gluLookAt(3) gluLookAt(3)

## NAME

gluLookAt- define a viewing transformation

## C SPECIFICATION

voidgluLookAt( GLdoubleeyeX, GLdoubleeyeY, GLdoubleeyeZ, GLdoublecenterX, GLdoublecenterY, GLdoublecenterZ, GLdoubleupX, GLdoubleupY, GLdoubleupZ)

## PARAMETERS

eyeX,eyeY,eyeZSpecifies the position of the eye point.centerX,centerY,centerZSpecifies the position of the reference point.upX,upY,upZSpecifies the direction of theupvector.

## DESCRIPTION

gluLookAtcreates a viewing matrix derived from an eye point, a refer- ence point indicating the center of the scene, and anUPvector. The matrix maps the reference point to the negativezaxis 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. Sim- ilarly, the direction described by theUPvector projected onto the viewing plane is mapped to the positiveyaxis so that it points upward in the viewport. TheUPvector must not be parallel to the line of sight from the eye point to the reference point. Let centerX - eyeX F = centerY - eyeY centerZ - eyeZ LetUPbe the vector (upX, upY, upZ). Then normalize as follows: f = F/ || F || UP' = UP/|| UP || Finally, let s = f X UP', and u = s X f. M is then constructed as follows: s[0] s[1] s[2] 0 u[0] u[1] u[2] 0 M = -f[0] -f[1] -f[2] 0 0 0 0 1 andgluLookAtis equivalent to glMultMatrixf(M); glTranslated (-eyeX, -eyeY, -eyeZ);

## SEE ALSO

glFrustum,gluPerspectivegluLookAt(3)

Mac OS X 10.8 - Generated Sat Aug 25 18:27:18 CDT 2012