ryanartecona / reprocessing

Experimental reason port of processing

Reprocessing

This is a high-level drawing library, heavily inspired by Processing and built on top of bsansouci/reasongl. This means you can write graphics code once, and have the (exact) same code compile to run on web (webgl) and native (opengl). Everything you need should be accessible from the Reprocessing module.

If you have trouble installing or want to give any input for how to make this library better, please open an issue! 😄

Install

npm install Schmavery/reprocessing#bsb-support-new

This is a library, meant to be installed as a dependency (though you can also clone and play in the examples directory). It builds using bsb-native, and you will need to install this as a devDependency of your project if you want to try out the native version. If you only want webgl support, regular bs-platform should be fine.

Example:

open Reprocessing;

let setup env => {
  Env.size width::600 height::600 env;
  Draw.fill Constants.red env
};

let draw state env => {
  Draw.background Constants.black env;
  Draw.rect pos::(150, 150) width::300 height::300 env
};

run ::setup ::draw ();

This will draw a simple red square on a black background. Compare this to reglexampleproject, which takes 200+ lines to do the exact same thing. This difference is even more notable on bigger projects. Check out the code for a draggable red square.

Some Differences from Processing

• There is no magic - everything is proper Reason code. This means that you have to call Reprocessing.run with the functions that you want to use. You also have a couple of options about which utility modules to open. See the examples directory for some different ways to do this. It is recommended to open Reprocessing at the top, and then you can optionally open Draw, Env and Utils to make it look more like Processing code. Alternatively, they can be used directly, as can be seen above.

• For state management, we encourage the use of the state value that Reprocessing manages for the user. To use this, decide on a datatype representing the state and return the initial value from setup. This will be persisted behind the scenes and passed to every callback (such as draw and mouseDown). Each callback should return the new value of the state (or the old value if it doesn't change).

• There are no built-in variables like width and mouseX. Instead, these are functions that are called, passing in an environment object that is always provided.

let draw state env => {
  let w = Env.width env;
  print_endline ("The current width is:" ^ string_of_int w)
};

• The builtin map function is called remap instead to avoid confusion with the well-known List.map function which maps over a list of values. As, according to the Processing docs, this function "Re-maps a number from one range to another.", this naming seems appropriate.

• Because of the limitations of Reason, several utility functions that would otherwise accept either an integer or a float now expose a version with an f suffix, which supports floats. Ex: random vs randomf.

• Points are expressed as tuples. Instead of exposing a mouseX and mouseY, there is a mouse, which is a tuple of x and y values.

let draw state env => {
  let (x, y) = Env.mouse env;
  print_endline ("The current mouse position is:" ^ string_of_int x ^ string_of_int y)
};

• This is 100% a work in progress. Only a small subset of Processing's functionality has been replicated. Please feel free to contribute as my knowledge of OpenGl is limited at best :)

Using Fonts

The story for using fonts in your Reprocessing app is still under some development to make it nicer. Right now we have support for writing text in a font defined in the Angel Code font format. This is basically a bitmap of packed glyph textures along with a text file that describes it. The above link gives a few different tools that can be used to generate these files. The assets folder of this repo also has an example of a font that can be copied to your project and used. In order to use a font once you have the files:

let font = Draw.loadFont ::filename env;
Draw.text ::font body::"Test!!!" pos::(10, 10) env