In the 3.x we have the function camera() to setup the view matrix:

```
camera(x, y, z, tx, ty, tz, ax, ay, az)
```

And we can use the functions of translate(), rotate(), scale() to setup the model matrix, we can use the ortho(), perspective() to setup the projection matrix.

Now in the Codea 4, we have the below functions:

```
-- for model matrix
matrix.translate()
matrix.rotate()
matrix.scale()
-- for projection matrix
matrix.ortho()
matrix.perspective()
-- for view matrix
?
```

In Codea 4, the camera is used as a namespace. Do we need a new function, matrix.lookAt() or other name?