Objects placement on random screens

[manu128k]

Random objects around the map didn't sound too hard to me but I'm sweating a bit with this. Have you already made this sometime in your games?

Thanks!

[highrise]

I recommend that you watch this video:

www.youtube.com/watch?v=URGGJWvgMCU

and also this one

www.youtube.com/watch?v=ViFSyfXYNKk

You should be able to combine these two ideas to create some random spawn points.

[alessandro]

I did it in a very simple way.

First of all, you need to set the points in the map where your objects will spawn before the start of each game. Write down the screen number and X/Y coordinates for each spawning point.

Then set a random value variable as a condition to spawn the objects in the Game Initialization event and assign each position according to that variable. If your variable is A, for instance, begin with:

IF A = 0
LET SCREEN 0
LET X 128
LET Y 44
PUT 0
LET SCREEN 2
LET X 64
LET Y 88
LET SCREEN 5
...
ENDIF
IF A = 1
LET SCREEN 4
LET X 64
LET Y 32
PUT 0
LET SCREEN 8
LET X 24
LET Y 80
PUT 1
...
ENDIF
and so on.

To save memory you can arrange the LET X, Y etc. commands so that, if a coordinate repeats itself, you can omit it. E.g. instead of:

LET SCREEN 1
LET X 128
LET Y 64
PUT 1
LET SCREEN 3
LET X 128
LET Y 96
PUT 2
you can do this:

LET SCREEN 1
LET X 128
LET Y 64
PUT 1
LET SCREEN 3
LET Y 96
PUT 2
On a side note, I did not use the RND function of AGD for this task, because it seems, especially when playing under emulation, to return the same sequence of values most of the times. I employ a very simple Assembly code snippet, derived from a short program developed by John Connolly:

 LD A,R             ; loads R register into the accumulator
 AND %00000011      ; masking to let the result always be 0, 1, 2 or 3
 LD (32029),A       ; AGD's A variable (located at address 32029) is loaded with the accumulator's value
 RET
which is then recalled in the Game initialization event with the usual ASM commands.

Games where I employed this method: Apulija-13 (latest version), Seto Taisho To Kazan, Sophia and Doom Pit.

[manu128k]

Thanks Highrise and Alessandro.

I'll try to get it working with your comments.