Sunday, March 27, 2016

Almost there with Solarus

Every so often I'll have a go at getting some games running on Tribblix. It's not a gaming platform, but having the odd distraction can't hurt.

I accidentally stumbled across Solarus, and was immediately intrigued. Back in the day, I remember playing Zelda on the SNES. A few years ago it was released for the Game Boy Advance, and I actually went out and bought the console and the game. I haven't added any more games, nothing seemed compelling, although we had a stock of old Game Boy games (all mono) and those still worked, which is great.

So I thought I would try and build Solarus for Tribblix. Having had a quick look at the prerequisites, most of those would be useful anyway so the effort wouldn't be wasted in any event.

First up was SDL 2.0. I've had the older 1.2.15 version for a while, but hadn't had anything actually demand version 2 yet. That was easy enough, and because all the filenames are versioned, it can happily be installed alongside the older version.

While I was at it, I installed the extras SDL_image, SDL_net, SDL_ttf, smpeg, and SDL_mixer. The only build tweak needed was to supply LIBS="-lsocket -lnsl" to the configure script for smpeg and SDL_net. I needed to version the plaympeg binary installed by smpeg to avoid a conflict with the older version of smpeg, but that was about it.

Then came OpenAL, which turned out to be a bit tricky to find. Some of the obvious search results didn't seem appropriate. I have no idea whether the SourceForge site is the current one, but it appears to have the source code I needed.

Another thing that looks abandoned is modplug, where the Solarus folks have a github mirror of the copy that's right for them.

Next up, PhysicsFS. This isn't quite what you expect from the name, it's an abstraction layer that replaces traditional file system access.

On to Solarus itself. This uses cmake to build, and I ended up with the following incantation in a new empty build directory:

cmake ../solarus-1.4.5 \
 -DCMAKE_INSTALL_RPATH=/opt/solarus/lib \

Let's go through that. The CMAKE_INSTALL_PREFIX is fairly obvious - that's where I'm going to install it. And SOLARUS_USE_LUAJIT is necessary because I've got Lua, but have never had LuaJIT working successfully.

The two RPATH lines are necessary because of the strange way that cmake handles RPATH. Usually, it builds with RPATH set to the build location, then installs with RPATH stripped. This is plain stupid, but works when you simply dump everything into a single swamp. So you need to manually force it to put the correct RPATH into the binary (which is the sort of thing you would actually want a build system to get right on its own).

Unfortunately, it doesn't actually work properly. There are two problems which I haven't really had a chance to look at - the first is that it fails fatally with an Xlib error if I move the mouse (which is a little odd as it doesn't actually use the mouse); the second is that it runs an order of magnitude or two slower than useful, so I suspect a timing error.

Still, the build is pretty simple and it's so close to working that it would be nice to finish the job.

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