lookat(3G) lookat(3G)
NAME
lookat - defines a viewing transformation
C SPECIFICATION
void lookat(vx, vy, vz, px, py, pz, twist)
Coord vx, vy, vz, px, py, pz;
Angle twist;
PARAMETERS
vx expects the x coordinate of the viewing point.
vy expects the y coordinate of the viewing point.
vz expects the z coordinate of the viewing point.
px expects the x coordinate of the reference point.
py expects the y coordinate of the reference point.
pz expects the z coordinate of the reference point.
twist expects the angle of rotation.
DESCRIPTION
lookat defines the viewpoint and a reference point on the line of sight
in world coordinates. The viewpoint is at (vx, vy, vz), and is the
position from which you are looking. The reference point is at
(px, py, pz), and is the location on which the viewpoint is centered.
The viewpoint and reference point define the line of sight. twist
measures right-hand rotation about the line of sight. A twist of 0
corresponds to the world coordinate Y axis being aligned with the screen
coordinate Y axis.
The matrix computed by lookat premultiplies the current matrix, as
specified by mmode. lookat is typically called only while mmode is
either MSINGLE or MVIEWING.
SEE ALSO
mmode, polarview
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