Blog update!

http://www.retrosoftware.co.uk/wiki/ind ... ry20110527

Yes, work on Blurp has started again! (it wasn't dead, it was resting).

Time bar - I guess you're mis-programming the palette there?

That was my guess too; as the ULA has 16 registers, that it uses for the lookup table, you can get some strange positional based colour effects by setting the "unused" 12 registers in a 4 colour mode.

(Yes i know they're not unused, it's based on the bit patterns; I was going to write something up about ULA palette register abuse, but it really requires an artist to make full use of the 5 or 6 colours you can get in mode 4 without an interrupt!)

Nice!


In that case, we'll demo it on an actual Arcade Cab at Replay, then (assuming you get it finished, of course!!).

Haha, great! I'm going all out on it now (lost my job recently, y'see...) It's close to finished now, code-wise, but just needs some good graphics and levels designed...

Regarding the time bar, yes it's true, misprogramming the palette might be one way of doing this (provided you could arrange the graphics to fit) - I've never even considered it as an option, I always thought it would be too hard to get right!

So, no one's got it yet. It's a surprisingly easy method, it doesn't require any careful timing or anything, although it is somewhat limited in which parts of the screen it can be done...

Sorry to hear about your job. Though the retro world will benefit (assuming you can afford to eat)!

On the time bar, the only other thing I can think of is abuse of flashing colours, but this requires timing tricks and as it's a horizontal break that rules it out.

Is the pattern of the cyan significant (i.e. the line of cyan, line of black, line of cyan etc.)?

No, the pattern's not significant. The colours are though.

Hmmmmmm.....

I can see that you are using palette switching at least twice on the screen:

• The main colours are black, yellow, red and blue
• The time bar colours are black, red, magenta, green and cyan
• The score line colours are black, red, white and unknown

This makes me wonder whether the cyan comes from the score line's palette and is somehow shifted up, though I'm not certain how this would be done.

Actually there's just one palette switch, which happens just after the bottom line of the 'frame'.

If it helps, the unused colour in the bottom score line is magenta.

You're using the cursor! (I think?)

Yeah spot on Tom!

I always wanted an opportunity to try out this little trick, as it's so easy to do. Basically, by setting a steady cursor for an entire character row:
...and then programming the Video ULA to generate a 32 byte wide cursor, this inverts the colours in a block of the screen 16 pixels wide.

So that's all I do. If you were to turn the cursor off, you'd see that the 'TIME' graphic is on a white background, written in magenta, with red 'trails'. The physical inverses of these become black, green, and cyan.

Easy when you know how!

Obviously this is rather limited to a single 32 byte block of screen - but I guess there's no reason why, with some careful timing, you couldn't change the cursor address midframe and get lots of cursors at once! Like multiplexing hardware sprites on the C64 or something...

Bumped to say there's a new diary entry.

Looks as if it's coming along really well now, Rich! Might a November release still be on the cards?

Yeah, I reckon! Code-wise it's pretty much entirely there (unless I have space left to add new gameplay features - bonus rounds and that kind of thing), and now I've finished the screen editor and made it nice and easy to use, the main hurdle that remains is designing some nice graphics and some challenging and fun screens.

And obviously it's gonna want a nice scrolltext or something on the loading screen

At some point when it's nearly ready, I'll need to send it yours (or someone's) way to check that it actually runs ok on real hardware... So far I have nothing but 100% faith in B-Em, but you never know.

Excellent news, looking really nice Rich

November release, cooool

man, if only we had somewhere big to launch it ... but I just can't think of anywhere ...



Sam.