[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Public WebGL] Issue with enable vertex attributes and re-binding VBOs



Hmm, do you have a testcase or a code snippet that shows what you're trying to do?  You shouldn't need to re-enable vertex attributes, unless there's a bug somewhere..

   - Vlad

----- Original Message -----
> Hi List
> 
> This may be a very dumb question, but is it actually specifically
> stated
> anywhere that you must enable vertex attributes each time you bind to
> a
> buffer target?
> 
> I've found (empirically) that unless you re-enable all the vertex
> attributes each time you *re-use* a buffer, the following
> drawElements/drawArrays displays the data from the last VBO originally
> created. In other words, if you create VBO A, B and C and then redraw
> A,
> B or C, each time you redraw them you must go through the
> enableVertexAttribute stuff, even if the bindings are unchanged. If
> you
> don't when you re-draw A or B you get the data from C.
> 
> What happened was the the first time I drew a scene everything was
> fine,
> but as soon as it was redrawn (e.g. camera move) all the rendered
> objects changed to the geometry of the last object originally created.
> I've fixed it by now specifically enabling vertex attributes as
> required
> (and then disabling them again). My inspiration in this was the San
> Angeles demo which appears to work this way.
> 
> I have no idea whether this is GL ES 2.0 behavior - I have found
> nothing
> in either the spec or the man pages to indicate that the above would
> happen. There's an example in the GL3.0/3.1 Programmer's guide which
> only enables the vertex attributes once, but of course, that's not GL
> ES
> 2/WebGL.
> 
> 
> Regards
> 
> Alan
> 
> 
> 
> 
> -----------------------------------------------------------
> You are currently subscribed to public_webgl@khronos.org.
> To unsubscribe, send an email to majordomo@khronos.org with
> the following command in the body of your email:
-----------------------------------------------------------
You are currently subscribed to public_webgl@khronos.org.
To unsubscribe, send an email to majordomo@khronos.org with
the following command in the body of your email: