Game Development Reference
In-Depth Information
Theviewmatrix placesthecamera attheoriginofthescene,theprojection matrixrequires
that the camera is placed at (0,0,-D), translated in the z-axis by -D, the concatenation of
these matrices yields the composite matrix:
This matrix translates andscales objects fromsome distance tothe camera'snear plane but
it does not take into account the field of view and the z values it produces at a distance
may be nearly identical making depth comparisons unreliable. To address these issues the
projection matrix can be adjusted to take into account the field of view.
Where
z
n
is the value of the near plane, that is, the distance from the camera to the start of
the viewing frustum, it stands that
z
f
represents the far plane, the idea of which is that any
objectthatfallsbeyondthisdistanceisnotconsideredtobevisible.Thefieldofviewofthe
camera can be represented by two angles, the horizontal field of view
Ɵ
w
and the vertical
field of view
Ɵ
h
which are used to derive the values for
w
and
h
.