Sprites a-la This Planet Sucks?

[rasty]

Hi everyone,

 

I'm having a lot of fun since I started programming on the 2600 some week ago, and finally came to the point where I'm starting to code an actual display kernel for what might eventually become a game (instead of just a bunch of test displays).

 

My display should look something like the one in This Planet Sucks, with several sprites scrolling horizontally (rocks) and the player moving among them.

Now, I can only do this by going for a 2 lines resolution, since my kernel looks something like this:

 

ScanLoop1:

Check for Player1 Y Position

Draw Player1 if Y position is correct

WSYNC

 

Draw rocks

WSYNC

JMP ScanLoop1

 

Ok it's not really a JMP to ScanLoop but you get the idea

I create a ScanLoop for every horizontal stripe of sprites.

 

It all works fine whis way, but I've noticed that This Planet Sucks does the same thing with a 1-line resolution and this upset me a little

I don't think I'm the only having problems to make a sprite move freely on a horizontally layered display, I clearly recall Frogger where the frog makes jumps of 8 pixels up or down to avoid having to check for the sprite's position on every line, something that I have to do.

 

So my question is: is there a way to make my player's sprite move freely on the display by keeping a 1-line resolution?

 

Thanks in advance!

ciao,

Rasty.-

 

[ 05-13-2002: Message edited by: rasty ]

 

[ 05-13-2002: Message edited by: rasty ]

[Thomas Jentzsch]

It's hard to answer your question without having a look at the code. And I think, AtariAge is not the optimal forum for a 2600 programmer. Must stuff is 5200 related here, which is AFAIK very different to program.

 

Nicer graphics on the 2600 normally require more optimized code. So, optimization is the key. The normal trick for getting 1 line resolution is using the VDELPx registers. Hard to understand, but very helpful.

 

You should definitely have a look at the archives of the Stella Mailing List first and then perhaps join too.

[rasty]

Thanks Thomas, I just didn't want to bother too much by posting code here

 

I've browsed the stella archives but my current skills still prevent me to achieve my goal, I obviously need some more time for research and lots of practice..

 

I'll follow your advice, join the list and also do some experimenting with the vertical delay registers!

 

Thanks,

Rasty.-