Visual stutters during gameplay

[Sereni]

If you're reading this and understand Stepmania/graphics, we need help :)

Got multiple reports of visual lags/freezing during gameplay. I suspect this isn't a theme issue, given that we don't have much theme UI on the screen at that point. Still, would be good to find out why.

What we know:

• Setups that didn't lag in horizontal start lagging in vertical
• Throwing more hardware at the problem can solve it, however some recent hardware isn't enough
• Changing noteskins, turning off background, turning on fast note rendering, and selecting lower res textures doesn't seem to help
• Stepmania 5.3 also lags

Open questions:

• Does lower resolution help?

Known setups that lag:

• AMD Ryzen 5 3600, NVIDIA GeForce RTX 2060, ?? RAM, 42" monitor connected with Displayport -> HDMI, HDD
• ?? CPU, NVIDIA Geforce GTX 1050, 8 GB RAM, 27" monitor via DVI, SSD (noticeably worse while streaming)
• Intel i5-7260U, Intel Iris Plus Graphics 640, 4 GB RAM, 27" monitor (lags horribly)

Setups that don't lag:

• Intel i5-6600K, NVIDIA GeForce GTX 980 Ti, "lots of RAM", HDD (little lag with background videos on)
• AMD Ryzen 5 3600, NVIDIA GeForce GTX 1660 SUPER, 16 GB RAM, (same as above) 27" monitor via DVI, SSD

[teejusb]

Maybe it has to do with the internal resolution of the theme?

Take a look at these links: https://github.com/stepmania/stepmania/blob/5_1-new/Themes/_fallback/metrics.ini#L18 https://github.com/stepmania/stepmania/blob/8ab7c7fab937acc684392b909b6b30b47d9a8c7b/src/ScreenDimensions.cpp#L11

Which show how the game scales the resolution of the game for the theme. Stock SL doesn't change override the fallback parameters.

I wonder if adding ScreenWidth=480 ScreenHeight=1 in your theme's metrics under [Common] (thus overriding the fallback's) will help.

[Roujo]

It looks like it might help, although my stuttering issues aren't consistent enough for me to say for sure. I applied the fix and there was no lagging anymore, but then I removed it and there wasn't any lag then either. =P

Most of the layout is broken with that resolution change, which was to be expected, so I'll try and make a branch where the game is playable (although visually broken) and we could get players with more issues to try it out. =)

[Sereni]

I chatted with Squirrel, who said our problem might be the odd height, which upsets opengl. In the snippet below, note a width-= width % 2;, but no such line for height.

{
    float fAspect = PREFSMAN->m_fDisplayAspectRatio;
    float fScale = 1;
    if( fAspect > THEME_NATIVE_ASPECT )
        fScale = fAspect / THEME_NATIVE_ASPECT;
    ASSERT( fScale >= 1 );
    // ceilf causes the width to come out odd when it shouldn't.
    // 576 * 1.7778 = 1024.0128, which is rounded to 1025. -Kyz
    int width= (int)ceilf(THEME_SCREEN_WIDTH * fScale);
    width-= width % 2;
    return (float)width;
}

float ScreenDimensions::GetScreenHeight()
{
    float fAspect = PREFSMAN->m_fDisplayAspectRatio;
    float fScale = 1;
    if( fAspect < THEME_NATIVE_ASPECT )
        fScale = THEME_NATIVE_ASPECT / fAspect;
    ASSERT( fScale >= 1 );
    return (float) ceilf(THEME_SCREEN_HEIGHT * fScale);
}

They said that 5.3 does the same at the moment, which aligns with us seeing the issue on both 5.1 and 5.3.

We could try adding a height-=height%2, compiling 5.1, and seeing if it gets any better?

https://github.com/stepmania/stepmania/blob/8ab7c7fab937acc684392b909b6b30b47d9a8c7b/src/ScreenDimensions.cpp#L31

[Roujo]

We could try adding a height-=height%2, compiling 5.1, and seeing if it gets any better?

Sure, on it.

[teejusb]

Do you know if the height is an odd number to begin with with the given dimensions as is? If it's not then the changes wouldn't do anything.

SCREENMAN:SystemMessage(SCREEN_HEIGHT) should tell you

[teejusb]

Also if it is an odd number, you can also first slightly change the Preferences of screen height/width to make it an even number to see if that's the cause. I think it would be a easier than recompiling/distributing StepMania.

[Roujo]

Bad news: I was playing with my wife yesterday, so I was using vanilla Simply Love. I had the same lagging issues on the same kind of songs that usually trigger them on Simply Love Vertical, so it looks like I can't really reproduce this issue after all. =/