go-opengl-pixel/README.md

Pixel

A hand-crafted 2D game library in Go. Take a look into the features to see what it can do.

go get github.com/faiface/pixel

If you are using Modules (Go 1.11 or higher) and want a mutable copy of the source code:

git clone https://github.com/faiface/pixel # clone outside of $GOPATH
cd pixel
go install ./...

See requirements for the list of libraries necessary for compilation.

All significant changes are documented in CHANGELOG.md.

Tutorial

The Wiki of this repo contains an extensive tutorial covering several topics of Pixel. Here's the content of the tutorial parts so far:

• Creating a Window
• Drawing a Sprite
• Moving, scaling and rotating with Matrix
• Pressing keys and clicking mouse
• Drawing efficiently with Batch
• Drawing shapes with IMDraw
• Typing text on the screen
• Using a custom fragment shader

Examples

The examples repository contains a few examples demonstrating Pixel's functionality.

To run an example, navigate to it's directory, then go run the main.go file. For example:

$ cd pixel-examples/platformer
$ go run main.go

Here are some screenshots from the examples!

Lights	Platformer

Smoke	Typewriter

Raycaster	Gizmo

Features

Here's the list of the main features in Pixel. Although Pixel is still under heavy development, there should be no major breakage in the API. This is not a 100% guarantee, though.

• Fast 2D graphics
  • Sprites
  • Primitive shapes with immediate mode style IMDraw (circles, rectangles, lines, ...)
  • Optimized drawing with Batch
  • Text drawing with text package
• Audio through a separate Beep library.
• Simple and convenient API
  • Drawing a sprite to a window is as simple as sprite.Draw(window, matrix)
  • Wanna know where the center of a window is? window.Bounds().Center()
  • ...
• Full documentation and tutorial
• Works on Linux, macOS and Windows
• Window creation and manipulation (resizing, fullscreen, multiple windows, ...)
• Keyboard (key presses, text input) and mouse input without events
• Well integrated with the Go standard library
  • Use "image" package for loading pictures
  • Use "time" package for measuring delta time and FPS
  • Use "image/color" for colors, or use Pixel's own color.Color format, which supports easy multiplication and a few more features
  • Pixel uses float64 throughout the library, compatible with "math" package
• Geometry transformations with Matrix
  • Moving, scaling, rotating
  • Easy camera implementation
• Off-screen drawing to Canvas or any other target (Batch, IMDraw, ...)
• Fully garbage collected, no Close or Dispose methods
• Full Porter-Duff composition, which enables
  • 2D lighting
  • Cutting holes into objects
  • Much more...
• Pixel let's you draw stuff and do your job, it doesn't impose any particular style or paradigm
• Platform and backend independent core
• Core Target/Triangles/Picture pattern makes it easy to create new drawing targets that do arbitrarily crazy stuff (e.g. graphical effects)
• Small codebase, ~5K lines of code, including the backend glhf package

Related repositories

Here are some packages which use Pixel:

• TilePix Makes handling TMX files built with Tiled trivially easy to work with using Pixel.
• spriteplus Basic SpriteSheet and Animation implementations
• PixelUI Imgui-based GUIs for Pixel
• pixelutils Variety of game related utilities (sprite packer, id generator, ticker, sprite loader, voronoia diagrams)

Missing features

Pixel is in development and still missing few critical features. Here're the most critical ones.

• Audio
• Drawing text
• Antialiasing (filtering is supported, though)
• Advanced window manipulation (cursor hiding, window icon, ...)
• Better support for Hi-DPI displays
• Mobile (and perhaps HTML5?) backend
• More advanced graphical effects (e.g. blur) (solved with the addition of GLSL effects)
• Tests and benchmarks
• Vulkan support

Implementing these features will get us to the 1.0 release. Contribute, so that it's as soon as possible!

Requirements

If you're using Windows and having trouble building Pixel, please check this guide on the wiki.

PixelGL backend uses OpenGL to render graphics. Because of that, OpenGL development libraries are needed for compilation. The dependencies are same as for GLFW.

The OpenGL version used is OpenGL 3.3.

• On macOS, you need Xcode or Command Line Tools for Xcode (xcode-select --install) for required headers and libraries.
• On Ubuntu/Debian-like Linux distributions, you need libgl1-mesa-dev and xorg-dev packages.
• On CentOS/Fedora-like Linux distributions, you need libX11-devel libXcursor-devel libXrandr-devel libXinerama-devel mesa-libGL-devel libXi-devel libXxf86vm-devel packages.
• See here for full details.

The combination of Go 1.8, macOS and latest XCode seems to be problematic as mentioned in issue #7. This issue is probably not related to Pixel. Upgrading to Go 1.8.1 fixes the issue.

Contributing

Join us in the Discord Chat!

Pixel is in, let's say, mid-stage of development. Many of the important features are here, some are missing. That's why contributions are very important and welcome! All alone, I will be able to finish the library, but it'll take a lot of time. With your help, it'll take much less. I encourage everyone to contribute, even with just an idea. Especially welcome are issues and pull requests.

However, I won't accept everything. Pixel is being developed with thought and care. Each component was designed and re-designed multiple times. Code and API quality is very important here. API is focused on simplicity and expressiveness.

When contributing, keep these goals in mind. It doesn't mean that I'll only accept perfect pull requests. It just means that I might not like your idea. Or that your pull requests could need some rewriting. That's perfectly fine, don't let it put you off. In the end, we'll just end up with a better result.

Take a look at CONTRIBUTING.md for further information.

License

MIT