_uv( double* u, double* v, const vec2* source, const vec2* reference_vector )
{
   vec2 unit_parallel, unit_perpendicular;
 
   vec2_uv_decomp( &unit_parallel, &unit_perpendicular, reference_vector );
 
   *u = vec2_dot(source, &unit_parallel);
   *v = vec2_dot(source, &unit_perpendicular);
}
 
void vec2_uv_decomp( vec2* u, vec2* v, const vec2* reference_vector )
{
   vec2_pset(u, 1, VANGLE(*reference_vector));
   vec2_pset(v, 1, VANGLE(*reference_vector)+M_PI_2);
}