jotego
commented
5 years ago Hi @Aquas77, thanks for your inputs. The main repository for this core is actually here. I will reply to some items here and open issues on the main repo where appropriate.
BGM vs SFX
The problem is that the PCB has two sound potentiometers. One affects the whole sound and the other just the FM (i.e. BGM). The sound balance is actually arbitrary and it will depend on how it was set on your specific board. It could be made adjustable in MiST(er) so users can set it to their specific memory.
You can check the schematic here: VR2 affects BGM only and VR1 affects both BGM and SFX.
The Stomp of the Ogres You are totally right. I think I know how it happens. It is probably related to a different issue seen on a Megadrive game. It is easier to debug it here. I have open an issue for it here.
Sprites are off by 2 pixels This is a bug in the latest version. You can go back one version and it should be ok. I have it in my to-do list already.
Graphic issue This may be genuine to the game under those circumstances.
Rainbow flicker I have seen that effect happen many times. The flicker occurs because the palette RAM can only be written during vertical blanking but the CPU is not fast enough to finish a whole transfer in just one blanking. Whether you see it or not is a bit of a fluke. In old arcade PCBs the effect can be more noticeable because aging circuits will have more delay through them and because of the way bus arbitrion works in this hardware that can end up slowing down the CPU. Consider the FPGA version as a brand new PCB. This effect is more difficult to see in emulation because the palette RAM is not blocked from writting outside blanking and because bus arbitrion is basically non existent so the CPU works faster. Nonetheless, you can --very rarely-- see it in emulation too.
I plan to update this core during August. I won't be able to upload the binary to this repository straight away. So please stay tuned to the main repository.
There are some issues with the sound and some other things.
BGM vs SFX: -The big one is that the background music isn't balanced properly to the SFX. The BGM is low in comparison.
Sound effects: -The stomp of the ogres in the ladders building of Stage 2 is very hissy and doesn't have the same 'thud' to it.
Gameplay issue: -Arthur seems to be off-center to the left side when he climbs ladders by one or two pixels. -Somehow I made Arthur go up a ladder while he was still crouched. Not sure if related to the above notation about being off-center to the left. Never saw that before...
Graphic issue: -Arthur's icon on the overworld transition sometimes flickers as a white box instead of the icon.
Misc. Issue: -No "rainbow flicker" occurs which is present on all GnG Arcade PCBs. It occurs pretty randomly and supposedly happens differently on every PCB and also supposedly happens more often as you get into further loops of the game, like loops 4-5 and beyond but can happen on the first loop as well. -One thing of note though, is that the rainbow flicker doesn't occur on any forms of emulation or other ports of the game.
Including a video that is taken direct capture from an US version Arcade PCB from YouTube for comparison: https://www.youtube.com/watch?v=bjQuOFV9xkg&t=3163s
-The rainbow flicker will be seen occasionally in this video as well.