Game Development Reference

In-Depth Information

nical terms). The following diagram is an example of a camera frustum, where
FOV

stands for
field of view
:

gluLookAt

The
gluLookAt
function multiplies the currently selected matrix by a view matrix

generated from nine
double
s (essentially three vectors), which represents the eye

position, the point at which the camera is looking at, and a vector that represents

which direction is up. The up vector is used to assist in defining the camera's rotation.

To use common angular rotation vernacular, if we only define a position and target,

that gives us the pitch and yaw we need, but there's still the question of the roll, so

we use the up vector to help us calculate it.

glViewport

Finally,
glViewport
() is used to describe the current
Viewport
, or where we

should draw the current camera's view of the scene in the application window. Typ-

ically, this would stretch to the bounds of the window from
0
,
0
to w,
h
(where
w
and

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