regl-model

Generate a model matrix from position, scale, and rotation vectors. This module will generate a regl command that will provide a uniform mat4 model derived from input variables. The command will also expose context variables

Installation

$ npm install regl-model --save

See demo here

Example

const quat = require('gl-quat')
const regl = require('regl')()
const model = require('regl-model')(regl)
const bunny = require('regl-primitive')(regl, require('bunny'))
const camera = require('regl-camera')(regl, {distance: 40})
const material = regl({
  vert: `
  precision mediump float;
  attribute vec3 position, normal;
  uniform mat4 projection, model, view;
  varying vec3 vnormal;
  void main () {
    vnormal = normal;
    gl_Position = projection * view * model * vec4(position, 1.0);
  }
  `,

  frag: `
  precision mediump float;
  varying vec3 vnormal;
  void main () {
    gl_FragColor = vec4(abs(vnormal), 1.0);
  }
  `,
})

const rotation = [0, 0, 0, 1]
regl.frame(({time}) => {
  regl.clear({color: [0, 0, 0, 1], depth: true})
  quat.identity(rotation)
  quat.rotateX(rotation, rotation, 0.8*time)
  quat.rotateY(rotation, rotation, 0.8*time)
  camera(() => {
    model({rotation}, () => {
      material(() => {
        bunny()
      })
    })
  })
})

API

Constructor

const model = require('regl-model)(regl[, initialState])

where regl-model expects the following arguments:

• regl - A handle to a regl instance
• initialState - Initial model state

where initialState can contain one of the following properties:

• position - Initial position vector (default: [0, 0, 0])
• scale - Initial scale vector (default: [1, 1, 1])
• rotation - Initial rotation quaternion (default: [0, 0, 0, 1])

and model is now a function that accepts the same input as the initialState object.

Usage

regl.frame(() => {
  model({rotation, position, scale}, ({transform}) => {
    drawCommand()
  })
})

Input

The model function accepts following context variables:

• transform - Parent model transform that will be applied to model matrix
• rotation - Rotation quaternion
• position - Position vector
• scale - Scale vector

Context

The model function will expose the following context variables:

• transform - Local model transform that can be used as input to another regl-model command
• rotation - Rotation quaternion applied to model matrix
• position - Position vector applied to model matrix
• scale - Scale vector applied to model matrix

License

API