Scrolling without S.E.U.C.K

From Richard's C64 blog!

25th January 2016

 Flipping heck. This week has been a SEUCK marathon. Anyway, time for a little change. Back in 2015, I mentioned to some people in the past that I’d love to attempt to create a vertical scrolling shoot ’em up game, without the aid of SEUCK. I examined the code in Codebase64 and I managed to get a rough map scroller. However getting a soft scroll to work right was a plain in the backside. So I left the code for a couple of years or so backed up.

However last week, I attempted to continue achieve my goal. Basically by getting the soft scroll to work much better. There were a few mistakes left in the scrolling code last time. It turned out that I wasn’t copying the last row, and pasting it inside a subroutine. Also the score panel at the bottom of the screen was flickering like hell. In order to solve the problem, I examined some code in an old TND Contributor’s C64 game, to see how the status panel stayed static while a vertical scrolling map was scrolling down. I noticed something very interesting. A stack inside an interrupt, had a control over the VIC2 Screen vertical position, which made the status panel more still. I attempted to place a similar routine, and that trick worked. The VSP scroll worked a treat.

This week, I have been making some more alterations to the scroller framework, and started a little game project. At the moment it is an Unnamed Shoot Em Up, (which the video below will show you). However I’m feeling ambitious to make a sort of a onward scrolling Denarius/Warhawk style futuristic shoot ’em up, without the aid of SEUCK. I created some test sprites and a little test panel in order to get the player moving and blasting. The asteroids that move constantly cannot be shot, and will not be the only thing in the game. This is just the start of a fresh new C64 game project I am willing to produce this year 🙂

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