gl-error-bars

Draws error bars around scatter points.

Example

var shell           = require('gl-now')({ clearColor: [0,0,0,0] })
var camera          = require('game-shell-orbit-camera')(shell)
var createAxes      = require('gl-axes')
var createErrorBars = require('gl-error-bars')
var mat4            = require('gl-mat4')
 
var bounds = [[-5,-5,-5], [5,5,5]]
var errorbars, axes
 
shell.on('gl-init', function() {
  var gl = shell.gl
 
  camera.lookAt(bounds[1], [0,0,0], [0, 1, 0])
 
  axes = createAxes(gl, {
    bounds: bounds
  })
 
  errorbars = createErrorBars(gl, {
    position: [
      [0,0,0],
      [0,2,0],
      [-2,-3,0]
    ],
 
    error: [
      [[-0.5,-0.5,-0.1], [0.5,0.5,0.5]],
      [[0,0,0], [0.5,0.5,0.5]],
      [[-0.5,-0.5,0], [0,0,0]]
    ],
 
    color: [
      [1,0,0],
      [0,1,0],
      [0,0,1]
    ]
  })
})
 
shell.on('gl-render', function() {
  var gl = shell.gl
  gl.enable(gl.DEPTH_TEST)
 
  var cameraParameters = {
    view: camera.view(),
    projection: mat4.perspective(
        mat4.create(),
        Math.PI/4.0,
        shell.width/shell.height,
        0.1,
        1000.0)
  }
 
  axes.draw(cameraParameters)
  errorbars.draw(cameraParameters)
})

API

Constructor

var errorBars = require('gl-error-bars')(gl, options)

Creates a new error bar object.

• gl is a WebGL context
• object is a collection of properties which are used to initialize the object

Returns A new error bar object

Methods

errorBars.draw(camera)

Draws the error bars

• camera is an object storing the parameters to draw

  • camera.model is the model matrix
  • camera.view is the view matrix
  • camera.projection is the projection matrix

errorBars.update(options)

Updates the error bar object

• position is the position of each point in the plot
• error is an array of error bounds represented as [lo,hi] for each point
• color a length 3 array of arrays giving the color of the error bars along each axis.
• lineWidth is the width of the error bar lines in pixels
• capSize is the size of the cap for error bars
• clipBounds is a box to which all error bars will be clipped

errorBars.dispose()

Destroy the error bars and release all associated resources

errorBars.bounds

Bounds on the error bar object for display purposes

Credits

(c) 2014 Mikola Lysenko. MIT License