New version of Frogger (was: A demo of what is looking like a new Frogger for the beeb)

[tricky]

I have been trying to make a version of frogger that can be *RUN or loaded into SWR (RAM or EPROM) and the result is attached (r.frogger).
I seem to have broken it a bit, in that it now has flicker which it didn't have before, so I have some debugging to do!
This version can be used with keyboard (Z X / or with joystick (activated by fire button).

There are three files in the .zip
r.frogger - the ROM / whole game
r.frogger.inf in case you want to import it into an existing disc image
game.ssd to make it easier to test in an emulator.

I will replace it once I have identified the cause of the flicker and fixed it.

[nama]

Hi tricky,
Did you ever figure out the flicker issue with frogger in ROM version?
Also, I see you have a ROM version of AstroBlaster, that's great! And at one point you had a earlier beta version of Phoenix that ran in ROM, but did you ever get the final Phoenix to work in ROM?

There are so many versions, it's a little hard to keep up. It would be great if there was one place to download and get info on all your great games.

Cheers

Phil

[tricky]

I had completely forgotten about this, I'll have a look once I sync up my holiday work from my laptop - I don't do online stuff!

I have done AstroBlaster and Phoenix in their threads and I have a fairly up to date summary in the post linked from my signature A bit more about my beeb life, but I really should try to make a homepage somewhere!

AstroBlaster still has a bit more tidying to do and the sample for "To battle stations" seems a little odd on HW, so that probably needs looking at too!

Phoenix has my name misspelt, soI should probably fix that!

I will do Carnival and Centipede once I finish it.

I just seem to be getting worse at spending constructive time on these things

I have just remembered Space Invaders, which I should also do.

Perhaps I should go and read my own post - doh!

[tricky]

Looks like the flicker in Frogger was my new monitor, I think I will go back to the (newer) old one.

I might still tidy the build side of things, but let me know if there are any issues.

[tricky]

I've tidied up my build process and added auto boot if in SWR bank 0 (hopefully one of the cartridge slots on a master).
The frogger file can be programmed in an EPROM or *SRLOADed for testing, then activated with *FROGGER.
I have also tidied up the files on the disc a little to use less files and less room. (!BOOT still sets G%, but this could be moved to FROG_LD).
The game hasn't changed and I think it is still identical to the one on BBCMicro.co.uk.

[nama]

Hi tricky,
Thanks for the reply.

I downloaded you latest Frogger zip file, but it only contains a .ssd file. Are you saying this .ssd can be burnt to an EPROM too?
Look forward to you other game updates too.

Much thanks

Phil

[tricky]

The frogger file in the .ssd can be burnt as a ROM or *run or tested with *srload if you have that option.

[tricky]

I've just started looking at VideoNULA (yes I know, I haven't even installed mine yet! and it was one of the early ones).
This is an update to my Frogger game, which hopefully is still compatible with everything (same .ssd NuLA or not), including burning $.frogger as a ROM.
I haven't tested it on hardware, but after a false start (didn't realise I would have to program 4 physical colours as per &FE21) I am now using logical colours to write less data (good for everything except possibly Phoenix stars).

NuLAshot.png (3.64 KiB) Viewed 910 times

Please try it out if you have hardware, or use the b-em emulator (like I did). I have "found" the extra 24 bytes (12 colours) I needed on the stack and am not sure that I can't overwrite them. If the colours go wonky after a while, all 24 probably weren't "unused".

EDIT: It detects NuLA by looking for "VideoNuLA" at the start of the ROM's name.

[RobC]

Please try it out if you have hardware, or use the b-em emulator (like I did).

Just had a quick play on my setup and it works - looks brilliant, just like the original

I haven't tested it on hardware, but after a false start (didn't realise I would have to program 4 physical colours as per &FE21) I am now using logical colours to write less data (good for everything except possibly Phoenix stars).

Could you clarify this as I think it might be an emulator issue? If you're using the logical-mode palette, I didn't think you needed to program 4 physical colours for each colour in mode 1 (but it's a while since I've played with it so I could be wrong ).

EDIT: If this issue is what I think it is, I'm pretty sure that it's confined to the emulator. On real hardware, I've just had a horizontally split mode 1/mode 2 display running in logical palette mode without any need to reprogram the physical colours.

[tricky]

I am now using logical mode, which does only need one colour setting (2 bytes) per colour.

My mistake was thinking that the physical colour was the colour coming out of the RGB socket and the logical was the value going into the ULA.
So, I just had them the wrong way around.

For Frogger NuLA mode, I use the standard palette code to set MODE 1 colours to Black, Red, Blue and Green (the actual colour choices don't really matter, but colour 3 is always green in my Frogger).
Then I reset the NuLA lda #&40 : sta &FE22 and change colour 1 with lda #&1r : sta &FE23 : lda #&gb : sta &FE23.

Thanks Rob for an excellent add-on that is very easy to use

[tricky]

Rob, or anyone with hardware, do you get the white dots just above the middle magenta ground, or is it only on b-em?

[RobC]

Rob, or anyone with hardware, do you get the white dots just above the middle magenta ground, or is it only on b-em?

Yes - they're there on my real hardware too (BBC B). There's a little bit of flickering on the RHS of the white dots too.

[tricky]

Thanks, can't think what can have changed with the timing.

[RobC]

Just checked an earlier version on my NuLA-equipped Beeb and there aren't any issues - colours are correct and rock steady.

[tricky]

OK, tweaked it slightly, please let me know if there is any other flicker that I haven't noticed.

[RobC]

Looks fine now on my machine

[fwibbler]

Probably a silly question, but how do I eenable Nula in B-Em?
I couldn't find the option anywhere and yet I'm sure I've had it working before...
Thanks.

[RobC]

Probably a silly question, but how do I eenable Nula in B-Em?

I don't think you enable it - you just boot up a NuLA-modded version and it's there.

[tricky]

The version I am using is 170913 and doesn't have any NuLA options, but does show the NuLA ROM with *HELP.
I am using |Settings|Model|BBC B w/8271 +SWRAM

[sbadger]

I've just started looking at VideoNULA (yes I know, I haven't even installed mine yet! and it was one of the early ones).
This is an update to my Frogger game, which hopefully is still compatible with everything (same .ssd NuLA or not), including burning $.frogger as a ROM.
I haven't tested it on hardware, but after a false start (didn't realise I would have to program 4 physical colours as per &FE21) I am now using logical colours to write less data (good for everything except possibly Phoenix stars).
NuLAshot.pngPlease try it out if you have hardware, or use the b-em emulator (like I did). I have "found" the extra 24 bytes (12 colours) I needed on the stack and am not sure that I can't overwrite them. If the colours go wonky after a while, all 24 probably weren't "unused".

EDIT: It detects NuLA by looking for "VideoNuLA" at the start of the ROM's name.

Hi Richard,

I've a NULA but not the ROM fitted, is there a way for force nula without the ROM?

[tricky]

Not easily as Frogger is compressed and you would need to patch it and recompress.

If I get time tomorrow, I will change the way it uses NuLA so that it uses the flashing colours for the extra colours, but with flashing disabled, so that the colours can be "NuLAed" before running Frogger.

If you are in a hurry and have sideways RAM, you could load the ROM there temporarily.
It checks for the 9 characters "VideoNuLA" at &8009 onwards.

[crj]

Dumb question: are you actually using the ROM, or just using its presence as a sign that the NULA is present? (I'm guessing the NULA is read-only so its presence can't be detected directly.)

If the latter, you could provide some obscure keystroke to engage NULA mode even without the ROM.

[tricky]

Here is a quick hacked NuLA ONLY version, only tested on B-Em.

[tricky]

I'm trying to support NuLA without the ROM, but it involves some compromises as I have only 1 byte spare when running!

Yellow logs or Cyan logs or don't support NuLA without the ROM!

The other option would be to make the magenta "grass" on either side of the road either yellow or cyan.

[tricky]

Here is a comparison of No NULA detect beeb, Arcade and NuLA versions.
I can't remember when I had to sacrifice the numbers font to squeeze in something else!

PS I have a cunning plan to get the magenta logs back!

[sbadger]

I'm trying to support NuLA without the ROM, but it involves some compromises as I have only 1 byte spare when running!

Yellow logs or Cyan logs or don't support NuLA without the ROM!

The other option would be to make the magenta "grass" on either side of the road either yellow or cyan.

are you changing pallette halfway through scanlines or something like that?

[tricky]

I'm reprogramming the palette every 16 scan lines, but to make it work with or without NuLA, I'm programming all the colours I need up front and then using the usual palette swaps.
To get the magenta logs to be brown in the top half, I set flashing magenta/X to be brown and leave magenta alone so that it can be used for the magenta parts of the cars. The problem comes when I need a third magenta (non NuLA) that isn't brown or magenta, but I think I can set flashing colour 1 for the bottom half and use flashing X/magenta as long as i don't need any flashing 0 colours.

[sbadger]

I'm reprogramming the palette every 16 scan lines, but to make it work with our without NuLA, I'm programming all the colours I need up front and then using the usual palette swaps.
To get the magenta logs to be brown in the top half, I set flashing magenta/X to be brown and leave magenta alone so that it can be used for the magenta parts of the cars. The problem comes when I need a third magenta (non NuLA) that isn't brown or magenta, but I think I can set flashing colour 1 for the bottom half and use flashing X/magenta as long as i don't need any flashing 0 colours.

wouldn't it be easier to instead of changing how it works, i.e. the already working nula version, but insead of checking for the rom name, just check 1=1 in a special build or are you actually using the rom features?

[tricky]

So here is hopefully a version of Frogger that will work with or without a NuLA and look its best either way.
I have only tested this on keyboard on my beeb (+b-em w/wo NuLA and beebem) and still haven't installed my NuLA.

FroggerNuLA.zip

Compatible with or without NuLA

(13.47 KiB) Downloaded 11 times

I have had to tweak the timing slightly, so please let me know if there are any compatibility issues.
It should work on B, B+, Master and Compact with keyboard or Joystick (press fire to activate).

I'm not using anything from the ROM, but don't want people to have to choose, or even know if they have a NuLA, although I guess they would know.

Anyway, here is a version that doesn't need to check, it just resets the NuLA (corrupting the ULA if no NuLA), resets the ULA, then sets 12 of the colours to those used by Frogger (corrupting the ULA palette) then resets the ULA palette so that the game works as expected.
For example the Magenta logs are actually Flashing:Magenta/Green, but NuLA has that set to brown. The Magenta middle and bottom safe zones are actually Flashing:Green/Magenta (purple in NuLA) but I set the flash colours to the second one for the middle and below, but to the first colour above. The Magenta in the middle row of cars is actually Magenta, which is nearly the same shade in NuLA.
By jumping through these hoops, I can leave all the rest of the code the same and only need one version.
The red border around the homes at the top is actually Flashing:Red/Cyan (first colour as it is in the top half).

If a game can be changed to use colours like this, then the NuLA palette can be set outside of the game and the code never needs to know. This is why there was a flurry of activity about changing game graphics, although without touching the game code, you can probably only have two of each colour, that is two colours in NuLA which become 1 colour without it.

[Bagpuss]

Hi Richard,

I've just tried the new SSD on my NuLA equipped Master and the game runs with standard colours only.
I've got the 1.02 version of the NuLA rom installed, and other NuLA enabled demos etc. work just fine.

There might be one small difference in my setup, as I have just updated the NuLA with the new code from Rob to give me attribute mode for the Spectrum emulator.

I've now tried the NuLA only SSD, and this displays the enhanced colours just fine.

Am I missing something? Do I need to set a NuLA palette before running the game?

EDIT: Just tried it again with the NuLA rom unplugged, and the MODE 7 colours go totally wonky before starting the game, but the in game colours are still standard.

Thanks,

Andy.