More Boulder Dash!

[raspberrypioneer]

Yes, while reading up on the subject I discovered that - in the later games - it's possible to interact with an adjacent square without moving the character. Obviously any level that requires this functionality would be of little use.

You can do this in BD1, hold down return and choose one of the direction keys. Makes the game a lot more playable especially on the more difficult levels, I'd be struggling without it! BD2 introduces a couple of new elements - slime and a growing wall. I think those are the main things - maybe one for further down the track and would probably need the BD1 disassembly. I checked the Level 7 link on the earlier message but is broken for me - sounds interesting.

[billcarr2005]

Are you going ahead with the nybble per block approach, perhaps with an initial parameters section for cave times, diamonds needed etc? That would seriously get into construction set territory and allow tapping into other good designs found on sites like https://www.boulder-dash.nl/ (would need to be for the BD1 engine of course).

I've not got far with the level decoding routines yet though, so any info appreciated.

Code: Select all

2e00 jsr 2900
	2966 jsr 2d90
	297f jsr 2d50
	29a9 jsr 2d00
2e2c lda #00 ; sta 21dc ; jsr 2404
2e34 lda #23 ; sta 21dc ; jsr 2404

This is the bulk of the level creation / modification

[TobyLobster]

Code: Select all

2e00 jsr 2900
	2966 jsr 2d90
	297f jsr 2d50
	29a9 jsr 2d00
2e2c lda #00 ; sta 21dc ; jsr 2404
2e34 lda #23 ; sta 21dc ; jsr 2404

This is the bulk of the level creation / modification

Thanks Bill!

[billcarr2005]

If anybody would care to give the following disk image a try, Caves A-P are all present. I'm unsure if the bonus caves exist, but haven't played it extensively to find out.

I've written the a map / parameter editor in BBC BASIC for Windows, but I'm not sure if it'll be robust enough to release publicly!

Added the updated SSD with the bonus caves below

[raspberrypioneer]

Brilliant effort Bill! I've given it a quick whirl. All good until the first bonus cave after cave D, then "bad program". I can see you have separate files for the caves. Perhaps needs cave files 1, 2, 3, 4? They're a bit smaller than the main caves, so might be a bit special in other ways. Would love to know more about the way you've constructed the caves - I've a few new ones I'd love to try in due course! Wow, really impressed with this!

[billcarr2005]

Luckily the bonus caves are numbered sequentially from the main caves, so I just needed to add Q, R, S and T
They're the same sized caves from the program's storage perspective. I had to modify the third bonus cave, but it was quick and easy with the editor, so I guess it works well enough

[raspberrypioneer]

Brilliant the bonus caves work! That was turned around quickly (and in the early hours! ) I've gone about half way through the game, no problem. I wondered if there would be any noticeable delay in reading the next cave as you progress, but there isn't any (also using real hardware).

I guess one sacrifice with this (so far at least) is the bypass of the pseudo-random routines for placing rocks, diamonds etc for the different levels. For me that's a fair trade for the option of having new user-defined caves. Related to that (ideally and easy for me to say of course) is having the cave parameters like the cave time, number of diamonds needed, included in the cave file.

I'll run through the game end to end today. Before that I'm going to try tweaking / hacking a cave file or two!

[billcarr2005]

The game is just loading the "crunched" level, 400 bytes in length and expanding it to 800 bytes, so it's probably quicker than calling the 4/5 routines to create the cave.
I hadn't actually played it so much realise that the level changed the cave layout, i just figured the parameters of time & diamonds required was what made it trickier.
It would be certainly possible to create more disks with level 2,3,4 and 5 layouts - it's as close at it can be to automated at this point!
The cave files A-T are just the raw layout. The parameters are still stored (and editable!) in the main program.
If you'd like, I can send you the editor to try out, it might allow for easier tweaking

[raspberrypioneer]

The latest version is a step change forward for this game. Would be very keen on trying out the editor please Bill

[Cybershark]

Yes, while reading up on the subject I discovered that - in the later games - it's possible to interact with an adjacent square without moving the character. Obviously any level that requires this functionality would be of little use.

You can do this in BD1, hold down return and choose one of the direction keys. Makes the game a lot more playable especially on the more difficult levels, I'd be struggling without it!

Oh, so you can! I thought I'd tried it, but I must've been using the wrong key

I hadn't actually played it so much realise that the level changed the cave layout, i just figured the parameters of time & diamonds required was what made it trickier.

Yes, it's an unusual approach, and I had initially assumed the same as you. That was one of the reasons I had written off the idea of being able to edit the caves. I think BD1 is the only game in the series that has the difficulty levels affect the cave layout (as well as the exit parameters)?

This is amazing progress you've made Bill! I'd also be interested in looking at your editor. I suppose that, if levels are to be loaded on an individual basis that, conceivably, extra code could be written to fill up the now unused space. Would be cool to have the original game's high score table added - or to see elements from later games, such as the slime or growing wall

Not that it's much good for anything now - and it's slow as hell - but here is my BASIC program to display Cave 1 (level 1). Well, the "random" elements and the overlaid items at least - no walls. Added Rockford start and end positions to it but never did figure out why that dumb boulder appears in the top left!

Boulder Dash level1 display.ssd

(72.5 KiB) Downloaded 5 times

The great thing about Bill's split-cave approach is that it'd leave a ton of memory for an editor (on real hardware). Would be able to use a MODE 1 display to accurately display an entire cave on one screen

[raspberrypioneer]

Thanks for the test version of the cave editor Bill. This opens the door to creating many more of them!

I focussed on tests using cave A mainly, trying out all the characters / elements.

The space, ground, wall, diamond, rock and firefly characters look and behave perfectly. Even the amoeba works which surprised me a bit.

The magic wall, character D (decimal 13) partly works but instead of morphing rocks to diamonds, makes them disappear. I think this is probably because the cave doesn't have a magic wall milling time. I found the amoeba growth / magic wall times starting at 4C50 for the 20 caves, mostly are 0, not used. It would be handy to have this value updateable in the cave editor alongside the other parameters.

Minor thing - the titanium wall, character 3, can't be added to the cave. For BD1 it is only used around the borders so not really a problem, but handy to have if possible.

The main thing isn't the editor, it is the strange way the butterfly character changes. From the earlier part of the chat you've' come across this too. This is character E (decimal 14) in caves D and N where there is a ground tile to the left of them (as in 1E), and also in cave M unless there are two next to each other, in which case they are grouped as 9E. It also seems to create in a 2x2 space with surrounding ground when used in cave D. If used in cave A, it turns into a firefly, character 6 in a 2x2 space with ground surrounding. Not sure if much can be done about this easily, ideally would just be character 9 I think, and the caves could be edited for it. Worst case, will be a bit of a quirky one!

Many thanks for all this, it's come a long way!

[billcarr2005]

I've compiled a list of memory locations within the editor and think amoeba growth / magic wall time would be at 4C54
Since there's only one or the other (or neither) on a level, I suppose it's a useful space saving technique!

Code: Select all

3C00 CAVE O, LEVEL 5

3C46 CAVE H, LEVEL 1
3C70 CAVE H, LEVEL 2
3C9B CAVE H, LEVEL 3
3CBF CAVE H, LEVEL 4
3CDA CAVE H, LEVEL 5

3CFF CAVE G, LEVEL 1
3D2A CAVE G, LEVEL 2
3D5A CAVE G, LEVEL 3
3D88 CAVE G, LEVEL 4
3DAD CAVE G, LEVEL 5

3E00 CAVE L, LEVEL 4
3E43 CAVE L, LEVEL 5

3E69 CAVE D, LEVEL 1
3EA1 CAVE D, LEVEL 2
3EDA CAVE D, LEVEL 3
3F29 CAVE D, LEVEL 4
3F5E CAVE D, LEVEL 5

3F92 CAVE K, LEVEL 1
3FC9 CAVE K, LEVEL 2
4015 CAVE K, LEVEL 3
4052 CAVE K, LEVEL 4
40B4 CAVE K, LEVEL 5

40F5 CAVE I, LEVEL 1
4140 CAVE I, LEVEL 2
416C CAVE I, LEVEL 3
4199 CAVE I, LEVEL 4
41C4 CAVE I, LEVEL 5

41F1 CAVE O, LEVEL 1
423E CAVE O, LEVEL 2
426E CAVE O, LEVEL 3
42A6 CAVE O, LEVEL 4
4300 CAVE C, LEVEL 2
4307 CAVE C, LEVEL 4
431B CAVE C, LEVEL 5

4324 CAVE P, LEVEL 1
433B CAVE P, LEVEL 3
4354 CAVE P, LEVEL 5

436F CAVE A, LEVEL 1
43BB CAVE A, LEVEL 2
43EA CAVE A, LEVEL 3
4419 CAVE A, LEVEL 4
4454 CAVE A, LEVEL 5

4484 CAVE M, LEVEL 1
44B8 CAVE M, LEVEL 2
44EE CAVE M, LEVEL 3
4511 CAVE M, LEVEL 4
453D CAVE M, LEVEL 5

4579 CAVE B, LEVEL 1
45B0 CAVE B, LEVEL 2
45DE CAVE B, LEVEL 3
460F CAVE B, LEVEL 4
463E CAVE B, LEVEL 5

4664 CAVE L, LEVEL 1
468A CAVE L, LEVEL 2
46BC CAVE L, LEVEL 3

4B00 DIAMOND VALUE
4B14 DIAMOND BONUS VALUE
4B28 DIAMONDS REQUIRED LEVEL1
4B3C TIME LIMIT LEVEL1
4B50 DIAMONDS REQUIRED LEVEL2
4B64 TIME LIMIT LEVEL2
4B78 DIAMONDS REQUIRED LEVEL3
4B8C TIME LIMIT LEVEL3
4BA0 DIAMONDS REQUIRED LEVEL4
4BB4 TIME LIMIT LEVEL4
4BC8 DIAMONDS REQUIRED LEVEL5
4BDC TIME LIMIT LEVEL5
4BF0 START Y
4C04 START X
4C18 END Y
4C2C END X
4C40 LEVEL PLAY ORDER
        1, 2, 3,16, 5, 6, 7,17, 9,10,11,18,13,14,15,19, 4, 8,12, 0

                     A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T
4C54 WALL/SLIME TIME 0, 0, 0, 0, 0, 0,40,25, 0, 0, 0, 0,32, 0,10,20, 0, 0, 0, 4
                          S  W              S     W  W           W
     Magic Wall 51
     Slime 55

4C68 CAVE ACCESSIBILITY
4C78 80 80 80 80 (BONUS CAVES)
4C7C INCREMENTAL FOR "WALLS" OFFSET
4C90 AND 15 FILL CAVE
4CA4 DIV 16 "DETAIL TILES" + AND 15 COLOUR1 
4CB8 DIV 16 "DETAIL TILES" + AND 15 COLOUR2 
4CCC DIV 16 "DETAIL TILES" + AND 15 COLOUR3 
4CE0 CAVE LOOKUP (FF USES ONLY "WALLS", IE NO BASE OR DETAILS) E,J,N,Q,R,S,T
4CF4 CAVE A, LEVEL 1-5
4D08 CAVE B, LEVEL 1-5
4D1C CAVE C, LEVEL 1-5
4D30 CAVE D, LEVEL 1-5
4D44 CAVE F, LEVEL 1-5
4D58 CAVE G, LEVEL 1-5
4D6C CAVE H, LEVEL 1-5
4D80 CAVE I, LEVEL 1-5
4D94 CAVE K, LEVEL 1-5
4DA8 CAVE L, LEVEL 1-5
4DBC CAVE M, LEVEL 1-5
4DD0 CAVE O, LEVEL 1-5
4DE4 CAVE P, LEVEL 1-5
4DF8
4E00
4E1B BASE, CAVE G
4E28 BASE, CAVE C,D,F,K,L,M
4E52 BASE, CAVE B
4E9D BASE, CAVE A
4EAE BASE, CAVE I
4ECD BASE, CAVE H,O,P

5000 to 5580-ish CAVE 

[Cybershark]

The magic wall, character D (decimal 13) partly works but instead of morphing rocks to diamonds, makes them disappear. I think this is probably because the cave doesn't have a magic wall milling time.

Did you have opportunity to see if that was the cause? Must confess that I've not tried "milling" yet!

The main thing isn't the editor, it is the strange way the butterfly character changes. From the earlier part of the chat you've' come across this too. This is character E (decimal 14) in caves D and N where there is a ground tile to the left of them (as in 1E), and also in cave M unless there are two next to each other, in which case they are grouped as 9E. It also seems to create in a 2x2 space with surrounding ground when used in cave D. If used in cave A, it turns into a firefly, character 6 in a 2x2 space with ground surrounding. Not sure if much can be done about this easily, ideally would just be character 9 I think, and the caves could be edited for it. Worst case, will be a bit of a quirky one!

Ugh. Yet another wrinkle! If we're lucky then Bill can identify which routine the butterflies are triggering and circumvent it. As you say, the cave layout should not be influenced by anything in it.

[bob147]

Well done @billcarr2005, it's particularly impressive to create an editor for a game which is seemingly written in such a way as to make it as hard as possible to create custom content!

[raspberrypioneer]

Ok done some testing using the latest version of Bill's cave editor and trying out the resulting caves.

I've not checked everything but what I have tested is looking awesome!

Magic wall milling time / also amoeba growth time works (these elements are usually used in separate caves so one value for both - although now we can add both elements to a single cave)!

Did you have opportunity to see if that was the cause? Must confess that I've not tried "milling" yet!

This was just missing the parameter value in the editor and cave A which does not have these elements (had the value set to 0). These are held in 20 bytes starting at 4C54.

Titanium wall with a cave works - nice to have.

Minor thing - the titanium wall, character 3, can't be added to the cave. For BD1 it is only used around the borders so not really a problem, but handy to have if possible.

and the big one for me ... there is a mechanism for importing caves from other sources via the editor! This is the BDCFF format thing. To get an idea of this, a version of Boulder Dash was created using these caves: https://www.boulder-dash.nl/down/maps/A ... 0Dash.html. I've not run through all caves (they need unlocking as you go) but the ones I did are working and are totally playable. Some are quite difficult.

Cybershark - in this version you need to be able to interact with an adjacent square without moving Rockford (hold down return and choose one of the direction keys).

The things remaining that I've seen so far.
Main issue - the strange butterfly character. Can be worked around to some extent.

Ugh. Yet another wrinkle! If we're lucky then Bill can identify which routine the butterflies are triggering and circumvent it. As you say, the cave layout should not be influenced by anything in it.

It would be handy to import the cave parameters (cave times etc) from the BDCFF files. Currently can be edited in although just for level 1.

Not a huge deal but there is another format of the BDCFF files which use the levels and pseudo random element generation, so there might be a place for using the code from below to some extent ... perhaps to generate caves in the format we can deal with.

Not that it's much good for anything now - and it's slow as hell - but here is my BASIC program to display Cave 1 (level 1). Well, the "random" elements and the overlaid items at least - no walls. Added Rockford start and end positions to it but never did figure out why that dumb boulder appears in the top left!

Sent to me via Bill, not fully tested yet ... the imported caves version mentioned above:

[raspberrypioneer]

Well done @billcarr2005, it's particularly impressive to create an editor for a game which is seemingly written in such a way as to make it as hard as possible to create custom content!

Absolutely same here! Plus the amendments in the code / SSD to bypass this and add a more intuitive method stored in individual cave files instead! With the editor being able to import caves from other sources as well, this game is transformed!

[Cybershark]

No import capabilities here - and I still have a few Ts to cross and Is to dot - but I'm almost done putting together an editor that allows Bill's standalone level files to be edited on a Beeb/Elk

[billcarr2005]

No import capabilities here - and I still have a few Ts to cross and Is to dot - but I'm almost done putting together an editor that allows Bill's standalone level files to be edited on a Beeb/Elk

It amazes me that you've squished it down to a single screen! Do you have plenty of memory for the underlying program? I expect that changing the colour will be considerably easier on the BBC rather than BBC BASIC for Windows, which I've finally managed, although i'm not sure if i'm doing it correctly

[raspberrypioneer]

Looks fab! Choice of colours too, very nice. One option that would be handy is to allow access to the cave from the menu or not? This is the setting of locations &4C68 to 4C77 = 1 (allow access) or 0. For 'testing', I like them all set to 1

Not had too much chance to progress with more on the testing front, but should get some time tomorrow.

[Cybershark]

One option that would be handy is to allow access to the cave from the menu or not? This is the setting of locations &4C68 to 4C77 = 1 (allow access) or 0. For 'testing', I like them all set to 1

When I come to bundle everything together, I will have this as a startup option every time the game runs - "Allow access to all caves? (Y/N)"

Do you have plenty of memory for the underlying program?

No problems there. The standalone level format - and only reading in the essential parameter data - from the game code file means there's lots to play with.

Editor has a little way to go, but is currently around the 4k mark. Haven't had to drop PAGE yet, and that's with the (entirely frivolous) clutter of the game's large A-Z text sprites loaded in too

[raspberrypioneer]

When I come to bundle everything together, I will have this as a startup option every time the game runs - "Allow access to all caves? (Y/N)"

This sounds good to me! It's going to be handy to have editors in both Windows and on the Electron . Currently working with Bill on figuring out the butterfly issue. Will keep you posted if there's an impact on the editor for this.

[bob147]

Editors are like buses, you wait 36 years for one then two come along at once

[raspberrypioneer]

Editors are like buses, you wait 36 years for one then two come along at once

Classic! Hopefully there are still enough Boulder Dash fans out there to enjoy all this!

[TobyLobster]

Did people know about pressing 'B' on the menu to see the credits? (Not sure why 'B' but there you go)

[billcarr2005]

Did people know about pressing 'B' on the menu to see the credits? (Not sure why 'B' but there you go)

I diiscovered that whilst tracing the input routine

[raspberrypioneer]

Did people know about pressing 'B' on the menu to see the credits? (Not sure why 'B' but there you go)

So it does, B for Bennett, developers surname maybe? Quite a cast in there!

Update on this one - the strange butterfly character - discovered that the mapping for this should be hex E, not 9. 9 has the effect of drawing either a butterfly or firefly (depends on cave) in a 2x2 box surrounded by the earth tile. E is a just a plain butterfly character, just what we need!

Ugh. Yet another wrinkle! If we're lucky then Bill can identify which routine the butterflies are triggering and circumvent it. As you say, the cave layout should not be influenced by anything in it.

So on this this one Cybershark - should just be a tweak to your editor

For testing end to end, I've created a set of basic caves including the intermission bonus caves to check all elements / tiles display correctly, that the sequence is correct and cave parameters line up properly. That all works perfectly

The demo mode navigation of Rockford along the original cave A is the only thing I found that doesn't work with new caves (obviously). It seems quite benign, doesn't crash the program. Suspect most of the time Rockford will get stuck or die. Might be better to remove demo mode.

Next up is testing the newer versions of the editors.

[Cybershark]

Editors are like buses, you wait 36 years for one then two come along at once

How you getting on with Bubble Bobble? Maybe we can turn our attention to that when we're done here

Very close to the finish line with my own editor - even has its own front end and loading screen now

the strange butterfly character - discovered that the mapping for this should be hex E, not 9. 9 has the effect of drawing either a butterfly or firefly (depends on cave) in a 2x2 box surrounded by the earth tile. E is a just a plain butterfly character, just what we need!

So on this this one Cybershark - should just be a tweak to your editor

Yes, indeed! That's a very happy outcome

The demo mode navigation of Rockford along the original cave A is the only thing I found that doesn't work with new caves (obviously). It seems quite benign, doesn't crash the program. Suspect most of the time Rockford will get stuck or die. Might be better to remove demo mode.

Didn't realise there was a demo mode on our version!

[TobyLobster]

The demo mode navigation of Rockford along the original cave A is the only thing I found that doesn't work with new caves (obviously). It seems quite benign, doesn't crash the program. Suspect most of the time Rockford will get stuck or die. Might be better to remove demo mode.

If you want to change the demo mode, the keys are stored at $3100-$315f and the duration for each key is stored at $3160-$31bf.
The keys have bits 0-4 set for RIGHT,LEFT,UP,DOWN,RETURN respectively.

I'm still working on my disassembly.

[raspberrypioneer]

How you getting on with Bubble Bobble? Maybe we can turn our attention to that when we're done here

Does the Electron have Bubble Bobble?! Not seen it but if so, I'd be interested to see what it's about (would probably need Bill on board though!)

I did wonder about replacing the graphics used for the tiles as another enhancement. Maybe adapt some of the Repton character graphics? I don't know that much about the series, but think there is some overlap in types of characters / elements and the graphics will need adapting I think for different sizes and animation differences. Another use could be a Christmas edition which I've seen some C64 versions of.

[/quote]

Very close to the finish line with my own editor - even has its own front end and loading screen now

This is looking awesome, looking forward to trying it out!

It's great the butterfly mapping turned out well. I think 9 was picked originally because it was used so much in the original. The demo is just from the original, so we've 'inherited' it, quite a nice touch, you don't often see that in retro games!

Another thought - I'll probably be creating a number of versions of this using the existing cave definitions BDCFF files found on https://www.boulder-dash.nl/. Any ideas on where they can live for others to play with?

[bob147]

Bbcmicro.co.uk is really good at adding new homebrew as its released. Do a release thread here and I'm sure they'll pick it up as well?