Gameboy Development Forum

I've been testing my game on live hardware without issue, but I will start doing that in the future.

I wasn't aware of OAM being cleared except on startup because of how GBDK works. I'm guessing OAM clears are tied to something else I'm doing and haven't been aware of the connection. I know GBDK throws an absurd number of exceptions in BGB on startup just because of how the GBDK runtime starts. I will look into it.

nitro2k01 wrote:

It is recommended to run BGB with exceptions enabled which warns about various things a ROM might do which can cause problems on hardware. In your case, it seems the ROM clears OAM while the display is enabled. You should do that while the LCD is off.

Correction to my earlier statement: The only time I know of anything being actively cleared out of OAM instead of replaced is after game over screens where the game is reset. Sprites for enemy ships that are defeated are not cleared, only moved out of the gameplay boundaries. Unless that is what you were referring to by OAM being cleared. I recall hearing that the GBDK runtime does some weird stuff to clear OAM at boot and throws a mountain of errors in BGB.

I have been testing, and demoing, the game on live hardware and haven't run across any issues exclusive to live systems. That said, I do not currently have access to a GBA or CGB so my testing is not complete. My testing has been limited to a DMG, SGB and MGB.

bbbbbr wrote:

Thanks for sharing, it looks like you're off to a good start.

A minor suggestion- Increasing how fast the star background scrolls might make it feel like there is more action while playing.

I'm going to tinker with the scrolling background speed and see what happens. I originally slowed it down because of the enemy heavy bombers. I worried it would look strange if the background scrolled faster than enemy ships moved across the screen.

Ardis wrote:

I recall hearing that the GBDK runtime does some weird stuff to clear OAM at boot and throws a mountain of errors in BGB.

you may try to recompile with gbdk-2020, that problem is solved there.

don't you want to make enemies explode or something when you hit them?

Last edited by toxa (2020-06-22 08:23:19)

I released an updated version compiled with GBDK-2020 along with some fixes for more minor/rare bugs (and the bugs introduced by those fixes.) Changes are as follows:



Update-2020-09-06:
    Recompiled the game in GBDK-2020. The game should:
        Throw fewer errors in BGB and other debugging emulators
            The errors in question almost never affect the game when running on live hardware
        Run smoother, allow implementation of more enemies in future updates
        Use less space within the ROM file, allowing for future content to be added in more easily
    Slightly altered armor sprites to make them a little more distinct
    Dying no longer resets the entire game and instead resets the current level from the game over screen
    Fixed code that was only allowing 7 of the 8 allotted bullet slots to be used in memory
    Fixed a rare bug where a bullet would appear on screen, but never move, usually the first one fired

A lot of the planned changes require rewriting of the spawning code and how sprites are handled (since in the current build, all ship sprites are loaded into VRAM and assigned to as needed, meaning I can't make explosion sprites without finding some free OAM slots (which I currently lack as all OAM slots are in use for ships, projectiles and torpedoes that don't spawn yet.)