how do I pass an array name to a function?

Blitz3D Forums/Blitz3D Beginners Area/how do I pass an array name to a function?

Pongo

(Posted 2005) [#1]

Ok,... I've got a function to do bilinear interpolation on an array, but I don't know how to pass the array name to the function. In the example below, I have it hard coded to the array "grid" I would like to be able to specify that name when I call the function if possible.

for example,...
BilinearInterpValue2# ( x1# , y1# , arrayname$)

Function BilinearInterpValue2# ( x1# , y1# )
	X_low	= Int ( Floor(x1) )  
	X_hi 	= Int ( Ceil (x1) )
	Y_low	= Int ( Floor(y1) )
	Y_hi	= Int ( Ceil (y1) )
	
	x_per#	= x1 - x_low
	y_per#	= y1 - y_low
	
	p00 = grid ( x_low  , y_low  )
	p10 = grid ( x_hi 	, y_low  )
	p01 = grid ( x_low  , y_hi )
	p11 = grid ( x_hi 	, y_hi )	

	i1 = p00 + (p10 - p00) * x_per
	i2 = p01 + (p11 - p01) * x_per
	
	Return i1 + (i2-i1) * y_per	
		
End Function

Floyd

(Posted 2005) [#2]

This is an unfortunate limitation of Blitz3D.

There is another kind of array, denoted with a[ ] rather than a( ). This can be passed to a function. However, such arrays are one dimensional.

So you are stuck with the hard coded approach.

fall_x

(Posted 2005) [#3]

[] arrays are one-dimensional, but there are ways to fake multidimensional arrays with one-dimensional arrays.
You'll probably have to use something like this :

Function GetPosition (x,y,ym)
	Return x*ym+y
End Function

Instance\Array[GetPosition(xpos,ypos,ymaxpos)]

For getting the size of the one-dimensional array for initializing, I think you'll have to use xmaxpos*ymaxpos.

Never tried using something like this before, so I'm not 100% sure it would work.

GfK	(Posted 2005) [#4]

Since arrays are global, why would you need to pass them to an function? You can access arrays from inside a function anyway.

fall_x

(Posted 2005) [#5]

Because he wants his function to work on multiple arrays maybe?

Pongo

(Posted 2005) [#6]

yes,... that was what I wanted to be able to do. I don't really need it for this current code, but I wanted to make the function something that was self-contained rather than having to hard code the proper array into it.

Thanks for the answers btw.