How to create 2D shadows

Question

Could help about creating lighting and shadows in a 2D environment, like the image below.

http://i.stack.imgur.com/0FEQz.gif

I did several searches but got no results

( ps: sorry my bad english i'm brazilian )

The link to the actual article in Luis' linked blog post is dead, but here's a link to the archived article (which, incidentally, seems to be the source of your image): archive.gamedev.net/archive/reference/programming/features/…. Note that this requires GL, which for JavaScript means using WebGL. You can recreate almost all of that logic on plain 2D canvas if you really want, but it'll take more work, more math, and won't be nearly as efficient.
One more note: that article is pretty old and I wouldn't claim it's the best way to do things on modern hardware. If you go with WebGL and are comfortable with shaders and framebuffer objects, you can likely do a lot better.
That's what I saw and have studied this article and do not really feel comfortable with it, I'm trying to develop my own shadow and I like the results anyway thanks for listening =)

JCM · Accepted Answer · 2012-12-26 14:23:41Z

up vote 2 down vote accepted

Take a look at this library: Illuminated.js

it's an work in progress, but just reading the source code you can absorb some information about how they made it.

answered Dec 26 '12 at 14:23

JCM
2318

	very bad performance for animations =( – user24310 Dec 26 '12 at 20:39
	-1 because you're not explaining anything. Answers should include helpful information by themselves. – Yannbane Jan 20 at 13:21

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