spectrum graphics - OpenLibra

Program Breakdown
A brief program is included in the form of REM statements within
the program but for those of you who are interested what follows
is a more detailed program including notes on what certain
special commands (e.g. the POKEs) do.
1 5 GOSUBs the UDGs. Originally these were part
of the main program but were changed to a
subroutine so that they were set up to be
printed in the instructions.
20 The POKE sets the computer in CAPS LOCK
mode.
25 Sets up variables that should not be reset at
the start of a new game.
30 Initialises variables that need defining at the
beginning of each new game.
52 GOSUBs the main instructions.
60 99 Asks for the User Defined keys. Enter can be
used as a key but will present problems in
lines 9300 9550.
900 995 Sets up variables needed for stage one
including:
91 0 P is set up to hold the print positions and
types of obstacles.
950 GOSUBs the NEXT STAGE and brief
instruction reminders subroutine.
990 This POKE stops the computer asking
'scroll ?' at line 1070.
995 GOSUBs the traffic light countdown
subroutine, Both this and the subroutine
activated at line 950 occur at the start of each
stage.
1000-1 070 Contains the main body of Stage 1.
1900 1 980 Checks for INKEY$ and detects collisions.
2000 Gives you a bonus for completing Stage 1 and
GOSUBs the congratulations message (also
activated each stage).
2020-2040 Determines the width of the roof and sets up
the screen.
2100-2220 Contains the Stage 2 'action'.
2510-2590 Prints the chimney and determines the speed
for Stage 3.
2600-2800 Stage 3 proper.
301 0 3090 Initialises screen and variables for Stage 4.
3100 31 30 Stage 4 routine when there is no snowball.
3200 3240 Ditto for when there is a snowball present.
3300 3330 Performs Santa's leap over the Christmas
tree.
3600 361 7 Sets up the variables and screen for the next
stage. Note that the INK colour is set to 5
(cyan) yet the houses are printed in yellow so
that their ATTRibutes are different. Thus a
collision with the houses can be detected
using the ATTR command in line 372.
3620 3800 Contains the main part of Stage 5.
From there on the REM statements serve |ust as well as a
description would so you can go through them if you need a
breakdown of the latter parts of the program $ mainly
subroutines.
1 REM
•Underlined characters*
*are entered in *
*GRAPHTCS mode. *
TT IT R ~ W TiTTTirTTTTTTTTTItinr
M ¥ ¥ If ¥ ¥ ¥ ¥ ¥ ¥ ¥ W M w
10 REM INITIALISE SREEN AND
27 GO SUB 101
SOME VARIABLES
SANTA'S CAME
75 LET H = 0: DIM H*(10)
10 LET Y=l: DIM K*(4): LET L=*5
: LET S = 0
40 BRIGHT 0: PAPER 0: BORDER 0
: CLS t POKE 23658,8
50 INK 6: PRINT AT 0,2} BRIGHT
1?"SANTA'S CHRISTMAS NIGHTMARE'
"JTAB 2 ; - * —— •• '"- " 1
52 GO SUB 9200
55 RFM DFFINE KEYS
S7 INK 6: PRINT AT 0,2; BRIGHT
ti"SANTA'S CHRISTMAS NIGHTMARE'
" ; T A B 25" ""* 'J—f »••
60 INK 5: PRINT AT 5,0;"WHICH
KEYS WOULD YOU LIKE LEFT:"
'*"RIGHT:'''"UP:"''"DOWN!•
70 FOR F=1 TO 4: PRINT AT F*7 +
6, 10; FLASH 1 J
80 LET R*=INKEY«: IF R$"" TH
EN GO TO 80
90 LET R*»INKEY«: IF R*«"" THE
N GO TO 90
95 BEEP .03,20: PRINT AT F*2 + 6
,10;RS: LET K$(F)=R«: NEXT F