Re: [stella] RPG progress

Subject: Re: [stella] RPG progress
From: "Paul Slocum" <paul-stella@xxxxxxxxxxxxxx>
Date: Fri, 20 Feb 2004 13:02:00 -0600

Here's an animation I created, just going upwards from the start:

Hehe, that looks really weird, and kinda cool.

Take a closer look at the water coming in on the last three sprites on the right.

Okay, I see what you mean. Well the "grass" tile is what I consider the blank tile. It is tile value 0 and I "OR" in any other tiles from the map data.

The map definition is divided into 10x10 cells. So each time you move/scroll and a new row or column has to be filled, usually map data has to be read from TWO different map cells (unless you happen to be standing right in the vertical/horizontal middle of a cell). Each move, the first frame is used to scroll all the visible tiles over 1 and clearing an empty row or column, the next frame the program fills in tiles from one of the 10x10 cells, then the third frame it fills in tiles from the other 10x10 cell required to complete the row or column. So often you'll see the new row/column filled partially, then the following frame it will be completely filled. Since the color shading is done on the fly in the kernal, it won't shade anything until the tiles are actually there.

Keep in mind that in the real game, you won't be able to move as fast as you are now, so it won't be as obvious.

I've considered just removing the grass and making that tile blank. The flicker really isn't that bad at all on my TVs, but removing the grass just means less objects on the screen flickering at any given time. And maybe it would make the scrolling look less odd?

I've attached the source. The main stuff you want to look at is in rpg.asm. The water wrapping to the right is a kernal problem, although I looked at it on my TV last night, and it's barely visible. But the problem Manuel showed in that GIF is just a characteristic of the scrolling system. Without a HUGE improvement in the speed of the map generation, I don't know of a way to fix it. And rewriting the map generation system is not something I'm too excited about. It is pretty complicated, and there's not a lot of memory to spare.

I just hacked that new character display system into the second bank. Should have an inventory/status screen working soon.


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