viewport flikering

pin3 · Post by **pin3** » Sat Aug 29, 2009 3:11 pm

I`m trying to draw multiple viewports on screen. The problem is I don`t want to update the viewports in each beginScene() cycle. I.e each viewport gets updated once uponatime. However on each beginScene all the viewports get cleared so it all white until the viewport is drawn again
If draw a viewport per frame, with 4 vp I end up with the each viewport being white 3/4 of the time.
[update] I got it to work with setting the beginScene clear Backbuffer to false however I still get the gui flikering. Unlike the viewports I want the gui updated on a per frame basis.

DavidJE13 · Post by **DavidJE13** » Sat Aug 29, 2009 3:45 pm

try only calling endScene after the last render. I'm not sure how safe this is, but it should do what you want.

Virion · Post by **Virion** » Sat Aug 29, 2009 3:49 pm

put your gui to another separate viewport?

pin3 · Post by **pin3** » Sat Aug 29, 2009 3:57 pm

the way I have it

beginScene()

setVP(1);
sceneManager->drawAll
setVP(2);
sceneManager->drawAll
setVP(3);
sceneManager->drawAll
setVP(4);
sceneManager->drawAll
setVp(5);
guiManager->drawAll

endScene();

how do I endScene after the last render?

DavidJE13 · Post by **DavidJE13** » Mon Aug 31, 2009 3:37 am

hmm, that's what I had in mind. I can't see why it wouldn't work, since Irrlicht isn't supposed to copy the view to the screen until endScene is called. maybe the problem is with another bit of the code.. can you post your actual code? (the bit between begin/end scene should be enough)

pin3 · Post by **pin3** » Mon Aug 31, 2009 6:54 am

DavidJE13 your right that's pseudo code for how things used to be but I changed things in the mean time .

DrawViewport(int Frame)
{
if(Frame == 0)
{
setVP(1);
sceneManager->DrawEverything
}
if(Frame == 1)
{
setVP(2);
sceneManager->DrawEverything
}
if(Frame == 2)
{
//setVP(3);
sceneManager->DrawEverything
}
}

int Frame

beginScene()
Frame++
if(Frame ==4)
{
Frame =0
}
DrawViewport(Frame)
setVp(5);
guiManager->DrawEverything

endScene();

DavidJE13 · Post by **DavidJE13** » Mon Aug 31, 2009 5:19 pm

hmm, again that should work (although you will have a problem with the gui showing ~3 previous frames in each segment)

Either the code you posted isn't entirely representative of your app, or the bug is elsewhere. Possibly in the setup - what driver/OS are you using?
I'm going to do a few tests with this, see if I can reproduce the glitch.

vitek · Post by **vitek** » Mon Aug 31, 2009 6:30 pm

Code: Select all

int Frame 

beginScene() 
Frame++ 
if(Frame ==4) 
{ 
Frame =0 
} 
DrawViewport(Frame) 
setVp(5); 
guiManager->DrawEverything 

endScene();

No, this will not work because it only draws one viewport between the begin and end scene calls. If you want to avoid flicker, you need to draw all viewports between those calls.

Travis