[Coco] Rampage screens

Steve Bjork 6809er at bjork-huffman.net
Wed Jan 16 15:33:51 EST 2008


At 11:38 AM 1/16/2008, Roger wrote:
>Steve,
>Also, I was wondering how you copied the background scene (building 
>shadows, grass/bushes, sidewalk, road) to the screen quickly for 
>each page-flipped frame.  Did you use stack blasting?  There seems 
>to be a lot of overlayed graphics like the buildings and people and 
>it looks very CPU draining.  I'm guessing there are two background 
>scene pages and you just restore/replot each graphics element before 
>showing them on the current page.

Steve now writes:

There are 3 screens. two are the standard "screen flipping" pages so 
you can draw on while displaying the other.
The third screen holds what the background screen should look like 
without any the sprites (moving graphics objects).

When it comes time to remove the sprites off the screen, I just grab 
the graphics data off the third background screen and draw over where 
the old sprite.

Remember, the background is also changing (buildings are falling 
down) and have to updated the background screen and the flipping 
screens too.  That's where Rampage shines because it's able to keep 
the frame rate up while doing all that work on a full 320 by 210 by 
16 color screen, no less.

In my opinion, Rampage was one of best game for the Color 
Computer.  Not only did it turned out well, but also how it came to 
be.  It only took 35 days from start to end and each of days the code 
was well behaved without any bugs to delay it.  It was a real joy 
working it and I even got a early completion bonus to boot!  (About 
75% of the contract price.)

Steve (Rampage) Bjork




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