Forums - glBlendFunc on Adreno320

4 posts / 0 new
or Register
Last post
glBlendFunc on Adreno320
RichardAngryAngry
Join Date: 26 Jul 13
Posts: 3
Posted: Tue, 2013-10-01 14:37
Top

We ran into an issue with setting the blend functions that occured only on the Adreno chips, the following two pieces of code were not equivalent for us:

   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

and

 

   glBlendFunc(GL_SRC_ALPHA, GL_ONE);
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
I'm guessing the driver code (or some other underlying code) is caching the blend mode incorrectly in some circumstances. This was on Android.
 
Let me know if I can provide any other useful information.
  • Up0
  • Down0
Re: glBlendFunc on Adreno320
mhfeldma Moderator
Join Date: 29 Nov 12
Posts: 310
Posted: Tue, 2013-10-01 15:34
Top

Yes, agree these should be equivalent.  Are you able to query the blend state and verify that the glstate is correct?

Could you let us know which device you are seeing this on?

Are you able to capture a log file?

Also, would you have a test apk that you are using to demonstrate the problem?

thanks...

  • Up0
  • Down0
Re: glBlendFunc on Adreno320
RichardAngryAngry
Join Date: 26 Jul 13
Posts: 3
Posted: Tue, 2013-10-01 16:39
Top

We can repro this on the S4 and the Nexus 7, the blend func reports as GL_ONE_MINUS_SRC_ALPHA in both cases, we came across the "fix" when some code was querying the state, setting to one, then setting back. What sort of log file were you thinking of? We run the alpha set every frame so it's buried in a bunch of other opengl calls. I'm following up on whether I can give out an apk right now.

  • Up0
  • Down0
Re: glBlendFunc on Adreno320
RichardAngryAngry
Join Date: 26 Jul 13
Posts: 3
Posted: Tue, 2013-10-01 17:18
Top

I've got an apk for you, let me know how to deliver it :-)

  • Up0
  • Down0
or Register

Opinions expressed in the content posted here are the personal opinions of the original authors, and do not necessarily reflect those of Qualcomm Incorporated or its subsidiaries (“Qualcomm”). The content is provided for informational purposes only and is not meant to be an endorsement or representation by Qualcomm or any other party. This site may also provide links or references to non-Qualcomm sites and resources. Qualcomm makes no representations, warranties, or other commitments whatsoever about any non-Qualcomm sites or third-party resources that may be referenced, accessible from, or linked to this site.