Hi, everyone!!!

I´m play with Pd a few months ago and I have a doubt with GEM. I would like to know how works [pix_data] object, because I follow the example patch but does´nt work. I need to find the way to "read" the data of any pixel (colours, mostly), at the position of the mouse pointer in the gemwin. The question is:
-Where is the error in my patch (anexed)?

-Is another way to obtain the pixel data in the gemwin (any pixel)?

Thank´s for your time and help. Nice day.

http://www.pdpatchrepo.info/hurleur/pix_data.pd

that isn't doing what you think it is doing, i think

pix_data grabs data from the "pix" chain, not the frame buffer, so if you move the square, or the window is a different shape, the displayed position of the image texture differs from the mouse coordinates.

you need to grab the frame buffer, which is slow in general - but if you only have 1 pixel to grab (I assume there is only one mouse!) then it shouldn't be too bad.

try using pix_snap before pix_data, setting the dimensions to snap to 1x1 pixels and setting the position of pix_snap from mouse coordinates, then set pix_data to just output that single point.

... some time passes, while patching ...

ah, maybe it's that gemmouse returns window manager coordinates where (0,0) is top-left not opengl where (0,0) is bottom-left?

at least the attached "works" here to some extent

http://www.pdpatchrepo.info/hurleur/gem-grab-mouse-pixel-example.pd

Hi, Claudius!!! Thank´s for your reply.

I´ll check the patch you made. I do this one. I think the way I use isn´t exactly, but work´s fine for my purpose. What do you think? Try different jpeg´s. Sorry for the mess in the patch and my english, I work in that

Greetings!!! Nice day.

http://www.pdpatchrepo.info/hurleur/mouse-gem-sound4-fin.pd