# Using dontclear parameter of Flip command

**URL:** <https://psychtoolbox.discourse.group/t/using-dontclear-parameter-of-flip-command/1788>\
**Category:** Uncategorized\
**Created:** [March 14, 2007, 4:08pm UTC](https://psychtoolbox.discourse.group/t/using-dontclear-parameter-of-flip-command/1788 "2007-03-14T16:08:58Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![empedia](https://avatars.discourse-cdn.com/v4/letter/e/e19adc/32.png) [@empedia](https://psychtoolbox.discourse.group/u/empedia)\
**Post date:** [March 14, 2007, 4:08pm UTC](https://psychtoolbox.discourse.group/t/using-dontclear-parameter-of-flip-command/1788/1 "2007-03-14T16:08:58Z")

</div>

Hi,  
  
I am converting some PTB2 code to PTB3. The code originally utilised  
the ability to draw into an off screen window then display the window  
then wait for some time for a response then draw some more into the  
window and then redisplay it with the original drawing still intact.  
  
I thought I could use the dontclear parameter of flip to do this but I  
get an error:  
  
OpenGL AUX buffers unavailable! dontclear=1 in Screen-Flip doesn't  
work without them.  
Either unsupported by your graphics card, or you disabled them via  
call to Screen('Preference', 'ConserveVRAM')?  
  
To the best of my knowledge I haven't set ConserveVRAM and I am using  
an ATI X300 based graphics card. I also tried vblsynctest with  
dontclear=1 and I got the same problem.  
  
Without this I have to create the drawing again completely before and  
after waiting for a response which is to say the least inefficient.  
  
Is this a known problem or am I doing something else wrong.  
  
Thanks a lot,  
  
Regards,  
  
Matthew.