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Re: [Public WebGL] Chrome sampler2D issue



That's good news that we can rely on a common shader validator.
I am sorry if this mailing list was not the right one to handle the problem, please correct me.


thank you guys.
Marco



On 13/09/2010 22:48, Kenneth Russell wrote:
On Mon, Sep 13, 2010 at 9:38 AM, Marco Di Benedetto
<marco.dibenedetto@isti.cnr.it>  wrote:
  Hi,

I noticed that on some systems, launching chrome without --use-gl=desktop
(without it, it means it's using ANGLE, am I right?) causes
gl.getActiveUniform() to return a wrong type for sampler2D program uniforms.
More in detail, result.type is gl.INT instead of gl.SAMPLER_2D. Actually you
use gl.uniform1i() to set the sampler texture unit index, but indeed it must
be reported as a sampler2D. This causes several problems when reflection on
uniforms is heavily used (see SpiderGL).
The problem does not arise in all systems I tried, it seems an unknown
mixture of OS, graphics board and graphics drivers.
Gregg found recently that many OpenGL drivers are reporting incorrect
types for matrix uniforms as well (reporting them as vectors instead
of matrices). There is a plan to use the ANGLE shader validator to
store the types of uniforms and use its information rather than that
from the underlying GL implementation for these queries. Since the
majority of browsers supporting WebGL are using the ANGLE validator,
this would fix this issue in all of them.

-Ken


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