Elm bindings for regl.
Aims to provide a set of declarative APIs to use WebGL in Elm through regl. Users don't need to worry about the low-level implementation but can write flexible, powerful effects using shaders efficiently.
You can learn how to use Elm-regl in the following ways:
- See the examples in test.
- Read the API docs.
HTML:
<!DOCTYPE HTML>
<html>
<head>
<meta charset="UTF-8">
<title>Elm</title>
<script type="text/javascript" src="Main.js"></script>
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/elm-regl-js@1.2.1/dist/regl.js"></script>
<link rel="stylesheet" href="style.css">
</head>
<body oncontextmenu="return false;">
<div id="myapp"></div>
</body>
<script type="text/javascript">
var app = Elm.Main.init({
node: document.getElementById('myapp')
});
if (app.ports.setView) {
app.ports.setView.subscribe(function (v) {
ElmREGL.setView(v);
});
}
if (app.ports.execREGLCmd) {
app.ports.execREGLCmd.subscribe(function (v) {
ElmREGL.execCmd(v);
});
}
const canvas = document.getElementById('elm-regl-canvas');
ElmREGL.init(canvas, app, []);
</script>
</html>Note. Change Main to your top-level module.
A basic elm module:
port module Basic exposing (..)
import Browser
import Color
import Html exposing (..)
import Html.Attributes exposing (..)
import Html.Events exposing (..)
import REGL exposing (REGLStartConfig, startREGL, toHtmlWith)
import String exposing (fromInt)
port setView : Encode.Value -> Cmd msg
port execREGLCmd : Encode.Value -> Cmd msg
port recvREGLCmd : (Encode.Value -> msg) -> Sub msg
port reglupdate : (Float -> msg) -> Sub msg
main : Program () Model Msg
main =
Browser.element
{ init = init
, view = view
, update = update
, subscriptions = subscriptions
}
type alias Model =
{}
init : () -> ( Model, Cmd Msg )
init _ =
( {}
, Cmd.batch
(batchExec execREGLCmd
[ startREGL (REGLStartConfig 1920 1080 5 Nothing)
]
)
)
type Msg
= Tick Float
| REGLRecv Encode.Value
update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
(model, Cmd.none)
subscriptions : Model -> Sub Msg
subscriptions _ =
Sub.batch
[ reglupdate Tick
, recvREGLCmd REGLRecv
]
view : Model -> Html Msg
view _ =
toHtmlWith { width = 1280, height = 720 }
[ style "left" "0px"
, style "top" "0px"
, style "position" "fixed"
]Check examples in test to see how to render!
REGL.group [ REGL.crt 50 ]
[ REGL.clear (Color.rgba 1 1 1 1)
, REGL.textbox ( 0, 1050 ) 100 ("hello :)" "arial"
, REGL.quad ( 0, 0 ) ( 1920, 0 ) ( 1920 / 3, 1080 / 3 ) ( 0, 1080 ) (Color.rgba 1 0.2 0.4 1)
, REGL.group [ REGL.blur 1 ]
[ REGL.clear (Color.rgba 1 0.2 0.4 0)
, REGL.triangle ( 700, 100 ) ( 700 + 100, 100 ) ( 700 + 100, 100 / 2 ) Color.red
, REGL.triangle ( 500, 100 ) ( 500 + 100, 100 ) ( 500 + 100, 100 / 2 ) Color.green
]
, REGL.poly
[ ( 1100, 600 )
, ( 1100, 650 )
, ( 1200, 680 )
, ( 1300, 650 )
, ( 1200, 600 )
]
Color.blue
, REGL.texture ( 0, 0 ) ( 600, 0 ) ( 600, 300 ) ( 0, 300 ) "enemy"REGL.group is similar to group in Elm-Canvas.
It groups a list of Renderables into one. Renderable is a drawing command. Elm-regl provides several basic drawing commands like triangles, circles, etc.
Unlike Elm Canvas, Elm-regl provides higher flexibility for one to operate on Renderables.
First, every Effect (similar to Setting in Elm-Canvas) is a shader that could be parameterized or customized by the users.
Second, users could use Compositors, e.g.,
REGL.Compositors.imgFade "mask" t renderable1 renderable2to composite two groups of Renderables. Users also could write custom compositors through the GLSL shader language.
- Use Framebuffer Objects (FBO) to draw.
- Use Multi-channel Signed Distance Field (MSDF) to render text.
- Efficient port implementation in JS.
The corresponding JS port is at elm-regl-js.