Homebrew Bottom screen Flickering using libctru

[Peanut42]

Hi

Another difficult question, I have some flickering in my Paddle Puffle game. Especially when drawing to the bottom screen. I'm using libctru and a loop like this:

while (aptMainLoop () && !done) {
     last_time = svcGetSystemTick ();
     hidScanInput ();
     keys = hidKeysDown ();
     
     if (keys & KEY_START) {
       done = 1;
     }
     
     // Draw all the stuff to the top screen here
     
     //Wait for VBlank
     gspWaitForVBlank();
     
     gfxFlushBuffers();
     gfxSwapBuffers();
     
     // Draw all stuff to the bottom screen here
    
     // Here is the flickering !!!
     now_time = svcGetSystemTick ();
     if (now_time < last_time + FPS) svcSleepThread (last_time + FPS - now_time);
}

Some suggestions to avoid the bottom screen flickering?

 

[nop90]

There is something broken in ctrulib HW rendering, and if you're using the ctulib console, it uses HW rendering.

I had similar problems till last week, then there was a rollback on the ctrulib github to solve some HW rendering problems.

I installed that version and most of the problems are now solved (sometime the flickering starts again, but very seldom).

Try to update yout ctrulib to fix the problem.

P.S. : I don't know if the latest commit works fine, i'm abroad with a very bad connection.

 

[Rinnegatamante]

Why you draw bottom screen after flushing and swapping buffers?

Anyway, to solve various flickering issues i had with lpp-3ds i've added gfxFlushBuffers() after any drawing function ( https://github.com/Rinnegatamante/lpp-3ds/blob/master/source/luaScreen.cpp )

I know it's not very good but it seems to work quite good.

 

[Peanut42]

Why you draw bottom screen after flushing and swapping buffers?

That's my point, I don't know if flush buffers pushes both buffers. I found functions named gspWaitForVBlank0, gspWaitForVBlank1 and gspWaitForVBlank. The macro "gspWaitForVBlank" is an alias for "gspWaitForVBlank0". Don't know what exactly do gspWaitForVBlank1.

After drawing both screens, should I flush buffers, Wait for VBlank (for both? the 0 and 1) and swapbuffers?
The bottom screen uses doble buffering too?

 

[MRJPGames]

That's my point, I don't know if flush buffers pushes both buffers. I found functions named gspWaitForVBlank0, gspWaitForVBlank1 and gspWaitForVBlank. The macro "gspWaitForVBlank" is an alias for "gspWaitForVBlank0". Don't know what exactly do gspWaitForVBlank1.

After drawing both screens, should I flush buffers, Wait for VBlank (for both? the 0 and 1) and swapbuffers?
The bottom screen uses doble buffering too?

gfxFlushBuffers();
gfxSwapBuffers();
gspWaitForEvent(GSPEVENT_VBlank0, false);
The order I use.

 

[Peanut42]

gfxFlushBuffers();
gfxSwapBuffers();
gspWaitForEvent(GSPEVENT_VBlank0, false);
The order I use.

This is for the Top Screen. This apply for the bottom screen too?

 

[MRJPGames]

This is for the Top Screen. This apply for the bottom screen too?

I never had any problems with this, so I would assume so.

 

[hippy dave]

Yeah, you draw both screens, and then swap/flush/wait which does both screens.

 

[Peanut42]

Yeah, you draw both screens, and then swap/flush/wait which does both screens.

You were right! The correct order is swap, flush, wait

No more flickering!

Thanks for all the responses.

 

[Deleted User]

There is something broken in ctrulib HW rendering, and if you're using the ctulib console, it uses HW rendering.

I had similar problems till last week, then there was a rollback on the ctrulib github to solve some HW rendering problems.

I installed that version and most of the problems are now solved (sometime the flickering starts again, but very seldom).

Try to update yout ctrulib to fix the problem.

P.S. : I don't know if the latest commit works fine, i'm abroad with a very bad connection.

Just an FYI, the ctrulib console does NOT use HW rendering, it draws directly to the framebuffer in software.