Array Problems

faz808

but got a bit lost !

It's probably in the help but I couldn't find it.

1 stars=200
2 zdepth=60
3 fudge=128.0
4 speed=0.19
5 star_size=6
6 array star0[201]
7 array star1[201]
8 array star2[201]
9 // generate star list...
10 for i = 1 to stars loop
11 star0[i] = (random(50)-25)
12 star1[i] = (random(50)-25)
13 star2[i] = (random(zdepth))
14 repeat
15 //ensure screen centre
16 cx = gWidth()/2
17 cy = gHeight()/2
18
19 while 1 loop
20 for pp = 1 to stars loop
21 star2[pp] -= speed
22 if star2[pp] <= 0 then //off screen? redo
23 star0[i] = (random(50))-25
24 star1[i] = (random(50))-25
25 star2[i] = zdepth
26 endif
27 //x,y,z to x,y
28 w = fudge/star2[pp]
29 x = (star0[pp] * w +cx)
30 y = (star1[pp] * w +cy)
31 col = {1,1,1,1}
32 //plot(x,y,col) //dots or
33 // circles...
34 circle(x,y,w/star_size,32,col,false)
35
36 repeat
37 update
38
39 clear()
40 repeat

Richard

Arrays are 0 indexed, so each of your for loops should start at 0 rather than 1.

PB____

probably a typo, but update isn't written as a function call (update()). And Richard beat me to it with the 0 based comment, but here is your code formatted anyway:

stars=200
zdepth=60
fudge=128.0
speed=0.19
star_size=6
array star0[201]
array star1[201]
array star2[201]

// generate star list...
for i = 1 to stars loop
	star0[i] = (random(50)-25)
	star1[i] = (random(50)-25)
	star2[i] = (random(zdepth))
repeat

//ensure screen centre
cx = gWidth()/2
cy = gHeight()/2

while 1 loop
	for pp = 1 to stars loop
		star2[pp] -= speed
		if star2[pp] <= 0 then //off screen? redo
			star0[i] = (random(50))-25
			star1[i] = (random(50))-25
			star2[i] = zdepth
		endif
		//x,y,z to x,y
		w = fudge/star2[pp]
		x = (star0[pp] * w +cx)
		y = (star1[pp] * w +cy)
		col = {1,1,1,1}
		//plot(x,y,col) //dots or
		// circles...
		circle(x,y,w/star_size,32,col,false)
	repeat
	update() //added the () that where left out
	clear()
repeat

faz808

@PB____ Sorry about the errors. Had to retype code into note pad. There really should be a better way of sharing code.

PB____

@faz808 I know, that's really not a problem. I just formatted the code so I could see easier what the problem was. Did @Richard s suggestion fix the problem?

faz808

Yes, Richard's suggestion sorted out the array problem a treat. I remember with python, if you didn't format correctly - tabs etc - the compiler came up with a bucket load of errors which were a pain to find ! LUA was easier in that respect. Thanks again for the help.

Martin

Also, always a good idea to use len(array) as the upper bound of your for loop to save any accidental errors as well. Assuming that you want to loop all the way to the end of course. There could be times when you genuinely don't want to loop over all elements.