regl triangle moving in a loop by vlandham

Intro to regl

Part of a tutorial by Jim Vallandingham introducing regl for data visualization.

Blocks associated with this tutorial:

index.js

// In practice, you would probably import/require regl
// const regl = require('regl')();

// In this block, it is already loaded, so we just
// initialize it. For more info, see:
// https://github.com/regl-project/regl#standalone-script-tag

var regl = createREGL();

var drawTriangle = regl({

  frag: `
  precision mediump float;
  uniform vec4 color;
  void main () {
    gl_FragColor = color;
  }`,

  vert: `
  precision mediump float;
  attribute vec2 position;
  void main () {
    gl_Position = vec4(position, 0, 1);
  }`,

  // Here we use context.tick to make the
  // triangle move!
  attributes: {
    position: function(context, props) {
      return [
        [-1 * Math.cos(context.tick / 100), 0],
        [Math.sin(context.tick / 100), -1],
        [Math.sin(context.tick / 100), 1]
      ];
    }
  },

  uniforms: {
    color: [1, 0, 0, 1]
  },

  count: 3,
})

regl.frame(function(context) {
  drawTriangle();
});

index.html

<!DOCTYPE html>
<title>Simple regl Triangle Example using context </title>
<body>
  <script src="https://npmcdn.com/regl@1.3.0/dist/regl.js"></script>
	<script src="index.js"></script>
</body>