What is this?

luminance is an effort to make graphics rendering simple and elegant in Haskell. It’s forked from a larger project which was closed because way too complex and bloated. The aims of luminance are:

• providing a simple API ;
• abstract over the trending hardware interfaces (i.e. OpenGL up to now) and approach as close as possible a stateless design ;
• being a tiny API, so that new comers don’t have to learn a lot of new concepts to get their feet wet.

The first version of luminance will be released of hackage and stackage as a BSD3 library.

What’s included?

luminance is a rendering framework, not a 3D engine. As so, it doesn’t include stuff like lights, materials, asset management nor scene description. It only provides a rendering framework you can plug in whatever libraries you want to. The single restriction – yet – is that you must have an operating system with OpenGL installed.

Features set

• buffers: buffers are way to communicate with the GPU; they represent regions of memory you can write to and read from. There’re several kinds of buffers you can create, among vertex and index buffers, shader buffer, compute buffer, and so on and so forth… ;
• framebuffers: framebuffers are used to hold renders. Each time you want to perform a render, you need to perform it into a framebuffer. Framebuffers can then be combined with each other to produce nice effects ;
• shaders: luminance support six kinds of shader stages:
  • tessellation control shaders ;
  • tessellation evaluation shaders ;
  • vertex shaders ;
  • geometry shaders ;
  • fragment shaders ;
  • compute shaders ;
• vertices, indices, primitives and shapes: those are used to define a shape you can render into a framebuffer
• textures: textures represent information packed into arrays on the GPU, and can be used to customize a visual aspect or pass information around ;
• blending: blending is the process of taking two colors from two framebuffers and mix them between each other ;
• and a lot of other cool things

What are the prerequisites?

In order to use luminance, you need several prerequisites to be fulfilled. Those prerequisites determine which backend you will be able to use. Currently, two backends are available: gl33 and gl45.

• a library to setup an OpenGL context.
• gl33
  • a decent OpenGL 3.3 implementation
  • support for extension GL_ARB_texture_cube_map
• gl45
  • a decent OpenGL 4.5 implementation
• gl-45-bindless-textures (bonus)
  • a decent OpenGL 4.5 implementation
  • support for extension GL_ARB_bindless_texture ;

The backends can be enabled through compilation flags. You should only pick one as the more recent will be preferred over others. However, some of the flags can be combined. If you want bindless textures, you should enable the flags gl45 and gl-bindless-textures.

luminance does not provide point a way to create windows because it’s important that it not depend on windowing libraries so that end-users can use whatever they like. Furthermore, such libraries typically implement windowing and events features, which have nothing to do with our initial purposes. However, a few packages might come up, like luminance-glfw if such libraries are judged useful.

How to dig in?

luminance is written to be fairly simple. The documentation – on hackage – is very transparent about what the library does and several articles will appear as the development goes on. Keep tuned!