[Caml-list] SDL2 bindings, testers and feedback welcome

["Daniel Bünzli" <daniel.buenzli@erratique.ch>]

Hello, 

I have written thin bindings to SDL 2 using ocaml-ctypes. The binding
is finished but should be considered unstable: it was not thoroughly
tested and may still change as it has not been *used* yet. The purpose
of this unstable release is to:

1) Iron out the install procedure and test on a variety of platforms.
2) Get feedback about the design of the binding (see below). 

More precisely, apart from the eventual bugs, I'm interested in
getting feedback in the following areas:

* I used an 'a result = [ `Error | `Ok of 'a ] rather than an exception 
for functions that return error codes/null is error. I tend to lean
on exceptionless designs but I'm still unsure whether it is a good
idea that case. One of the problems is that SDL doesn't make a clear
distinction (at the signature level *and* in the documentation)
between programming errors (invalid_arg), exceptional errors
(e.g. out of memory) and non-exceptional errors (e.g. could not
access/setup a resource).

* The signature/approach of certain binding functions may be disputable 
or may need change to achieve reasonable performance. 

* Testing the binding to the joystick/game controller/force feedback api, 
I have none of these things in my hands.

I welcome discussions/ideas about these points and the general design
of the binding on github's issue tracker (http://github.com/dbuenzli/tsdl)

Note that the philosophy of the binding is to be "thin", that is a
mostly type-safe(r), minimal, hopefully efficient, one-to-one
binding. This means that I'm not interested in prettyfing the C API
like OCamlSDL does. I expect tsdl code to look like C SDL code
(including the inconsistent naming schemes) and the binding to be used
by programmers to build higher-level, more OCaml friendly, abstractions.

To install (only tested on osx and linux so far) you'll need at least SDL 2.0.1
installed on your system. Then:

opam repo add erratique-u http://erratique.ch/software/opam/unreleased
opam update && opam install tsdl 

On osx 10.8.5 with OCaml 4.01.0 there's a heisenbug I couldn't track so far
(see [1] for more info). Use 4.00.1 instead for now but note that the binding 
takes a long time to compile (~8 min on my machine) with that. 

If you want to hack the sources:

  git clone http://github.com/dbuenzli/tsdl 
  cd tsdl && ./build test.native && ./test.native

The documentation of the binding is here:

  http://erratique.ch/software/tsdl/doc/Tsdl

Best,

Daniel

[1] http://lists.ocaml.org/pipermail/ctypes/2013-December/000027.html

P.S. If anyone wonders, the existing OCamlSDL is a very good binding
to SDL 1.X, but SDL 2.0 is an entirely new, incompatible, API. Besides
SDL 2.0 changed to a zlib license, tsdl is under BSD3, OCamlSDL is
LGPL.