Spectrum Computing

20% for code seems right to me. You can load .SNA or .TAP files into an image viewer and get an idea of what's code and what's graphics and data. I used Irfanview to generate these images and added my own guesses about what was data and code. Irfanview lets you import any file as raw data so I set ...

jpnz wrote: ↑Wed May 08, 2024 4:23 pm I posted about that tip a while back - it's not quite right

I'm not very good at finding things in the forum it seems. I supposed someone would have guessed the key combination to see the message at the end of the game, as mentioned in the message.

Couldn't this info be added to ZXDB?

This hidden message reveals information about the development of Predator. I couldn't find anything in this site so I thought I could post it. https://tcrf.net/Predator_(ZX_Spectrum) PREDATOR - (c) 1987/8 20th Century Fox. This program was written in an incredible two months in Leeds and the last we...

TomD wrote: ↑Wed May 08, 2024 10:58 am Some details on why here

viewtopic.php?t=8297

Thanks, I wasn't able to find it. It's indeed sad that such iconic titles are distribution denied.

I think they used to be available. The availability field says "available" but still there are no files to download. It says denied.

What's up with the availability? Is there a way to know the reason they're denied?

Also an azimut alignment issue.

So the recommended speed is 12.5fps? Probably I didn't get the message right. I was precisely asking for responsiveness at 25fps but everything else moving at a more moderate pace which would make sense. At 25fps, when a movement key is pressed the sprite starts moving in the screen around 1/25s lat...

Fantastic!

Would it be possible to have the game run at 25fps but with the characters moving at a moderate/adequate speed with the timers readjusted to make the game still fair?

The intention would be to have the minimum lag, highest fluidity, and a balanced movement speed and timing difficulty.

Anything that is 2 opcodes like your border colour example and is used more than once is probably better as a macro. Sometimes it's worth commenting stuff that isn't obvious on a first scan through the code e.g. inc a ; does not affect carry flag! inc hl ; does not affect flags! Both of those can b...

Code has usually been the smallest portion of a game by far. Even if it doubled in size it would still be a very small part. Most of the increase in size comes from graphics and audio, making the code size an even smaller percentage even when the code may have grown in size. The size of the code can...

Since the Z80 is kinda asymmetric though it does help to know about the implementation details. HL can do more stuff than DE and BC is best used as a loop counter for example, so you try and write your routines to take advantage of that. It's not like these days where every register is the same. HL...

Interesting I’ve been writing what each line does but actually the block is much better. Do you have any rules around the size of a block? You've already got a lot of good answers, I'll just add mine. I wouldn't worry about the size of the block as long as you can think of it as a task without the ...

Thinking in functional blocks that do one thing is always useful. You can comment what each block does and which registers hold what at the block entry. Same for output registers if there are any. This way you think in abstractions, you don't need to remember every instruction and what every registe...

I guess you're trying to implement vertical attribute scrolling but your code is pretty incomprehensible. It's been also some time since I've written assembler routines for the Spectrum but this could be a starting point without any optimisations. ; Scroll up ld bc, 0x2e0 ; size of the attribute map...

DVDfever wrote: ↑Mon Jan 29, 2024 3:09 pm I see there's a v.1.1 of this. Not sure what the difference is off-hand, but it's still fun

Here's a changelog: https://marco-leal-zx.itch.io/zx-pacman ... -available

I guess the persistent dot bug will be fixed. Sometimes a dot will be eaten but still be visible.

This looks like a worthy successor of OTLA. It can use compression, it's maintained and works on Windows and Linux.

I haven't tried it yet but I thought it deserved a mention.

https://github.com/oxidaan/zqloader

Perhaps it is stupid question, but I will ask anyway. I read some articles about ZX Microdive and I noticed that microdrive used two tracks for data. So I wonder, in general, could home computers use stereo recording to double data density (and halve loading times) ? And is it really as simple as a...

Not mine, but I found it interesting. I wonder how much faster it would run in machine code.

https://gabrielgambetta.com/zx-raytracer.html

If another device puts an address on the bus in order to access lower RAM, that surely will cause contention (although said device will need to be paying attention to the signals from the ULA that it is accessing the bus or you'll just get snow on screen and garbage reads) right? It's not the Z80 t...

Thanks Mark. Unfortunately, in my attempt at brevity, I didn't quite ask the question I wanted to, which was this: If I assert the Z80's /RESET pin (via a device on the Spectrum's edge connector), and hold that /RESET pin asserted , am I guaranteed that memory contention will never happen and the U...

TakuikaNinja wrote: ↑Tue Jan 16, 2024 8:55 pm I don't think any of the YouTube videos linked here so far contain AY music...?
How about we confuse people further with this one?

This isn't the beeper.

Edit: you did it, confusion has started.

AndyC wrote: ↑Tue Jan 16, 2024 9:28 pm Clock speed. The AY in the CPC is clocked lower than the one in the Speccy

I don't think the clock would change the sound, only the entonation and that's corrected in the code.

It's probably the audio output circuitry that uses different filters and amplifiers.

I'm surprised by the number of beeper music fans. I'm not too fond because it's normally too noisy although they did some impressive things I wasn't aware of. I though Renegade had good music for the beeper but I'm proven it falls short. Specially impressed by the clean sound in Ping Pong with sever...

I feel this is frequently neglected in games and also in best-of rankings. I'd like to know your votes for best game music/sound of all time. I'd consider menu and in-game music separately because of the challenge differences. Maybe also favourite music/sound author. Name as much as you want. I coul...

Not that I'd ever see it, but I wish he reproduced the kill screen bug where level 255 clocks over :mrgreen: That's not a bug, it's a feature. I'm surprised nobody has corrected you yet. :D I've also found that bug where some pellet doesn't disappear. I've created a snapshot but I don't know how to...