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mist-devel / mist-binaries

Firmware and core binaries for the MIST board
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Amstrad_alt - Led Storm graphic bug #110

Closed AxelStone closed 2 years ago

AxelStone commented 3 years ago

Good day, I've seen an error with game LED Storm that can affect to other games. When you go slow with the car, the scroll does strange jumps up - bottom instead of a normal scroll.

Thanks so much for your work!

gyurco commented 2 years ago

It works on a 15kHz display (what the original machine supports). VGA displays seems doesn't like the scroll method used (messing with VSYNC position).

AxelStone commented 2 years ago

Hello, the fact is that I use 15khz output connected to a CRT TV with scart cable (mini din output of the Mistica FPGA), I didn't try using VGA monitor or VGA to scart cable.

Thanks.

harbaum commented 2 years ago

Doesn't that Mistica board use some video encoder Chip? If that's the case then this encoder may not cope with the inconsistent sync pulses.

I am sure you are aware that this Mistica board is a clone of the original Mist and that you are asking the makers of the original device for help, aren't you?

You should really get in touch with the makers of your board.

AxelStone commented 2 years ago

Doesn't that Mistica board use some video encoder Chip? If that's the case then this encoder may not cope with the inconsistent sync pulses.

I am sure you are aware that this Mistica board is a clone of the original Mist and that you are asking the makers of the original device for help, aren't you?

You should really get in touch with the makers of your board.

No video encoder chip present for scart output, only RCA output has specific video encoder. For VGA/Scart it works in the same way than Mist.

ManuFerHi commented 2 years ago

The user has no problem with synchronism, he has a problem with a core that has a fault. Mistica only has the composite video chip different from MIST, but Axelstorm connects via RGB 15khz and in this case it is exactly the same as the original Mist.

harbaum commented 2 years ago

I've never seen a Mistica. It's just a 98% clone of my work made by some Spanish guys I think. I still think they should support their users and not just rely on us to help them.

Back to the topic: Some machines simply had instable sync. Some even did this on purpose to create some soft scrolling effect. Maybe the same here. Are you sure it's a fault?

ManuFerHi commented 2 years ago

We are talking about it in the chat where I support Mistica and SiDi (also guys who have official mist) and this core behaves with the same fault in Mister, so it is clear that the core has a fault. But I think the core is from Sorgerlig so it is possible that the query should be to him. Although I do not know if I want to respond to someone who does not have a Mister.

harbaum commented 2 years ago

I think it's pretty understandable if people prefer to primarily support their own projects. Fortunately there are great people like Gyurco who support all of these boards.

gyurco commented 2 years ago

I support all boards until it's MiST compatible :)

@AxelStone: What I remember that this game worked well on a 15kHz SCART input on a Samsung LCD TV. Did you turn off sync filtering in the OSD?

gyurco commented 2 years ago

I've re-checked how the scrolling is done in LED Storm. It simply uses R5 to add extra scanlines to the frame, and variable frame lengths are not always tolerated by displays. My VGA display just goes blank, but my Samsung LCD TV via SCART displays the game properly. I don't think anything can be done in the core. I don't see any error in the R5 implementation on FPGA. Is the game on the same display on a real CPC works correctly?

AxelStone commented 2 years ago

Hello @gyurco sorry for delay, you are right, after some checks and ask CPC comunity it seems that the trick depends on the original CPC screen, so it's something related to the screen itself not the machine.

Thanks for your support.