[c++, OpenGL] View Frustum

Na tej strani ( https://cgvr.cs.uni-bremen.de/teaching/... ) si pomagam izracunati oddaljeno levo zgordnjo tocko in ne dobim pravi rezultat. Na koncu sem moral x pomnoziti z -1.0f da mi pravilno deluje, ampak y je previsok. farTL = x=-5.22808695 y=4.99525404 z=-10.0000000.

	float farDinstance	= 10.0f;

	Vec3	camPos( 0.0f, 0.0f, 0.0f ),
			camForward( 0.0f, 0.0f, -10.0f );
		
	camForward.Normalize();

	Vec3	farCenter	= camPos + camForward * farDinstance,
			camUp( 0.0f, 1.0f, 0.0f ),
			a;

	float	farH	= 2 * tanf( DEG2RAD(54.0f) * 0.5f ) * farDinstance,
			farW	= farH * ogl.GetRatio(); // ratio: 1.04569602

	a	= camUp;
	Vec3	camRight = a.CrossProduct( camForward );
	camRight.Normalize();

	Vec3	farTL	= farCenter + (camUp * farH * 0.5f) - (camRight * farW * 0.5f);

	farTL.x *= -1.0f;