Implementing XY instead of Polar Coordinates for Vbap Query.

Implementing XY instead of Polar Coordinates for Vbap Query.

Date	2017-02-27 14:33
From	Nitram
Subject	Implementing XY instead of Polar Coordinates for Vbap Query.
	Hi folks. I'm trying to use an XYpad as a crude control to position sound within a 2d space using and 8 channel Vbap setup. As Vbap works in angles ranging from 0 to 360 degrees (as in below image) in a scenario that does not correspond at all to the way trigonometric angles are usually set up, I'm having lots of trouble working this out. As this is a math issue, I posted the query in a maths forum and these are the instructions I got back: I'm currently trying to implement these equations, but the results do not correspond to what they should be (Also I get crashes if the XY coordinates are at 0). Here is my current code. Would anyone care to offer some advice, please and thank you? -- View this message in context: http://csound.1045644.n5.nabble.com/Implementing-XY-instead-of-Polar-Coordinates-for-Vbap-Query-tp5754854.html Sent from the Csound - General mailing list archive at Nabble.com. Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2017-02-27 14:40
From	Nitram
Subject	Re: Implementing XY instead of Polar Coordinates for Vbap Query.
	-- View this message in context: http://csound.1045644.n5.nabble.com/Implementing-XY-instead-of-Polar-Coordinates-for-Vbap-Query-tp5754854p5754855.html Sent from the Csound - General mailing list archive at Nabble.com. Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2017-02-27 16:09
From	Anton Kholomiov
Subject	Re: Implementing XY instead of Polar Coordinates for Vbap Query.
	Hi, Martin! My guess that the problem is with taninv(kX / kY) If kY is zero you should get divizion by zero error. This is very common case to get the polar coordinates. It's so common that there is a special function that doesn't brakes on zero input taninv2: http://www.csounds.com/manual/html/taninv2.html Also note that taninv output is in radians not in degrees! So to get degrees you need to rescale it taninv or taninv2 output lies in -pi/2 to pi/2 and if you want it to be -180 to 180 you need to do ksig * 180 / (pi * 0.5) also do you have a center in the left top-most corner? or is it placed in the middle of XY-pad If it's in the middle you have to do: kx1 = kx - kcenterX ky1 = ky - kcenterY Hope this helps! Anton 2017-02-27 17:40 GMT+03:00 Nitram <martcrowl@gmail.com>: <http://csound.1045644.n5.nabble.com/file/n5754855/Code.png> -- View this message in context: http://csound.1045644.n5.nabble.com/Implementing-XY-instead-of-Polar-Coordinates-for-Vbap-Query-tp5754854p5754855.html Sent from the Csound - General mailing list archive at Nabble.com. Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2017-02-27 17:54
From	Nitram
Subject	Re: Implementing XY instead of Polar Coordinates for Vbap Query.
	Thanks for replying, Anton. I'm trying to follow your instructions so I have input the data as follows. The angles shown by the print are way off so clearly I'm doing something wrong. Also this circle goes from 0-360 degrees, as shown in the image in my first post. You mentioned something about "-180 to 180". Thanks! -- View this message in context: http://csound.1045644.n5.nabble.com/Implementing-XY-instead-of-Polar-Coordinates-for-Vbap-Query-tp5754854p5754857.html Sent from the Csound - General mailing list archive at Nabble.com. Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2017-02-28 05:44
From	Anton Kholomiov
Subject	Re: Implementing XY instead of Polar Coordinates for Vbap Query.
	I'm doing that kind of thing by trial and error myself. But the thing I see from the code you reversed the arguments for taninv2. it should be: taninv2 ky, kx not kx, ky Also my guess is that taninv2 expects the Oy axis to point to up but in UI widgets like XY-pad it's often points to down. So maybe you need to reverse the Oy by negotiation ky1 = - (ky - kCenterY) And I think that you don't need to check whether kX or kY are positive or negative it should be built in the taninv2 2017-02-27 20:54 GMT+03:00 Nitram <martcrowl@gmail.com>: Thanks for replying, Anton. I'm trying to follow your instructions so I have input the data as follows. <http://csound.1045644.n5.nabble.com/file/n5754857/Conundrum.png> The angles shown by the print are way off so clearly I'm doing something wrong. Also this circle goes from 0-360 degrees, as shown in the image in my first post. You mentioned something about "-180 to 180". Thanks! -- View this message in context: http://csound.1045644.n5.nabble.com/Implementing-XY-instead-of-Polar-Coordinates-for-Vbap-Query-tp5754854p5754857.html Sent from the Csound - General mailing list archive at Nabble.com. Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here