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Re: [Public WebGL] Need to start getting serious about shaders



And of course we have to ensure compatible behaviour across all implementations across as many systems as possible which means that all the implementations will have to ensure as close to identical behaviour as possible, regardless of platform.

eg. with the exception of resource constraints all code that works on one combination of device+platform should work on another.  So the validator will need to either reject all code using implicit casts, or correct for the absence of explicit casts.

--Oliver

On Jun 14, 2010, at 7:52 AM, Benjamin DeLillo wrote:

Intel integrated drivers also lack the implicit cast.

On Mon, Jun 14, 2010 at 1:47 AM, Vladimir Vukicevic <vladimir@mozilla.com> wrote:

----- "Mark Callow" <callow_mark@hicorp.co.jp> wrote:

> On 12/06/2010 23:26, Chris Marrin wrote:
> > 1) doing math between floats and ints without an explicit cast
> (allowed on some NVidia drivers but not ATI on Mac)
>
> It's not really relevant for WebGL but you have to go as far back as the
> very first version of GLSL for desktop, i.e. v1.10, to find no implicit
> casting. Since v1.20, int expressions can be implicitly converted to
> float but not vice-versa. Without knowing the _expression_ involved it is
> not possible say if you are suffering from a very old ATI driver or a
> buggy driver (either ATI or NVidia).

Unless the shader included a #version directive though, it should have been treated as 110 and the lack of casting should have failed.  Granted, not having implicit casting is a little annoying, but GLSL ES doesn't have them, so..

  - Vlad
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