Starlet: Stage lighting control in Lisp
=======================================

Starlet is an experimental Lisp-based domain-specific language (DSL) for
theatrical lighting control.  It's based on
[Guile](https://www.gnu.org/software/guile/) and sends its DMX output via
[OLA](https://openlighting.org) to almost any type of lighting control
interface - DMX, sACN, Art-Net etc.  Starlet also undertands MIDI, enabling you
to control lights and cues with physical faders, knobs and buttons.

Click for a video demonstration:
[![Video demonstration](screenshot.png)](https://vimeo.com/520547229)

With Starlet, a cue list looks like this:

```
(define my-cue-list
  (cue-list

   (cue 1
        (lighting-state (at dim1 '100))
                        (at mh1 'pan 25))
        #:fade-up 3
        #:fade-down 5)

   (cue 2
        (lighting-state (at dim1 '50)
                        (at dim2 '100)
                        (at mh1 'pan 50))
        #:fade-up 3
        #:fade-down 1
        #:down-delay 3)

   (cue 3
        (lighting-state #f)  ; blackout
        #:fade-down 2
```

Creating a playback object and running a cue list looks like this:

```
(define pb (make-playback #:cue-list my-cue-list))

(cut-to-cue-number! pb 1)
(go! pb)
(go! pb)
(go! pb)  ; and so on
```

Lighting states can be prepared separately and assigned to variables:

```
(define spooky-dungeon
  (lighting-state
    (at dimmer1 20)
    (at dimmer2 20)
    (at moving-light 70)
    (at moving-light 'red 100)
    (at moving-light 'green 10)
    (at moving-light 'blue 12)))
```

You can use pre-prepared states in cues, even if some minor modifications are
needed.  This makes it really easy to understand the contents of a cue without
having to interpret a screenful of numbers:

```
(cue 57
     (lighting-state (apply-state spooky-dungeon)
                     (at follow-spot 100))
     #:fade-up 3
     #:fade-down 3)
```

Multi-part cues are supported.  Simply specify the fade parameters and which
fixtures should be in the part:

```
(cue 64
     (lighting-state (apply-state indoor-act1-general)
     #:fade-up 3
     #:fade-down 3

     (cue-part (dim3
                dim4
                dim8
                (list moving-light 'pan 'tilt))
               #:down-time 2
               #:down-delay 1))
```


Everything from a simple dimmers to wacky multi-parameter fixtures are
supported.  New fixture classes can be defined using some simple Scheme code.
Patching fixtures looks like this:

```
(patch-fixture! dimmer1 <generic-dimmer> 1))
(patch-fixture! dimmer2 <generic-dimmer> 3))
(patch-fixture! balcony-backlight1 <generic-dimmer> 18))
(patch-fixture! balcony-backlight2 <generic-dimmer> 19))
(patch-fixture! footlights <generic-dimmer> 23))
;; Universe numbering starts at zero, matching OLA
(patch-fixture! moving-light <robe-dl7s-mode1> 1 #:universe 4))
```

Note that the names of the fixtures are just normal Scheme variables.  They can
be anything you like, and you're encouraged to make the names more descriptive
than logical channel numbers, where appropriate.


Getting started
---------------

1. Install and set up [OLA](https://openlighting.org) for your lighting
   environment.
2. Install [Guile](https://www.gnu.org/software/guile/), if it's not already
   there.  Version 3 is required.
3. Install Starlet:
    `meson build`, `ninja -C build` and `sudo ninja -C build install`
4. Start olad if it's not already running: `olad -l 3` (in a separate
   terminal).
5. Run `guile`.
6. Once in the Guile REPL, import some Starlet modules:
    `(use-modules (starlet scanout) (starlet state) (starlet fixture-library
    generic dimmer))`
7. Patch a fixture:
    `(patch-fixture! mydimmer <generic-dimmer> 1 #:universe 2)`
   Replace 1 and 2 with the DMX address and universe (respectively) of a real
   dimmer.
8. Turn the dimmer on with `(at mydimmer 100)`
9. Look in the _examples_ and _docs_ folders for more advanced ideas.


Related projects
----------------

There are many stage lighting software projects, but most of them seem to
concentrate on "disco style" effects and chases whereas Starlet is aimed more
towards theatre shows.  Here are some that I found especially interesting:


* [Fivetwelve-CSS](https://github.com/beyondscreen/fivetwelve-css) DMX lighting
  control using CSS. [Watch this video](https://www.youtube.com/watch?v=ani_MOZt5_c)
* [Afterglow](https://github.com/Deep-Symmetry/afterglow) Clojure live coding
  environment using OLA
* [QLC+](https://qlcplus.org/) the most popular open-source lighting control
  program

It's also worth taking a look at the
[stage-lighting topic](https://github.com/topics/stage-lighting) on Github.


Licence
-------

Starlet is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.

Starlet is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.  See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
Starlet.  If not, see <http://www.gnu.org/licenses/>.