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Comments:
<0> hey all
<1> hi
<0> I have a performance issue in my openGL app and not sur how to solve it ... am displaying images (rgba images) and upon user action I only want to display one channel (r or g or b etc..) and for that I use the colorMatrix of openGL
<0> but he performances are just terrible, going from 190fps down to 20 ...
<2> Look up glColorMask()
<0> I do lMatrixMode(GL_COLOR); glLoadMatrixf(_m.m);
<0> wow
<0> how come i never heard of that :)
<2> :) It's exactly what you need, and pretty much a free setting
<0> yeah i can see that
<0> there's only one point that is annoying me
<0> can't display the luminance
<0> only rgba
<2> What do you mean exactly? Converting to grayscale?
<0> yeah sort of
<0> u have coefs for r,g,b to compute the luminance
<2> You'll need a fragment program/shader to do that
<0> that's why I was using a colorMatrix
<0> so I could choose exactly what I wanted
<3> don't you just times the green by 0.62? :)
<0> nope
<2> That color matrix might not have hardware support in your drivers, while fragment programs/shaders probably do
<0> usually 0.3*r + 0.59*g + 0.11*b
<0> I have a 6800Go
<3> 59? i read 62/3 I'm sure
<3> I have a 6800 Ultra
<0> well that's the values we use for film :p
<3> maybe that looks better
<3> but in acctuality it's higher
<0> well it's just a representation anyway
<3> Maloeran
<3> what's a texel
<0> a piece of texture?
<2> Pixel of texture
<3> ah cool
<3> I can do 6.4 gigatexels a second
<3> so 6.4 million for 1000fps?
<4> I hate that approach of measurement.
<3> texels/sec or fps?
<2> The reality is always a bit different than these... theorical maximums
<4> Because it sounds much for those not familiar with the measuring.
<3> it is much
<4> In reality, you want to know the number of lookups per frame, given a fps count.
<3> I upgraded from a crippled gefroce 2
<3> it's *VERY VERY* good :P
<4> By the way, what is a gigatexel? One million what? Texel lookups?
<3> million? can you not do math?
<3> it's 1000 million * 6.4
<4> Ops. 1000^3
<3> pixel fill rate
<2> That's not exactly the pixel fill rate...
<4> But still, the unit name is kind of weird. I've never heard of gigatexels.
<3> it is on my card, peak theoretical texels = 6.4, peak theoretical pixels = 6.4
<2> Anyway, it doesn't say much. You access 8 texels per trilinear filtering lookup
<3> would you prefer 6400000000texels/sec ?
<4> According to SI units, you add kilo, giga, tera and so on to measurment units.
<4> texel is not such a unit.
<3> ergh
<3> it means 'billion of'
<4> That's like saying gigacars when you mean a billion cars.
<3> no
<3> you can't pluralize it like that ;)
<3> texels/sec is a measurement
<3> cars isn't
<4> Well, remove the 's' then. That wasn't my point.
<2> It's not clear it's a mesurement of what exactly
<3> yea but replace texels with something more accurate and the giga- part still works fine
<3> it's a measurement
<4> ..
<3> just like 10 kilograms/second
<4> It's a NVidia/AMD buzzword for me, until someone proves otherwise.
<3> I'm not arguing that
<4> kilograms and seconds are units for measurement.
<4> a texel is an abstract entity
<4> Not a unit.
<4> Just as a car is an object, not a unit.
<3> I KNOW
<3> I was never arguing that1
<3> s/1/!
<4> You just want to change 'texel' with something else?
<4> You don't have a darn clue what they actually are measuring, are you? ;-)
<3> yep
<3> we already agreed on that
<3> neither of us do
<3> because it's a buzzword
<3> you were saying that you can't measure texel lookups or anything else to do with texels in giga-
<4> Almost right :)
<4> I'm saying that a texel isn't a unit.
<3> I never said otherwise
<4> So I have no idea what they mean. Not that it should make sense for anyone.
<3> correct
<4> Same thing is almost true for digital cameras, which are measured in megapixels.
<4> That is a bunch of crap.
<3> I'm fine with that
<4> Big numbers are suppose to trick consumers.
<3> it has 1 million pixels in the image
<4> Allthough the standard resolutions make perfect sense.
<3> so, megapixel
<3> I wanna make a camera that is 1000000*1
<4> Yes, but then what? You don't know the width or height?
<4> Or what aspect ratio it supports.
<3> who cares, it's going to be in a normal enough aspect ratio, and have at least a million pixels
<4> Consumers don't do that math in the head. Thinking that would be naive.
<1> a texel is a the smallest element of the texture, if you're looking at the texture at 100% size, 1 texel = 1 pixel
<3> that's good enough for the common person who barely knwos what a pixel is
<3> Rulzern: we know
<1> oh, so what's the confusion about?
<3> we were saying that texels/sec doesn't mean much
<3> texel what, blits? lookups?
<1> ah
<1> it's not as if you can actually use those numbers for anything than a loose guess at real-world performance
<2> It's probably the theorical maximum based on the speed of the video memory, how many times per second can it query the same texel
<2> Which is most meaningless
<1> I think the latest nvidia drivers messed up my shader :(
<3> *but* those 'meaningless' numbers are all derived in the same way, it means nothing of performance, but is perfectly acceptable for comparing cards
<1> that's ***uming those numbers address a bottleneck, and that they are derived in the same way
<1> if anybody has knowledge of quaternions and has time to help me with this problem, please look here http://rafb.net/p/qfVC2224.html
<3> quarter of an onion?
<4> Rulzern: First, ***ert that length is never zero when using it.
<3> Maloeran: how does one go about texturing a model usualy?
<4> Afaik you shouldn't store the length as a member.
<4> zid`: CAD tools usually have a UV editor.
<1> Madsy: I should be doing GetLength() before doing anything involving the length
<3> Madsy: i meant programatically
<3> I'm new to gl
<4> Rulzern: But the length might be zero.
<3> I can texture a quad, no idea how i'd do it for a model with multiple polys
<4> Rulzern: Also, I wonder about line 130
<4> viewVec is not initialized.
<1> fixed, no difference, going to do some testing on the length now, give me a few seconds
<4> "fixed"? No difference?
<1> yeah, initializing it now :p
<4> When I can find such errors in 2 minutes, you better look more closely yourself.
<1> that's the thing, I've been trying lots and lots of things with this for a long time, I just can't produce any different results, it _seems_ to be working correctly, I'm thinking that the real error comes when I'm trying to make the matrix out of the view vector
<4> Rulzern: Still here?
<4> http://www.mechcore.net/code/algebra/vec.h
<4> If you want.
<1> thanks :)
<4> Not the best vector cl*** ever, but better than nothing.
<4> I even use it for fixedpoint.
<1> it can't be worse than what I have :p
<4> I've just made my own "fixed" type with its own operator rules.
<4> Then I just do: std::vector< alg::POS3D<fixed> > vertices;
<5> what libs do i need to do ogl developing in VS .net? and where can i get em?
<4> What language?
<5> cpp
<6> C preprocessor? or c++?
<4> HARLEM: You need the PlatformSDK
<5> c++
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