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<canvas id=c></canvas>
<span>Try disturbing the particles with mouse</span>
body { margin: 0; }
span { position: absolute; top: 15px; left: 5px; color: white; }
###
Text masked spring particles
Author: Kushagra Gour a.k.a. Chin Chang
(@chinchang457)
###
# requestanimationframe polyfill
window.requestAnimFrame = (->
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
(callback) ->
window.setTimeout callback, 1000 / 60
)();
# variables
canvas = null
ctx = null
num_particles = 500
density = 8
min_distance = 70
text_array = []
display_list = []
last_time = null
spring_constant = 0.2
damping_constant = 0.08
colors = ['#184DF4', '#F49A03', '#E01730', '#00A415']
W = window.innerWidth
H = window.innerHeight
init = (e) ->
canvas = document.getElementById 'c'
ctx = canvas.getContext '2d'
canvas.width = W
canvas.height = H
canvas.addEventListener 'mousemove', onMouseMove
changeWord 'code'
# create particles
if text_array.length
for i in [0...num_particles]
display_list.push new Particle
getTextArray = (ox, oy, w, h) ->
text_array = []
data = ctx.getImageData(ox, oy, w, h).data
for i in [0...h] by density
for j in [0...w] by density
linear_index = (i * w + j) * 4
if data[linear_index + 3] isnt 0
text_array.push {x: j, y: i}
return text_array
onMouseMove = (e) ->
mx = e.offsetX || e.pageX
my = e.offsetY || e.pageY
for child in display_list
dx = child.x - mx
dy = child.y - my
d = Math.sqrt dx * dx + dy * dy
if d < min_distance
child.speed_x += dx * 0.05
child.speed_y += dy * 0.05
changeWord = (str) ->
# clear the canvas first
ctx.clearRect 0, 0, W, H
# draw the new text
ctx.fillStyle = "#000"
ctx.textBaseline = 'top'
ctx.textAlign = 'center'
ctx.font = "200px Arial"
ctx.fillText str, W/2, 0
# get the text points
text_array = getTextArray 0, 0, W, H
for child in display_list
child.reposition()
animate = ->
animationLoop()
requestAnimFrame animate
animationLoop = ->
if !last_time then last_time = (new Date).getTime()
current_time = (new Date).getTime()
dt = (current_time - last_time) / 1000
last_time = current_time
window.fps = 1 / dt
draw()
update()
draw = ->
ctx.fillStyle = "#111"
ctx.fillRect 0, 0, W, H
for child in display_list
continue if typeof child.draw isnt 'function'
ctx.save();
ctx.translate child.x, child.y unless isNaN child.x or isNaN child.y
ctx.scale child.scale_x, child.scale_y unless isNaN child.scale_x or isNaN child.scale_y
ctx.globalAlpha = child.alpha unless isNaN child.alpha
child.draw()
ctx.restore();
update = ->
# update particles
for child in display_list
child.update() if typeof child.update is 'function'
class Particle
constructor: (@radius = 1, @x = Math.random() * W, @y = Math.random() * H) ->
@speed_x = 10 - Math.random() * 20
@speed_y = 10 - Math.random() * 20
@color = "#ff0"
@alpha = 1
@reposition()
@reset()
draw: ->
#ctx.drawImage canvas2, 0, 0
ctx.fillStyle = @color
ctx.beginPath()
ctx.arc 4, 4, 4, 0, Math.PI*2, true
ctx.fill()
update: ->
acc_x = -spring_constant * (@x - @ox) - damping_constant * @speed_x
acc_y = -spring_constant * (@y - @oy) - damping_constant * @speed_y
@speed_x += acc_x
@speed_y += acc_y
@alpha -= 0.019
@scale_x += 0.06
@scale_y += 0.06
@x += @speed_x
@y += @speed_y
if @alpha <= 0
@reset()
reset: ->
@alpha = Math.random()
@scale_x = @scale_y = 0
@color = colors[~~(Math.random() * colors.length)]
reposition: ->
point = text_array[~~(Math.random() * text_array.length)]
@ox = @x = point.x + ~~(3 + Math.random() * 6)
@oy = @y = point.y + ~~(3 + Math.random() * 6)
init()
animate()
Also see: Tab Triggers