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more slabby questions- the td.rota.jxs slab

June 23, 2006 | 9:41 pm

first off, before i start whining- i want to say that the feedback
transformations i usually work with in performance with the mop
operators consistently result in like 23fps at 320×240. and now that
i’m finally moving things to the slab world, a first effort resulted
in 15fps at 1280×854. staggering. thank you for the shader helper
files- they go a long way towards breaking the mental block i’ve had
with shaders.

now, to whining:

i use jit.rota @interp 1 a lot. i’ve gotten very good at knowing
exactly what settings to feed jit.brcosa to make up for the
corresponding decrease in matrix values that comes with interpolation
in a feedback system. but now that i’m moving this chain

source–>jit.xfade–>jit.brcosa–>jit.rota–>jit.xfade 2nd inlet

to this one:

640×480 source–>jit.gl.slab bork @file co.average.jxs–>jit.gl.slab
bork @file cc.brightness.ip.jxs–>jit.gl.slab bork @file
cc.contrast.ip.jxs–>jit.gl.slab bork @file cc.saturation.ip.jxs–
>jit.gl.slab bork @file td.rota.jxs–>averaging slab (in render
context bork)

of course, everything has changed. it’s MEGA FAST, but it’s changed.

is there a shader equivalent to the @interp attribute on jit.rota?
and also: how can i alter the td.rota.jxs file to include the weird
trig stuff- the cosoffsets and sinscales and thetasinscales of
jit.rota? i’m not going to go so far as to ask that i be given a new
td.rota.jxs, but can you at least point me in the right direction on
how to do it myself?

many thanks again for the upgrade. this is great.

j


June 23, 2006 | 10:11 pm

Hi Joshua,
Thanks for looking at this.
First off, textures will automatically use linear interpolation unless
specified otherwise using the @filter attribute to jit.gl.texture.

The jit.rota helpfile gives the equation used to calculate
locations, so you could try making a shader based on that if you want
all the trig params. I opted for a linear algebra approach in this shader.

Developing this shader was a real headache on a Mobility card. We
ended up moving a lot of the code over to the vertex program because we
were hitting the instruction limit on AluBooks. For some reason, the
calculations necessary for "boundmode" make it difficult to add much
other stuff. If you were to remove the boundmode code, you would have a
lot more headroom for other parameters and calculation.

Arguably, it’s probably way easier to simply rotate a videoplane in GL
space.

It’s cool that you’re getting into slab stuff.

Enjoy!
Andrew B.


June 25, 2006 | 5:09 pm

the boundmodes are important to me, so i’m not going to mess with those.

another question now- i see from the archives that there is a
performance benefit to combining slabs.

if i’m trying to use shaders to imitate jit.brcosa, in what order
should i do brightness/contrast/saturation?


June 25, 2006 | 5:16 pm

Try saturation – contrast – brightness.

jb

Am 25.06.2006 um 19:09 schrieb joshua goldberg:

> if i’m trying to use shaders to imitate jit.brcosa, in what order
> should i do brightness/contrast/saturation?


June 25, 2006 | 8:12 pm

Hi,

I just noticed this thread that deals with td.rota.jxs. This shader isn’t
part of the bundle I’m using (11/NOV/05). I couldn’t see a new shader bundle
distributed on the cycling74 website. Is the td.rota.jxs a free-floating
shader that is privately distributed or part of a distribution that I
somehow missed?

thx,
E.


June 26, 2006 | 10:53 pm

This is one of many shaders that were added to the public UB beta of
Jitter 1.6 for intel mac. This will be included in the next release
version of Jitter for all platforms.

Cheers,
Andrew B.


June 26, 2006 | 11:26 pm

>This is one of many shaders that were added to the public UB beta of Jitter
>1.6 for intel mac. This will be included in the next release version of
>Jitter for all platforms.

thx

E.


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