CONSTELLATION

by Paul Wardle

from Your Sinclair #31 (July 1988)

[files CONSTELL.*]



Whooo-whoo-who-who-whooooooooo! Ahem, er yes! Watching this program

brought back memories of Star Trek, a five year mission that lasted

yonks, pointed ears (wagga! wagga!), a cocked eyebrow, the unknown but

very dead crew member, and the captain's log! As you may've guessed,

this routine, courtesy of Paul Wardle, is very star-studded, starry

eyed, twinkling (plus any other cliche you can think of with a star in

it). He wrote it in answer to my challenge of eons back for a 3D star

routine. Not only does this routine scroll stars parallaxly in eight

(eight!) directions, but it also has a density, twinkle, colour and

window size option. Absolutely fascinating (captain).



He's Dead Jim!



No he's not, he's just a non-speaking extra! Type in the 36 line Basic

proggie and type GO TO 340 to save it. [This is wrong. The machine code

has to have been entered first as well, as line 340 saves both. JimG]

Then use the Hex Loader to insert the 548 bytes of machine code and save

it with SAVE "starcode" CODE 64670,548. Then run the Basic controller.



Klingons On The ...



You should now have a menu in front of you and four options:



1) CREATE NEW WINDOW - allows you to input the parameters of your star

window. The X, Y co-ords refer to the top left-hand corner. DENSITY

refers to the number of stars on-screen to a max. of 63. The less dense

the faster the routine works.



2) SEE WINDOW - use this option to see the results of your labour. Move

the stars with keys 6789 (diagonals included) and 0 will return you to

the main menu.



3) SAVE WINDOW - will save your defined window (along with the routine's

code) to tape for use in your own programs. The code saved starts a6

64932 and is 603 bytes long. RANDOMIZE USR 64932 will clear the star

window; RANDOMIZE USR 65011 will shift the stars in the wanted direction

(see table). Repeated calls to this address will make the stars move

continuously. To govern the direction of the stars, POKE these values:



            POKE   POKE

            65046  65085    

DIRECTION   with   with

------------------------

none        0      0

left        255    0

up-left     255    255

up          0      255

up-right    1      255

right       1      0

down-right  1      1

down        0      1

down-left   255    1



4) LOAD WINDOW - this'll load a previously saved window for inspection

or alteration.