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2005-10-03 18:43

Bastet

Registered: Jul 2005
Posts: 88

[gamedev] Reading level data problem

Hi Folks!

I try to code something in asm, and as i like them its going to be a simple RPG.
But now i have a little problem, how to read the map data?
I have this, hardcoded for now, testdungeon in my programm:

party: ;X first and then Y
!byte $01,$02

dungeon1: ;16x16 grid of map data
!byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$01,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$01,$01,$01,$00,$01,$01,$01,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$01,$00,$01,$00,$01,$00,$01,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$01,$00,$01,$01,$01,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$01,$01,$01,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
!byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00

As i am used to do high level programming, i cant figure out how to get something from there with the party coordinates.
I hope somebody can give at least a hint how to get an address out of x and y.

... 19 posts hidden. Click here to view all posts....

2005-10-09 07:30

Bastet

Registered: Jul 2005
Posts: 88

Hey, i am coding a game, not a demo ;)
Aaaand i got an idea of manipulating the charset. Ok, i have done it the cheapest way possible, made it with cuneinform, inserted it into the source at $2000 and told the VIC where to find it.

If you want to see.
--> http://fileanchor.com/5356-d (1683 byte -ZIP)

Dev is slow but steady.
Next stop is a messaging system using the last 5 lines on the screen or so.
After that i will include the PCs and then the first NPCs, with them a battle screen.

If anyone wants to give me some GFX, be my guest ^.^

2005-10-09 12:24

Ben
Account closed

Registered: Feb 2003
Posts: 163

Looks better already :)
What kind of game is this supposed to become?

2005-10-09 14:40

Laxity

Registered: Aug 2005
Posts: 459

"lda y"?... what compiler are you guys using? Shouldn't that be "tay"?

2005-10-09 15:14

Ben
Account closed

Registered: Feb 2003
Posts: 163

Quote: "lda y"?... what compiler are you guys using? Shouldn't that be "tay"?

Hehe :)

x and y are variables of some sort..
This pseudocode would obviously become

a)
"y lda #0"
with y the label, where you would need to "sta y+1".
This would compile to something like "sta $1001"

b)
"y .byte 0
[..]
lda y"
where you would need to "sta y", which would compile to something like
"1000 0
1001 lda $1001
"
and "sta $1000"

c)
"y = $d0
[..]
lda y"
where you would need to "sta y", which would compile to
"lda $d0" and "sta $d0"

et cetera.. et cetera..

2005-10-09 16:38

Bastet

Registered: Jul 2005
Posts: 88

Quote: Looks better already :)
What kind of game is this supposed to become?

A RPG of some sort

2005-10-09 17:04

Laxity

Registered: Aug 2005
Posts: 459

Quote: Hehe :)

x and y are variables of some sort..
This pseudocode would obviously become

a)
"y lda #0"
with y the label, where you would need to "sta y+1".
This would compile to something like "sta $1001"

b)
"y .byte 0
[..]
lda y"
where you would need to "sta y", which would compile to something like
"1000 0
1001 lda $1001
"
and "sta $1000"

c)
"y = $d0
[..]
lda y"
where you would need to "sta y", which would compile to
"lda $d0" and "sta $d0"

et cetera.. et cetera..

doh! Stupid me ;)

2005-10-10 13:20

White Flame

Registered: Sep 2002
Posts: 136

Using ORA instead of ADC lets you get rid of the CLC:

lda party+1 ;y
asl
asl
asl
asl
ora party ;x
tax
lda dungeon1,x

Then again, if your party 'x' and 'y' are guaranteed to be between 0 and 15, carry would be clear at that point regardless.

2005-10-10 14:08

Oswald

Registered: Apr 2002
Posts: 5076

gah, I shouldnt at first post into this topic, I knew all smartheads will show up and tell how it could be done 1 cycle faster or 1 byte shorter :)

2005-10-10 14:28

JackAsser

Registered: Jun 2002
Posts: 2014

@Oswald: Isn't that what C64 is all about? :D

2005-10-10 14:30

Bastet

Registered: Jul 2005
Posts: 88

@Oswald:
I find it funny, lets see when this cant be optimized any further.

@White Flame:
Cool, with this i can trow away the multiplication table for 16x16 maps.
BTW: In wich dimeonsions is that code working?
Can i easily switch to 32x32 with it?

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