ZXodus Engine (rainbow tiles)

[cheveron]

Hola!

I know na_th_an of the Mojon Twins has already spotted this, but I thought I'd share with the rest of the Spanish language scene:

ZXodus is a rainbow processor and tile engine that gives you a 9x9 grid of tiles (144x144 pixels with 8x1 attributes) on the original 48K Spectrum. It does work on other models but the timing may need tweaking.

The engine is available here (with source):
http://www.worldofspectrum.org/infoseek ... id=0026639

A simple PNG to tile converter (by na_th_an) is available here:
http://www.mojontwins.com/warehouse/zxodus-conv-0.1.rar

Cheers!

-chev

[mcleod_ideafix]

Cool!! Is the tile block located always at the same screen position, or can you move the 9x9 block to any other screen position (or character position).

PS: I haven't read the source code. Maybe the answer is already there...

[cheveron]

Cool!! Is the tile block located always at the same screen position, or can you move the 9x9 block to any other screen position (or character position).

PS: I haven't read the source code. Maybe the answer is already there...

Well, because of the timing critical nature of the thing you'd have to recalculate the loops and change the screen offsets to put the grid somewhere else, but in theory it is possible. The grid would actually benefit from being on the right hand side of the screen as the attributes are drawn from right to left and the scan line updates from left to right but I wanted to push the machine as hard as possible. The further down the screen you place it, the longer the delay loop you'll have to use before the first line is drawn, so the ideal place to put the grid is in the top right hand corner.

-chev

[radastan]

Wooooowowowowowowowo! Great effect!

¿How many CPU time is free for the game engine?

[cheveron]

Wooooowowowowowowowo! Great effect!

Thanks.

¿How many CPU time is free for the game engine?

Not a vast amount, but then the engine draws the tiles for you so all you have to do is the I/O and game logic.

-chev

[na_th_an]

Is there any way of synchronizing with the tile display? In my test from pure BASIC I've found that it's relatively hard to control what delay to introduce so you can "animate" the screen (make a character move from tile to tile) without flickers or ghosting. Is there some memory address where we can read the tile counter and "wait" until the buffered screen is completely updated?

[cheveron]

Is there any way of synchronizing with the tile display? In my test from pure BASIC I've found that it's relatively hard to control what delay to introduce so you can "animate" the screen (make a character move from tile to tile) without flickers or ghosting. Is there some memory address where we can read the tile counter and "wait" until the buffered screen is completely updated?

There is no tile counter. But it's relatively easy to add one. Make the following changes to the source:

atflg:
defb 0
+counter:
+ defb 0

t00:
+ xor a
+ ld (counter), a
ld hl, tile_map ; point to tile map

t26:
ld hl, tile_map + 78 ; point to tile map
...
+ ld a, 1
+ ld (counter), a
ret

Now counter (PEEK 65532) will be 0 while the tiles are being drawn and 1 when the map is fully drawn. That will give you a window of 1 interrupt to do anything before it starts drawing the tile map again.

A different approach would be to switch off the drawing of the tile map until you've made your change (by temporarily NOPing the jump to the tNN tile drawing routines) but then it will still take 27 interrupts to draw the map. However you do it you're probably going to end up with some tearing.

[na_th_an]

That's exactly what I needed. Thank you. If I find the time, I'd like to experiment with it to make some kind of roguelike of sorts. Great job

[radastan]

That's exactly what I needed. Thank you. If I find the time, I'd like to experiment with it to make some kind of roguelike of sorts. Great job

Se me acaban de caer las pelotas al suelo, lo juro.

[na_th_an]

Bueno, es una de las cosas anotadas en nuestra libreta de ideas de cosas para sartar en la corchoneta de sartar (la famosa LIDEIDDECOPASARENLACORDESAR). Estoy dándole vueltas a un generador aleatorio de mapeados que no tarde una hora en hacer uno molón.

[radastan]

Si, pero no olvides que tiene que haber colchonetas para saltar entre niveles y puticlubs en las mazmorras. Si no, no es juego mojono.

[na_th_an]

Nah, a nosotros no nos gusta eso del sexo comercial.