Glulookat - HP b2600 Reference Manual

gluLookAt

gluLookAt: define a viewing transformation.
C Specification
void gluLookAt(
Parameters
eyeX, eyeY, eyeZ Specifies the position of the eye point.
centerX, centerY, centerZ
upX, upY, upZ
Description
gluLookAt creates a viewing matrix derived from an eye point, a reference point
indicating the center of the scene, and an up-vector.
The matrix maps the reference point to the negative Z axis and the eye point to the
origin. When a typical projection matrix is used, the center of the scene therefore maps
to the center of the viewport. Similarly, the direction described by the up-vector projected
onto the viewing plane is mapped to the positive Y axis so that it points upward in the
viewport. The up-vector must not be parallel to the line of sight from the eye point to the
reference point.
Let
F = (centerx - eyex, centery - eyey, centerz- eyez), let up be the vector (upX, upY, upZ),
and then normalize as follows:
f
and
Finally, let s = f
M is then constructed as follows:
Chapter 10
GLdouble eyeX.
GLdouble eyeY,
GLdouble eyeZ,
GLdouble centerX,
GLdouble centerY,
GLdouble centerZ,
GLdouble upX,
GLdouble upY,
GLdouble upZ)
Specifies the position of the reference point.
Specifies the direction of the up-vector.
F
= -------- -
F
up
up = ----------- -
up
up, and u = s f.
L
gluLookAt
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