Friday, 24 February 2017

8-bit journeys into pop culture

Again, some recent 8-bit images, added with musings and reflections. Funny how it all tends to go back to TV/Sci-fi/film themes...


Dallas (128x192 Texas Instruments 99/4A bitmap)

The first image is for the mega-demo Don't Mess with Texas by Desire, for the Texas Instruments 99/4A computer. The coders have done an amazing work in demonstrating the hidden capabilities of this very limited and idiosyncratic old computer. I had a small piece in the demo, a half-screen image which is shown for a couple of seconds of the eight-minute runtime.

I went with "Dallas", as it was one of the first things that came into my mind with that Texas-theme. It also fits nicely as Desire and Dallas have both a D and the same amount of letters.

I never really watched Dallas but in no way could the phenomenon be avoided
As the TI99/4A has the VDP chip, the graphics capabilities are nearly the same as in MSX. The TI community claims that the palette is at least somewhat different, so although I worked the image mostly in the MSX colors the end result is in an interpretation of the TI99 values.

I don't like to use references, but here I needed to use photographs of the actors. Even then these are not very directly worked from any one photograph, and the 8x1 colorspace really makes you reinvent the images anyway. Ok, the MAD Magazine parody "Dullus" opening shot probably influenced me more than I'd like to admit.

The aim was to showcase the color capabilities of the VDP/TI. So, superfluous horizontal color bars and candy-like coloring here and there. The pic is a bit rough in the details but I supposed that as the authentic target is a television tube, it would not matter so much.


Alien (160x200 Commodore 64 multicolor bitmap)

The second image was made to enhance a cracked C64 version of the game Alien (1984), based on the film. The Hokuto Force crack (Alien +6DG) enhances the original and I was asked for a xenomorph pic to accompany the release.

Somehow it reminds me of the Mortal Kombat logo?
I now examined some images of the Alien, going back to the original film props when possible. The more I looked at images of the actual suit that was used in the filming, the less impressive it became. Don't get me wrong, Giger's work is obviously a classic. It's simply that the way the prop/suit is used in the film does not reveal how humanoid-like the costume really was.

So, the mystique of the Alien is not only about showing it in very few scenes, but also revealing very little of the actual shape, the guy-in-a-suit nature of it. I wonder which then is the "correct" alien, the impression left by the film or the actual prop used?

However, these thoughts did not really impact the result that much. This is more a graphic emblem of the Alien than an impression. I changed the proportions a bit, exaggerating the tail size and shape to create a circular composition that is partly reinforced by semi-circular elements in the centre.

The game is pretty neat, I've played it on a ZX Spectrum a few times. It's a bit similar to the later Shadowfire in having multiple characters that are real-time icon controlled. According to World of Spectrum, John Heap has worked on both of them, so that maybe explains the similarity!

Info about the release at CSDb


Beam Us Up (16x23 characters PETSCII directory art)

The third image is my first attempt to make "dir art" for the Commodore 64. Directory Art refers to graphics made inside the directory portion of the disc filesystem. So instead of seeing the ordinary list of files via LOAD "$",8 there are logos and visuals instead. Crackers and demo groups used to embellish their releases with such graphics, and still do.

Screenshot of the directory, but LOAD "$",8 is the real way to experience them.
I made a very old-school PETSCII that fits the screen. My main motive was to include the " characters into the image, as these normally frame the filenames. I came up with this Star Trek themed pic, a little bit related to the non-standard PETSCII of Mr. Spock that I once made for the print magazine Skrolli (see below).

In my dir art the " characters work as edges for the transporter beam. Also, there is always some motion inherent to a directory listing so Spock and Kirk are sort of being "beamed". This could have been enhanced by having a longer dir list.

Once again I used Marq's PETSCII editor to create the image. The c1541 tool was used to generate a D64 disk image with a bunch of files with dummy names. With a hex editor I collected the offsets for the file names. I then modified the PETSCII editor to overwrite the D64 file using the offsets. The character encoding also needed to be changed for the directory environment. Afterwards the file identifiers were trashed in such a way that the first file could not be loaded, again with the hex editor.

The file at CSDb

The CSDb dir art compo

A "non-standard" PETSCII, for Skrolli magazine

Tuesday, 14 February 2017

Fort Django v1.1



I made a small update to my Commodore 64 game Fort Django. The most important changes are:

-A choice of a whole new map with new background graphics
-New enemy behavior (in the new map)
-Music and Sound FX and a choice between them

The old game mode (map1) should play almost identically as before.

Use joystick in port 2. Turn up and down in the title screen to select the map. Turn left and right to switch between sound fx and music. Fire starts the game.

As before, you shoot enemies and try to find the exit. Collecting bags gives extra bonus depending on how quickly you have moved from the last bag. (The bonus keeps decreasing from $900)


Internally, I changed a few things to make the new map fit. The memory use was extremely lazy in the old version. Many c variables and arrays are now changed to direct memory read/writes. I relocated these higher up, so the compiled code and data area have more room to breath.

I added a scanline interrupt for the music routine, which plays out the in-game music I created with Goattracker 2, using subtunes for different program sections. The main game tune can be turned off. The sound effects make use of the Goattracker sound fx routines which are simple but suitable for this type of game. If the music is off, there are more sounds, but one channel is always reserved for sound fx. I'd say overall the sounds are better than the old ones, even though I sort of miss the sharp gunshot sound. The tunes try hard to sound something between Rambo/Platoon but a Galway or Dunn I ain't.

The sprite updates are more rigorously done during the vblank so I have more time during the frame for doing other calculations, should they be needed. However the game pretty much runs during the vblank anyway.


The new map takes the player to a vaguely central american temple, giving the game some more of that Pitfall/Rick Dangerous vibe. The new map has a bit different play style too. The rooms are more open and there's more opportunities for platform game elements.

There's new enemy behavior in this new map. For example, the enemies only shoot when facing the player. The enemies can also crouch like the player, so the player can't use always the same trick when entering the screen. Some of the enemy behavior and timing is adjusted on a room-by-room basis, so the rooms can contain a small pre-defined "action puzzle".

Internally, the two enemies are switched occasionally. Inside the program logic only one of them does the shooting and crouching. But the switching gives an impression of both having the same freedom. This is not especially elegant but given how the two enemies have been programmed it's a nice fix.

The splash screen and ending have been adjusted, but I felt a weird respect toward the old map and did not alter the graphics there at all.

It was nice to revisit the program, but in the future, I'd probably prefer making something new than try to continue adding to Fort Django.

About the first version

Fort Django v1.1 at CSDb