aglet

A safe, high-level core OpenGL 3.3+ context manager and wrapper for Nim.

Documentation

Note: As of June 2021, I'm no longer actively working on aglet. Since the project is still quite unfinished, I'm willing to accept contributions via PRs. If anyone contributes code frequently enough, I'm willing to give them contributor status to make working on the project easier.

Features

No state machine

OpenGL is a mess—it's a giant state machine, and it's hard to keep track of its current state. Modern programming languages are more suited towards using objects for resource allocation and managenent, and that's what aglet strives to provide. aglet uses Nim's type system to ensure OpenGL type safety. When you get a Texture2D object, you can be sure it's a 2D texture. It's not a vague GLuint that does not really describe anything. Apart from that, you don't have to worry about keeping track of all this state—aglet does all the bookkeeping for you, and even avoids unnecessary API calls via some simple and cheap if statements.

The main goal is to provide a safe API around the core GL API, which is made primarily for C. aglet embraces Nim's features like concepts to make the wrapper generic and extendable. Forget having to deal with pointers and other unsafe features—aglet abstracts that away by using safe containers, like openArrays. Forget all the state management—aglet abstracts it away via safe, stateless objects that make your code much easier to maintain. What your code reads is really what it does—you don't have to scan your codebase to find out which texture is currently bound.

No global variables

Forget about GLAD's global variables—aglet is fully safe for dynamic loading via the std/dynlib module. All loaded OpenGL procs are stored in the abstract Window class.

Fast check times

Import the context backend once, and don't think about it ever since. The abstract codebase is lightweight and does not use any Nimterop wrappers, which are known to slow down nim check, which is used by many editor extensions (most notably the Visual Studio Code extension). At some point aglet will remove its GLFW dependency completely, but that's what it uses for now to help develop core features quicker.

Short, generic code

Code written using aglet is much shorter than the equivalent code written in libraries imported from C. It abstracts all the verbosity away to keep your codebase small and concise.

Idiomatic and error-free

aglet takes advantage of Nim features such as distinct types to make your code less error-prone. For instance, it's not possible to attach a Renderbuffer[Depth32f] to a color-only framebuffer, because a Renderbuffer[Depth32f] does not implement a converter to ColorSource. Combine this with other small utility features, and aglet code is much less error-prone than the equivalent C code.

It's free

aglet is and will always be free. It's licensed under the MIT license, so you're free to use it in commercial projects.

Examples

Opening a window

import aglet
import aglet/window/glfw  # we need a backend for windowing

# initialize the library state
var agl = initAglet()
agl.initWindow()

# create our window
var win = agl.newWindowGlfw(800, 600, "window example",
                            winHints(resizable = false))

# begin the render loop
while not win.closeRequested:

  # render
  var frame = win.render()
  frame.clearColor(rgba(0.0, 0.0, 1.0, 1.0))
  frame.finish()

  # handle events
  win.pollEvents do (event: InputEvent):
    echo event

You can find more examples in the tests/ directory.

Roadmap

• Context management
  • via GLFW
  • pure Nim implementation
• Generic render target
  • DrawParams object as a replacement for the state machine
• Vertex buffers (Mesh)
  • Vertex buffer
  • Element (index) buffer
  • Buffer slicing
  • Instancing
• Shaders and programs
• Textures
  • Types
    • 1D, 2D, 3D
    • 1D array, 2D array
    • Cube map
  • Features
    • Texture units
    • Sampler objects
    • Texture swizzle mask
• Framebuffers
  • Renderbuffers
  • SimpleFramebuffer (one color attachment)
  • MultiFramebuffer (≥1 color attachment)

Please report any extra features you'd like to see in the Issues tab!

Installation

By adding it your dependencies:

requires "aglet >= 0.1.0"

Via the nimble command:

$ nimble install aglet

Manually:

$ git clone https://github.com/liquid600pgm/aglet
$ cd aglet
$ nimble install