Spectrum Computing

R-Tape wrote: ↑Sat Dec 28, 2019 8:46 pm Ta for sharing, and a good example. A few of us have been unsuccessfully snorkeling through Firelord recently trying to find the bell chime sound.

Lethargeek wrote: ↑Fri Jan 03, 2020 2:39 pm - "New game from z80 file" does literally nothing for any new snapshots (checked and working in other emulators) added by me. Even after the restart. I was able to load only the snapshots included with the preview (even those without any other data in the subfolders) but nothing else!

Lethargeek wrote: ↑Fri Jan 03, 2020 2:39 pm - "New game from z80 file" does literally nothing for any new snapshots (checked and working in other emulators) added by me. Even after the restart. I was able to load only the snapshots included with the preview (even those without any other data in the subfolders) but nothing else!

Lethargeek wrote: ↑Fri Jan 03, 2020 2:39 pm Tried it, my initial observations:

- Support for the sna format is a must;
I will put this in at some point. It didn't seem a high priority as most of the games I wanted to reverse engineer were available in .z80 format

- Snapshots to be put into a separate dedicated folder instead of creating a mess in the root folder;
Yes, I'm going to do this as it annoys me too!

- "New game from z80 file" does literally nothing for any new snapshots (checked and working in other emulators) added by me. Even after the restart. I was able to load only the snapshots included with the preview (even those without any other data in the subfolders) but nothing else!

So what this is supposed to do is load the .z80 and internally set up the logic for reverse engineering the game. You can then save out the data by either choosing save or closing the application.
If as you say it is doing nothing then that could be due to a missing feature in the .z80 loader that someone else discovered the other day. This issue has been fixed and I'll release a new version shortly.

- F5 key (i mean pressed on the keyboard, not clicked) doesn't work as Break, only as Continue;
I'll have a look at this, could be a keyboard focus issue.

- Graphics View arrangement is very inconvenient and uncomfortable. The slider and the view move in opposite directions and for some reason it can't go above #BFFF. Also rows of fixed height measured in characters is very bad idea for graphics view. Spectrum sprites are often of arbitrary pixel height, so at the very least the view should be arranged column by column of selected byte width. Even better if it will have the ability to reshuffle byte columns inside a sprite column (and then separately for even/odd pixel rows) and to filter out sprite descriptors breaking this view. Or even a simple scripting to describe sprite formats.

Yes this is still very much WIP. The more games I try to reverse engineer, the more issues I find with it. Initially it was used to find the graphics.
The view goes only goes to #bfff because that's the address range minus how much can be displayed, It'll probably be better if I run off to blank rather than clamp the address range controls - I'll have a look.
The slider is a pain, I'll have another look at that.
I'll change the Y height to be in pixel rows rather than characters (or have a fine control as a lots of games use character heights.
I have been thinking about putting some scripting in but I want to look at a few more games before I formulate a plan. It would be good to know some games that it has difficulty viewing.


(didn't check other features yet)

Lethargeek wrote: ↑Sat Jan 04, 2020 3:29 pm Even if you clamp the address range, the last one should have been #С000, not #BFFF. But yeah, better to blank the overflow or wrap around.

As how to arrange the view, first look at "sprite scanner" in Xpeccy (one column of selectable width) or repaint tool in EmuZWin (several such columns as fit in the window). Also it's useful to have possible width of column >32 bytes, as some games might use backbuffers wider than ZX screen.

As for the sprite formats, these are the examples i've seen:

- sprite made on the fly in the buffer out of 8x8 tiles
- sprite and mask separately, row by row
- sprite and mask side by side, row by row
- sprite and mask bytes interleaved in a row
- sprite and mask bytes reshuffled - (rick dangerous)
- sprite and mask are interleaved nibbles (!) - (opera soft games)
- interleaved sprite rows (the next row of specific sprite is its previous row+256)
- compressed mask of lower resolution than its sprite (but same byte width) - (capitan Trueno)

This might be complicated further with sprite descriptors put between the sprite pixel data shifting the beginning of the new sprite. Furthermore, bytes in the each row usually all go left to right but sometimes it is different for odd/even rows. Eg Commando sprites (3 bytes wide) have no mask, but even row bytes go left to right, odd row bytes right to left. I'm yet to see this combined with other methods, but won't be surprised.

TheGoodDoktor wrote: ↑Sat Dec 28, 2019 8:30 pm I don't imagine many other people are interested in reverse engineering old games.

TheGoodDoktor wrote: ↑Sat Jan 04, 2020 8:45 pm Here's an updated version with some improvements to the graphics viewer, games directory & z80 loader fix:
https://www.dropbox.com/sh/74olu8a70l14 ... nZQfa?dl=0

djnzx48 wrote: ↑Fri Jan 10, 2020 6:15 am Is it possible to change the type of a text/code/data segment if it's been set incorrectly? After setting memory to the code type, it doesn't seem possible to change it back, and there's no undo feature.

Also, are breakpoints able to be saved along with the project?

druellan wrote: ↑Thu Jan 16, 2020 9:29 pm Suggestion: a memory heatmap mode similar to the ones found on the Spud emulator:

TheGoodDoktor wrote: ↑Sun Jan 19, 2020 4:52 pm Any more feedback/suggestions will be gratefully received!

TheGoodDoktor wrote: ↑Sat Dec 28, 2019 8:30 pm I discovered Skoolkit a few months ago and ultimately I want this tool to generate output for it in some form

SkoolKid wrote: ↑Tue Jan 28, 2020 5:00 pm Also, by the way, today is SkoolKit's 10th birthday!

Bedazzle wrote: ↑Thu Oct 01, 2020 3:26 pm It had so big potential.