/* 		---------------							*/
/* 		Data structures							*/
/* 		---------------							*/
typedef	float					Scalar;
typedef struct { Scalar x, y; } Vector;

/*		---------------------------				*/
/*		Vector Operation Prototypes				*/
/*		---------------------------				*/

void 	SetVector(Vector *v, Scalar x, Scalar y);
Scalar	Distance(Vector v1, Vector v2);
Scalar	Magnitude(Vector v);
void 	Direction(Vector vin, Vector *vout);
void 	VectorSum(Vector v1, Vector v2, Vector *vsum);
void 	VectorDifference(Vector v1, Vector v2, Vector *vdiff);
void 	VectorByScalar(Vector vin, Scalar s, Vector *vprod);
Scalar 	DotProduct(Vector v1, Vector v2);
Boolean	Constrain(Vector *v, Rect r);

/************************************************/
/*		Vector Operation Routines				*/
/************************************************/

void SetVector(Vector *v, Scalar x, Scalar y)
{
	v->x = x;
	v->y = y;
}

Scalar Distance(Vector v1, Vector v2)
{
	Scalar dx, dy;
	
	dx = v1.x - v2.x;
	dy = v1.y - v2.y;
	return (Scalar)sqrt((double)(dx * dx + dy * dy));
}

Scalar Magnitude(Vector v)
{
	return (Scalar)sqrt((double)(v.x * v.x + v.y * v.y));
}

void Direction(Vector vin, Vector *vout)
{
	Scalar mag;
	
	mag = Magnitude(vin);
	if (mag == 0.0) mag = 0.01;
	vout->x = vin.x / mag;
	vout->y = vin.y / mag;
}

void VectorSum(Vector v1, Vector v2, Vector *vsum)
{
	vsum->x = v1.x + v2.x;
	vsum->y = v1.y + v2.y;
}

void VectorDifference(Vector v1, Vector v2, Vector *vdiff)
{
	vdiff->x = v1.x - v2.x;
	vdiff->y = v1.y - v2.y;
}

void VectorByScalar(Vector vin, Scalar s, Vector *vprod)
{
	vprod->x = vin.x * s;
	vprod->y = vin.y * s;
}

Scalar DotProduct(Vector v1, Vector v2)
{
	return (v1.x * v2.x) + (v1.y * v2.y);
}

Boolean Constrain(Vector *v, Rect r)
{
	Boolean b = false;
	
	if (v->x > (Scalar)(r.right))
	{
		v->x = (Scalar)(r.right);
		b = true;
	}
	if (v->x < (Scalar)(r.left))
	{
		v->x = (Scalar)(r.left);
		b = true;
	}
	if (v->y > (Scalar)(r.bottom))
	{
		v->y = (Scalar)(r.bottom);
		b = true;
	}
	if (v->y < (Scalar)(r.left))
	{
		v->y = (Scalar)(r.left);
		b = true;
	}
	return b;
}

void ScalarToPString(Scalar num, StringPtr str, char *fmt)
{
	sprintf((char *)str, fmt, (double)num);
	CtoPstr((char *)str);
}

void PStringToScalar(StringPtr str, Scalar *num)
{
	int numargs;
	double d;
	
	PtoCstr((unsigned char *)str);
	numargs = sscanf((char *)str, "%lg", &d);
	*num = (Scalar)d;
}