Published
Edited
Dec 9, 2020
2 forks
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createRegl = require("regl")
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canvas = html`<canvas width="200px" height="200px"/>`
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regl = createRegl(canvas)
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drawTriangle = regl({
// Shaders in regl are just strings. You can use glslify or whatever you want
// to define them. No need to manually create shader objects.
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 define the vertex attributes for the above shader
attributes: {
// regl.buffer creates a new array buffer object
position: regl.buffer([
[-2, -2], // no need to flatten nested arrays, regl automatically
[4, -2], // unrolls them into a typedarray (default Float32)
[4, 4]
])
// regl automatically infers sane defaults for the vertex attribute pointers
},
uniforms: {
// This defines the color of the triangle to be a dynamic variable
color: regl.prop('color')
},
// This tells regl the number of vertices to draw in this command
count: 3
})
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{
let beginAt = Date.now()
while(true) {
let time = Date.now() - beginAt
// clear contents of the drawing buffer
regl.clear({
color: [0, 0, 0, 0],
depth: 1
})

// draw a triangle using the command defined above
drawTriangle({
color: [
Math.cos(time * 0.001),
Math.sin(time * 0.0008),
Math.cos(time * 0.003),
1
]
})
yield canvas
}
}
// regl.frame() wraps requestAnimationFrame and also handles viewport changes
//regl.frame(({time}) => {
//})
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