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Re: [Public WebGL] Move flipY and asPremultipliedAlpha parameters out of DOM helpers



On Thu, May 20, 2010 at 08:52, Kenneth Russell <kbr@google.com> wrote:
> Changes to texture parameters take effect immediately. There are no
> texture parameters which affect the behavior of later calls but whose changes are not otherwise seen.

I just realized my argument about this mutual misunderstanding could
have been better without relying on relatively confidential texture
parameters like GENERATE_MIPMAP or CROP_RECT_OES :-P :

Even changing the value of a core texture parameter like
GL_TEXTURE_MIN_FILTER has no demonstrable effect and is not otherwise
seen until a subsequent draw call is using the texture (e.g through
samplers in current shader).


Also, more interestingly, as you've made me doubt (which is always a
good thing :-) ) about if (and how) OpenGL spec defines texture
parameters as state bits and the behavior on changes, I've had a look
and learnt in section D.3 - Propagating Changes to Objects - the
actual definition that definitely clarifies that this is a non-issue :

"
GL objects contain two types of information, data and state. Collectively these
are referred to below as the /contents/ of an object.
(...)
When the /contents/ of an object T are changed, such changes are not always
immediately visible, and do not always immediately affect GL
operations involving
that object. Changes to an object may occur via any of the following means:
    â State-setting commands, such as TexParameter.
"


Cheers!

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