some questions about sliders in the .osu format

maboesanman

Joined August 2012

Topic Starter

maboesanman 2015-06-29T17:23:43+00:00

I'm making a replay viewing program, and I'm running into trouble with sliders.

there seem to be 4 different kinds of sliders as opposed to the wiki's two mentioned.

L - linear
B - bezier
C - catmul?
P - ????

I'm wondering what P is, and what degree of bezier curve (quadratic/cubic/etc...), and what the catmul curve equations are.

also, how are these rendered? it seems highly nontrivial to me. does osu! just draw a bunch of circles centered on the curve?

thanks.

Don't mind me, just climbing the ladder...

]fice

29 posts

Joined April 2015

]fice 2015-06-29T19:27:49+00:00

I analyzed the .osu file format myself and it seemed to me that the value (talking about L / B / C / P) can be ignored.

I used the amount of control points for the calculation. Up to four control points, its a trivial bezier curve, afterwards, the calculation is fucked up a little (my mashed up code delivered results veryclose to the curves drawn by osu!). However, I'm sure the original, strict calculation is easier and clean. If you desperately want to, I can try to explain my approach.

I hope curves are not rendered with stacked circles, because thats pretty much the most ineffizient way to draw curves (too many unnecessary points are calculated). The line segments are commonly represented by a triangle strip.

euphyy_old

68 posts

Joined July 2013

euphyy_old 2015-06-29T22:39:44+00:00

Feel free to use opsu/objects/curves, opsu/objects/Slider.java, and opsu/render if they're of any help.

maboesanman

35 posts

Joined August 2012

Topic Starter

maboesanman 2015-07-01T20:03:42+00:00

thanks everyone, I'll look into these suggestions!

Don't mind me, just climbing the ladder...