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Re: Arithmetic Nodes

From: Marcus Geelnard <mage@opera.com>
Date: Mon, 01 Jul 2013 16:50:10 +0200
Message-ID: <51D19722.4050809@opera.com>
To: chris.lowis@bbc.co.uk
CC: WebAudio <public-audio@w3.org>
Hi Chris,

2013-07-01 15:45, Chris Lowis skrev:
> Would it be useful to add some very basic arithmetic nodes to the Web
> Audio API?
> I'm thinking:
>   - addition
>   - multiplication
>   - subtraction
>   - division
>   - comparison (1 (HIGH) when A > B, -1 (LOW) otherwise)

I really think that ScriptProcessorNodes are sufficient for these kind 
of operations. If they are considered too heavy, I think that arithmetic 
nodes could built on top of them (it should be easy enough to do it as a 
JS lib).

You could also consider doing an even more generic node type that 
accepts an ECMAScript expression, such as "0.5 + 0.5*Math.sin(x)" 
(Simulink has something similar for instance: 
), but then we are getting seriously close to the ScriptProcessorNode.


> These nodes could be restricted to taking two inputs for simplicity, and
> performing their arithmetic in a channel-wise fashion. I appreciate that
> we have 'addition' implicity by summing-on-input on other nodes. I guess
> a ScriptProcessorNode can perform all of these operations, but they seem
> fundamental enough to include in the core set of nodes.
> I think this request has been raised before. I'd be happy to write a
> proposed specification if that would help?
> Cheers,
> Chris
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Marcus Geelnard
Technical Lead, Mobile Infrastructure
Opera Software
Received on Monday, 1 July 2013 14:57:23 UTC

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