CVector::ToScreen

CVector CVector::ToScreen(const CVector& CamPos, const CAngle& CamAngle, double FOV, unsigned int ScreenWidth, unsigned int ScreenHeight) const
{
	CVector up = CamAngle.Up();
	CVector right = CamAngle.Right();
	CVector forward = CamAngle.Forward();

	CVector dir = CamPos - *this;
	double fdp = forward.Dot(dir);

	if(fdp == 0)
		return CVector(0, 0);

	double d = 4.0 * ScreenHeight / (6.0 * tan(rads(0.5 * FOV)));
	CVector proj = dir * (d / fdp);

	double x = 0.5 * ScreenWidth + right.Dot(proj);
	double y = 0.5 * ScreenHeight - up.Dot(proj);

	return CVector(x, y, 0.0);
}