gl-spikes3d

gl-spikes3d
===========
Draws axis spikes compatible with gl-axes3d. This can be useful to illustrate selections or specific points in a point cloud

Example

Try it out here

``javascript
var shell = require("gl-now")({ clearColor: [0,0,0,0], tickRate: 5 })
var camera = require("game-shell-orbit-camera")(shell)
var mat4 = require("gl-matrix").mat4
var createAxes = require("gl-axes")
var createSpikes = require("gl-spikes")

//Bounds on function to plot
var bounds = [[-1,-1,-1], [1,1,1]]

//camera.lookAt([-15,20,-15], [0,0,0], [0, 1, 0])
camera.lookAt([2, 2, 2], [0,0,0], [0,1,0])

//State variables
var axes, spikes

shell.on("gl-init", function() {
var gl = shell.gl

axes = createAxes(gl, {
bounds: bounds,
tickSpacing: [0.1,0.1,0.1],
textSize: 0.05
})

spikes = createSpikes(gl, {
bounds: bounds,
colors: [[1,0,0,1], [0,1,0,1], [0,0,1,1]],
position: [0,0,0]
})
})

shell.on("gl-render", function() {
var gl = shell.gl
gl.enable(gl.DEPTH_TEST)

//Compute camera parameters
var cameraParameters = {
view: camera.view(),
projection: mat4.perspective(
mat4.create(),
Math.PI/4.0,
shell.width/shell.height,
0.1,
1000.0)
}


//Update spike position
var t = 0.001*Date.now()
spikes.position = [Math.cos(t), Math.sin(t), Math.cos(2*t+0.1)]

//Draw objects
axes.draw(cameraParameters)
spikes.draw(cameraParameters)
})
`

Install

`
npm install gl-spikes
`

API

$3

Creates a new spike object.

* gl is a WebGL context
* options is a list of optional parameters which are passed along

$3

#### spikes.draw(camera)
Draws the axis spikes using the given camera coordinates.

* camera.model is the model matrix for the camera
* camera.view is the view matrix
* camera.projection is the projection matrix

#### spikes.update(options)
Updates the parameters of the axes spikes. options is an object with the following properties:

* position the position of the spike ball in data coordinates
* bounds the bounds of the axes object
* colors an array of 3 length 4 arrays encoding the RGBA colors for the spikes along the x/y/z directions
* enabled an array of 3 flags which if set turns on or off the spikes
* drawSides an array of 3 flag which if set turns on or off the projected spikes in each data plane
* lineWidth an array of 3 numbers giving the thickness of the spikes for each axis

#### spikes.dispose()`
Destroys the spike object and releases all associated resources.

Credits

(c) 2014 Mikola Lysenko. MIT License