Hi all,

I've got a rather odd question. Could you please run the attached script, and see if it gives you an error?

The thing is that I have a trial which continuously updates the color red of a rectangle shape.

It always gives me an error, this error to be specific:

---
Unknown system error.
Line 760, File .\DirectDraw7.cpp
DirectX Error DDERR_SURFACEBUSY (0x887601AE): Access to this surface is being refused because the surface is already locked by another thread..
Line 644, File .\DirectDraw7.cpp
DirectX Error E_ACCESSDENIED (0x80070005): Access is denied.
Line 160, File .\DirInput.cpp
---

If I change the shape of the dot into a circle, this problem disappears.

Can anyone replicate this problem, and what might be causing it?

Thanks in advance,

Maikel

Attached is the data file. What I notice is that there is an abnormal large stimulusonset at the point where the color of the shape is exactly (1,0,0)...

Apparently it's a bug in Inquisit's handling of the RED color channel for rectangle <shape> elements. The problem does not occur for the other two color channels (try it for yourself). Anyway, I'll file a bug report for this. For the time being, you can use <text> elements instead of rectangular <shape>s to avoid the issue:

<text black>
/ items = (" ")
/ txbgcolor = (black)
/ position = (50%,50%)
/ size = (100%,100%)
/ erase = false
</text>

<text dot>
/ items = (" ")
/ txbgcolor = (black)
/ position = (50%,50%)
/ size = (100px,100px)
/ erase = false
</text>

<trial black_blacktored>
/ ontrialbegin = [text.dot.textbgcolor = black]
/ trialduration = 0
/ branch = [trial.black_blacktored2]
</trial>

<trial black_blacktored2>
/ stimulustimes = [0=black,dot]
/ ontrialend = [text.dot.textbgcolorred = min(text.dot.textbgcolorred + 1, 255)]
/ trialduration = 100
/ validresponse = (57)
/ branch = [if (trial.black_blacktored2.response == "57") trial.done]
/ branch = [trial.black_blacktored2]
</trial>

<trial done>
/ trialduration = 0
</trial>

<block test>
/ trials = [1 = black_blacktored]
</block>

Regards,

~Dave

Thanks for your reply Dave. I indeed also noticed that the problem does not occur when I change it to another color (ie. green or blue).

Also thanks for the slight modifications in the script. :)

Best,

Maikel