Tuesday, 13 October 2009

A8 :: shooty stuff

i've been thinking about writing a shoot 'em up for the Atari 8-bit for literally years now... but it's not the easiest machine to write that kind of game for. The current project started as something of a urine extraction of a particular person at Atari Age who rather ridiculously kept banging on about how more colours in a game somehow made it more beautiful. No, i couldn't see it either so i threw together something with three playfield colour splits a scanline that essentially looked like Rainbow Brite had vomited down the inside of the monitor to demonstrate:

i suspect a few people thought that was just a mock-up when i posted it (and it keeps getting complements, that's worrying...) but there's a fully functioning game engine behind that too... but the sprite engine being used isn't much more complicated than what games like Mirax Force or Humanoid already do (it has some wave sequencing behind it so there's more game logic going on, but the way it actually recycles hardware sprites is the same) so everything is on horizontal rails. It's workable, but seriously limited when it comes to what the nasties can actually do.

So i started thinking about other options and now i have a [i]second[/i] preview, this time far less busy on the playfield colour splits but changing the sprite colours every other scanline and able to recycle the three sprites assigned to nasties (the player's is dedicated) in order to give six relatively free standing objects whizzing around the play area with a more complex wave sequencing engine feeding them control data. Fantastic stuff and i can live with just one of the playfield colours being split... except to my mind the sprites simply don't look as good with one colour and splits (the splits are a scanline out on this screenshot, use your imaginations!):

So now i have something of a dilemma, do i go with this revised engine and carry on, look at the possibilities of changing it again to multiplex three colour objects (if i do, the player's ship becomes a software sprite and things are... fraught as far as available CPU grind go already) or is there a third option...

Decisions, decisions...

In the meantime, i might arse around with the scroll engine and multiplex to produce a much simpler game to see how things stand on CPU loads.

Monday, 14 September 2009

C64 :: GR9 Strike Force released

It's being called the "party version", but GR9 Strike Force has been released over on the Cosine website. Yay! Here's a screenshot from the final release:


Thursday, 10 September 2009

C64 :: so near...!

GR9 Strike Force is pretty much done bar the pretties now... here's the video!

Thursday, 3 September 2009

C64 :: bugs and tanks

The code that manages the likkle tanks went into GR9 Strike Force yesterday (for speed, the various objects are driven by discrete blocks of code rather than a generic management routine) along with a first draft of their firing routines; at first everything seemed happy bunnies and they'd tootle into the play area, stop after a distance set by the wave data and began firing, exactly what they're meant to do until something odd started happening...

It took about three damned hours to diagnose, but the symptom was that Tank 1 would drive into play from the bottom of the screen, park up and start shooting normally. Then the attack wave manager would throw a couple of passing aircraft into the mix before getting to the data for Tank 2. Just after Tank 2 was assigned (using up the last available object) Tank 1 wanted to fire and couldn't find a free object for it's bullet. The routine has a contingency which essentially suppresses the urge and resets the counter as though the shot happened... but it'd mangle one of the registers on the way out (it should've recovered it from a storage location, but the command got lost in the wash) with the result being that the attempted bullet firing dented a table of timers so Tank 1 forgot it was in "stopped and firing" mode and promptly drove away!

Silly likkle tank.

Saturday, 29 August 2009

C64 :: Whoosh!!

Here's a screenshot taken about thirty minutes ago with some "real" attack wave data in place and the status bar pretty much working as it's meant but on test pictures - there's also a video to see it moving on YouTube:

Thursday, 13 August 2009

C64 :: GR9 under way

Okeydokey, so i posted to Facebook, uploaded video to YouTube and mentioned it on a couple of forums whilst forgetting my own dev blog... the new C64 project is under way and called GR9 Strike Force; it's another horizontally scrolling shoot 'em up, being written for Retro Reunited and the overall theme is more current than most of my previous games. According to the finite "research" i did, the GR9 Harrier is the model in service with at least some of our military right now.

Here's that video i uploaded:

The status bar has been drawn and installed, along with a six by six character area for a digitised picture - the idea is that at the event someone'll win a door prize, be photographed making themselves look a plum and be inserted into the game as an avatar during play and on the loading screen "live". Today was spent writing a very specific converter that takes four blocks of 24 by 48 multicolour pixels and converts them into a six by four character block in the status font, two sprites with the extra sixteen pixels that are in the lower border and six high-res sprites that are horizontally expanded and used as overlays to give a total of six colours for the image.

And yes, the code running in the video already has the upper and lower borders open and is handling the masking as sprites leave vertically itself to within a couple of cycles - of course, nobody'll notice these things unless i bloody point 'em out [mutter, mutter!]

Sunday, 3 May 2009

C64 :: Armalyte menu sorted

The disk menu for Psytronik's release of Armalyte was finished yesterday; i recycled the loader from the Mayhem In Monsterland menu (try saying that three times when you're drunk!) and at Kenz's request added keyboard-based selection since i hadn't even noticed the option in the original!

Tuesday, 7 April 2009

C64 :: More menu manipulation

Yup, i've been asked to do some more disk menu coding for Psytronik, this time for the release of (wait for it...) Armalyte! How could i refuse, it's one of my all-time favourite games f'crying out loud...! Anyway, the brief was to produce something similar to the original disk menu and Kenz sent over a lovely mock-up with the text nicely placed (i changed the position of two words so that one of the raster effects was closer to the original) and this is a fully-functioning menu that just lacks the loaders for when something is selected.

Oh, before some smart-arse says anything, the code was written from scratch without once looking at the original, even the colour tables for the bars were worked out by grabbing screenshots and squinting - i even had to create half the numerals in the font since they weren't there on the original and even managed to get a couple of sprite overlays onto the raster bars in order to enhance the Psytronik logos that took over from Mr. Thalamus in the top corners (it's been ages since i did anything even approaching timing-specific demo code, that took a bit of remembering on it's own...)

There's been a little progress on Co-Axis 2189 an' all (the code itself changed a few weeks back but the tile re-colouring happened just a few days ago) - it now has a full colour-per-character scroller as opposed to the colour-per-tile one it was running previously and the fourth level's backgrounds are in but for the moment are running with attack wave data from the third as test. Here's the "before and after" images and pause for just a moment to consider how bloody hard it must have been to pause the game on exactly the same frame twice like that!!

Saturday, 21 March 2009

C64DTV :: Blok Copy DTV released!

Further to my previous post, Blok Copy for the C64DTV has "officially" been classed as done and dusted; i've literally just written it up for the main Cosine website, added a news item to Oldschool Gaming and uploaded an entry over at the CSDb. Phew!

Thinking about it a little bit, i'm not sure if this counts as the first DTV-specific game - there's a mod of Boulder Dash using 8BPP graphics, but in this case i wrote the game code as well as did the visuals so it's some kind of first! Anyway, it's got a superb tune in by Sean "Odie" Connolly called "Sporting Chance", some 8BPP graphics i'm quite pleased with and plays pretty nicely too (i hope). Here's a screenshot and enjoy!

Sunday, 1 March 2009

C64DTV :: Blok Copy just about done!

Just a quick update really, i've just removed the loader and included the two 16K 8 bits per pixel fonts into the main file (the beta version is still under 17K when compressed) and a couple of days ago Sean talked me through a work around to get the music playing correctly after compilation, so Blok Copy is ready apart from the final beta testing. Yay!

Sunday, 15 February 2009

C64 :: copy of more blockage

Well, as promised here is the video footage of Blok Copy... and the cryptic nature of my previous post might be explained since it actually runs on the C64DTV version 2 upwards, using an 8 bits per pixel display mode. i didn't quite get all the cosmetic glitches out and the music (by Sean Connolly and to date unreleased) has a small hiccup when it starts because the EMS compiler seems to have an issue but... well, it goes at least!

Saturday, 7 February 2009

C64 :: still copying bloks

i've almost got what amounts to a complete game going! It plays all the way through from titles to completion screen and back (i've got it dialled down to only play two stages during testing), all the cosmetics have been rewritten from the PET code so that they work in their new environment and i spent some of the night before last and most of yesterday morning drawing presentation graphics. There are some cosmetic glitches still, although i'm pretty sure i know where they're coming from and plan to flatten them over the next couple of days. The game won't be released just yet because there are a few variations on the theme to complete first (and the music isn't settled on) and yes, i know that's needlessly cryptic, but i'll post some screenshots or a video when i get the flickers repaired.

Wednesday, 4 February 2009

C64 :: Blok Copy

i've spent a couple of days beavering away at Blok Copy (since i've finally got myself into a state of mind where coding is possible now) and the game itself is functioning perfectly. A little too well in fact, in the way that i start expecting it to crash and burn hideously at any moment! The presentation is still assuming there's a PETSCII font and isn't doing what it's supposed to but i'll get around to that next.

Thinking about it a bit more, i want to try converting it to the BBC Micro as well; that could put up a bit more of a fight to be honest, there's only 32K of RAM on a stock BBC and the best bitmap mode to use needs 20K just for the display (and a character set in memory will need 4K as well) but there are other options and i need to read up on the hardware a bit more before i make a decision as to which mode to go for. It might end up in four colours if things get desperate! All told, the various versions will need at least four different graphics sets (all laid out in a similar way) and somehow i've got to find a musician willing to do tunes for at least five platforms...!