// written in the D programming language

module chipmunkd.cpVect;

import chipmunkd.cpVect_h;
import chipmunkd.chipmunk_types_h;

cpFloat
cpvlength(const cpVect v)
{
	return cpfsqrt( cpvdot(v, v) );
}

cpVect
cpvslerp(const cpVect v1, const cpVect v2, const cpFloat t)
{
	cpFloat omega = cpfacos(cpvdot(v1, v2));
	
	if(omega){
		cpFloat denom = 1.0f/cpfsin(omega);
		return cpvadd(cpvmult(v1, cpfsin((1.0f - t)*omega)*denom), cpvmult(v2, cpfsin(t*omega)*denom));
	} else {
		return v1;
	}
}

cpVect
cpvslerpconst(const cpVect v1, const cpVect v2, const cpFloat a)
{
	cpFloat angle = cpfacos(cpvdot(v1, v2));
	return cpvslerp(v1, v2, cpfmin(a, angle)/angle);
}

cpVect
cpvforangle(const cpFloat a)
{
	return cpv(cpfcos(a), cpfsin(a));
}

cpFloat
cpvtoangle(const cpVect v)
{
	return cpfatan2(v.y, v.x);
}

//char*
//cpvstr(const cpVect v)
//{
//	static char str[256];
//	sprintf(str, "(% .3f, % .3f)", v.x, v.y);
//	return str;
//}