readback from texture problem on laptop (works on desk)

    May 16 2006 | 4:36 pm

    • May 17 2006 | 7:36 am
      Hmm, that isn't working for me either. I had a similar problem when I was fooling with Jit.atari2600 and trying to output to a matrix. ATI mobility Radeon 9700 in a Dell Modify this code to fit your naming and resolution specs: Qmetro in the top, matrix out the bottom.
      Here's my method of reading back GL info. I like the fact that I can limit the rate to my preview window by this method. But I'm just getting my feet wet in GL, so I'm sure there are better ways.
      I'd be curious what sort of framerate you get on your example patch, since I may have to upgrade my laptop soon and was curious how the Dualcore's compare to my 3.2GHz pentium IV.
    • May 17 2006 | 2:19 pm
      thanks for a confirmation...Does the mo-9700 share memory w/ the cpu or is all memory resident on the graphics card? I couldn't find any specs about that. The x1300 definitely does, which could be part of my problem (esp. since the host only has 512MB...which will change in a day or so!).
      I wasn't quite sure how you are using that patch in the context of readback... is it that you are doing all your drawing in sketch and then read the pixels, or is there some trick that my tiny brain isn't seeing here? :) I haven't really explored glsketch a whole lot...
    • May 19 2006 | 4:02 pm
      well, the glsketch method doesn't seem to work either. the computer now has 1.5MB of ram, but that didn't change anything. the below patch just doesn't provide the desired results...Help!
    • May 23 2006 | 5:51 pm
      this patch, posted in another topic, does not work either. there seems to be some sort of bug with texture readback on this particular video card (ATI x1300 for laptop).
    • May 23 2006 | 6:14 pm
      Hi Peter,
      Can you confirm whether or not turning on/off doublebuffer makes any difference for you?
      Another thing worth testing is trying to install the latest ATi Catalyst drivers. If your laptop doesn't support them, you might consider trying the (unofficial/modded) ones from These have solved many user's problems with ATi laptop cards, though obviously they come without warrantee, and we can't officially recommend you use them.
    • May 23 2006 | 8:16 pm
      catalyst drivers were updated. ah...the secret switch. yes, that did work on the Dell. i also notice that with it off, the patch freaks out with a lot of blinking on my Mac 9800 ATI. is there a short version of "why" it works on the lappy?
    • May 23 2006 | 8:40 pm
      Good to know. Might be a weird problem with which buffer is valid for reading (front vs. back). We'll investigate further for the next update.
      Thanks, Joshua