Getting started

The deck system

While you can build all your slides in pure C++, you have to recompile each time you want to see an update. This can be frustrating for simple slide creation like text, math and images. To avoid this, you can instead build your presentation fully interactivly without having to recompile most of the time.

The deck system splits a presentation in two:

• composition (which content, on which slide, at which position) lives in a deck.yaml manifest, hot-reloaded while the presentation runs;
• behavior (updaters, computed meshes, anything that needs real code) stays in C++ and is exposed to the manifest by registering objects.

Editing the manifest, a latex definition, or a saved camera while the show runs recomposes the slides in place.

A minimal deck project

#include "slope.h"

using namespace slope;

DeckLoader deck;

int main(int argc, char** argv) {
    deck.init("my_talk", "deck.yaml", argc, argv);

    // C++-defined content, referenced by name in the manifest
    deck.registerObject("spot", [](){ return Mesh::Add("spot.obj"); });

    deck.run();
    return 0;
}

with next to it a deck.yaml:

slides:
  - frame:
      - title: My talk
      - latex: it starts \emph{here}
        at: [0.5, 0.6]
  - frame:
      - title: A mesh, from C++
      - object: spot
      - step:
          - load: my_key        # content from the latex definitions file

init also loads a latex definitions file (see dynamic latex) and a latex preamble, both hot-reloaded too. Their paths are given at the top of the manifest with the latex: and commands: keys; when omitted, the project's latex.json and commands.tex are used if they exist.

latex: my_definitions.json
commands: my_preamble.tex
slides:
  - ...

What hot reload watches

File	Effect when edited
deck.yaml	slides are recomposed in place
latex definitions file	edited entries are recompiled
latex preamble file	every formula is recompiled
saved camera views	the view is reloaded
views/params.json	tunable parameters are updated

A parse error in the manifest is printed to the terminal and the previous composition stays on screen.

Next: the full manifest format, and registering C++ objects.