SCP file image - game graphics corruption - Bad Dudes vs Dragon Ninja

[solarmon]

Hi,

I have an SCP dump made from Greaseweazle of a "Bad Dudes vs Dragon Ninja" cracked game disk:

https://drive.google.com/file/d/1wkJ...ew?usp=sharing

Essentially, it is the same as this ADF file:

/TOSEC/Games/[ADF]/B/Bad Dudes vs. Dragon Ninja (1989)(Imagine)[cr OCL][t +3 OCL].zip

It is the same as when the SCP file is converted to ADF, using HxC software, it has the same checksum - see visual disk images further below.

When the SCP file is used in WinUAE - with Quickstart A500 template, with Best Compatibility - it shows corruption on this screen, just before you start a game:



Then when the game starts, you get corruption too, this example is where the player sprite is missing:



Then the game graphics corrupts when you start to move around:



If I use the ADF file - either the converted one from SCP, or the ADF one from TOSEC, since they are essentially the same file with same checksum - the game loads fine without any apparent corruption:





As reference, and for interest, looking at the SCP image using HxC, you can see the typical "swirl" pattern of how tracks are written on an Amiga:



For the ADF image, it is the typical structured and uniform pattern:



Why does WinUAE have problems with the SCP image, but it is fine with the ADF image?

[Toni Wilen]

Probably slightly different SCP decoding or something like that. SCP support is not made by me and I won't touch it.

[solarmon]

Originally Posted by Toni Wilen

Probably slightly different SCP decoding or something like that. SCP support is not made by me and I won't touch it.

Hi Toni,

Thanks for the response.

Who wrote the SCP support so that I may ask this question to?

Do you think it is an issue with when/how the SCP image was created (using Greaseweazle) or with the SCP support in WinUAE itself?

[Jope]

This is not so much relevant to the bug, but since you have a cracked disk, you should be making ADFs anyway. :-) SCP doesn't give any added benefit here.

Flux level images such as SCP, KF Raw and so on are mainly useful for non-DOS disks (such as originals with protection). Cracked disks are always DOS disks.

[solarmon]

@Jope,

I know what you mean, but this is more about the workflow when trying to recover/restore disks.

When I dump the image of a floppy disk, I then view it in HxC software to get a visual view of it. Then I usually test it in WinUAE to check that the image is able to boot up.

I would like to be able to use the SCP image in WinUAE at this stage of the workflow, rather than having another step to convert it to ADF.

[rutra80]

Originally Posted by Jope

Cracked disks are always DOS disks.

Not at all.