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Re: [Public WebGL] Odd behavior on eePC netbook.

On 2010-10-09, at 2:06 PM, Steve Baker wrote:

Daniel Koch wrote:
Hi Steve,

That IS an interesting question.

There definitely are shader length and functionality limitations that
you'll hit on that machine even under DX9 (being only SM2 capable).
I certainly would have expected to get *some* form of error message
out of ANGLE if that is the case though (although maybe it depends on
the vintage of the driver).

Any chance you can try the shader using ANGLE independently from the

Yeah - this is a big fragment shader that hasn't been optimised yet -
and I'm surprised I didn't hit limits on my ancient nVidia 6800 box.
But Intel chipsets are by far the worst GPU's out there...so it's
entirely reasonable that I might have exceeded some limit.  It's also
possible that these are older drivers (although the EeePC netbook was
new out of it's box yesterday, there are no guarantees that the
manufacturer bothers to keep up with the latest driver releases).

It is unfortunate, but we've certainly seen some of those come with pretty horrendous drivers (even for D3D).

What's annoying is the total lack of any kind of error message beyond
that one 'false' return.  It would be nice to know (for example) whether
I exeeded the maximum instruction count or the max number of registers
or interpolators or...who knows?

Yes typically there would be some form of error message about that. 
ANGLE should be passing back any HLSL errors that occur, so this is pretty odd. 
Hence my request to test ANGLE stand-alone.

I'd be happy to try the shader under ANGLE directly - but I'm going to
need some help knowing how to do that.  I had no idea that ANGLE could
be run outside of the browser.

Yes, ANGLE actually provides a complete & stand-alone ES2 implementation for windows.

The project is hosted on Google code: https://code.google.com/p/angleproject/
And you can find the development setup instructions at https://code.google.com/p/angleproject/wiki/DevSetup

This simplest way to get started is to just grab one of the sample programs in samples/gles2_book
and modify it to load your shader.

...or if you like, I could just email you the shader and let you play
with it.

You could, but without that actual machine & driver combination, it's unlikely to be that insightful.

Hope this helps,

                        Daniel Koch -+- daniel@transgaming.com
Senior Graphics Architect -+- TransGaming Inc.  -+- www.transgaming.com