How are screenshots made?

[az]

I know this may sound like a stupid question. If you're going to answer like "Hit the PrintScreen key", thank you, but that's not what I wanted to know

I want to know how getting a screenshot (shooting the screen? ) works in my hardware - since it seems to show RAMDAC quality, it must be behind the RAMDAC, but I guess before the RF filters? Can anyone enlighten me?

Also, an unrelated question: Where do Matrox fab their chips?

Thank you in advance

AZ

[dZeus]

my guesses:
it just dumps the framebuffer? And it also does NOT show the quality of the ramdac?

[Kruzin]

Yes....screenshots will not show the difference in DAC output. They are grabbed from the frame buffer, before the image get to the DAC.

Matrox doesn't fab their chip. They design and engineer them, but farm out the actual fab work to NEC.

[az]

OIC - but how come people do claim to see differences in picture sharpness from screenshots? I, too, have seen a Diablo II screenshot that looks horribly blurry...

AZ

[Thundrchez]

You can take a screenshot using a program such as HyperSnap-DX from www.hyperionics.com

I primarily use this tool to get screen captures of 3D gaming or of DVDs for cool background pics.

It just grabs the image from the video memory, and any gamma correction has to be done to the image by software after it is captured. This is before the RAMDAC stage. I can't explain the picture sharpness issues that you mention.

[cbman]

Its my guess that the quality of the screenshot depends on the quality of the final picture file...

I could even make a matrox screenshot look like crap if I only saved it as a 50% Quality JPG file...

Oh and contrary to popular belief a screenshot from any new program just takes what your eyes see and transfer it via nano waves generated by EMI induced by the visual preceptors on your brains surface...

You can see the cheaper Non Cordless version of this if you pry the print screen key off your keyboard and look at the bottom.. it has a receptor that taps into your nervous system and sends a signal to your brain to output the image you are looking at on the screen through the nervous system and into the keyboard buffer where its passed through the PS/2 (Primary Sensory 2 Way Port) or USB (Universal Sensory Bidirectional Port)

So maybe that blurry picture you saw was a result of someone using the printscreen key while not wearing his glasses... or wearing alcohol induced ones

------------------
Canadian... Hell Ya!!!

[This message has been edited by cbman (edited 04 May 2001).]

[dZeus]

of course not every chip renders in the same way. That can cause quality differences in screenshots.. as well as FSAA, texture filtering, etc.

[az]

cbman that cannot be, as my keyboard uses a MiniDIN plug

And it can't be the compression because Diablo II's screenshot function always uses the same .jpg quality level, which is quite high. Maybe because it's a 3dfx card and D2 is running in glide mode? I did notice heavy blurring while in Glide mode with my V2 too..

AZ

[Tempest]

Yep, dZeus got it right.
Cards have varying arrays of effects, and even different ways of achieving the same effect. The drivers also matter. A good example is when you compare Matrox' and ATI's 16-bit 3D output (the Radeon calculates everything in 32-bit colour, and if you want to have 16-bit output I guess it just takes the closest 16-bit colour without any dithering whatsoever).