romulusnr

14th August 2004 01:25 UTC

Superscope: Timescope gaps
Been seeing strange behaviour in Superscope especially with AVS widths wider than 256.

Basically I'm trying to emulate a timescope in SuperScope. Each frame, a vertical line ('h' high) is drawn (with r/g/b set based on v, etc.). In the subsequent frame, another vertical line is drawn, one pixel to the right of the last line.

I find that at AVS widths higher than 256, there are vertical gaps where no line gets drawn. It gets worse as I widen the vis.

Basically I am doing:
[frame]
t=(t+1)%w;

[pixel]
x=(t/w*2)+1;

(Before you hit me for using division, I'm just putting it that way for explanation purposes. Incidentally though, I find that doing it as:

[init]
k=1/w;

[pixel]
x=(t*2-w)*k;

will cause a different pattern of gaps!)

Is there anything that can be done to eliminate those gaps?

TIA,
Rom

jheriko

14th August 2004 10:34 UTC

You can avoid the rounding errors in this sort of superscope by adding a tiny shift to the amount the scope moves. See attachment.

Tuggummi

14th August 2004 12:37 UTC

edit
Oops, sorry, never mind :)

edit2
btw. jheriko weren't you suppose to add half a pixel to fix these kind of things? http://forums.winamp.com/showthread....hreadid=188490

romulusnr

16th August 2004 20:11 UTC

Hmmm... adding a fractional pixel to the position... Odd, but it seems to resolve the problem. Thx!