# rotx

## rotation around x axis

Like all linear transformations that command is in 2 modes: direct and matrix.

## rotx obj

### rotx(an)obj(id)

Rotates the object id angle an around x axis versus its center of gravity.

### rotx(an) vertex(s) obj(id)

Rotates vertices s of the object id angle an around x axis versus its center of gravity.

### rotx(an) poi(x,y,z) obj(id)

Rotates the object id angle an around tth x axis versus point (x,y,z).
Note:
objt is fog, light, var, vol, view.
Exeamples:
`rotx(PI/2) poi(100,-20,50) vertex[1,5] vol(1,3);` x rotates vertices (1,2,3,4,5) of volumes 1 et 3 angle PI/2around point (100,-20,50).
`rotx(PI/2) var("x");` x rotates variable x angle PI/2 around its center of gravity.
`rotx(.1*PI) eye view(1);` angle .1*PI around x axis the eys of the view 1.

### rotx(a1,a2)vol(a)rotx(b1,b2)vol(b)

Varies rotx matrix vol(a) in the interval [a1,a2] when rotx matrix vol(b) varies in the interval [b1,b2].
May be used to attach rotx variations of volume a to those of its father b.
Note: rotx(b1,b2) can be any other transformation transf(b1,b2).

## rotx image

### rotx(an) image(id)

Makes identic first column and last column of the image id.
Notes:
1) an is ethe portion of the image (between 0 and PI) affected by this operation.
2) Blur appears in this portion.
3) Useful for mapping an image on a closed surface in x.
4) If identifier id is absent, the current image by default.
Example:
`rotx(.1*PI) image(1);` makes periodic the image by changing one tenth of its surface.

## rotx matrix

### rotx matrix vol(id)

Returns the angle of rotation about x of the matrix of the volume id.
Options:
format(f): modulo f.

### rotx(a)matrix vol(id)

Rotates angle a around x the volume id by changing its matrix.
Options:
ini: the transformation is the basic.

## rotx view

### rotx(an)eye view(id)

Rotates the eye of the view id angle an around x axis.

### rotx(an)aim view(id)

Rotates the aim point of the view id angle an around x axis.
Options:
validate(0): rotationfrom the initial position.