New demo: horizontal Logo-Scroller on 2600

[Simon]

Hi everybody,

 

after finishing my "Graz2004" demo, I thought about other demoeffects to program for the 2600.

 

A very popular thing in old demos has always been a horizontal logo-scroller. As I haven't seen such a routine on the 2600 by now, I decided to create it yesterday evening. The biggest problem on the 2600 is that softscrolling of playfield-graphics is not possible and the PF-pixels are quite blocky (only 40 pixels per line).

 

I realized that the effect looks much smoother if you put some sprite-pattern above/below the logo. The eye gets dirstracted from the blocky pf-scroller then and the whole effects looks much better.

 

Technical information: the routine is very flexible, the graphics of the logo can be stretched from one to maximum amount of scanlines. The demo is PAL with 312 scanlines. The logo-scroller is done in RAM for the calculation of the current logo - nine bytes RAM for each of the eight different logo-rows.

 

I think of adding color-fading for logo and sprites, color-bars in logo and usage of missiles and ball for further effects (more bars, stars etc.). I plan to use this part as introduction-sequence for my next game - hence the logo.

 

PLease let me know what you think of it.

 

Best regards,

Simon

03_parag.zip

[Paul Slocum]

That looks great! You should make it move up and down using a movement table. And it'd be cool to give it a gradient so it looks metalic.

 

-paul

[Simon]

Hi Paul,

 

> You should make it move up and down using a movement table. And

> it'd be cool to give it a gradient so it looks metalic

 

That's exactly what I'm thinking of. A free moving (up/down and left/right logo with color-bars inside) changing before/behind flashing and moving sprite-graphics (parallax scrolling).

 

Updates to follow, but for the first two hours of coding I'm quite satisfied.

 

Thanks and best regards,

Simon

[Rob Mitchell]

Looks nice on the cuttle cart 2 on a 7800. The line colors and background change during the first scroll.

 

Rob Mitchell, Atlanta, GA

[Dr. Van Thorp]

The biggest problem on the 2600 is that softscrolling of playfield-graphics is not possible

 

Why not?

[raindog]

Because the playfield is only 40 pixels across and no one's ever figured out how to make the position of the pixel boundaries change yet.

 

You could make an even lower resolution but soft scrollable "playfield" using color changes, as long as you weren't trying to do anything else but that.

[Dr. Van Thorp]

Then you could soft-scroll the playfield one big blocky pixel at a time. The Commodore 64 and Atari 8-bit machines had redefinable character graphics, and some programs "faked it" by moving blocks of graphics characters a whole character space at a time. A character space was 1/40th of the screen, just like a 2600 playfield pixel. As long as it wan't to slow, it really didn't look bad.

[Thomas Jentzsch]

Then you could soft-scroll the playfield one big blocky pixel at a time. As long as it wan't to slow, it really didn't look bad.

Right, that's what I am doing with Thrust. Compared to e.g. Vanguard, the "delayed scrolling" looks IMO much smoother.