LambdaCube and Bullet on Hackage at last

Yesterday we sat down with Csaba to finally clean up the code a little bit and wrap it into, ehm, cabbages. Since this is basically an early snapshot of a rather volatile codebase, there is no documentation beyond a simple start-up guide. In its present state, it is mainly aimed at fanatics, and we made it available in the hope of attracting early feedback.

So what is there on offer? As a first step, I recommend installing lambdacube-examples, which works out of the box. We tried it on Linux as well as a freshly installed Haskell Platform on XP. It gives you two executables: lambdacube-basic, a rather psychedelic experience that shows off some basic features, and lambdacube-cameratrack, a simple non-interactive example. Note the readme in lambdacube-engine, which tells you how to make resources (models, textures, scripts etc.) accessible to your program.

The other half of the deal is the Bullet binding, which contains a little C wrapper around the C++ API, so it doesn’t rely on the rather limited C interface that the library provides. Note that there is an example that requires OpenGL, which also uses unsafeCoerce to convert from CFloat (exposed by the Bullet binding) to GLfloat (which is actually a newtype wrapper around CFloat), because the performance of realToFrac is beyond obscene. We could use some advice on how to deal with this problem in a less fragile way.

Anyway, if you managed to install the binding, you can also try lambdacube-bullet, which shows how to use the two libraries together. Note that meshes can be turned into collision shapes. In this case, the same shape is used for rendering and dynamics, so the simulation is rather slow. If we used a less detailed convex mesh, animation would be smooth even with a hundred objects interacting.

Finally, if you checked the screenshots on the LambdaCube wiki page, you could see that we also have some code to load the content of Tile Racer to some extent. Unfortunately, we cannot distribute the content, and it needs some preprocessing (which requires a working Ogre3D installation) in order for our program to be able to deal with it, so you’ll have to do some manual work to get it working. The track loader can be found in the rather unorganised obsolete branch of the source repository.

That’s it for now. Have fun with it, but prepare for some bumps.

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