#include "usgard.h"
PlayerCoords = TEXT_MEM ;A word to hold the x and y coords of the player
BugCoords = TEXT_MEM+2 ;Another word to hold x+y coords of the bug
MoveCounter = TEXT_MEM+4 ;How long until a move
CurMove = TEXT_MEM+5 ;What move we are on
.org 0 ;Required- Say that this is the beginning of the prog.
.db "Bug Catcher",0 ;Title
ld hl,$0101 ;Put $0101 as the bug coords.
ld (BugCoords),hl
ld hl,$0A07 ;Put $0A07 as the players coords.
ld (PlayerCoords),hl
call CLEARLCD ;Clear the screen.
ld hl,&TitleScreen ;point hl to the title screen text
ld de,$0000
ld ($800C),de ;Put the cursor at 0,0
call D_ZT_STR ;Display The title screen
ld c,5 ;Our starting rate
ChangeRate:
ld de,$1002
ld ($800C),de ;Put the cursor at 17,2
ld a,c ;get a out of c
add a,'0' ;make it a printable character
call TR_CHARPUT ;Print the char on the screen
call GET_KEY ;Get a key.
cp $37 ;See if the key is EXIT
ret z ;Exit if it is
cp 9 ;See if it is enter
jr z,ToGame ;Start the game if it is
cp K_UP ;See if the key is up
jr z,incit ;increment the rate
cp K_DOWN ;Check if the key is down
jr z,decit ;dec the rate if it is.
jr ChangeRate ;Not one of the keys; loop arond.
incit:
ld a,c
cp 9 ;If c is 9, go back- its our max
jr z,ChangeRate
inc c
jr ChangeRate
decit:
ld a,c
cp 1 ;If c is 1, its our min so go back
jr z,ChangeRate
dec c
jr ChangeRate
ToGame:
ld a,c
ld (MoveCounter),a ;Save the rate
call &DrawScreen ;Draw!
Game_Loop: ;The game loop. This is the game's main loop.
call GET_KEY ;Get a key
ld hl,PlayerCoords ;Point hl to the player coords, will be useful later
cp K_UP ;\
jr z,Up ; \
cp K_DOWN ; \
jr z,Down ; You should know
cp K_LEFT ; what all these do.
jr z,Left ; /
cp K_RIGHT ; /
jr z,Right ;/
cp $37 ;$37 is the scancode for exit.
ret z
jr Game_Loop
P_Moved: ;Game will come here after a move has been made.
ld hl,(MoveCounter) ;l is the move counter; h is the curmove
ld a,h
inc a
cp l ;See if it is time to move the bug
call z,&MoveBug ;Move now if time
ld (CurMove),a ;save a for next time.
call &DrawScreen ;Draw!
ld hl,(PlayerCoords) ;get the player coords in hl
ld de,(BugCoords) ;get the bug coords in de
call CP_HL_DE ;only if cp hl,de was a legal command..
jr nz,Game_Loop ;Oh well, this rom call does the same exact thing
call CLEARLCD
set 3,(IY+05) ;Display white on black
ld hl,&Win ;point hl the the win text
ld de,0
ld ($800C),de ;cursor=(0,0)
call D_ZT_STR ;Display you win
res 3,(IY+05) ;Display black on white (normal)
wait:
call GET_KEY ;\
cp K_EXIT ; Wait for exit
jr nz,wait ;/
ret ;Back to Usgard for us.
Up:
ld a,(hl) ;I told you pointg hl earlier would be useful
cp 0 ;Find out if the val hl points to is 0.
jr z,Game_Loop ;Go back if it is.
dec (hl) ;dec the mem hl points at
jr P_Moved
Down:
ld a,(hl)
cp 7 ;7- bottom row
jr z,Game_Loop
inc (hl)
jr P_Moved
Left:
inc hl ;inc hl so it points to the x coord
ld a,(hl)
cp 0
jr z,Game_Loop
dec (hl)
jr P_Moved
Right:
inc hl
ld a,(hl)
cp 20 ;20 is the furthest right we can go.
jr z,Game_Loop
inc (hl)
jr P_Moved
DrawScreen:
call CLEARLCD ;Clear the screen
ld hl,(BugCoords) ;
ld ($800C),hl ;Copy the bug coords to the cursor location
ld a,'*'
call TR_CHARPUT ;put a "*" there.
ld a,'#'
ld hl,(PlayerCoords) ;Copy the bug coords to the cursor loc
ld ($800C),hl ;
call TR_CHARPUT ;Display a "#" there.
ret ;Go back to where we came
MoveBug:
call RANDOM ;This is an Usgard function
and %111 ;You don't know this yet.
ld l,a
push hl ;push hl away; random destroys it.
G_I_B:
call RANDOM
and %11111
cp 20
jr nc,G_I_B
pop hl ;Get hl back.
ld h,a
ld (BugCoords),hl
ld a,0
ret ;I will walk you through this section next lesson
;All the DB's for the game
TitleScreen:
;123456789012345678901
.db " BugCatcher! "
.db "Use up/down arrows to"
.db "Change 'Speed':",0
Win:
.db " YOU WIN!! ",0
.end ;Required by TASM (
geocities.com/tutorman_2000)