---
name: "gluLookAt"
section: "3x"
platform: "linux"
package: "xlibmesa-glu-dev"
version: "4.3.0.dfsg.1-14sarge7"
release: "Debian 3.1 (Sarge)"
platforms: ["linux"]
url: "https://new.carta.tech/gluLookAt"
---

# gluLookAt(3x)

define a viewing transformation

## NAME

**gluLookAt** - define a viewing transformation

## C SPECIFICATION

void **gluLookAt**( GLdouble *eyeX*,

```
	GLdouble eyeY,
	GLdouble eyeZ,
	GLdouble centerX,
	GLdouble centerY,
	GLdouble centerZ,
	GLdouble upX,
	GLdouble upY,
	GLdouble upZ )
```

delim $$

## PARAMETERS

- *eyeX*, *eyeY*, *eyeZ*

  Specifies the position of the eye point.

- *centerX*, *centerY*, *centerZ*

  Specifies the position of the reference point.

- *upX*, *upY*, *upZ*

  Specifies the direction of the *up* vector.

## 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 ~=~ left (  down 20 { ~ matrix {\
    ccol {"centerX" above "centerY" above "centerZ"}\
    ccol { ~-~ above ~-~ above ~-~}\
    ccol {"eyeX" above "eyeY" above "eyeZ"} } } ~~ right )

Let *UP* be the vector $("upX", "upY", "upZ")$.

Then normalize as follows:  f ~=~ F over {\|\| F \|\|}

UP sup prime ~=~ UP over {\|\| UP \|\|}

Finally, let $s ~=~ f ~times~ UP sup prime$, and $u ~=~ s ~times~ f$.

M is then constructed as follows: M ~=~ left (  matrix {\
    ccol { ~s\[0\] above ~u\[0\] above -f\[0\] above 0 }\
    ccol { ~s\[1\] above ~u\[1\] above -f\[1\] above 0 }\
    ccol { ~s\[2\] above ~u\[2\] above -f\[2\] above 0 }\
    ccol { 0 above 0 above 0  above 1 } } ~~right )

and **gluLookAt** is equivalent to  glMultMatrixf(M); glTranslated (-eyex, -eyey, -eyez);

## SEE ALSO

**glFrustum(3G)**, **gluPerspective(3G)**