[Public WebGL] debugging a shaderLinkError

[Daniel Koch]

I'd suggest trying with a more recent version of Chrome/ANGLE.  A number of limits have been bumped up in ANGLE since then.
(That said, I expect you'll still run out of varyings though). 

The current limits (on SM3 hardware) are: 
MAX_FRAGMENT_UNIFORM_VECTORS     221
MAX_VARYING_VECTORS                10
MAX_VERTEX_ATTRIBS                 16
MAX_VERTEX_TEXTURE_IMAGE_UNITS     16               0
MAX_VERTEX_UNIFORM_VECTORS       1024             254

Hope this helps,
Daniel

On 2011-02-27, at 2:18 PM, Stephen Bannasch wrote:

> 
> At 5:07 PM -0800 2/25/11, Gregg Tavares (wrk) wrote:
>> What Steve said.
>> 
>> You're using 17 varyings. WebGL is only required to support 8.  (see OpenGL ES 2.0 spec section 6.19)
>> 
>> Since you're only varying vec3s an amazing GL driver might be able to optimize that to 13 varyings but I wouldn't count on it and even that is over the minimum.
>> 
>> You might want to check that at startup.
>> 
>>   gl.getParameter(gl.MAX_VARYING_VECTORS);
> 
> That appears to have been the problem.
> 
> I created an html page that displays the various webgl maximums up here:
> 
>  http://visual-demos.dev.concord.org/seasons/webgl-maximums.html
> 
> These differences between my MacBook Pro and the HP 425 we are using in the classroom jumped out at me:
> 
>                                MacBook Pro       HP 425*
> -----------------------------------------------------------
> MAX_FRAGMENT_UNIFORM_VECTORS     1024              16
> MAX_VARYING_VECTORS                16               8
> MAX_VERTEX_ATTRIBS                 16              12
> MAX_VERTEX_TEXTURE_IMAGE_UNITS     16               0
> MAX_VERTEX_UNIFORM_VECTORS       1024             128
> 
> 
> * HP 425 with Windows 7:
> 
> Renderer: ATI Mobility Radeon HD 4250 Graphics 
> Vendor: ATI Technologies Inc.
> Memory: 256 MB
> Version: 3.2.9752 Forward-Compatible Context
> Shading language version: 1.50
> 

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

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