;### Mega upwards scroller

                 processor 6502


;In total, this is an image with the size
;x=96   pixels
;y=2436 pixels
;The uppermost 21 pixels must be empty

;Memory map:
;$80-$ff Zero page

;$7000-$7fff code

;$8000-$b9ff sprites
;58 rows with 4 sprites in each
;= $1d * 2 * 4 * $40 = $3a00 bytes
;= $1d * 2 * 21 = 1218 pixels
$ba00-$baff 4 sprites Static image, original position
;$bbf8 - $bbff screen sprite pointers1
$bc00-$bcff 4 sprites Static image, shifted 7 pixels
$bd00-$bdff 4 sprites Static image, shifted 2*7 pixels
;$bff8 - $bfff screen sprite pointers1

;$c000-$f9ff sprites
;58 rows with 4 sprites in each
;= $1d * 2 * 4 * $40 = $3a00 bytes
;= $1d * 2 * 21 = 1218 pixels
;$fbf8 - $fbff screen sprite pointers1
$fa00-$faff 4 sprites Static image, original position
;$fff8 - $ffff screen sprite pointers1
$fc00-$fcff 4 sprites Static image, shifted 7 pixels
$fd00-$fdff 4 sprites Static image, shifted 2*7 pixels


;Should be able to instantly scroll this, 7 pixels at a time

;there are 3 different positions of the sprites in the y-direction

;The other four sprites could show a static, but repetitive image. (enlarged in the x-direction)
;This image is then (24*4)x21 pixels = 96x21 pixels
;We need 12 sprites in each bank for doing this image.
;Each one shifted so that the image is still, eventhough the sprites are moving in the y-direction

;This can be combined with enlargment in the y-direction (only up to double size, to make it easier)

;on every rasterline must be set:
;$d016
;$d016
;$d017
;and sometimes y-positions, $d001-$d00f
;
;When changing sprites:
;$d016
;$d016
;$d017
;$dd00 (Can safely be done while displaying the static image)
;$d018 (Can safely be done while displaying the static image)

;Background colour must be black.

