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Re: [Public WebGL] debugging a shaderLinkError



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