Get the refresh rate to run Vizard in

[Jeff]

I'll have to ask a developer if there is a way to get the refresh rate from a connected HMD. You could check to see if the HMD is connected and hardcode the rate based on that.

The following shows how to create create an action from a node3d command:

import viz
import vizact
viz.go()

viz.MainView.getHeadLight().disable()
viz.clearcolor(viz.SLATE)
ball = viz.addChild('basketball.osgb',pos=[0,1.8,3])

light = viz.addLight()
light.intensity(0)

mix = vizact.mix(0.0, 1.0, time=1.0)
change_intensity = vizact.method.intensity(mix)
light.addAction(change_intensity)

[peterparker]

Thanks for the info regrading actions, that would be the second way I outlined above. Good enough for now. As I pointed out earlier, hard coding would not be preferable. I do think, though, that the option for getting the current refresh rate would be great for a graphics/3D engine.

Btw., is there a Vizard command to get the current system time? Or do you have to rely on python's 'time' library?

From using the PsychToolbox I am used to have a command that waits for a particular system. There you can get a time stamp from basically every time critical command and then wait for this time stamp plus 10 ms, e.g.

But then the minimum time interval you can wait in the Vizard is bound to the refresh rate, correct? Unless you are using the director function, of course (which spawns another thread, iirc).

[Jeff]

Btw., is there a Vizard command to get the current system time? Or do you have to rely on python's 'time' library?

For the system time, you would need to use the Python library. Vizard provides the viz.tick command which returns the time elapsed from when the script was started.

But then the minimum time interval you can wait in the Vizard is bound to the refresh rate, correct? Unless you are using the director function, of course (which spawns another thread, iirc).

If you're yielding for a Vizard action or event then it's bound to the refresh rate. What is it that you want to wait for and get a timestamp of?

[peterparker]

Thanks, viz.tick would suffice for this purpose.

If I was under time pressure I could have just coded this from scratch: change the light intensity by 1% and wait for 10 ms. Rinse, repeat. I would just ignore the fact that these slight changes do not coincide with frame buffer swaps. Like this I wouldn't have had to know the framerate.

Ideally, I would wait for 'lastTimeStamp + 10 ms' in order to be precise, which would basically be possible with the viz.tick command. But only using the 'viz.director', of course.

Sometimes it is faster to code yourself than to find out whether designated methods exist and how they work.