1. Additional Video Pages
I am making a game and would like to know how to get more video pages in
mode 19, 320x200 256 colors. I think I've seen it before but don't
remember where. I don't have a whole lot of the details of the game worked
out, but I am planning on making it some sort of a strategy game. Thanks
for any help.
William
2. Re: Additional Video Pages
> I am making a game and would like to know how to get more video pages in
> mode 19, 320x200 256 colors. I think I've seen it before but don't
> remember where. I don't have a whole lot of the details of the game
worked
> out, but I am planning on making it some sort of a strategy game. Thanks
> for any help.
>
> William
Well, remember that you can always save a screen using save_image(), to
store the current screen display if you want to generate a new screen. When
you want one of the screens redisplayed, just redisplay using
display_image(). This way, you can swap between as many screens as desired.
Hope this helps
David Gay
http://www.interlog.com/~moggie/Euphoria
"A Beginner's Guide To Euphoria"
3. Re: Additional Video Pages
On Wed, 26 Mar 1997, William Eiten wrote:
>
> I am making a game and would like to know how to get more video pages in
> mode 19, 320x200 256 colors. I think I've seen it before but don't
> remember where. I don't have a whole lot of the details of the game worked
> out, but I am planning on making it some sort of a strategy game. Thanks
> for any help.
You get one display page in 320x200x256 mode. The best way I know to work
with it is to have a Virtual Screen, a screen sized sequence in ram, then
"draw" your sprites into it by indexing into the sequence. After you
"draw" all your sprites, you update the actual graphics screen by grabbing
the changed regions of the Virtual Screen (with a few pixel border to
help erase the previous sprite positions) and display_image() them to the
screen. It sounds pretty complicated, but once you figure it out, it's
VERY straightforward. The only confusing part is the actual "drawing."
In my SpriteEngine I do something like:
setVS -- this makes a clean copy of the background
screen_update={0,1,0,1} -- is is my table of regions in VS to update to
the screen.
for each sprite
procedure draw_sprite(atom x, atom y)
for i = 1 to length(sprite) --height
for j= 1 to length(sprite[1]) --width
a=sprite[i][j] -- color of pixel in sprite
if a>0 then -- if the color is 0 don't draw it, thus masking the
sprite with the background
VS[y+i][x+j]=a -- replace whatever is at that location with a
end for end for
screen_update=append
-- add a 3 pixel safety region around it to erase the last position,
-- increase this is if it moves more than 3 pixels in any direction
end procedure
Then after you get done with all your sprites, do through the
screen_update() table and grab regions from the VS and display_image them.
The format above for that table is {x1,x2,y1,y2} for the regions from
{x1,y1} to {x2,y2}.
Michael Packard
Lord Generic Productions
lgp at exo.com http://exo.com/~lgp
A Crash Course in Game Design and Production
http://exo.com/~lgp/euphoria
4. Re: Additional Video Pages
re: Video pages
I'm under the impression that one of the unchained Mode X resolutions
actually supports 4 video screens. The problem is, you would need to write
all your own tools to use the mode, since Euphoria doesn't support it. There
is a good tutorial with C-code examples in the PC-GPE (PC Game Programmer's
Encyclopedia), an excellent freeware collection of articles on game
programming related topics. It looks like an easy enough port to Euphoria,
if you use Jacques' port writing tools.
It's also got a nice series of tutorials on Mode 13h, including one on
writing virtual screens.
If you want to get more speed, take a look at Jiri's "Aliens!" program,
which uses mem_copy() to do video moves, which is much faster than working
with sequences, but again, you would need to write your own primitives.
-- David Cuny
