Gameboy Development Forum

The only things I can think of is to tell you to move SHOW_WIN; to a VBL interrupt handler, and to not use HIDE_WIN; until you are sure you are in HBL. Basically, for the HBL thing, set your interrupt to go off the line before, and then have a wait loop until the STAT mode is 0, then hide the window.

I'm still new to programming in C and using GBDK. How would I go about writing a while loop that checks for the stat mode?

Initially, I entered the code in wrong and got something a little off...


What I got instead was the HUD with one layer of background tiles, seemingly on the window layer, then nothing. It looks like it's displaying the entire window layer (and the UI map only covers the first two rows. That third is an anomaly...)

After getting the code entered in properly, it still shows that row of tiles flickering over the window layer. I don't think I implemented it correctly, but that line of background tiles got me thinking...



I wanted to catch a screenshot of the flickering stars both on and off, so I froze the emulator (BGB) by right clicking the screen and took more screenshots of the issue and found something interesting.

Flickering stars off (What it should look like):


Flickering stars on:


That flickering row of tiles matches the row of tiles from there. Somehow the window layer is getting split and pushed further down screen. It isn't just that one row of tiles, it's the entire window layer and it masks out the background from there down, but at such a rate that my eyes don't pick it up.

However, showing me that STAT_REG is something that I can check in a logic statement really helped.

void smartDelay(UINT8 interval){
    UINT8 ii;
    for(ii=0; ii < interval; ii++){
        if (gameActive == 1 && STAT_REG == 0){ //Keeps the HUD from window layer HUD during smart delays during gameplay.
            SHOW_WIN;
        }
        wait_vbl_done();
    }
}

BREAKTHROUGH! Fixed it.

Mostly.

The extra row of pixels very briefly flashes in at the halfway point on the screen when you pause the game, but it's not as bothersome. If I can't fix it or it becomes too big of a problem, I'll just make it hide the window layer when you pause. This isn't as big of an issue, so I can focus on the rest of the game now.

I might try to see if I can manipulate that row of tiles later and turn it into a pause banner of some kind.

The part I found most confusing was that the window layer was somehow getting split in two and starts up again partway down the screen (which was why the stars in the lower portion of the screen were missing in the last screenshot in my previous post.)