Easy software request: a box that flashes black and white

[cirthix]

I need a box that reads the current refresh rate and flashes a white/black screen, alternating each frame. I plan to use this for testing a display that I'm doing modifications to. Target os =win7, but if it only works in xp, that's cool too.

It is crucial that the screen alternates only at every output frame.

Resizable box would be perfect, but if it's fixed, something like an 800*600 window size would be nice.

[Scubar]

you sure ur not some evil person trying to either hypnotize people to take over the world or play horrible tricks on epileptics ?

[cirthix]

Oh no, someone's on to me, I'm secretely creating an anti-epileptic virus!

Nah, I've got a strange monitor that can display up to a 300Hz signal, but I want to know how fast it's really refreshing (it is NOT 60Hz) internally, so I'll use this black+white flashing app with a photosensor and oscilloscope to find the exact maximum internal refresh frequency.

[m411b]

Excuse me for my ignorance, but why would you want to go through all that to find the refresh rate of a monitor? Cant you go to the manufacturers website and get the specs for it?

[cirthix]

specs allow 12-85hz, but it actually displays 10-300. I know that the panel update is tied to the input rather than an internally generated clock for at least some (maybe all) of the input modes, so I want to find the limit.

This is NOT a normal monitor, it's driven by 6 FPGAs and has four dvi inputs for simultaneous use. (google vp2290b or ibm t221 for more info)

[Particle]

Flashing colors is easy enough, but what you're asking for is a lot harder than what you think since typical draw operations lack the following things:

- No way to know what output frame you're hitting, necessarily.
- No way to know when what you've instructed the computer to draw has been displayed and thus when to start the next.
- Video output frame rate may or may not correspond to monitor's refresh rate.
- Screen output may or may not represent a whole frame from the frame buffer during any given refresh cycle.

[IFMU]

While I will admit, I have near zero idea what it is you're needing this for...

I can make a gif file that flashes between black and white at I think .01 second timing...
Is that what you need or am I just showing my ignorance?

[cirthix]

@particle: wouldn't forcing vsync on take care of those issues?

screen tear is acceptable for this test, but it is necessary that the image alternates at every output frame.

@IFMU: that won't be adjusted to the screen refresh properly.

[IFMU]

@IFMU: that won't be adjusted to the screen refresh properly.
Okies, no prob. Wasn't sure if I could help but thought I'd offer. ^_^

[Particle]

My recent endeavor shows that if you're willing to get an FPGA board, that offers low enough level support to sync frames directly since your own programming drives the VGA signal. Probably cost about $100 to find out.

[cirthix]

yeah, i might be forced to make some fpga code up :(