Caves and levels in original BD games

[igormakovsky]

Hello,

Since playing BD on ZX spectrum I was wondering, why does levels (1–5) do not alter additional items to the cave (that weren't present in the cave on the lowest levels), nor changing wall structure. Typically, it's just about re-placement of already existed items like boulders, jewels (that look like random, though more intensive), amount of jewels to finish the cave etc. But never you could face newly placed set of fireflies, sudden amoeba or new holes in walls, etc.

Does that made intentionally to keep limited resources? Does BD keeps 100 separate levels, or that, say, 20 original levels with some additions?

[altermaven]

It's to save space. In the original Boulder Dash, certain elements remain static while the random number generator (RNG) seed influences element fill. However, specific seeds are used to ensure the random fill does not generate themes of impossibility -- something that was overlooked at in Amercian Action's BD3, for example. Other statistics are adjusted to compensate: in cave C and L, all diamonds present are required, so the # required is actually the # of diamonds present in the cave.

That being said, the packaging for BD1/BD3 was not exactly robust, but having the specifics of using a minimum of static elements, while allowing for randomness in the remainder, has overall returned a net save in storage space. 640 blocks of space = ~128KB, but you're looking at system targets that at most had 16KB of RAM, with ~12K usable.

[igormakovsky]

Amazing. So does it mean, that if you encounter a cave with seemingly random rocks/jewels placement in a BD original room — that is always the result of RNG seed placement and never manual?

[LogicDeLuxe]

You could easily check this out in GDash. Load BD1 to see how the caves are set up, and you can play with the random settings, if you want.
Of course, Gdash has much more possibilities than the original BD1, including placing anything on a per level basis, which BD1 can't.

[igormakovsky]

My story of getting familiar with GDash began this summer with Rocks'N'Diamonds implementation of that engine, because I'm too dumb to figure out how to run GDash on Mac by myself. Before that, it was my first absolute lovable game on ancient 48K ZX Spectrum 30 years old.

I messed up that time with BDKIT, which had random placement, as well, yet haven't had difficulty levels implemented. As far as I understand, there were no division between the random elements and constant ones there.

Can this be reproduced in R'n'D GDash editor?

[LogicDeLuxe]

I messed up that time with BDKIT, which had random placement, as well

While BD1 uses the pseudo random generator with a seed. PLCK uses real random.

As far as I understand, there were no division between the random elements and constant ones there.

Indeed, while BD1 has those drawing instructions taking just a few bytes each, PLCK uses a nybble map. Thus there are only 16 different elements which can be placed, most notable limitation of this: Fireflies and Butterflies can be placed in one direction only. Once you roll the dice, the random placement is done. If not done before actual construction, you'll get quite a mess, while the BD1/BD2 way can be easily adjusted afterwards.
1stB and CrLi, use a byte map, which has no limitations on placements at all, but the same limitations go for the random setup as in PLCK. Check out my Crazy Light Tools.

The Profiboulder series joint both worlds by adding a bit map and a nybble map instruction to the BD2 drawing instruction set, so the later games could easily base BD2 engine caves on a PLCK cave occasionally.

[artsoft]

My story of getting familiar with GDash began this summer with Rocks'N'Diamonds implementation of that engine, because I'm too dumb to figure out how to run GDash on Mac by myself. Before that, it was my first absolute lovable game on ancient 48K ZX Spectrum 30 years old.

I messed up that time with BDKIT, which had random placement, as well, yet haven't had difficulty levels implemented. As far as I understand, there were no division between the random elements and constant ones there.

Can this be reproduced in R'n'D GDash editor?

Even though supporting native BD cave (level) files now through GDash engine code, the level editor of R'n'D only supports working with map based levels, but not "BD style, constructed caves". That is, BD caves that are read into R'n'D are converted into map based caves, and therefore can only be edited as maps in the level editor, so there is no way to tweak a random seed and check how this changes the resulting cave (as it can be done in the GDash level editor).

However, you can do something similar with R'n'D's level editor, which also offers a "random element placement" functionality. But it works differently from the generic approach used in BD, as it also just manipulates map content instead of defining "instructions" to dynamically build a cave on-the-fly.

[igormakovsky]

...the level editor of R'n'D only supports working with map based levels, but not "BD style, constructed caves"

In other words, it is exactly like it was in original BDKit, am I right?