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From: pfratar@watserv1.waterloo.edu (Paul Frattaroli - DCS)
Newsgroups: rec.games.programmer,comp.os.msdos.programmer
Subject: A big map with scrolling.  How???
Keywords: map bitmap scroll
Message-ID: <1990Sep10.183857.15821@watserv1.waterloo.edu>
Date: 10 Sep 90 18:38:57 GMT
Distribution: rec
Organization: University of Waterloo
Lines: 49

Hi,

	I have some questions regarding a very large graphic or bitmap
image.  I am programming a game which will have a large map surface
displayed on the screen.  This map will be larger than the displayable
screen size, so it will need to scroll.  Much like a spreadsheet.

	First of all, I would like to give some info on architechture
and graphics so I can put people in the right context when answering
this posting.  The program will be for an IBM PC or compatible
runnning DOS 3.x or later.  I am planning on using the MCGA
320x200x256 color mode (I can't remember the mode number) for the
graphics display.  I will be programming in TURBO C version 2.01 using
the BGI stuff.

	I am not sure about the best way to do this.  I have thought
about the following ways.  These may be "out to lunch".

	- A bitmap image - This could get very large, not good.
  
	- An encoded bitmap: I don't need an extremly good amount
	of resolution, so I could encode the bitmap in chunks.  I
	could have a byte-value represent a color, and a routine that
	would actually display a chunk of that color that may be
	say 3 pixels x 9 pixels.

	- A tiling effect: similar to the encoded bitmap, but with
	larger chunks that are more like tiles.  A two byte code, one
	for color, one for pattern.  Separate routine to decode and
	display tiles.

	If I use a bitmap like image or data, I am trying to decide
whether to include the data in the executible or in a separate file.

	As to scrolling, I think that the only acceptable method may
be direct screen memory writes.  Unless someone can direct me
otherwise.

	For all I know I'm probably doing this all the wrong way.
Also, if anyone can suggest some good books that might help I would
greatly appreciate it.

Thanks in advance,
....Paul

-- 
              Paul Frattaroli - Department of Computing Services                          University of Waterloo  Waterloo, Ontario Canada  N2L-3G1
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