How2UseGfx-P2

Short:        Part2 of How2UseGfxV39
Author:       jschober@campusart.com (Jürgen Schober)
Uploader:     jschober campusart com (Jürgen Schober)
Type:         dev/src
Architecture: m68k-amigaos
Date:         96/11/30

This archive contains some example material how scrolling
bitmaps could be handled. It is just an example how things 
could be done, because I am bretty sure, none of you will
use ScollLayers() in a SuperBitmap window for a real application.
But with a fast board (e.g. a PiccoloSD64) and a good driver
(e.g. EGSPlus :) it shows what could be done if the Amiga
would have the right chips.
This demo opens a 320x256 window on any screen (currently a
WB clone or the WB itself) with a 640x512 custom superbitmap
attached to it. The backdrop is a 256 color image (640x512)
which is scrolled thru the window. On top of it a green ball is
jumping around. Both images where created in 24 bit and color
reduced to 256 colors. The real colors are calculated on startup 
using a shared palette. It looks best when run on a 256 color
screen (but will reduce the colors if less). It should run on any
board (ECS/AGA too) but isn't really useable on native amiga chips...
I haven't tried CyberGraphics yet (but I should) but I think it
would run more smoothly on EGS systems (with EGSPlus) since
the SuperBitMap is held in boardmemory in this case which makes
the scrolling much better :)

It does no buffer blitting yet (e.g. double buffer, refresh buffer or such).
And it does not use an custom scrolling code, which would sure
help for slow boards...(e.g. a delta frame scrolling would be a lot
faster).
But maybe you find some things what would be intuitiv for your ideas.
So check it out ... and if you have a fast EGS board enjoy :)

PS.: I haven't either included the Backdground image nor the Image source
since this have about 1.2 MB...the object code should be ok if
you want to recompile it.
The colortableformat is a modified Amiga Colortable format
and looks like this:

struct Colors
{
    ULONG red,green,blue; // left justified 32 bits
} colors[256];

all other things should be clear from the source code. You should be
able to hook another image in ...

---
Jürgen Schober
Graz · Austria
e-mail: point@sbox.tu-graz.ac.at (private)
        jschober@campusart.com   (business)
WWW:    http://www.sbox.tu-graz.ac.at/home/point/Welcome.html
        http://www.pointdesign.campusart.com/